 Abstract lake ecosystems are highly sensitive to changes in seasonal temperatures which can lead to significant shifts in the timing of key events such as breeding and feeding. In recent decades, these seasonal temperatures have shifted earlier in the northern hemisphere, resulting in longer summers and shorter winters. Under a high emission scenario, this trend is expected to continue, with spring and summer temperatures arriving earlier still, autumn temperatures arriving later, and the summer season extending further. These changes could have positive effects for some species, but negative consequences for others due to phenological mismatches between key life stages. This article was authored by our ISD in Norway.