Marine biomass decline due to climate change
The negative effects of climate change on the distribution and abundance of marine organisms, and the ecological and economic consequences of such impacts are already being documented. However, the full extent of these changes under future warming has been difficult to predict due to the limitations of the individual ecosystem models used.
A group of international researchers used for the first time a comparative and standardized approach of six global marine ecosystem models forced with two Earth system models and four emission scenarios with and without fishing. This model ensemble reveals that global marine biomass will decline under all emission scenarios, largely because of increasing temperatures and subsequent decrease in primary production. The analysis also suggests that this biomass loss disproportionately impacts top predators, meaning that marine mammals and economically important fish may show a particular vulnerability to climate-driven effects.
Marine biomass will be more affected in lower latitudes, where marine ecosystems already suffer from cumulative anthropogenic impacts, and where people highly depend on seafood supply. The research shows that achieving zero hunger by 2030 will require the development of adaptive resource management to climate change and drastic global emission reductions.
Keike K. Lotze et al. 2019. Global ensemble projections reveal trophic amplification of ocean biomass declines with climate change https://www.pnas.org/content/early/2019/06/10/1900194116
