With the help of satellite observations from 188 lakes worldwide, scientists at the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) have shown that the warming of large lakes amplifies their colour. Lakes which are green due to their high phytoplankton content tend to become greener in warm years as phytoplankton content increases. Clear, blue lakes with little phytoplankton, on the other hand, tend to become even bluer in warm years caused by declines in phytoplankton. Thus, contrary to previous assumptions, the warming of lakes tends to amplify their richness or poverty of phytoplankton.