Global lake thermal regions shift under climate change

Abstract

Water temperature is critical for the ecology of lakes. However, the ability to predict its spatial and seasonal variation is constrained by the lack of a thermal classification system. Here we define lake thermal regions using objective analysis of seasonal surface temperature dynamics from satellite observations. Nine lake thermal regions are identified that mapped robustly and largely contiguously globally, even for small lakes. The regions differed from other global patterns, and so provide unique information. Using a lake model forced by 21 st century climate projections, we found that 12%, 27% and 66% of lakes will change to a lower latitude thermal region by 2080-2099 for low, medium and high greenhouse gas concentration trajectories (Representative Concentration Pathways 2.6, 6.0 and 8.5) respectively. Under the worst-case scenario, a 79% reduction in the number of lakes in the northernmost thermal region is projected. This thermal region framework can facilitate the global scaling of lake-research.

Effect of climate warming on a change in thermal and ice conditions in the largest lake in Poland – Lake Śniardwy

“…Further perspectives of changes in thermal regime of lakes point to their continuous warming. Based on climatic forecasts from the 21 st century, Maberly et al (2020) determined that by 2080-2099, many lakes will be transformed into a thermal region with a lower latitude. Detailed data concerning the territory of Poland are presented by Czernecki and Ptak (2018), predicting changes in water temperature by the end of the 21 st century.…”

Global lake responses to climate change

“…Most global studies of LSWT responses to climate change focus on summer observations in temperate and high latitude regions, and winter observations in the tropics, partly because of obscuration of satellite retrievals by tropical clouds during summer or because a large proportion of lakes in northern latitudes are frozen during winter. We could, therefore, be missing impor tant changes that are taking place in other seasons 44,[58][59][60] , which merits future study.…”

Deeper waters are changing less consistently than surface waters in a global analysis of 102 lakes

“…The suite of lakes spans a wide range in location, elevation, water quality, trophic status, and morphometry, with high representation of globally-dominant small lakes 29 (45% with surface area ≤ 5 km 226 , 32% with maximum depth ≤ 20 m). We classified these lakes based on lake thermal region 30 to characterize the nature of this dataset and to analyse its global relevance for predicting trends in lake thermal structure. Lake thermal region is a global classification system based on seasonal dynamics of lake surface temperature, and thereby implicitly integrates other factors like location and elevation 30 .…”

“…We classified these lakes based on lake thermal region 30 to characterize the nature of this dataset and to analyse its global relevance for predicting trends in lake thermal structure. Lake thermal region is a global classification system based on seasonal dynamics of lake surface temperature, and thereby implicitly integrates other factors like location and elevation 30 . Lake thermal region is not closely linked to air temperature trends or other terrestrial-based or ecoregion-derived classification systems, which indicates that the drivers of changes in lakes, including lake thermal structure, are likely different from those for terrestrial-or vegetation-based ecosystems.…”