Tue, Aug 16, 2022: 5:00 PM-6:30 PM
ESA Exhibit Hall
Background/Question/MethodsIncreased greenhouse gas emissions are causing unprecedented climate change, which is, in turn, altering the production and consumption of methane (CH4) in terrestrial ecosystems. Previous manipulation experiments have improved our understanding of the impact of climate change on soil CH4 fluxes; however, these responses varied widely between experiments (including positive, null, and negative responses). At present, it is still unclear in the comprehensive response of soil CH4 fluxes (that is, methane uptake and emissions) from natural terrestrial ecosystems to various warming and precipitation scenarios. Here, we synthesize 730 observations of in situ soil CH4 flux data from the past three decades related to temperature and precipitation changes across major terrestrial ecosystems worldwide.
Results/ConclusionsMeta-analysis reveals that warming (ranging from +0.1°C to +11°C) and decreased precipitation (ranging from −60% to −7% of local mean annual precipitation) not only stimulate soil CH4 uptake from natural uplands but also promote soil CH4 emission from natural wetlands. Increased precipitation (ranging from +4% to +94% of local mean annual precipitation) also stimulates soil CH4 emission from natural uplands. Climate change is estimated to add 11.14 ± 0.42 Tg CH4 yr–1 as an additional global CH4 source, with natural uplands and natural wetlands contributing 4.43 ± 0.36 Tg CH4 yr–1 and 6.71 ± 0.07 Tg CH4 yr–1, respectively. A global positive effect of climate change on CH4 emissions was mainly attributed to increased CH4 emissions from natural terrestrial ecosystems. Although an increased CH4 uptake by forest and grassland soils caused by increased temperature and decreased precipitation can offset some of these additional CH4 sources, the substantial effect of increased precipitation on CH4 emissions makes these sinks insignificant. Our meta-analysis strongly suggests that climate change will weaken the natural buffering ability of terrestrial ecosystems on CH4 fluxes and thus contribute to a positive feedback spiral.
Results/ConclusionsMeta-analysis reveals that warming (ranging from +0.1°C to +11°C) and decreased precipitation (ranging from −60% to −7% of local mean annual precipitation) not only stimulate soil CH4 uptake from natural uplands but also promote soil CH4 emission from natural wetlands. Increased precipitation (ranging from +4% to +94% of local mean annual precipitation) also stimulates soil CH4 emission from natural uplands. Climate change is estimated to add 11.14 ± 0.42 Tg CH4 yr–1 as an additional global CH4 source, with natural uplands and natural wetlands contributing 4.43 ± 0.36 Tg CH4 yr–1 and 6.71 ± 0.07 Tg CH4 yr–1, respectively. A global positive effect of climate change on CH4 emissions was mainly attributed to increased CH4 emissions from natural terrestrial ecosystems. Although an increased CH4 uptake by forest and grassland soils caused by increased temperature and decreased precipitation can offset some of these additional CH4 sources, the substantial effect of increased precipitation on CH4 emissions makes these sinks insignificant. Our meta-analysis strongly suggests that climate change will weaken the natural buffering ability of terrestrial ecosystems on CH4 fluxes and thus contribute to a positive feedback spiral.