Methane fluxes show consistent temperature dependence across microbial to ecosystem scales

Area of Science:

• Environmental Science
• Microbiology
• Climate Science

Background:

• Methane (CH4) is a potent greenhouse gas, contributing significantly to global warming.
• Understanding ecosystem CH4 emissions under rising temperatures is crucial for climate change prediction.
• Methanogenesis, the process of CH4 production, is temperature-dependent but its ecosystem-level response is complex.

Purpose of the Study:

• To determine the temperature dependence of ecosystem-level CH4 emissions.
• To compare the temperature sensitivity of CH4 emissions with other carbon cycle fluxes like respiration and photosynthesis.
• To assess the potential impact of rising temperatures on CH4 and CO2 emissions from various ecosystems.

Main Methods:

• Meta-analysis of seasonal CH4 emission data from diverse ecosystems.
• Comparison of observed temperature dependence with pure culture methanogenesis data.
• Analysis of CH4 to CO2 emission ratios across temperature gradients.

Main Results:

• Ecosystem CH4 emissions show a strong average temperature dependence (0.96 eV), a 57-fold increase from 0-30°C.
• This temperature sensitivity is substantially higher than that of respiration (0.65 eV) and photosynthesis (0.3 eV).
• Both CH4 emissions and the CH4 to CO2 ratio increase significantly with seasonal temperature rises.

Conclusions:

• Ecosystem-level CH4 emissions exhibit a higher temperature sensitivity than other major carbon cycle processes.
• Global warming may disproportionately increase CH4 contributions to greenhouse gas emissions from key ecosystems.
• Findings highlight the critical role of temperature in regulating CH4 fluxes and their climate impact.