Cooley_et_al_data__Agg_Nov2024_dP.csv

<b><i>A global 'climate opportunity benefit' of regeneration: meta-analysis shows warming from soil CH</i></b>_{<i><strong>4</strong></i>}<b><i> and N</i></b>_{<i><strong>2</strong></i>}<b><i>O is small in forests relative to agriculture</i></b>Savannah S. Cooley^1*, Elisabeth Moore¹, Jianna Martinez¹, Jocelyn Fahlen¹, Erin Maybach¹, Maya Gollerkeri¹, Anjali Rao Vasa¹, Sian Kou-Giesbrecht², Alexandra M. Huddell³, Linnea Norton¹, Kerry Cawse-Nicholson⁴, Ruth DeFries¹, Maria Uriarte¹, Duncan N.L. Menge¹¹ Department of Ecology, Evolution and Environmental Biology, Columbia University² Department of Earth and Environmental Sciences, Dalhousie University³ Department of Department of Plant and Soil Sciences, University of Delaware⁴ NASA Jet Propulsion Laboratory, California Institute of Technology<br>* Corresponding author: [e-mail]<b>Abstract</b>Global assessments of ecosystem regeneration as a climate mitigation strategy have traditionally focused on CO₂, despite the acknowledgement that methane (CH₄) and nitrous oxide (N₂O) are also important greenhouse gasses (GHGs). We conducted a meta-analysis of studies that measured soil CH₄ and N₂O fluxes in unmanaged regenerating forested and savanna ecosystems, with a focus on understanding biome-specific differences in these GHG fluxes compared to a counterfactual of agricultural land use. We expected most regenerating ecosystems to act as small CH₄sinks and relatively larger N₂O sources, with a net warming combined CH₄-N₂O effect. Three of the five forested biomes we studied followed this pattern: subtropical/tropical forest, subtropical/tropical savanna and temperate conifer forest (0.98 ± 0.44, 0.23 ± 0.07, and 0.63 ± 0.37 Mg CO₂e ha^-1 yr^-1, respectively). Results suggest that even after 100 years of regeneration, the radiative cooling of the climate from CO₂ sequestration still exceeds the radiative warming driven by the net CH₄-N₂O effect among all ecosystems on average globally. We also found that the “climate opportunity benefit” of ecosystem regeneration—the difference of the net CH₄-N₂O effects of agriculture vs. regeneration—yields a net cooling effect for all biomes. However, our results underscore that it is unsound to use ecosystem regeneration as a justification for the continuation of fossil fuel emissions.