diff --git a/CITATION.cff b/CITATION.cff
index c49677641..bed40a559 100644
--- a/CITATION.cff
+++ b/CITATION.cff
@@ -1,4 +1,4 @@
-cff-version: 3.5.0
+cff-version: 3.5.6
 message: "If you use this software in your work, please cite it as below."
 authors:
 - family-names: "Dorheim"
@@ -34,7 +34,7 @@ authors:
   given-names: "Dawn"
   orcid: "https://orcid.org/0000-0002-0468-4660"
 title: "Hector a simple carbon-climate model"
-version: 3.5.0
+version: 3.5.6
 doi: 10.5281/zenodo.821645
 date-released: 2025-10-24
 url: "https://github.com/jgcri/hector"
diff --git a/DESCRIPTION b/DESCRIPTION
index 4e713b06d..96c3be874 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: hector
 Title: The Hector Simple Climate Model
-Version: 3.5.0
+Version: 3.5.6
 Authors@R: c(person("Kalyn", "Dorheim", 
 	        email = "kalyn.dorheim@pnnl.gov",
 	        role = c("aut", "cre"),
diff --git a/NAMESPACE b/NAMESPACE
index 2f703ceb9..21ee4913b 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -18,6 +18,7 @@ export(CH3BR_CONSTRAIN)
 export(CH3CCL3_CONSTRAIN)
 export(CH3CL_CONSTRAIN)
 export(CH4_CONSTRAIN)
+export(CH4_LIFETIME_OH)
 export(CO2_CONSTRAIN)
 export(CO3)
 export(CO3_HL)
@@ -76,6 +77,7 @@ export(EMISSIONS_CH3CCL3)
 export(EMISSIONS_CH3CL)
 export(EMISSIONS_CH4)
 export(EMISSIONS_CO)
+export(EMISSIONS_H2)
 export(EMISSIONS_HALON1211)
 export(EMISSIONS_HALON1301)
 export(EMISSIONS_HALON2402)
diff --git a/NEWS.md b/NEWS.md
index 1a849db01..dea3cc62f 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,8 @@
+# hector 3.5.6 
+
+under development, adding H2 
+
+
 # hector 3.5.0 
 
 * Minor documentation changes 
@@ -10,9 +15,6 @@
 * New default parameter values for ocean heat diffusivity, CO2 fertilization, and heterotrophic respiration temperature sensitivity 
 
 
-
-
-
 # hector 3.2.0 
 [![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.10698028.svg)](https://doi.org/10.5281/zenodo.10698028)
 
diff --git a/R/RcppExports.R b/R/RcppExports.R
index bb3f4eb56..0e7f51184 100644
--- a/R/RcppExports.R
+++ b/R/RcppExports.R
@@ -1082,6 +1082,18 @@ EMISSIONS_NMVOC <- function() {
     .Call('_hector_EMISSIONS_NMVOC', PACKAGE = 'hector')
 }
 
+#' @describeIn emissions Emissions hydrogen gas (\code{"Tg H2"})
+#' @export
+EMISSIONS_H2 <- function() {
+    .Call('_hector_EMISSIONS_H2', PACKAGE = 'hector')
+}
+
+#' @describeIn methane CH4 lifetime with respect to the OH sink (\code{"Yr"})
+#' @export
+CH4_LIFETIME_OH <- function() {
+    .Call('_hector_CH4_LIFETIME_OH', PACKAGE = 'hector')
+}
+
 #' @describeIn emissions Emissions for organic carbon (\code{"Tg"})
 #' @export
 EMISSIONS_OC <- function() {
diff --git a/data-raw/input_params.csv b/data-raw/input_params.csv
index 26bfd6354..e75acc96b 100644
--- a/data-raw/input_params.csv
+++ b/data-raw/input_params.csv
@@ -1,244 +1,249 @@
-section,parameter,biome-specific,time-variant,required,default,units,description
-core,run_name,n,n,y,,(unitless),Name of model run
-core,startDate,n,n,y,1745,year,Start date of model run
-core,endDate,n,n,y,2300,year,End date of model run
-core,trackingDate,n,n,y,9999,year,Year to start tracking carbon
-core,do_spinup,n,n,y,1,(unitless),"If 1, spin up model before running (default=1)"
-core,max_spinup,n,n,y,2000,(unitless),Maximum steps allowed for spinup (default=2000)
-ocean,enabled,n,n,y,1,(unitless),Putting 'enabled=0' will disable any component
-ocean,spinup_chem,n,n,y,0,(unitless),Run ocean surface chemistry during spinup phase?
-ocean,tt,n,n,y,7.20E+07,m3 s-1,Ocean thermohaline circulation
-ocean,tu,n,n,y,4.90E+07,m3 s-1,Ocean high latitude overturning
-ocean,twi,n,n,y,1.25E+07,m3 s-1,Ocean warm-intermediate exchange
-ocean,tid,n,n,y,2.00E+08,m3 s-1,Ocean intermediate-deep exchange
-ocean,preind_surface_c,n,n,n,900,Pg C,Initial surface ocean carbon
-ocean,preind_interdeep_c,n,n,n,37100,Pg C,Initial intermediate + deep ocean carbon
-simpleNbox,atmos_co2,n,n,y,588.071,Pg C,Initial atmospheric CO2
-simpleNbox,C0,n,n,y,277.15,Pg C,Initial atmospheric C pool
-simpleNbox,pf.veg_c,y,n,n,55,Pg C,Initial vegetation C pool
-simpleNbox,nonpf.veg_c,y,n,n,495,Pg C,Initial vegetation C pool
-simpleNbox,veg_c,n,n,y,550,Pg C,Initial vegetation C pool
-simpleNbox,pf.detritus_c,y,n,n,5,Pg C,Initial detritus C pool
-simpleNbox,nonpf.detritus_c,y,n,n,50,Pg C,Initial detritus C pool
-simpleNbox,detritus_c,n,n,y,55,Pg C,Initial detritus C pool
-simpleNbox,pf.soil_c,y,n,n,308,Pg C,Initial soil C pool
-simpleNbox,nonpf.soil_c,y,n,n,609,Pg C,Initial soil C pool
-simpleNbox,soil_c,n,n,y,917,Pg C,Initial soil C pool
-simpleNbox,pf.permafrost_c,y,n,n,865,Pg C,Initial permafrost C pool
-simpleNbox,nonpf.permafrost_c,y,n,n,0,Pg C,Initial permafrost C pool
-simpleNbox,permafrost_c,n,n,y,865,Pg C,Initial permafrost C pool
-simpleNbox,pf.npp_flux0,y,n,n,5.6,Pg C yr-1,Preindustrial net primary production
-simpleNbox,nonpf.npp_flux0,y,n,n,50.6,Pg C yr-1,Preindustrial net primary production
-simpleNbox,npp_flux0,n,n,y,56.2,Pg C yr-1,Preindustrial net primary production
-simpleNbox,pf.f_nppv,n,n,y,0.35,(unitless),Fraction of NPP to vegetation
-simpleNbox,nonpf.f_nppv,n,n,y,0.35,(unitless),Fraction of NPP to vegetation
-simpleNbox,f_nppv,n,n,y,0.35,(unitless),Fraction of NPP to vegetation
-simpleNbox,pf.f_nppd,n,n,y,0.35,(unitless),Fraction of NPP to vegetation
-simpleNbox,nonpf.f_nppd,n,n,y,0.35,(unitless),Fraction of NPP to vegetation
-simpleNbox,f_nppd,n,n,y,0.6,(unitless),Fraction of NPP to detritus (balance to soil)
-simpleNbox,pf.f_litterd,n,n,n,0.35,(unitless),Fraction of NPP to vegetation
-simpleNbox,nonpf.f_litterd,n,n,n,0.35,(unitless),Fraction of NPP to vegetation
-simpleNbox,f_litterd,n,n,y,0.98,(unitless),Fraction of litter flux to detritus (balance to soil)
-simpleNbox,ffi_emissions,n,y,y,"""(csv)""",Pg C yr-1,Anthropogenic contributions: emissions
-simpleNbox,daccs_uptake,n,y,y,"""(csv)""",Pg C yr-1,Anthropogenic contributions: direct air carbon capture and storage
-simpleNbox,luc_emissions,n,y,y,"""(csv)""",Pg C yr-1,Anthropogenic contributions: land use change
-simpleNbox,luc_uptake,n,y,y,"""(csv)""",Pg C yr-2,Anthropogenic contributions: land use change
-simpleNbox,CO2_constrain,n,y,n,"""(csv)""",ppmv,Atmospheric CO2 constraint
-simpleNbox,NBP_constrain,n,y,n,"""(csv)""",Pg C yr-1,Net biome production (land-atmosphere C flux) constaint
-simpleNbox,pf.beta,n,n,n,0.36,(unitless),CO2 fertilization factor
-simpleNbox,nonpf.beta,n,n,n,0.36,(unitless),CO2 fertilization factor
-simpleNbox,beta,n,n,y,0.36,(unitless),CO2 fertilization factor
-simpleNbox,pf.q10_rh,n,n,n,2,(unitless),Respiration temperature response (Q10)
-simpleNbox,nonpf.q10_rh,n,n,n,2,(unitless),Respiration temperature response (Q10)
-simpleNbox,q10_rh,n,n,y,2,(unitless),Respiration temperature response (Q10)
-simpleNbox,pf.warmingfactor,y,n,n,2,(unitless),biome-specific warming factors
-simpleNbox,RF_albedo,n,n,y,"""(csv)""",W m-2,Albedo radiative forcing effect
-simpleNbox,permafrost_c,y,n,y,0,Pg C,Preindustrial permafrost carbon pool
-simpleNbox,fpf_static,y,n,n,0.74,(unitless),Fraction of permafrost that is static (non-labile)
-simpleNbox,rh_ch4_frac,y,n,n,0.023,(unitless),Fraction of thawed permafrost decomposed as CH4
-simpleNbox,pf_mu,y,n,n,1.67,(unitless),Permafrost thaw parameter; see Woodard et al. 2021
-simpleNbox,pf_sigma,y,n,n,0.986,(unitless),Permafrost thaw parameter; see Woodard et al. 2021
-carbon-cycle-solver,eps_abs,n,n,y,1.00E-06,(unitless),Solver solution tolerance
-carbon-cycle-solver,eps_rel,n,n,y,1.00E-06,(unitless),Solver solution tolerance
-carbon-cycle-solver,dt,n,n,y,0.25,(unitless),Solver default time step
-carbon-cycle-solver,eps_spinup,n,n,y,0.001,Pg C,"Model spinup tolerance (drift), Pg C"
-so2,SO2_emissions,n,y,y,"""(csv)""",,emissions time series
-so2,SV,n,y,y,"""(csv)""",,volcanic radiative forcing time series
-CH4,M0,n,n,y,731.41,ppb,"preindustrial methane IPCC AR6 Table 7.SM.1, the CH4 forcing equations is calibrated to a M0 of 731.41 ppb"
-CH4,Tsoil,n,n,y,160,years,CH4 loss to soil
-CH4,Tstrat,n,n,y,120,years,CH4 loss to stratosphere
-CH4,UC_CH4,n,n,y,2.78,Tg CH4 ppb-1,unit conversion between emissions and concentrations
-CH4,CH4N,n,n,y,341,,best fit
-CH4,CH4_emissions,n,y,y,"""(csv)""",,emissions time series
-CH5,CH4_constrain,n,y,n,"""(csv)""",,CH4 concentration constraint
-OH,NOX_emissions,n,y,y,"""(csv)""",,emissions time series
-OH,CO_emissions,n,y,y,"""(csv)""",,emissions time series
-OH,NMVOC_emissions,n,y,y,"""(csv)""",,emissions time series
-OH,TOH0,n,n,y,6.6,years,initial OH lifetime
-OH,CNOX,n,n,y,0.0042,,coefficient for NOX
-OH,CCO,n,n,y,-1.05E-04,,coefficient for CO
-OH,CNMVOC,n,n,y,-3.15E-04,,coefficient for NMVOC (non methane VOC)
-OH,CCH4,n,n,y,-0.32,,coefficient for CH4
-ozone,PO3,n,n,y,30,,preindustrial O3 concentration
-ozone,NOX_emissions,n,y,y,"""(csv)""",,emissions time series
-ozone,CO_emissions,n,y,y,"""(csv)""",,emissions time series
-ozone,NMVOC_emissions,n,y,y,"""(csv)""",,emissions time series
-N2O,N0,n,n,y,273.87,ppb,preindustrial nitrous oxide from IPCC AR6 table 7.SM.1
-N2O,UC_N2O,n,n,y,4.8,TgN ppbv-1,unit conversion between emissions and concentrations
-N2O,TN2O0,n,n,y,132,years,initial lifetime of N2O
-N2O,N2O_natural_emissions,n,y,y,9.5,,default natural emissions based on a best fit to IPCC AR6 N2O RF
-N2O,N2O_emissions,n,y,y,"""(csv)""",,emissions time series
-N2O,N2O_constrain,n,y,n,"""(csv)""",,N2O concentration constraint
-forcing,baseyear,n,n,y,1750,,"when to start reporting; by definition, all F=0 in this year"
-forcing,RF_tot_constrain,n,y,n,"""(csv)""",,"If supplied, the model will use these data, ignoring what it calculates"
-forcing,delta_co2,n,n,y,0.05,(unitless),forcing tropospheric adjustments for CO2 (7.3.2.1 of IPCC AR6)
-forcing,delta_ch4,n,n,y,-0.14,(unitless),forcing tropospheric adjustments for CH4 (7.3.2.2 of IPCC AR6)
-forcing,delta_n2o,n,n,y,0.07,(unitless),forcing tropospheric adjustments for N2O (7.3.2.3 of IPCC AR6)
-forcing,rho_bc,n,n,y,0.0508,W yr m-2 C Tg-1,IPCC AR6 radiative efficiency BC (7.SM.1.3 of IPCC AR6)
-forcing,rho_oc,n,n,y,-0.00621,W yr m-2 C Tg-1,IPCC AR6 radiative efficiency OC (7.SM.1.3.1 of IPCC AR6)
-forcing,rho_so2,n,n,y,-7.24E-06,W yr m-2 S Gg-1,IPCC AR6 radiative efficiency SO2 (7.SM.1.3.1 of IPCC AR6)
-forcing,rho_nh3,n,n,y,-0.00208,W yr m-2 NH3 Tg-1,IPCC AR6 radiative efficiency NH3 (7.SM.1.3.1 of IPCC AR6)
-forcing,RF_misc,n,n,n,"""(csv)""",,Miscellaneous radiative forcings default set to 0
-forcing,RF_misc,n,n,y,0,,"Miscellaneous radiative forcings default set to 0, or read in from a input table, may be used to read in additional forcings not modeled by Hector (i.e. solar, bc on snow , contrails from)"
-forcing,aero_scalar,n,n,y,1,(unitless),scaling factor for aerosol forcing
-forcing,vol_scalar,n,n,y,1,(unitless),scaling factor for volcanic forcing
-temperature,S,n,n,y,3,degC,equilibrium climate sensitivity for 2xCO2
-temperature,diff,n,n,y,2.3,cm2 s-1,ocean heat diffusivity
-temperature,qco2,n,n,y,3.75,,CO2 RF (7.3.2 of IPCC AR6)
-temperature,tas_constrain,n,y,n,"""(csv)""",,"Optional global temperature constraint; If supplied, the model will use these data, ignoring what it calculates"
-bc,BC_emissions,n,y,y,"""(csv)""",,
-oc,OC_emissions,n,y,y,"""(csv)""",,
-nh3,NH3_emissions,n,y,y,"""(csv)""",,
-CF4_halocarbon,tau,n,n,y,50000,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-CF4_halocarbon,rho_CF4,n,n,y,9.90E-05,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-CF4_halocarbon,delta_CF4,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-CF4_halocarbon,H0,n,n,y,35,pptv,preindustrial concentration
-CF4_halocarbon,molarMass,n,n,y,88.0043,g,molar mass
-CF4_halocarbon,CF4_emissions,n,y,y,"""(csv)""",,
-C2F6_halocarbon,tau,n,n,y,10000,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-C2F6_halocarbon,rho_C2F6,n,n,y,2.61E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-C2F6_halocarbon,delta_C2F6,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-C2F6_halocarbon,molarMass,n,n,y,138.01,g,molar mass
-C2F6_halocarbon,C2F6_emissions,n,y,y,"""(csv)""",,
-HFC23_halocarbon,tau,n,n,y,228,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-HFC23_halocarbon,rho_HFC23,n,n,y,1.91E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-HFC23_halocarbon,delta_HFC23,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-HFC23_halocarbon,molarMass,n,n,y,70,g,molar mass
-HFC23_halocarbon,HFC23_emissions,n,y,y,"""(csv)""",,
-HFC32_halocarbon,tau,n,n,y,5.4,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-HFC32_halocarbon,rho_HFC32,n,n,y,1.11E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-HFC32_halocarbon,delta_HFC32,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-HFC32_halocarbon,molarMass,n,n,y,52,g,molar mass
-HFC32_halocarbon,HFC32_emissions,n,y,y,"""(csv)""",,
-HFC4310_halocarbon,tau,n,n,y,17,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-HFC4310_halocarbon,rho_HFC4310,n,n,y,3.57E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-HFC4310_halocarbon,delta_HFC4310,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-HFC4310_halocarbon,molarMass,n,n,y,252,g,molar mass
-HFC4310_halocarbon,HFC4310_emissions,n,y,y,"""(csv)""",,
-HFC125_halocarbon,tau,n,n,y,30,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-HFC125_halocarbon,rho_HFC125,n,n,y,2.34E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-HFC125_halocarbon,delta_HFC125,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-HFC125_halocarbon,molarMass,n,n,y,120.02,g,molar mass
-HFC125_halocarbon,HFC125_emissions,n,y,y,"""(csv)""",,
-HFC134a_halocarbon,tau,n,n,y,14,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-HFC134a_halocarbon,rho_HFC134a,n,n,y,1.67E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-HFC134a_halocarbon,delta_HFC134a,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-HFC134a_halocarbon,molarMass,n,n,y,102.02,g,molar mass
-HFC134a_halocarbon,HFC134a_emissions,n,y,y,"""(csv)""",,
-HFC143a_halocarbon,tau,n,n,y,51,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-HFC143a_halocarbon,rho_HFC143a,n,n,y,1.68E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-HFC143a_halocarbon,delta_HFC143a,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-HFC143a_halocarbon,molarMass,n,n,y,84.04,g,molar mass
-HFC143a_halocarbon,HFC143a_emissions,n,y,y,"""(csv)""",,
-HFC227ea_halocarbon,tau,n,n,y,36,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-HFC227ea_halocarbon,rho_HFC227ea,n,n,y,2.73E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-HFC227ea_halocarbon,delta_HFC227ea,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-HFC227ea_halocarbon,molarMass,n,n,y,170.03,g,molar mass
-HFC227ea_halocarbon,HFC227ea_emissions,n,y,y,"""(csv)""",,
-HFC245fa_halocarbon,tau,n,n,y,7.9,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-HFC245fa_halocarbon,rho_HFC245fa,n,n,y,2.45E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-HFC245fa_halocarbon,delta_HFC245fa,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-HFC245fa_halocarbon,molarMass,n,n,y,134,g,molar mass
-HFC245fa_halocarbon,HFC245fa_emissions,n,y,y,"""(csv)""",,
-SF6_halocarbon,tau,n,n,y,3200,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-SF6_halocarbon,rho_SF6,n,n,y,5.67E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-SF6_halocarbon,delta_SF6,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-SF6_halocarbon,molarMass,n,n,y,146.06,g,molar mass
-SF6_halocarbon,SF6_emissions,n,y,y,"""(csv)""",,
-CFC11_halocarbon,tau,n,n,y,52,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-CFC11_halocarbon,rho_CFC11,n,n,y,2.59E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-CFC11_halocarbon,delta_CFC11,n,n,y,0.13,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-CFC11_halocarbon,molarMass,n,n,y,137.35,g,molar mass
-CFC11_halocarbon,CFC11_emissions,n,y,y,"""(csv)""",,
-CFC12_halocarbon,tau,n,n,y,102,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-CFC12_halocarbon,rho_CFC12,n,n,y,3.20E-03,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-CFC12_halocarbon,delta_CFC12,n,n,y,0.13,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-CFC12_halocarbon,molarMass,n,n,y,120.9,g,molar mass
-CFC12_halocarbon,CFC12_emissions,n,y,y,"""(csv)""",,
-CFC113_halocarbon,tau,n,n,y,93,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-CFC113_halocarbon,rho_CFC113,n,n,y,3.01E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-CFC113_halocarbon,delta_CFC113,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-CFC113_halocarbon,molarMass,n,n,y,187.35,g,molar mass
-CFC113_halocarbon,CFC113_emissions,n,y,y,"""(csv)""",,
-CFC114_halocarbon,tau,n,n,y,189,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-CFC114_halocarbon,rho_CFC114,n,n,y,3.14E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-CFC114_halocarbon,delta_CFC114,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-CFC114_halocarbon,molarMass,n,n,y,170.9,g,molar mass
-CFC114_halocarbon,CFC114_emissions,n,y,y,"""(csv)""",,
-CFC115_halocarbon,tau,n,n,y,540,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-CFC115_halocarbon,rho_CFC115,n,n,y,2.46E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-CFC115_halocarbon,delta_CFC115,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-CFC115_halocarbon,molarMass,n,n,y,154.45,g,molar mass
-CFC115_halocarbon,CCl4_emissions,n,y,y,"""(csv)""",,
-CCl4_halocarbon,tau,n,n,y,32,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-CCl4_halocarbon,rho_CCl4,n,n,y,1.66E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-CCl4_halocarbon,delta_CCl4,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-CCl4_halocarbon,molarMass,n,n,y,153.8,g,molar mass
-CCl4_halocarbon,CFC115_emissions,n,y,y,"""(csv)""",,
-CH3CC13_halocarbon,tau,n,n,y,5,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-CH3CC13_halocarbon,rho_CH3CCl3,n,n,y,6.50E-05,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-CH3CC13_halocarbon,delta_CH3CCl3,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-CH3CC13_halocarbon,molarMass,n,n,y,133.35,g,molar mass
-CH3CC13_halocarbon,CH3CCl3_emissions,n,y,y,"""(csv)""",,
-halon1211_halocarbon,tau,n,n,y,16,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-halon1211_halocarbon,rho_halon1211,n,n,y,3.00E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-halon1211_halocarbon,delta_halon1211,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-halon1211_halocarbon,molarMass,n,n,y,165.35,g,molar mass
-halon1211_halocarbon,halon1211_emissions,n,y,y,"""(csv)""",,
-halon1301_halocarbon,tau,n,n,y,72,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-halon1301_halocarbon,rho_halon1301,n,n,y,2.99E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-halon1301_halocarbon,delta_halon1301,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-halon1301_halocarbon,molarMass,n,n,y,148.9,g,molar mass
-halon1301_halocarbon,halon1301_emissions,n,y,y,"""(csv)""",,
-halon2402_halocarbon,tau,n,n,y,28,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-halon2402_halocarbon,rho_halon2402,n,n,y,3.12E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-halon2402_halocarbon,delta_halon2402,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-halon2402_halocarbon,molarMass,n,n,y,259.8,g,molar mass
-halon2402_halocarbon,halon2402_emissions,n,y,y,"""(csv)""",,
-HCF22_halocarbon,tau,n,n,y,11.9,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-HCF22_halocarbon,rho_HCFC22,n,n,y,2.14E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-HCF22_halocarbon,delta_HCFC22,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-HCF22_halocarbon,molarMass,n,n,y,86.45,g,molar mass
-HCF22_halocarbon,HCFC22_emissions,n,y,y,"""(csv)""",,
-HCFC141b_halocarbon,tau,n,n,y,9.4,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-HCFC141b_halocarbon,rho_HCFC141b,n,n,y,1.61E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-HCFC141b_halocarbon,delta_HCFC141b,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-HCFC141b_halocarbon,molarMass,n,n,y,116.9,g,molar mass
-HCFC141b_halocarbon,HCFC141b_emissions,n,y,y,"""(csv)""",,
-HCFC142b_halocarbon,tau,n,n,y,18,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-HCFC142b_halocarbon,rho_HCFC142b,n,n,y,1.93E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-HCFC142b_halocarbon,delta_HCFC142b,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-HCFC142b_halocarbon,molarMass,n,n,y,100.45,g,molar mass
-HCFC142b_halocarbon,HCFC142b_emissions,n,y,y,"""(csv)""",,
-CH3Cl_halocarbon,tau,n,n,y,0.9,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-CH3Cl_halocarbon,rho_CH3Cl,n,n,y,5.00E-06,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-CH3Cl_halocarbon,delta_CH3Cl,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-CH3Cl_halocarbon,H0,n,n,y,504,pptv,"preindustrial concentration, from Saito et al 2007 GRL"
-CH3Cl_halocarbon,molarMass,n,n,y,50.45,g,molar mass
-CH3Cl_halocarbon,CH3Cl_emissions,n,y,y,"""(csv)""",,
-CH3Br_halocarbon,tau,n,n,y,0.8,years,lifetime in years (Table 7.SM.7 IPPC AR6)
-CH3Br_halocarbon,rho_CH3Br,n,n,y,4.00E-06,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
-CH3Br_halocarbon,delta_CH3Br,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
-CH3Br_halocarbon,H0,n,n,y,5.8,pptv,"preindustrial concentration, from Saltzman et al 2004 JGR"
-CH3Br_halocarbon,molarMass,n,n,y,50.45,g,molar mass
-CH3Br_halocarbon,CH3Br_emissions,n,y,y,"""(csv)""",,
+section,parameter,biome-specific,time-variant,required,default,units,description
+core,run_name,n,n,y,,(unitless),Name of model run
+core,startDate,n,n,y,1745,year,Start date of model run
+core,endDate,n,n,y,2300,year,End date of model run
+core,trackingDate,n,n,y,9999,year,Year to start tracking carbon
+core,do_spinup,n,n,y,1,(unitless),"If 1, spin up model before running (default=1)"
+core,max_spinup,n,n,y,2000,(unitless),Maximum steps allowed for spinup (default=2000)
+ocean,enabled,n,n,y,1,(unitless),Putting 'enabled=0' will disable any component
+ocean,spinup_chem,n,n,y,0,(unitless),Run ocean surface chemistry during spinup phase?
+ocean,tt,n,n,y,7.20E+07,m3 s-1,Ocean thermohaline circulation
+ocean,tu,n,n,y,4.90E+07,m3 s-1,Ocean high latitude overturning
+ocean,twi,n,n,y,1.25E+07,m3 s-1,Ocean warm-intermediate exchange
+ocean,tid,n,n,y,2.00E+08,m3 s-1,Ocean intermediate-deep exchange
+ocean,preind_surface_c,n,n,n,900,Pg C,Initial surface ocean carbon
+ocean,preind_interdeep_c,n,n,n,37100,Pg C,Initial intermediate + deep ocean carbon
+simpleNbox,atmos_co2,n,n,y,588.071,Pg C,Initial atmospheric CO2
+simpleNbox,C0,n,n,y,277.15,Pg C,Initial atmospheric C pool
+simpleNbox,pf.veg_c,y,n,n,55,Pg C,Initial vegetation C pool
+simpleNbox,nonpf.veg_c,y,n,n,495,Pg C,Initial vegetation C pool
+simpleNbox,veg_c,n,n,y,550,Pg C,Initial vegetation C pool
+simpleNbox,pf.detritus_c,y,n,n,5,Pg C,Initial detritus C pool
+simpleNbox,nonpf.detritus_c,y,n,n,50,Pg C,Initial detritus C pool
+simpleNbox,detritus_c,n,n,y,55,Pg C,Initial detritus C pool
+simpleNbox,pf.soil_c,y,n,n,308,Pg C,Initial soil C pool
+simpleNbox,nonpf.soil_c,y,n,n,609,Pg C,Initial soil C pool
+simpleNbox,soil_c,n,n,y,917,Pg C,Initial soil C pool
+simpleNbox,pf.permafrost_c,y,n,n,865,Pg C,Initial permafrost C pool
+simpleNbox,nonpf.permafrost_c,y,n,n,0,Pg C,Initial permafrost C pool
+simpleNbox,permafrost_c,n,n,y,865,Pg C,Initial permafrost C pool
+simpleNbox,pf.npp_flux0,y,n,n,5.6,Pg C yr-1,Preindustrial net primary production
+simpleNbox,nonpf.npp_flux0,y,n,n,50.6,Pg C yr-1,Preindustrial net primary production
+simpleNbox,npp_flux0,n,n,y,56.2,Pg C yr-1,Preindustrial net primary production
+simpleNbox,pf.f_nppv,n,n,y,0.35,(unitless),Fraction of NPP to vegetation
+simpleNbox,nonpf.f_nppv,n,n,y,0.35,(unitless),Fraction of NPP to vegetation
+simpleNbox,f_nppv,n,n,y,0.35,(unitless),Fraction of NPP to vegetation
+simpleNbox,pf.f_nppd,n,n,y,0.35,(unitless),Fraction of NPP to vegetation
+simpleNbox,nonpf.f_nppd,n,n,y,0.35,(unitless),Fraction of NPP to vegetation
+simpleNbox,f_nppd,n,n,y,0.6,(unitless),Fraction of NPP to detritus (balance to soil)
+simpleNbox,pf.f_litterd,n,n,n,0.35,(unitless),Fraction of NPP to vegetation
+simpleNbox,nonpf.f_litterd,n,n,n,0.35,(unitless),Fraction of NPP to vegetation
+simpleNbox,f_litterd,n,n,y,0.98,(unitless),Fraction of litter flux to detritus (balance to soil)
+simpleNbox,ffi_emissions,n,y,y,"""(csv)""",Pg C yr-1,Anthropogenic contributions: emissions
+simpleNbox,daccs_uptake,n,y,y,"""(csv)""",Pg C yr-1,Anthropogenic contributions: direct air carbon capture and storage
+simpleNbox,luc_emissions,n,y,y,"""(csv)""",Pg C yr-1,Anthropogenic contributions: land use change
+simpleNbox,luc_uptake,n,y,y,"""(csv)""",Pg C yr-2,Anthropogenic contributions: land use change
+simpleNbox,CO2_constrain,n,y,n,"""(csv)""",ppmv,Atmospheric CO2 constraint
+simpleNbox,NBP_constrain,n,y,n,"""(csv)""",Pg C yr-1,Net biome production (land-atmosphere C flux) constaint
+simpleNbox,pf.beta,n,n,n,0.36,(unitless),CO2 fertilization factor
+simpleNbox,nonpf.beta,n,n,n,0.36,(unitless),CO2 fertilization factor
+simpleNbox,beta,n,n,y,0.36,(unitless),CO2 fertilization factor
+simpleNbox,pf.q10_rh,n,n,n,2,(unitless),Respiration temperature response (Q10)
+simpleNbox,nonpf.q10_rh,n,n,n,2,(unitless),Respiration temperature response (Q10)
+simpleNbox,q10_rh,n,n,y,2,(unitless),Respiration temperature response (Q10)
+simpleNbox,pf.warmingfactor,y,n,n,2,(unitless),biome-specific warming factors
+simpleNbox,RF_albedo,n,n,y,"""(csv)""",W m-2,Albedo radiative forcing effect
+simpleNbox,permafrost_c,y,n,y,0,Pg C,Preindustrial permafrost carbon pool
+simpleNbox,fpf_static,y,n,n,0.74,(unitless),Fraction of permafrost that is static (non-labile)
+simpleNbox,rh_ch4_frac,y,n,n,0.023,(unitless),Fraction of thawed permafrost decomposed as CH4
+simpleNbox,pf_mu,y,n,n,1.67,(unitless),Permafrost thaw parameter; see Woodard et al. 2021
+simpleNbox,pf_sigma,y,n,n,0.986,(unitless),Permafrost thaw parameter; see Woodard et al. 2021
+carbon-cycle-solver,eps_abs,n,n,y,1.00E-06,(unitless),Solver solution tolerance
+carbon-cycle-solver,eps_rel,n,n,y,1.00E-06,(unitless),Solver solution tolerance
+carbon-cycle-solver,dt,n,n,y,0.25,(unitless),Solver default time step
+carbon-cycle-solver,eps_spinup,n,n,y,0.001,Pg C,"Model spinup tolerance (drift), Pg C"
+so2,SO2_emissions,n,y,y,"""(csv)""",,emissions time series
+so2,SV,n,y,y,"""(csv)""",,volcanic radiative forcing time series
+CH4,M0,n,n,y,731.41,ppb,"preindustrial methane IPCC AR6 Table 7.SM.1, the CH4 forcing equations is calibrated to a M0 of 731.41 ppb"
+CH4,Tsoil,n,n,y,160,years,CH4 loss to soil
+CH4,Tstrat,n,n,y,120,years,CH4 loss to stratosphere
+CH4,UC_CH4,n,n,y,2.78,Tg CH4 ppb-1,unit conversion between emissions and concentrations
+CH4,CH4N,n,n,y,341,,best fit
+CH4,CH4_emissions,n,y,y,"""(csv)""",,emissions time series
+CH5,CH4_constrain,n,y,n,"""(csv)""",,CH4 concentration constraint
+OH,NOX_emissions,n,y,y,"""(csv)""",,emissions time series
+OH,CO_emissions,n,y,y,"""(csv)""",,emissions time series
+OH,NMVOC_emissions,n,y,y,"""(csv)""",,emissions time series
+OH,TOH0,n,n,y,6.6,years,initial OH lifetime
+OH,CNOX,n,n,y,0.0042,,coefficient for NOX
+OH,CCO,n,n,y,-1.05E-04,,coefficient for CO
+OH,CNMVOC,n,n,y,-3.15E-04,,coefficient for NMVOC (non methane VOC)
+OH,CCH4,n,n,y,-0.32,,coefficient for CH4
+OH,H2_CCO,n,n,y,4.25,, H2 adjustment for CO coefficient
+OH,H2_emissions[1745],n,y,y,0,,emissions time series
+ozone,PO3,n,n,y,30,,preindustrial O3 concentration
+ozone,CO3_H2,n,n,y,4.09E-03,DU O3 Tg H2-1,"coefficient for H2 contribution to trop. O3 RF (DU O3 Tg H2-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8"
+ozone,NOX_emissions,n,y,y,"""(csv)""",,emissions time series
+ozone,CO_emissions,n,y,y,"""(csv)""",,emissions time series
+ozone,H2_emissions[1745],n,y,y,0,,emissions time series
+ozone,NMVOC_emissions,n,y,y,"""(csv)""",,emissions time series
+N2O,N0,n,n,y,273.87,ppb,preindustrial nitrous oxide from IPCC AR6 table 7.SM.1
+N2O,UC_N2O,n,n,y,4.8,TgN ppbv-1,unit conversion between emissions and concentrations
+N2O,TN2O0,n,n,y,132,years,initial lifetime of N2O
+N2O,N2O_natural_emissions,n,y,y,9.5,,default natural emissions based on a best fit to IPCC AR6 N2O RF
+N2O,N2O_emissions,n,y,y,"""(csv)""",,emissions time series
+N2O,N2O_constrain,n,y,n,"""(csv)""",,N2O concentration constraint
+forcing,baseyear,n,n,y,1750,,"when to start reporting; by definition, all F=0 in this year"
+forcing,RF_tot_constrain,n,y,n,"""(csv)""",,"If supplied, the model will use these data, ignoring what it calculates"
+forcing,delta_co2,n,n,y,0.05,(unitless),forcing tropospheric adjustments for CO2 (7.3.2.1 of IPCC AR6)
+forcing,delta_ch4,n,n,y,-0.14,(unitless),forcing tropospheric adjustments for CH4 (7.3.2.2 of IPCC AR6)
+forcing,delta_n2o,n,n,y,0.07,(unitless),forcing tropospheric adjustments for N2O (7.3.2.3 of IPCC AR6)
+forcing,rho_bc,n,n,y,0.0508,W yr m-2 C Tg-1,IPCC AR6 radiative efficiency BC (7.SM.1.3 of IPCC AR6)
+forcing,rho_oc,n,n,y,-0.00621,W yr m-2 C Tg-1,IPCC AR6 radiative efficiency OC (7.SM.1.3.1 of IPCC AR6)
+forcing,rho_so2,n,n,y,-7.24E-06,W yr m-2 S Gg-1,IPCC AR6 radiative efficiency SO2 (7.SM.1.3.1 of IPCC AR6)
+forcing,rho_nh3,n,n,y,-0.00208,W yr m-2 NH3 Tg-1,IPCC AR6 radiative efficiency NH3 (7.SM.1.3.1 of IPCC AR6)
+forcing,rho_h2o_h2,n,n,y,1.30E-04,W m _2 H2 Tg_1,"strat. H2O vapor forcing from H2 emissions without CH4 effects Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8"
+forcing,RF_misc,n,n,n,"""(csv)""",,Miscellaneous radiative forcings default set to 0
+forcing,aero_scalar,n,n,y,1,(unitless),Uncerainty scalar
+forcing,vol_scalar,n,n,y,1,(unitless),Uncerainty scalar
+forcing,RF_misc,n,n,y,0,,"Miscellaneous radiative forcings default set to 0, or read in from a input table, may be used to read in additional forcings not modeled by Hector (i.e. solar, bc on snow , contrails from)"
+temperature,S,n,n,y,3,degC,equilibrium climate sensitivity for 2xCO2
+temperature,diff,n,n,y,2.3,cm2 s-1,ocean heat diffusivity
+temperature,qco2,n,n,y,3.75,,CO2 RF (7.3.2 of IPCC AR6)
+temperature,tas_constrain,n,y,n,"""(csv)""",,"Optional global temperature constraint; If supplied, the model will use these data, ignoring what it calculates"
+bc,BC_emissions,n,y,y,"""(csv)""",,
+oc,OC_emissions,n,y,y,"""(csv)""",,
+nh3,NH3_emissions,n,y,y,"""(csv)""",,
+CF4_halocarbon,tau,n,n,y,50000,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+CF4_halocarbon,rho_CF4,n,n,y,9.90E-05,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+CF4_halocarbon,delta_CF4,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+CF4_halocarbon,H0,n,n,y,35,pptv,preindustrial concentration
+CF4_halocarbon,molarMass,n,n,y,88.0043,g,molar mass
+CF4_halocarbon,CF4_emissions,n,y,y,"""(csv)""",,
+C2F6_halocarbon,tau,n,n,y,10000,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+C2F6_halocarbon,rho_C2F6,n,n,y,2.61E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+C2F6_halocarbon,delta_C2F6,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+C2F6_halocarbon,molarMass,n,n,y,138.01,g,molar mass
+C2F6_halocarbon,C2F6_emissions,n,y,y,"""(csv)""",,
+HFC23_halocarbon,tau,n,n,y,228,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+HFC23_halocarbon,rho_HFC23,n,n,y,1.91E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+HFC23_halocarbon,delta_HFC23,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+HFC23_halocarbon,molarMass,n,n,y,70,g,molar mass
+HFC23_halocarbon,HFC23_emissions,n,y,y,"""(csv)""",,
+HFC32_halocarbon,tau,n,n,y,5.4,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+HFC32_halocarbon,rho_HFC32,n,n,y,1.11E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+HFC32_halocarbon,delta_HFC32,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+HFC32_halocarbon,molarMass,n,n,y,52,g,molar mass
+HFC32_halocarbon,HFC32_emissions,n,y,y,"""(csv)""",,
+HFC4310_halocarbon,tau,n,n,y,17,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+HFC4310_halocarbon,rho_HFC4310,n,n,y,3.57E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+HFC4310_halocarbon,delta_HFC4310,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+HFC4310_halocarbon,molarMass,n,n,y,252,g,molar mass
+HFC4310_halocarbon,HFC4310_emissions,n,y,y,"""(csv)""",,
+HFC125_halocarbon,tau,n,n,y,30,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+HFC125_halocarbon,rho_HFC125,n,n,y,2.34E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+HFC125_halocarbon,delta_HFC125,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+HFC125_halocarbon,molarMass,n,n,y,120.02,g,molar mass
+HFC125_halocarbon,HFC125_emissions,n,y,y,"""(csv)""",,
+HFC134a_halocarbon,tau,n,n,y,14,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+HFC134a_halocarbon,rho_HFC134a,n,n,y,1.67E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+HFC134a_halocarbon,delta_HFC134a,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+HFC134a_halocarbon,molarMass,n,n,y,102.02,g,molar mass
+HFC134a_halocarbon,HFC134a_emissions,n,y,y,"""(csv)""",,
+HFC143a_halocarbon,tau,n,n,y,51,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+HFC143a_halocarbon,rho_HFC143a,n,n,y,1.68E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+HFC143a_halocarbon,delta_HFC143a,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+HFC143a_halocarbon,molarMass,n,n,y,84.04,g,molar mass
+HFC143a_halocarbon,HFC143a_emissions,n,y,y,"""(csv)""",,
+HFC227ea_halocarbon,tau,n,n,y,36,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+HFC227ea_halocarbon,rho_HFC227ea,n,n,y,2.73E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+HFC227ea_halocarbon,delta_HFC227ea,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+HFC227ea_halocarbon,molarMass,n,n,y,170.03,g,molar mass
+HFC227ea_halocarbon,HFC227ea_emissions,n,y,y,"""(csv)""",,
+HFC245fa_halocarbon,tau,n,n,y,7.9,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+HFC245fa_halocarbon,rho_HFC245fa,n,n,y,2.45E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+HFC245fa_halocarbon,delta_HFC245fa,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+HFC245fa_halocarbon,molarMass,n,n,y,134,g,molar mass
+HFC245fa_halocarbon,HFC245fa_emissions,n,y,y,"""(csv)""",,
+SF6_halocarbon,tau,n,n,y,3200,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+SF6_halocarbon,rho_SF6,n,n,y,5.67E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+SF6_halocarbon,delta_SF6,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+SF6_halocarbon,molarMass,n,n,y,146.06,g,molar mass
+SF6_halocarbon,SF6_emissions,n,y,y,"""(csv)""",,
+CFC11_halocarbon,tau,n,n,y,52,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+CFC11_halocarbon,rho_CFC11,n,n,y,2.59E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+CFC11_halocarbon,delta_CFC11,n,n,y,0.13,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+CFC11_halocarbon,molarMass,n,n,y,137.35,g,molar mass
+CFC11_halocarbon,CFC11_emissions,n,y,y,"""(csv)""",,
+CFC12_halocarbon,tau,n,n,y,102,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+CFC12_halocarbon,rho_CFC12,n,n,y,3.20E-03,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+CFC12_halocarbon,delta_CFC12,n,n,y,0.13,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+CFC12_halocarbon,molarMass,n,n,y,120.9,g,molar mass
+CFC12_halocarbon,CFC12_emissions,n,y,y,"""(csv)""",,
+CFC113_halocarbon,tau,n,n,y,93,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+CFC113_halocarbon,rho_CFC113,n,n,y,3.01E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+CFC113_halocarbon,delta_CFC113,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+CFC113_halocarbon,molarMass,n,n,y,187.35,g,molar mass
+CFC113_halocarbon,CFC113_emissions,n,y,y,"""(csv)""",,
+CFC114_halocarbon,tau,n,n,y,189,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+CFC114_halocarbon,rho_CFC114,n,n,y,3.14E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+CFC114_halocarbon,delta_CFC114,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+CFC114_halocarbon,molarMass,n,n,y,170.9,g,molar mass
+CFC114_halocarbon,CFC114_emissions,n,y,y,"""(csv)""",,
+CFC115_halocarbon,tau,n,n,y,540,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+CFC115_halocarbon,rho_CFC115,n,n,y,2.46E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+CFC115_halocarbon,delta_CFC115,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+CFC115_halocarbon,molarMass,n,n,y,154.45,g,molar mass
+CFC115_halocarbon,CCl4_emissions,n,y,y,"""(csv)""",,
+CCl4_halocarbon,tau,n,n,y,32,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+CCl4_halocarbon,rho_CCl4,n,n,y,1.66E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+CCl4_halocarbon,delta_CCl4,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+CCl4_halocarbon,molarMass,n,n,y,153.8,g,molar mass
+CCl4_halocarbon,CFC115_emissions,n,y,y,"""(csv)""",,
+CH3CC13_halocarbon,tau,n,n,y,5,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+CH3CC13_halocarbon,rho_CH3CCl3,n,n,y,6.50E-05,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+CH3CC13_halocarbon,delta_CH3CCl3,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+CH3CC13_halocarbon,molarMass,n,n,y,133.35,g,molar mass
+CH3CC13_halocarbon,CH3CCl3_emissions,n,y,y,"""(csv)""",,
+halon1211_halocarbon,tau,n,n,y,16,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+halon1211_halocarbon,rho_halon1211,n,n,y,3.00E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+halon1211_halocarbon,delta_halon1211,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+halon1211_halocarbon,molarMass,n,n,y,165.35,g,molar mass
+halon1211_halocarbon,halon1211_emissions,n,y,y,"""(csv)""",,
+halon1301_halocarbon,tau,n,n,y,72,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+halon1301_halocarbon,rho_halon1301,n,n,y,2.99E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+halon1301_halocarbon,delta_halon1301,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+halon1301_halocarbon,molarMass,n,n,y,148.9,g,molar mass
+halon1301_halocarbon,halon1301_emissions,n,y,y,"""(csv)""",,
+halon2402_halocarbon,tau,n,n,y,28,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+halon2402_halocarbon,rho_halon2402,n,n,y,3.12E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+halon2402_halocarbon,delta_halon2402,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+halon2402_halocarbon,molarMass,n,n,y,259.8,g,molar mass
+halon2402_halocarbon,halon2402_emissions,n,y,y,"""(csv)""",,
+HCF22_halocarbon,tau,n,n,y,11.9,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+HCF22_halocarbon,rho_HCFC22,n,n,y,2.14E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+HCF22_halocarbon,delta_HCFC22,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+HCF22_halocarbon,molarMass,n,n,y,86.45,g,molar mass
+HCF22_halocarbon,HCFC22_emissions,n,y,y,"""(csv)""",,
+HCFC141b_halocarbon,tau,n,n,y,9.4,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+HCFC141b_halocarbon,rho_HCFC141b,n,n,y,1.61E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+HCFC141b_halocarbon,delta_HCFC141b,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+HCFC141b_halocarbon,molarMass,n,n,y,116.9,g,molar mass
+HCFC141b_halocarbon,HCFC141b_emissions,n,y,y,"""(csv)""",,
+HCFC142b_halocarbon,tau,n,n,y,18,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+HCFC142b_halocarbon,rho_HCFC142b,n,n,y,1.93E-04,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+HCFC142b_halocarbon,delta_HCFC142b,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+HCFC142b_halocarbon,molarMass,n,n,y,100.45,g,molar mass
+HCFC142b_halocarbon,HCFC142b_emissions,n,y,y,"""(csv)""",,
+CH3Cl_halocarbon,tau,n,n,y,0.9,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+CH3Cl_halocarbon,rho_CH3Cl,n,n,y,5.00E-06,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+CH3Cl_halocarbon,delta_CH3Cl,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+CH3Cl_halocarbon,H0,n,n,y,504,pptv,"preindustrial concentration, from Saito et al 2007 GRL"
+CH3Cl_halocarbon,molarMass,n,n,y,50.45,g,molar mass
+CH3Cl_halocarbon,CH3Cl_emissions,n,y,y,"""(csv)""",,
+CH3Br_halocarbon,tau,n,n,y,0.8,years,lifetime in years (Table 7.SM.7 IPPC AR6)
+CH3Br_halocarbon,rho_CH3Br,n,n,y,4.00E-06,W m-2 ppt-1,radiative efficiencies (Table 7.SM.7 IPPC AR6)
+CH3Br_halocarbon,delta_CH3Br,n,n,y,0,(unitless),tropospheric adjustments scalar (7.3.2.4 IPCC AR6)
+CH3Br_halocarbon,H0,n,n,y,5.8,pptv,"preindustrial concentration, from Saltzman et al 2004 JGR"
+CH3Br_halocarbon,molarMass,n,n,y,50.45,g,molar mass
+CH3Br_halocarbon,CH3Br_emissions,n,y,y,"""(csv)""",,
\ No newline at end of file
diff --git a/data-raw/units-data.R b/data-raw/units-data.R
index 3dae49371..471ece063 100644
--- a/data-raw/units-data.R
+++ b/data-raw/units-data.R
@@ -26,8 +26,8 @@ ch4_vars <- c(
 )
 ch4_uni <- c("ppbv CH4", "Tg CH4", "Tg CH4", "ppbv CH4", "Years", "Years")
 
-oh_vars <- c(EMISSIONS_NOX(), EMISSIONS_CO(), EMISSIONS_NMVOC())
-oh_uni <- c("Tg N", "Tg CO", "Tg NMVOC")
+oh_vars <- c(EMISSIONS_NOX(), EMISSIONS_CO(), EMISSIONS_NMVOC(), EMISSIONS_H2())
+oh_uni <- c("Tg N", "Tg CO", "Tg NMVOC", "Tg H2")
 
 n2o_vars <- c(EMISSIONS_N2O(), N2O_CONSTRAIN(), NAT_EMISSIONS_N2O(), PREINDUSTRIAL_N2O())
 n2o_uni <- c("Tg N", "ppbv N2O", "Tg N", "ppbv N2O")
diff --git a/data/inputstable.rda b/data/inputstable.rda
index c7df81fca..bce134edb 100644
Binary files a/data/inputstable.rda and b/data/inputstable.rda differ
diff --git a/data/unitstable.rda b/data/unitstable.rda
index 7a2558a83..706e74e96 100644
Binary files a/data/unitstable.rda and b/data/unitstable.rda differ
diff --git a/inst/include/component_data.hpp b/inst/include/component_data.hpp
index de2a9efc4..c6b89dc35 100644
--- a/inst/include/component_data.hpp
+++ b/inst/include/component_data.hpp
@@ -65,9 +65,11 @@
 #define D_RHO_OC "rho_oc"            // BC radiative efficiency
 #define D_RHO_SO2 "rho_so2"          // SO2 radiative efficiency
 #define D_RHO_NH3 "rho_nh3"          // NH3 radiative efficiency
+#define D_RHO_H2O_H2 "rho_h2o_h2"    // radiative efficiency of H2 emissions on strat. H2O vapor
 #define D_AERO_SCALE "aero_scalar"
 #define D_VOLCANIC_SCALE "vol_scalar"
 
+
 // halocarbon components
 #define D_RF_CF4 D_RF_PREFIX CF4_COMPONENT_BASE
 #define D_RF_C2F6 D_RF_PREFIX C2F6_COMPONENT_BASE
@@ -279,13 +281,17 @@
 // oh component
 #define D_LIFETIME_OH "TAU_OH"
 #define D_INITIAL_LIFETIME_OH "TOH0"
-#define D_COEFFICENT_NOX "CNOX"
-#define D_COEFFICENT_CH4 "CCH4"
-#define D_COEFFICENT_NMVOC "CNMVOC"
-#define D_COEFFICENT_CO "CCO"
+#define D_COEFFICIENT_NOX "CNOX"
+#define D_COEFFICIENT_CH4 "CCH4"
+#define D_COEFFICIENT_NMVOC "CNMVOC"
+#define D_COEFFICIENT_CO "CCO"
+#define D_COEFFICIENT_H2 "H2_CCO"
+#define D_EMISSIONS_H2 "H2_emissions"
+
 
 // o3 component
 #define D_PREINDUSTRIAL_O3 "PO3"
+#define D_COEFF_O3_H2 "CO3_H2"
 #define D_ATMOSPHERIC_O3 "O3" CONCENTRATION_EXTENSION
 #define D_ATMOSPHERIC_EM_CH4 "CH4"
 #define D_EMISSIONS_NOX "NOX_emissions"
diff --git a/inst/include/forcing_component.hpp b/inst/include/forcing_component.hpp
index ea21395c9..f61528fdb 100644
--- a/inst/include/forcing_component.hpp
+++ b/inst/include/forcing_component.hpp
@@ -109,6 +109,9 @@ class ForcingComponent : public IModelComponent {
   unitval delta_ch4; // forcing tropospheric adjustment for CH4 see 7.3.2.2 of
                      // IPCC AR6
 
+  // Stratospheric water vapor (strat. H2O) parameters
+  unitval rho_h2o_h2; // W m −2 per Tg yr− 1 from Sand et al. 2023
+
   // Aerosol parameters for aerosol-radiation interactions (RFari) see
   // equation 7.SM.1.1 of IPCC AR6
   unitval rho_bc; // (W yr m–2 Tg–1) IPCC AR6 radiative efficiency BC 7.SM.1.3
diff --git a/inst/include/h_util.hpp b/inst/include/h_util.hpp
index c34af5dde..253777b80 100644
--- a/inst/include/h_util.hpp
+++ b/inst/include/h_util.hpp
@@ -26,7 +26,9 @@
  * \brief The model version number to be included in logs and outputs.
  * \note  Manually update the git tag to match this.
  */
-#define MODEL_VERSION "3.5.0"
+
+#define MODEL_VERSION "3.5.6"
+
 
 #define OUTPUT_DIRECTORY "output/"
 
diff --git a/inst/include/o3_component.hpp b/inst/include/o3_component.hpp
index c047a28e7..f1f9bdb32 100644
--- a/inst/include/o3_component.hpp
+++ b/inst/include/o3_component.hpp
@@ -58,10 +58,12 @@ class OzoneComponent : public IModelComponent {
 
   //! Current ozone concentration, relative to preindustrial, Dobson units
   unitval PO3;
+  unitval CO3_H2;
   tseries<unitval> O3;
   tseries<unitval> CO_emissions;
   tseries<unitval> NMVOC_emissions;
   tseries<unitval> NOX_emissions;
+  tseries<unitval> H2_emissions;
 
   //! logger
   Logger logger;
diff --git a/inst/include/oh_component.hpp b/inst/include/oh_component.hpp
index 59812d848..dad65df06 100644
--- a/inst/include/oh_component.hpp
+++ b/inst/include/oh_component.hpp
@@ -61,15 +61,18 @@ class OHComponent : public IModelComponent {
   tseries<unitval> CO_emissions;
   tseries<unitval> NOX_emissions;
   tseries<unitval> NMVOC_emissions;
+  tseries<unitval> H2_emissions;
   tseries<unitval> TAU_OH;
 
   unitval M0;   // initial CH4 concentration
   unitval TOH0; // preindustrial OH lifetime
 
-  double CCO;    // coefficent for CO
-  double CNMVOC; // coefficent for NMVOC
-  double CNOX;   // coefficent for NOX
-  double CCH4;   // coefficent for CH4
+  double CCO;    // coefficient for CO
+  double CNMVOC; // coefficient for NMVOC
+  double CNOX;   // coefficient for NOX
+  double CCH4;   // coefficient for CH4
+  unitval H2_CCO;   // adjust CO coefficient for H2
+
 
   // logger
   Logger logger;
diff --git a/inst/include/unitval.hpp b/inst/include/unitval.hpp
index 97bd88337..41563746f 100644
--- a/inst/include/unitval.hpp
+++ b/inst/include/unitval.hpp
@@ -80,7 +80,9 @@ enum unit_types {
   U_TG_CH4,
   U_TG_N,
   U_TG_NMVOC,
+  U_TG_H2,
   U_DU_O3,
+  U_DU_O3_TG,
   U_GG_S, // SO2 emissions in Gg-S/yr
 
   U_TG_PPBV, // Conversion for CH4 and N2O emission to concentrations
diff --git a/inst/input/hector_picontrol.ini b/inst/input/hector_picontrol.ini
index f43df54d6..6a4e41432 100644
--- a/inst/input/hector_picontrol.ini
+++ b/inst/input/hector_picontrol.ini
@@ -114,9 +114,11 @@ CH4_emissions[1745]=0           ;
 
 ;------------------------------------------------------------------------
 [OH]
-NOX_emissions[1745]=3.877282     ; emissions time series
-CO_emissions[1745]=348.5273588      ; emissions time series
+
+NOX_emissions[1745]=3.877282         ; emissions time series
+CO_emissions[1745]=348.5273588       ; emissions time series
 NMVOC_emissions[1745]= 60.02182622   ; emissions time series
+H2_emissions[1745]=0     	     ; emissions time series
 
 
 TOH0=9.6			; initial OH lifetime (years) Wigley et al. 2002
@@ -128,6 +130,7 @@ CCH4=-0.32			; coefficient for CH4 (unitless) Wigley et al. 2002
 ;------------------------------------------------------------------------
 [ozone]
 PO3=30.0 					; preindustrial O3 concentration
+CO3_H2=4.09e-3 		       	; coefficient for H2 contribution to trop. O3 RF (DU O3 Tg H2-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
 NOX_emissions[1745]=3.877282     ; emissions time series
 CO_emissions[1745]=348.5273588      ; emissions time series
 NMVOC_emissions[1745]= 60.02182622   ; emissions time series
@@ -160,6 +163,7 @@ rho_bc=0.0508           ; (W yr m–2 C Tg–1) IPCC AR6 radiative efficiency BC
 rho_oc=-.00621          ; (W yr m–2 C Tg–1) IPCC AR6 radiative efficiency OC (7.SM.1.3.1 of IPCC AR6)
 rho_so2=-.00000724      ; (W yr m–2 S Gg-1) IPCC AR6 radiative efficiency SO2 (7.SM.1.3.1 of IPCC AR6)
 rho_nh3=-.00208         ; (W yr m–2 NH3Tg–1) IPCC AR6 radiative efficiency NH3 (7.SM.1.3.1 of IPCC AR6)
+rho_h2o_h2=1.3e-4      ; (W m −2 H2 Tg-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
 
 ; Miscellaneous radiative forcings default set to 0, or read in from a input table, may be used to read in
 ; additional forcings not modeled by Hector (i.e. solar, bc on snow , contrails from)
diff --git a/inst/input/hector_ssp119.ini b/inst/input/hector_ssp119.ini
index 38124d6c5..9dffe4ac0 100644
--- a/inst/input/hector_ssp119.ini
+++ b/inst/input/hector_ssp119.ini
@@ -130,19 +130,24 @@ CH4_emissions=csv:tables/ssp119_emiss-constraints_rf.csv     ; emissions time se
 NOX_emissions=csv:tables/ssp119_emiss-constraints_rf.csv     ; emissions time series
 CO_emissions=csv:tables/ssp119_emiss-constraints_rf.csv      ; emissions time series
 NMVOC_emissions=csv:tables/ssp119_emiss-constraints_rf.csv   ; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
 
 TOH0=9.6			; initial OH lifetime (years) Wigley et al. 2002
 CNOX=8.4e-3			; coefficient for NOX, see PR #786
 CCO=-1.575e-4		; coefficient for CO, see PR #786
 CNMVOC=-4.725e-4	; coefficient for NMVOC (non methane VOC), see PR #786
 CCH4=-0.32			; coefficient for CH4 (unitless) Wigley et al. 2002
+H2_CCO=4.25         ; scaling factor for the CO coefficient that affects OH lifetime; see PR787
 
 ;------------------------------------------------------------------------
 [ozone]
 PO3=30.0 			; preindustrial O3 concentration
+CO3_H2=4.09e-3 		       	; coefficient for H2 contribution to trop. O3 RF (DU O3 Tg H2-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
 NOX_emissions=csv:tables/ssp119_emiss-constraints_rf.csv  	; emissions time series
 CO_emissions=csv:tables/ssp119_emiss-constraints_rf.csv		; emissions time series
 NMVOC_emissions=csv:tables/ssp119_emiss-constraints_rf.csv 	; emissions time series
+H2_emissions[1745]=0                                        ; assumed 0 emissions for the RCMIP era SSPs
+
 
 ;------------------------------------------------------------------------
 [N2O]
@@ -171,6 +176,8 @@ rho_bc=0.06386286       ; (W yr m–2 C Tg–1) Dorheim et al. 2024
 rho_oc=-0.006407143     ; (W yr m–2 C Tg–1) Dorheim et al. 2024
 rho_so2=-7.469841e-06   ; (W yr m–2 S Gg-1) Dorheim et al. 2024
 rho_nh3=-0.002146032    ; (W yr m–2 NH3Tg–1) Dorheim et al. 2024
+rho_h2o_h2=1.3e-4      ; (W m −2 H2 Tg-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
+
 
 ; Miscellaneous radiative forcings are by default zero, but can read in from a input table to
 ; represent additional forcings not modeled by Hector (e.g. solar, bc on snow, jet contrails)
diff --git a/inst/input/hector_ssp126.ini b/inst/input/hector_ssp126.ini
index 417a3a6d2..99b8da104 100644
--- a/inst/input/hector_ssp126.ini
+++ b/inst/input/hector_ssp126.ini
@@ -130,19 +130,23 @@ CH4_emissions=csv:tables/ssp126_emiss-constraints_rf.csv     ; emissions time se
 NOX_emissions=csv:tables/ssp126_emiss-constraints_rf.csv     ; emissions time series
 CO_emissions=csv:tables/ssp126_emiss-constraints_rf.csv      ; emissions time series
 NMVOC_emissions=csv:tables/ssp126_emiss-constraints_rf.csv   ; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
 
 TOH0=9.6			; initial OH lifetime (years) Wigley et al. 2002
 CNOX=8.4e-3			; coefficient for NOX, see PR #786
 CCO=-1.575e-4		; coefficient for CO, see PR #786
 CNMVOC=-4.725e-4	; coefficient for NMVOC (non methane VOC), see PR #786
 CCH4=-0.32			; coefficient for CH4 (unitless) Wigley et al. 2002
+H2_CCO=4.25         ; scaling factor for the CO coefficient that affects OH lifetime; see PR787
 
 ;------------------------------------------------------------------------
 [ozone]
 PO3=30.0 			; preindustrial O3 concentration
+CO3_H2=4.09e-3 		       	; coefficient for H2 contribution to trop. O3 RF (DU O3 Tg H2-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
 NOX_emissions=csv:tables/ssp126_emiss-constraints_rf.csv  	; emissions time series
 CO_emissions=csv:tables/ssp126_emiss-constraints_rf.csv		; emissions time series
 NMVOC_emissions=csv:tables/ssp126_emiss-constraints_rf.csv 	; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
 
 ;------------------------------------------------------------------------
 [N2O]
@@ -171,6 +175,8 @@ rho_bc=0.06386286       ; (W yr m–2 C Tg–1) Dorheim et al. 2024
 rho_oc=-0.006407143     ; (W yr m–2 C Tg–1) Dorheim et al. 2024
 rho_so2=-7.469841e-06   ; (W yr m–2 S Gg-1) Dorheim et al. 2024
 rho_nh3=-0.002146032    ; (W yr m–2 NH3Tg–1) Dorheim et al. 2024
+rho_h2o_h2=1.3e-4      ; (W m −2 H2 Tg-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
+
 
 ; Miscellaneous radiative forcings are by default zero, but can read in from a input table to
 ; represent additional forcings not modeled by Hector (e.g. solar, bc on snow, jet contrails)
diff --git a/inst/input/hector_ssp245.ini b/inst/input/hector_ssp245.ini
index 2bd7259af..a59102561 100644
--- a/inst/input/hector_ssp245.ini
+++ b/inst/input/hector_ssp245.ini
@@ -130,19 +130,25 @@ CH4_emissions=csv:tables/ssp245_emiss-constraints_rf.csv     ; emissions time se
 NOX_emissions=csv:tables/ssp245_emiss-constraints_rf.csv     ; emissions time series
 CO_emissions=csv:tables/ssp245_emiss-constraints_rf.csv      ; emissions time series
 NMVOC_emissions=csv:tables/ssp245_emiss-constraints_rf.csv   ; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
+
 
 TOH0=9.6			; initial OH lifetime (years) Wigley et al. 2002
 CNOX=8.4e-3			; coefficient for NOX, see PR #786
 CCO=-1.575e-4		; coefficient for CO, see PR #786
 CNMVOC=-4.725e-4	; coefficient for NMVOC (non methane VOC), see PR #786
 CCH4=-0.32			; coefficient for CH4 (unitless) Wigley et al. 2002
+H2_CCO=4.25         ; scaling factor for the CO coefficient that affects OH lifetime; see PR787
 
 ;------------------------------------------------------------------------
 [ozone]
-PO3=30.0 			; preindustrial O3 concentration
+PO3=30.0 			    ; preindustrial O3 concentration
+CO3_H2=4.09e-3 		       	; coefficient for H2 contribution to trop. O3 RF (DU O3 Tg H2-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
 NOX_emissions=csv:tables/ssp245_emiss-constraints_rf.csv  	; emissions time series
 CO_emissions=csv:tables/ssp245_emiss-constraints_rf.csv		; emissions time series
 NMVOC_emissions=csv:tables/ssp245_emiss-constraints_rf.csv 	; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
+
 
 ;------------------------------------------------------------------------
 [N2O]
@@ -171,6 +177,9 @@ rho_bc=0.06386286       ; (W yr m–2 C Tg–1) Dorheim et al. 2024
 rho_oc=-0.006407143     ; (W yr m–2 C Tg–1) Dorheim et al. 2024
 rho_so2=-7.469841e-06   ; (W yr m–2 S Gg-1) Dorheim et al. 2024
 rho_nh3=-0.002146032    ; (W yr m–2 NH3Tg–1) Dorheim et al. 2024
+rho_h2o_h2=1.3e-4      ; (W m −2 H2 Tg-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
+
+
 
 ; Miscellaneous radiative forcings are by default zero, but can read in from a input table to
 ; represent additional forcings not modeled by Hector (e.g. solar, bc on snow, jet contrails)
diff --git a/inst/input/hector_ssp370.ini b/inst/input/hector_ssp370.ini
index 2a0782ba3..f0c106f48 100644
--- a/inst/input/hector_ssp370.ini
+++ b/inst/input/hector_ssp370.ini
@@ -130,19 +130,23 @@ CH4_emissions=csv:tables/ssp370_emiss-constraints_rf.csv     ; emissions time se
 NOX_emissions=csv:tables/ssp370_emiss-constraints_rf.csv     ; emissions time series
 CO_emissions=csv:tables/ssp370_emiss-constraints_rf.csv      ; emissions time series
 NMVOC_emissions=csv:tables/ssp370_emiss-constraints_rf.csv   ; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
 
 TOH0=9.6			; initial OH lifetime (years) Wigley et al. 2002
 CNOX=8.4e-3			; coefficient for NOX, see PR #786
 CCO=-1.575e-4		; coefficient for CO, see PR #786
 CNMVOC=-4.725e-4	; coefficient for NMVOC (non methane VOC), see PR #786
 CCH4=-0.32			; coefficient for CH4 (unitless) Wigley et al. 2002
+H2_CCO=4.25         ; scaling factor for the CO coefficient that affects OH lifetime; see PR787
 
 ;------------------------------------------------------------------------
 [ozone]
 PO3=30.0 			; preindustrial O3 concentration
+CO3_H2=4.09e-3 		       	; coefficient for H2 contribution to trop. O3 RF (DU O3 Tg H2-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
 NOX_emissions=csv:tables/ssp370_emiss-constraints_rf.csv  	; emissions time series
 CO_emissions=csv:tables/ssp370_emiss-constraints_rf.csv		; emissions time series
 NMVOC_emissions=csv:tables/ssp370_emiss-constraints_rf.csv 	; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
 
 ;------------------------------------------------------------------------
 [N2O]
@@ -171,6 +175,8 @@ rho_bc=0.06386286       ; (W yr m–2 C Tg–1) Dorheim et al. 2024
 rho_oc=-0.006407143     ; (W yr m–2 C Tg–1) Dorheim et al. 2024
 rho_so2=-7.469841e-06   ; (W yr m–2 S Gg-1) Dorheim et al. 2024
 rho_nh3=-0.002146032    ; (W yr m–2 NH3Tg–1) Dorheim et al. 2024
+rho_h2o_h2=1.3e-4      ; (W m −2 H2 Tg-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
+
 
 ; Miscellaneous radiative forcings are by default zero, but can read in from a input table to
 ; represent additional forcings not modeled by Hector (e.g. solar, bc on snow, jet contrails)
diff --git a/inst/input/hector_ssp434.ini b/inst/input/hector_ssp434.ini
index f4fecdf68..a84906f33 100644
--- a/inst/input/hector_ssp434.ini
+++ b/inst/input/hector_ssp434.ini
@@ -130,19 +130,23 @@ CH4_emissions=csv:tables/ssp434_emiss-constraints_rf.csv     ; emissions time se
 NOX_emissions=csv:tables/ssp434_emiss-constraints_rf.csv     ; emissions time series
 CO_emissions=csv:tables/ssp434_emiss-constraints_rf.csv      ; emissions time series
 NMVOC_emissions=csv:tables/ssp434_emiss-constraints_rf.csv   ; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
 
 TOH0=9.6			; initial OH lifetime (years) Wigley et al. 2002
 CNOX=8.4e-3			; coefficient for NOX, see PR #786
 CCO=-1.575e-4		; coefficient for CO, see PR #786
 CNMVOC=-4.725e-4	; coefficient for NMVOC (non methane VOC), see PR #786
 CCH4=-0.32			; coefficient for CH4 (unitless) Wigley et al. 2002
+H2_CCO=4.25         ; scaling factor for the CO coefficient that affects OH lifetime; see PR787
 
 ;------------------------------------------------------------------------
 [ozone]
 PO3=30.0 			; preindustrial O3 concentration
+CO3_H2=4.09e-3 		       	; coefficient for H2 contribution to trop. O3 RF (DU O3 Tg H2-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
 NOX_emissions=csv:tables/ssp434_emiss-constraints_rf.csv  	; emissions time series
 CO_emissions=csv:tables/ssp434_emiss-constraints_rf.csv		; emissions time series
 NMVOC_emissions=csv:tables/ssp434_emiss-constraints_rf.csv 	; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
 
 ;------------------------------------------------------------------------
 [N2O]
@@ -171,6 +175,8 @@ rho_bc=0.06386286       ; (W yr m–2 C Tg–1) Dorheim et al. 2024
 rho_oc=-0.006407143     ; (W yr m–2 C Tg–1) Dorheim et al. 2024
 rho_so2=-7.469841e-06   ; (W yr m–2 S Gg-1) Dorheim et al. 2024
 rho_nh3=-0.002146032    ; (W yr m–2 NH3Tg–1) Dorheim et al. 2024
+rho_h2o_h2=1.3e-4      ; (W m −2 H2 Tg-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
+
 
 ; Miscellaneous radiative forcings are by default zero, but can read in from a input table to
 ; represent additional forcings not modeled by Hector (e.g. solar, bc on snow, jet contrails)
diff --git a/inst/input/hector_ssp460.ini b/inst/input/hector_ssp460.ini
index ff0e1ff53..2b74932ae 100644
--- a/inst/input/hector_ssp460.ini
+++ b/inst/input/hector_ssp460.ini
@@ -130,19 +130,23 @@ CH4_emissions=csv:tables/ssp460_emiss-constraints_rf.csv     ; emissions time se
 NOX_emissions=csv:tables/ssp460_emiss-constraints_rf.csv     ; emissions time series
 CO_emissions=csv:tables/ssp460_emiss-constraints_rf.csv      ; emissions time series
 NMVOC_emissions=csv:tables/ssp460_emiss-constraints_rf.csv   ; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
 
 TOH0=9.6			; initial OH lifetime (years) Wigley et al. 2002
 CNOX=8.4e-3			; coefficient for NOX, see PR #786
 CCO=-1.575e-4		; coefficient for CO, see PR #786
 CNMVOC=-4.725e-4	; coefficient for NMVOC (non methane VOC), see PR #786
 CCH4=-0.32			; coefficient for CH4 (unitless) Wigley et al. 2002
+H2_CCO=4.25         ; scaling factor for the CO coefficient that affects OH lifetime; see PR787
 
 ;------------------------------------------------------------------------
 [ozone]
 PO3=30.0 			; preindustrial O3 concentration
+CO3_H2=4.09e-3 		       	; coefficient for H2 contribution to trop. O3 RF (DU O3 Tg H2-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
 NOX_emissions=csv:tables/ssp460_emiss-constraints_rf.csv  	; emissions time series
 CO_emissions=csv:tables/ssp460_emiss-constraints_rf.csv		; emissions time series
 NMVOC_emissions=csv:tables/ssp460_emiss-constraints_rf.csv 	; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
 
 ;------------------------------------------------------------------------
 [N2O]
@@ -171,6 +175,8 @@ rho_bc=0.06386286       ; (W yr m–2 C Tg–1) Dorheim et al. 2024
 rho_oc=-0.006407143     ; (W yr m–2 C Tg–1) Dorheim et al. 2024
 rho_so2=-7.469841e-06   ; (W yr m–2 S Gg-1) Dorheim et al. 2024
 rho_nh3=-0.002146032    ; (W yr m–2 NH3Tg–1) Dorheim et al. 2024
+rho_h2o_h2=1.3e-4      ; (W m −2 H2 Tg-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
+
 
 ; Miscellaneous radiative forcings are by default zero, but can read in from a input table to
 ; represent additional forcings not modeled by Hector (e.g. solar, bc on snow, jet contrails)
diff --git a/inst/input/hector_ssp534-over.ini b/inst/input/hector_ssp534-over.ini
index a969ad43e..d67066c2d 100644
--- a/inst/input/hector_ssp534-over.ini
+++ b/inst/input/hector_ssp534-over.ini
@@ -130,19 +130,23 @@ CH4_emissions=csv:tables/ssp534-over_emiss-constraints_rf.csv     ; emissions ti
 NOX_emissions=csv:tables/ssp534-over_emiss-constraints_rf.csv     ; emissions time series
 CO_emissions=csv:tables/ssp534-over_emiss-constraints_rf.csv      ; emissions time series
 NMVOC_emissions=csv:tables/ssp534-over_emiss-constraints_rf.csv   ; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
 
 TOH0=9.6			; initial OH lifetime (years) Wigley et al. 2002
 CNOX=8.4e-3			; coefficient for NOX, see PR #786
 CCO=-1.575e-4		; coefficient for CO, see PR #786
 CNMVOC=-4.725e-4	; coefficient for NMVOC (non methane VOC), see PR #786
 CCH4=-0.32			; coefficient for CH4 (unitless) Wigley et al. 2002
+H2_CCO=4.25         ; scaling factor for the CO coefficient that affects OH lifetime; see PR787
 
 ;------------------------------------------------------------------------
 [ozone]
 PO3=30.0 			; preindustrial O3 concentration
+CO3_H2=4.09e-3 		       	; coefficient for H2 contribution to trop. O3 RF (DU O3 Tg H2-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
 NOX_emissions=csv:tables/ssp534-over_emiss-constraints_rf.csv  	; emissions time series
 CO_emissions=csv:tables/ssp534-over_emiss-constraints_rf.csv		; emissions time series
 NMVOC_emissions=csv:tables/ssp534-over_emiss-constraints_rf.csv 	; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
 
 ;------------------------------------------------------------------------
 [N2O]
@@ -171,6 +175,8 @@ rho_bc=0.06386286       ; (W yr m–2 C Tg–1) Dorheim et al. 2024
 rho_oc=-0.006407143     ; (W yr m–2 C Tg–1) Dorheim et al. 2024
 rho_so2=-7.469841e-06   ; (W yr m–2 S Gg-1) Dorheim et al. 2024
 rho_nh3=-0.002146032    ; (W yr m–2 NH3Tg–1) Dorheim et al. 2024
+rho_h2o_h2=1.3e-4      ; (W m −2 H2 Tg-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
+
 
 ; Miscellaneous radiative forcings are by default zero, but can read in from a input table to
 ; represent additional forcings not modeled by Hector (e.g. solar, bc on snow, jet contrails)
diff --git a/inst/input/hector_ssp585.ini b/inst/input/hector_ssp585.ini
index 75a27fc14..77e81137b 100644
--- a/inst/input/hector_ssp585.ini
+++ b/inst/input/hector_ssp585.ini
@@ -130,19 +130,23 @@ CH4_emissions=csv:tables/ssp585_emiss-constraints_rf.csv     ; emissions time se
 NOX_emissions=csv:tables/ssp585_emiss-constraints_rf.csv     ; emissions time series
 CO_emissions=csv:tables/ssp585_emiss-constraints_rf.csv      ; emissions time series
 NMVOC_emissions=csv:tables/ssp585_emiss-constraints_rf.csv   ; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
 
 TOH0=9.6			; initial OH lifetime (years) Wigley et al. 2002
 CNOX=8.4e-3			; coefficient for NOX, see PR #786
 CCO=-1.575e-4		; coefficient for CO, see PR #786
 CNMVOC=-4.725e-4	; coefficient for NMVOC (non methane VOC), see PR #786
 CCH4=-0.32			; coefficient for CH4 (unitless) Wigley et al. 2002
+H2_CCO=4.25         ; scaling factor for the CO coefficient that affects OH lifetime; see PR787
 
 ;------------------------------------------------------------------------
 [ozone]
 PO3=30.0 			; preindustrial O3 concentration
+CO3_H2=4.09e-3 		       	; coefficient for H2 contribution to trop. O3 RF (DU O3 Tg H2-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
 NOX_emissions=csv:tables/ssp585_emiss-constraints_rf.csv  	; emissions time series
 CO_emissions=csv:tables/ssp585_emiss-constraints_rf.csv		; emissions time series
 NMVOC_emissions=csv:tables/ssp585_emiss-constraints_rf.csv 	; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
 
 ;------------------------------------------------------------------------
 [N2O]
@@ -171,6 +175,8 @@ rho_bc=0.06386286       ; (W yr m–2 C Tg–1) Dorheim et al. 2024
 rho_oc=-0.006407143     ; (W yr m–2 C Tg–1) Dorheim et al. 2024
 rho_so2=-7.469841e-06   ; (W yr m–2 S Gg-1) Dorheim et al. 2024
 rho_nh3=-0.002146032    ; (W yr m–2 NH3Tg–1) Dorheim et al. 2024
+rho_h2o_h2=1.3e-4      ; (W m −2 H2 Tg-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
+
 
 ; Miscellaneous radiative forcings are by default zero, but can read in from a input table to
 ; represent additional forcings not modeled by Hector (e.g. solar, bc on snow, jet contrails)
diff --git a/man/emissions.Rd b/man/emissions.Rd
index 553da1a16..68febfbcb 100644
--- a/man/emissions.Rd
+++ b/man/emissions.Rd
@@ -7,6 +7,7 @@
 \alias{EMISSIONS_NOX}
 \alias{EMISSIONS_CO}
 \alias{EMISSIONS_NMVOC}
+\alias{EMISSIONS_H2}
 \alias{EMISSIONS_OC}
 \alias{EMISSIONS_NH3}
 \alias{emissions}
@@ -24,6 +25,8 @@ EMISSIONS_CO()
 
 EMISSIONS_NMVOC()
 
+EMISSIONS_H2()
+
 EMISSIONS_OC()
 
 EMISSIONS_NH3()
@@ -46,6 +49,8 @@ type.
 
 \item \code{EMISSIONS_NMVOC()}: Emissions for non-methane volatile organic compounds (NMVOC) (\code{"Tg NMVOC"})
 
+\item \code{EMISSIONS_H2()}: Emissions hydrogen gas (\code{"Tg H2"})
+
 \item \code{EMISSIONS_OC()}: Emissions for organic carbon (\code{"Tg"})
 
 \item \code{EMISSIONS_NH3()}: Emissions for NH3 (\code{"Tg"})
diff --git a/man/methane.Rd b/man/methane.Rd
index e1f65bc76..0f6de0bce 100644
--- a/man/methane.Rd
+++ b/man/methane.Rd
@@ -7,6 +7,7 @@
 \alias{NATURAL_CH4}
 \alias{LIFETIME_SOIL}
 \alias{LIFETIME_STRAT}
+\alias{CH4_LIFETIME_OH}
 \alias{methane}
 \title{Identifiers for quantities in the methane component}
 \usage{
@@ -21,11 +22,18 @@ NATURAL_CH4()
 LIFETIME_SOIL()
 
 LIFETIME_STRAT()
+
+CH4_LIFETIME_OH()
 }
 \description{
 These identifiers correspond to variables that can be read and/or set in the
 methane component.
 }
+\section{Functions}{
+\itemize{
+\item \code{CH4_LIFETIME_OH()}: CH4 lifetime with respect to the OH sink (\code{"Yr"})
+
+}}
 \section{Output variables}{
 
 These variables can be read from the methane component.
diff --git a/src/RcppExports.cpp b/src/RcppExports.cpp
index 6cdb8cdf0..758268c73 100644
--- a/src/RcppExports.cpp
+++ b/src/RcppExports.cpp
@@ -1820,6 +1820,26 @@ BEGIN_RCPP
     return rcpp_result_gen;
 END_RCPP
 }
+// EMISSIONS_H2
+String EMISSIONS_H2();
+RcppExport SEXP _hector_EMISSIONS_H2() {
+BEGIN_RCPP
+    Rcpp::RObject rcpp_result_gen;
+    Rcpp::RNGScope rcpp_rngScope_gen;
+    rcpp_result_gen = Rcpp::wrap(EMISSIONS_H2());
+    return rcpp_result_gen;
+END_RCPP
+}
+// CH4_LIFETIME_OH
+String CH4_LIFETIME_OH();
+RcppExport SEXP _hector_CH4_LIFETIME_OH() {
+BEGIN_RCPP
+    Rcpp::RObject rcpp_result_gen;
+    Rcpp::RNGScope rcpp_rngScope_gen;
+    rcpp_result_gen = Rcpp::wrap(CH4_LIFETIME_OH());
+    return rcpp_result_gen;
+END_RCPP
+}
 // EMISSIONS_OC
 String EMISSIONS_OC();
 RcppExport SEXP _hector_EMISSIONS_OC() {
@@ -2956,6 +2976,8 @@ static const R_CallMethodDef CallEntries[] = {
     {"_hector_EMISSIONS_NOX", (DL_FUNC) &_hector_EMISSIONS_NOX, 0},
     {"_hector_EMISSIONS_CO", (DL_FUNC) &_hector_EMISSIONS_CO, 0},
     {"_hector_EMISSIONS_NMVOC", (DL_FUNC) &_hector_EMISSIONS_NMVOC, 0},
+    {"_hector_EMISSIONS_H2", (DL_FUNC) &_hector_EMISSIONS_H2, 0},
+    {"_hector_CH4_LIFETIME_OH", (DL_FUNC) &_hector_CH4_LIFETIME_OH, 0},
     {"_hector_EMISSIONS_OC", (DL_FUNC) &_hector_EMISSIONS_OC, 0},
     {"_hector_EMISSIONS_NH3", (DL_FUNC) &_hector_EMISSIONS_NH3, 0},
     {"_hector_OCEAN_UPTAKE", (DL_FUNC) &_hector_OCEAN_UPTAKE, 0},
diff --git a/src/ch4_component.cpp b/src/ch4_component.cpp
index 8d89bcfa9..dd91e17aa 100644
--- a/src/ch4_component.cpp
+++ b/src/ch4_component.cpp
@@ -167,7 +167,7 @@ void CH4Component::run(const double runToDate) {
         << std::endl;
 
 // Permafrost thaw produces CH4 emissions
-#define PG_C_TO_TG_CH4 (1000.0 * 16.04 / 12.01)
+    #define PG_C_TO_TG_CH4 (1000.0 * 16.04 / 12.01);
     const double rh_ch4 =
         core->sendMessage(M_GETDATA, D_RH_CH4).value(U_PGC_YR) * PG_C_TO_TG_CH4;
 
diff --git a/src/csv_outputstream_visitor.cpp b/src/csv_outputstream_visitor.cpp
index 25d05afdd..66149e7b3 100644
--- a/src/csv_outputstream_visitor.cpp
+++ b/src/csv_outputstream_visitor.cpp
@@ -74,6 +74,7 @@ CSVOutputStreamVisitor::CSVOutputStreamVisitor(ostream &outputStream,
   current_date = 0;
   datestring = "";
   spinupstring = "";
+  csvFile.precision(15);
 }
 
 //------------------------------------------------------------------------------
@@ -146,7 +147,6 @@ void CSVOutputStreamVisitor::visit(Core *c) {
 void CSVOutputStreamVisitor::visit(ForcingComponent *c) {
   if (!core->outputEnabled(c->getComponentName()))
     return;
-  streamsize oldPrecision = csvFile.precision(4);
 
   if (c->currentYear < c->baseyear)
     return;
@@ -158,7 +158,6 @@ void CSVOutputStreamVisitor::visit(ForcingComponent *c) {
     STREAM_UNITVAL(csvFile, c, f.first, f.second);
   }
 
-  csvFile.precision(oldPrecision);
 }
 
 //------------------------------------------------------------------------------
diff --git a/src/forcing_component.cpp b/src/forcing_component.cpp
index d90334729..f06f515e6 100644
--- a/src/forcing_component.cpp
+++ b/src/forcing_component.cpp
@@ -130,6 +130,7 @@ void ForcingComponent::init(Core *coreptr) {
   core->registerCapability(D_RHO_BC, getComponentName());
   core->registerCapability(D_RHO_OC, getComponentName());
   core->registerCapability(D_RHO_SO2, getComponentName());
+  core->registerCapability(D_RHO_H2O_H2, getComponentName());
   core->registerCapability(D_RF_SO2, getComponentName());
   core->registerCapability(D_RF_ACI, getComponentName());
   core->registerCapability(D_AERO_SCALE, getComponentName());
@@ -184,6 +185,7 @@ void ForcingComponent::init(Core *coreptr) {
   core->registerInput(D_RHO_OC, getComponentName());
   core->registerInput(D_RHO_SO2, getComponentName());
   core->registerInput(D_RHO_NH3, getComponentName());
+  core->registerInput(D_RHO_H2O_H2, getComponentName());
   core->registerInput(D_RF_MISC, getComponentName());
   core->registerInput(D_FTOT_CONSTRAIN, getComponentName());
   core->registerInput(D_AERO_SCALE, getComponentName());
@@ -243,6 +245,9 @@ void ForcingComponent::setData(const string &varName,
     } else if (varName == D_RHO_SO2) {
       H_ASSERT(data.date == Core::undefinedIndex(), "date not allowed");
       rho_so2 = data.getUnitval(U_W_M2_GG);
+    } else if (varName == D_RHO_H2O_H2) {
+        H_ASSERT(data.date == Core::undefinedIndex(), "date not allowed");
+        rho_h2o_h2 = data.getUnitval(U_W_M2_TG);
     } else if (varName == D_AERO_SCALE) {
       H_ASSERT(data.date == Core::undefinedIndex(), "date not allowed");
       alpha = data.getUnitval(U_UNITLESS);
@@ -378,13 +383,15 @@ void ForcingComponent::run(const double runToDate) {
       forcings[D_RF_CH4].set(fch4, U_W_M2);
 
       // ---------- Stratospheric H2O based on CH4 oxidation ----------
-      // The stratospheric water vapour RF based on changes in CH4
+      // The stratospheric water vapor RF based on changes in CH4
       // concentrations.
       const double Ma_base =
           1831; // 2014 CH4 concentration ppb from the cmip6 historical scenario
       const double stratH2O_base =
           0.0485; // W m-2 Strat H2O RF (1850 to 2014) from 7.3.2.6 IPCC AR6
-      const double fh2o_strat = stratH2O_base * ((Ma - M0) / (Ma_base - M0)); //
+      double inital_h2 = core->sendMessage(M_GETDATA, D_EMISSIONS_H2, baseyear).value(U_TG_H2);
+      double current_h2 = core->sendMessage(M_GETDATA, D_EMISSIONS_H2, message_data(runToDate)).value(U_TG_H2);
+      const double fh2o_strat = stratH2O_base * ((Ma - M0) / (Ma_base - M0)) + rho_h2o_h2  * (current_h2 - inital_h2); //
       forcings[D_RF_H2O_STRAT].set(fh2o_strat, U_W_M2);
     }
 
@@ -555,6 +562,8 @@ unitval ForcingComponent::getData(const std::string &varName,
     returnval = rho_so2;
   } else if (varName == D_RHO_NH3) {
     returnval = rho_nh3;
+  } else if (varName == D_RHO_H2O_H2) {
+      returnval = rho_h2o_h2;
   } else if (varName == D_AERO_SCALE) {
     returnval = alpha;
   } else if (varName == D_VOLCANIC_SCALE) {
diff --git a/src/o3_component.cpp b/src/o3_component.cpp
index 587bae918..f9676f43c 100644
--- a/src/o3_component.cpp
+++ b/src/o3_component.cpp
@@ -54,6 +54,8 @@ void OzoneComponent::init(Core *coreptr) {
   NMVOC_emissions.allowInterp(true);
   NOX_emissions.allowInterp(true); // Inputs like CO and NMVOC and NOX,
   O3.allowInterp(true);
+  H2_emissions.allowInterp(true);
+
 
   // Inform core what data we can provide
   core->registerCapability(D_ATMOSPHERIC_O3, getComponentName());
@@ -62,6 +64,11 @@ void OzoneComponent::init(Core *coreptr) {
   core->registerInput(D_EMISSIONS_CO, getComponentName());
   core->registerInput(D_EMISSIONS_NMVOC, getComponentName());
   core->registerInput(D_EMISSIONS_NOX, getComponentName());
+  core->registerInput(D_EMISSIONS_H2, getComponentName());
+  // Parameters read in from the ini
+  core->registerInput(D_COEFF_O3_H2, getComponentName());
+  core->registerInput(D_PREINDUSTRIAL_O3, getComponentName());
+
 }
 
 //------------------------------------------------------------------------------
@@ -94,6 +101,9 @@ void OzoneComponent::setData(const string &varName, const message_data &data) {
     if (varName == D_PREINDUSTRIAL_O3) {
       H_ASSERT(data.date == Core::undefinedIndex(), "date not allowed");
       PO3 = data.getUnitval(U_DU_O3);
+    } else if (varName == D_COEFF_O3_H2) {
+      H_ASSERT(data.date == Core::undefinedIndex(), "date not allowed");
+      CO3_H2 = data.getUnitval(U_DU_O3_TG);
     } else if (varName == D_EMISSIONS_NOX) {
       H_ASSERT(data.date != Core::undefinedIndex(), "date required");
       NOX_emissions.set(data.date, data.getUnitval(U_TG_N));
@@ -103,6 +113,9 @@ void OzoneComponent::setData(const string &varName, const message_data &data) {
     } else if (varName == D_EMISSIONS_NMVOC) {
       H_ASSERT(data.date != Core::undefinedIndex(), "date required");
       NMVOC_emissions.set(data.date, data.getUnitval(U_TG_NMVOC));
+    } else if (varName == D_EMISSIONS_H2) {
+      H_ASSERT(data.date != Core::undefinedIndex(), "date required");
+      H2_emissions.set(data.date, data.getUnitval(U_TG_H2));
     } else {
       H_THROW("Unknown variable name while parsing " + getComponentName() +
               ": " + varName);
@@ -131,12 +144,13 @@ void OzoneComponent::run(const double runToDate) {
   unitval current_nox = NOX_emissions.get(runToDate);
   unitval current_co = CO_emissions.get(runToDate);
   unitval current_nmvoc = NMVOC_emissions.get(runToDate);
+  unitval current_h2 = H2_emissions.get(runToDate);
   unitval current_ch4 = core->sendMessage(M_GETDATA, D_CH4_CONC, runToDate);
 
   O3.set(runToDate,
          unitval((5 * log(current_ch4)) + (0.125 * current_nox) +
-                     (0.0011 * current_co) + (0.0033 * current_nmvoc),
-                 U_DU_O3));
+                     (0.0011 * current_co) + (0.0033 * current_nmvoc) +
+                 (CO3_H2.value(U_DU_O3_TG) * current_h2), U_DU_O3));
 
   oldDate = runToDate;
 
diff --git a/src/oh_component.cpp b/src/oh_component.cpp
index 37de72875..ef32ef504 100644
--- a/src/oh_component.cpp
+++ b/src/oh_component.cpp
@@ -29,8 +29,7 @@ OHComponent::OHComponent() {
   NOX_emissions.allowInterp(true);
   NMVOC_emissions.allowInterp(true);
   CO_emissions.allowInterp(true);
-  TAU_OH.allowInterp(true);
-  // TOH0.set( 0.0, U_YRS );
+  H2_emissions.allowInterp(true);
 }
 
 //------------------------------------------------------------------------------
@@ -57,11 +56,16 @@ void OHComponent::init(Core *coreptr) {
 
   // Inform core what data we can provide
   core->registerCapability(D_LIFETIME_OH, getComponentName());
+  core->registerCapability(D_COEFFICIENT_H2, getComponentName());
   // Register inputs accepted.  Note that more than one component
   // can accept an input
   core->registerInput(D_EMISSIONS_CO, getComponentName());
   core->registerInput(D_EMISSIONS_NMVOC, getComponentName());
   core->registerInput(D_EMISSIONS_NOX, getComponentName());
+  core->registerInput(D_EMISSIONS_H2, getComponentName());
+  core->registerInput(D_COEFFICIENT_H2, getComponentName());
+
+
 }
 
 //------------------------------------------------------------------------------
@@ -97,21 +101,27 @@ void OHComponent::setData(const string &varName, const message_data &data) {
     } else if (varName == D_EMISSIONS_NMVOC) {
       H_ASSERT(data.date != Core::undefinedIndex(), "date required");
       NMVOC_emissions.set(data.date, data.getUnitval(U_TG_NMVOC));
+    } else if (varName == D_EMISSIONS_H2) {
+      H_ASSERT(data.date != Core::undefinedIndex(), "date required");
+      H2_emissions.set(data.date, data.getUnitval(U_TG_H2));
     } else if (varName == D_INITIAL_LIFETIME_OH) {
       H_ASSERT(data.date == Core::undefinedIndex(), "date not allowed");
       TOH0 = data.getUnitval(U_YRS);
-    } else if (varName == D_COEFFICENT_CH4) {
+    } else if (varName == D_COEFFICIENT_CH4) {
       H_ASSERT(data.date == Core::undefinedIndex(), "date not allowed");
       CCH4 = data.getUnitval(U_UNDEFINED);
-    } else if (varName == D_COEFFICENT_CO) {
+    } else if (varName == D_COEFFICIENT_CO) {
       H_ASSERT(data.date == Core::undefinedIndex(), "date not allowed");
       CCO = data.getUnitval(U_UNDEFINED);
-    } else if (varName == D_COEFFICENT_NMVOC) {
+    } else if (varName == D_COEFFICIENT_NMVOC) {
       H_ASSERT(data.date == Core::undefinedIndex(), "date not allowed");
       CNMVOC = data.getUnitval(U_UNDEFINED);
-    } else if (varName == D_COEFFICENT_NOX) {
+    } else if (varName == D_COEFFICIENT_NOX) {
       H_ASSERT(data.date == Core::undefinedIndex(), "date not allowed");
       CNOX = data.getUnitval(U_UNDEFINED);
+    } else if (varName == D_COEFFICIENT_H2) {
+      H_ASSERT(data.date == Core::undefinedIndex(), "date not allowed");
+      H2_CCO = data.getUnitval(U_UNDEFINED);
     } else {
       H_THROW("Unknown variable name while parsing " + getComponentName() +
               ": " + varName);
@@ -144,27 +154,35 @@ void OHComponent::run(const double runToDate) {
   unitval current_nox = NOX_emissions.get(runToDate);
   unitval current_co = CO_emissions.get(runToDate);
   unitval current_nmvoc = NMVOC_emissions.get(runToDate);
+  unitval current_h2 = H2_emissions.get(runToDate);
+
 
   // get this from CH4 component, this is last year's value
   const double previous_ch4 =
       core->sendMessage(M_GETDATA, D_CH4_CONC, oldDate).value(U_PPBV_CH4);
 
+  // toh is a sum of coefficients in an exponential representation of OH lifetime
   double toh = 0.0;
   if (previous_ch4 != M0) // if we are not at the first time
   {
-    const double a =
+    const double toh_ch4 =
         CCH4 * ((1.0 * log(previous_ch4)) - log(M0.value(U_PPBV_CH4)));
-    const double b =
+    const double toh_nox =
         CNOX * ((1.0 * current_nox) -
                 NOX_emissions.get(NOX_emissions.firstdate()).value(U_TG_N));
-    const double c =
+    const double toh_co =
         CCO * ((1.0 * +current_co) -
                CO_emissions.get(CO_emissions.firstdate()).value(U_TG_CO));
-    const double d =
+    const double toh_nmvoc =
         CNMVOC *
         ((1.0 * +current_nmvoc) -
          NMVOC_emissions.get(NMVOC_emissions.firstdate()).value(U_TG_NMVOC));
-    toh = a + b + c + d;
+    const double toh_h2 =
+        H2_CCO * CCO *
+          ((1.0 * +current_h2) -
+           H2_emissions.get(H2_emissions.firstdate()).value(U_TG_H2));
+
+    toh = toh_ch4 + toh_nox + toh_co + toh_nmvoc + toh_h2;
     H_LOG(logger, Logger::DEBUG)
         << "Year " << runToDate << " toh = " << toh << std::endl;
   }
@@ -196,6 +214,12 @@ unitval OHComponent::getData(const std::string &varName, const double date) {
     H_ASSERT(date != Core::undefinedIndex(),
              "Date required for NMVOC emissions");
     returnval = NMVOC_emissions.get(date);
+  } else if (varName == D_COEFFICIENT_H2) {
+    H_ASSERT(date == Core::undefinedIndex(), "Date not allowed for H2 coefficent");
+    returnval = H2_CCO ;
+  } else if (varName == D_EMISSIONS_H2) {
+    H_ASSERT(date != Core::undefinedIndex(), "Date required for H2 emissions");
+    returnval = H2_emissions.get(date);
   } else {
     H_THROW("Caller is requesting unknown variable: " + varName);
   }
diff --git a/src/rcpp_constants.cpp b/src/rcpp_constants.cpp
index 467437d1d..8de385a8b 100644
--- a/src/rcpp_constants.cpp
+++ b/src/rcpp_constants.cpp
@@ -949,6 +949,16 @@ String EMISSIONS_CO() { return D_EMISSIONS_CO; }
 // [[Rcpp::export]]
 String EMISSIONS_NMVOC() { return D_EMISSIONS_NMVOC; }
 
+//' @describeIn emissions Emissions hydrogen gas (\code{"Tg H2"})
+//' @export
+// [[Rcpp::export]]
+String EMISSIONS_H2() { return D_EMISSIONS_H2; }
+
+//' @describeIn methane CH4 lifetime with respect to the OH sink (\code{"Yr"})
+//' @export
+// [[Rcpp::export]]
+String CH4_LIFETIME_OH() { return D_LIFETIME_OH; }
+
 /* OC component */
 //' @describeIn emissions Emissions for organic carbon (\code{"Tg"})
 //' @export
@@ -1503,3 +1513,4 @@ String FLUX_INTERIOR() { return D_FLUX_INTERIOR; }
 //' @export
 // [[Rcpp::export]]
 String HEAT_FLUX() { return D_HEAT_FLUX; }
+
diff --git a/src/unitval.cpp b/src/unitval.cpp
index b38e8fa12..6f624e696 100644
--- a/src/unitval.cpp
+++ b/src/unitval.cpp
@@ -62,6 +62,9 @@ string unitval::unitsName(const unit_types u) {
   case U_DU_O3:
     return "DU O3";
     break;
+  case U_DU_O3_TG:
+    return "DU O3/Tg";
+    break;
   case U_TG_N:
     return "Tg N";
     break;
@@ -77,6 +80,9 @@ string unitval::unitsName(const unit_types u) {
   case U_TG_NMVOC:
     return "Tg NMVOC";
     break;
+  case U_TG_H2:
+      return "Tg H2";
+      break;
   case U_TG_PPBV:
     return "Tg/ppbv";
     break;
diff --git a/tests/testthat/input/luc_pulse.ini b/tests/testthat/input/luc_pulse.ini
index 901ef82d0..f0c86391d 100644
--- a/tests/testthat/input/luc_pulse.ini
+++ b/tests/testthat/input/luc_pulse.ini
@@ -110,19 +110,23 @@ CH4_emissions=csv:luc_pulse_tables.csv     ; emissions time series
 NOX_emissions=csv:luc_pulse_tables.csv     ; emissions time series
 CO_emissions=csv:luc_pulse_tables.csv      ; emissions time series
 NMVOC_emissions=csv:luc_pulse_tables.csv   ; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
 
 TOH0=9.6			; initial OH lifetime (years) Wigley et al. 2002
 CNOX=8.4e-3			; coefficient for NOX CITATION TODO
 CCO=-1.575e-4		; coefficient for CO CITATION TODO
 CNMVOC=-4.725e-4	; coefficient for NMVOC (non methane VOC) CITATION TODO
 CCH4=-0.32			; coefficient for CH4 (unitless) Wigley et al. 2002
+H2_CCO=4.25         ; scaling factor for the CO coefficient that affects OH lifetime; see PR787
 
 ;------------------------------------------------------------------------
 [ozone]
 PO3=30.0 					; preindustrial O3 concentration
+CO3_H2=4.09e-3 		       	; coefficient for H2 contribution to trop. O3 RF (DU O3 Tg H2-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
 NOX_emissions=csv:luc_pulse_tables.csv  	; emissions time series
 CO_emissions=csv:luc_pulse_tables.csv		; emissions time series
 NMVOC_emissions=csv:luc_pulse_tables.csv 	; emissions time series
+H2_emissions[1745]=0                                         ; assumed 0 emissions for the RCMIP era SSPs
 
 ;------------------------------------------------------------------------
 [N2O]
@@ -152,6 +156,7 @@ rho_bc=0.0508           ; (W yr m–2 C Tg–1) IPCC AR6 radiative efficiency BC
 rho_oc=-.00621          ; (W yr m–2 C Tg–1) IPCC AR6 radiative efficiency OC (7.SM.1.3.1 of IPCC AR6)
 rho_so2=-.00000724      ; (W yr m–2 S Gg-1) IPCC AR6 radiative efficiency SO2 (7.SM.1.3.1 of IPCC AR6)
 rho_nh3=-.00208         ; (W yr m–2 NH3Tg–1) IPCC AR6 radiative efficiency NH3 (7.SM.1.3.1 of IPCC AR6)
+rho_h2o_h2=1.3e-4      ; (W m −2 H2 Tg-1) Sand et al. 2023 ST4, 10.1038/s43247-023-00857-8
 
 ; Miscellaneous radiative forcings default set to 0, or read in from a input table, may be used to read in
 ; additional forcings not modeled by Hector (i.e. solar, bc on snow , contrails from)
diff --git a/tests/testthat/test-h2.R b/tests/testthat/test-h2.R
new file mode 100644
index 000000000..e8331c6ed
--- /dev/null
+++ b/tests/testthat/test-h2.R
@@ -0,0 +1,59 @@
+# Probably temporary testing or may be moved to other unit tests.
+
+
+ini <- system.file("input/hector_ssp245.ini", package = "hector")
+dates <- 1750:2100
+
+test_that("tau ", {
+
+    # Limited testing for now check to see tau oh can be read out...
+    # in the future might want to test the actual values but for now
+    # we are happy if the values range from 6.6 to 8
+    hc <- newcore(ini)
+    run(hc)
+    out <- fetchvars(hc, dates = 1750:2100, vars = CH4_LIFETIME_OH())
+
+    head(out)
+
+
+    expect_equal(CH4_LIFETIME_OH(), "TAU_OH")
+    expect_lte(mean(out$value), 8)
+    expect_gte(mean(out$value), 6.6)
+
+})
+
+
+test_that("H2 emissions ", {
+
+    # Check to make sure that can fetch and set the H2 emissions and
+    # that the effects of adding some H2 emissions change things
+    # now that we have the CH4 indirect effects implement.
+
+    hc <- newcore(ini)
+    run(hc)
+    d <- 1750:2100
+    out <- fetchvars(hc, dates = d,
+                     vars = c(EMISSIONS_H2(), CONCENTRATIONS_CH4(), CH4_LIFETIME_OH()))
+
+    new_val <- 10
+    setvar(core = hc, dates = d, var = c(EMISSIONS_H2()), values = rep(new_val, length(d)),
+           unit = getunits(EMISSIONS_H2()))
+    reset(hc)
+    run(hc)
+    out2 <- fetchvars(hc, dates = d,
+                     vars = c(EMISSIONS_H2(), CONCENTRATIONS_CH4(), CH4_LIFETIME_OH()))
+
+    diff <- abs(out$value - out2$value)
+
+    # Now we do expect to see changes in CH4 concentrations in response
+    # to H2 emissions
+    expect_gt(mean(diff[out$variable == CONCENTRATIONS_CH4()]), 0)
+    expect_gt(mean(diff[out$variable == CH4_LIFETIME_OH()]), 0)
+
+    # Since we are working off of some default H2 emissions = 0, then
+    # changing the H2 emissions we should see a difference.
+    expect_equal(mean(diff[out$variable == EMISSIONS_H2()]), new_val)
+
+    })
+
+