PNNL

Abstract

Millions of lakes around the world inversely stratify during winter. Seemingly subtle variations in the duration of winter stratification can have major ecological effects by, for example, altering the vertical distribution of oxygen and nutrients in the water column. Yet, the influence of climate change on winter stratification has been largely unexplored. To fill this major knowledge-gap, here we used a lake-climate model ensemble to investigate changes in winter stratification across Northern Hemisphere lakes from 1901-2099. Under the high-greenhouse-gas-emission scenario, our projections suggest that winter stratification will last 52.7±19.8 days shorter by the end of the 21st century compared to the historic period. Projected changes are faster in warmer geographical regions, in which 69% of lakes will no longer inversely stratify by 2070-2099. It is likely that the shortening and loss of winter stratification will have numerous implications for lakes, including the misalignment of lifecycle events causing shifts in biodiversity.