Lakes, with their rich biodiversity and important ecological services, face a concerning trend: rapidly increasing temperatures. A recent study published in Nature Geoscience by an international team of limnologists and climate modelers reveals that if current anthropogenic warming continues until the end of this century, lakes worldwide will likely experience pervasive and unprecedented surface and subsurface warming, far outside the range of what they have encountered before.
The study uses lake temperature data simulated by a state-of-the art climate computer model (Community Earth System Model, version 2) covering the period from 1850-2100 CE. It is the first model of its kind, which captures the dynamics and thermodynamics of lake systems in an integrated way with the atmosphere. Rather than running the computer model into the future only once, the scientists used an ensemble of 100 past-to-future simulations, which were run on one of South Korea’s fastest computers (‘Aleph’ at the Institute for Basic Science). Each simulation generates a slightly different realization of natural climate variability while it also responds to the anthropogenic warming effects from increasing greenhouse gas concentrations. With this ensemble modelling approach, the scientists were able disentangle the range of naturally occurring lake temperature variations from those caused by human interference (Figure 1). This allowed the team for the first time to estimate the time when lake temperatures will permanently exceed natural bounds – a situation referred to as no-analogue conditions. READ FULL ARTICLE