If ocean temperatures continue to rise, which process could lead to a rapid rise in atmospheric methane?

• A. Melting of clathrates on the ocean floor
• B. Increased methane oxidation in the atmosphere
• C. Decreased microbial activity in sediments
• D. Lower solar radiation absorption by the ocean

Answer: (A)

Rising ocean temperatures threaten the stability of methane hydrates on the seafloor. These hydrates are methane trapped in a lattice of water ice under high pressure and low temperature. When the water warms, the hydrates dissociate and release methane gas into the surrounding sediments and seawater. If a large amount reaches the atmosphere, methane acts as a very powerful greenhouse gas, potentially creating a positive feedback that drives a rapid rise in atmospheric methane. While some of this methane can be oxidized in the water or consumed by microbes, a rapid or substantial release could overwhelm these sinks and lead to more methane entering the air.

Other factors would work against a rapid rise: increased methane oxidation would remove methane from the atmosphere, not add to it; decreased microbial activity in sediments would reduce methane production; and lower solar radiation absorption by the ocean affects energy balance broadly but doesn’t directly trigger a significant methane release.