Contemporary and projected biogenic fluxes of methane and nitrous oxide in North American terrestrial ecosystems

Accurately estimating biogenic methane (CH 4 ) and nitrous oxide (N 2 O) fluxes in terrestrial ecosystems is critical for resolving global budgets of these greenhouse gases (GHGs) and continuing to mitigate climate warming. Here, we assess contemporary biogenic CH 4 and N 2 O budgets and probable climate‐change‐related impacts on CH 4 and N 2 O emissions in terrestrial North America. Multi‐approach estimations show that, during 1990–2010, biogenic CH 4 emissions ranged from 0.159 to 0.502 petagrams of carbon dioxide (CO 2 ) equivalents per year (Pg CO 2 eq yr −1 , where 1 Pg = 1 × 10 15 g) and N 2 O emissions ranged from 0.802 to 1.016 Pg CO 2 eq yr −1 , which offset 47–166% of terrestrial CO 2 sequestration (0.915–2.040 Pg CO 2 eq yr −1 , as indicated elsewhere in this Special Issue). According to two future climate scenarios, CH 4 and N 2 O emissions are projected to continue increasing by 137–151% and 157–227%, respectively, by the end of this century, as compared with levels during 2000–2010. Strategies to mitigate climate change must account for non‐CO 2 GHG emissions, given their substantial warming potentials.