A new large-scale analysis of lake temperatures provides further evidence of some of the seasonal changes caused by climate change.
The research paper (in) uses lake temperature data, both historical and modelled to look at when typical spring or autumn conditions occur in lakes worldwide, to show exactly how much the seasons have shifted in different regions of the world and estimate how seasons will change in the future.
Since 1980, spring and summer temperatures in Northern Hemisphere lakes have arrived earlier (2.0- and 4.3-days per decade, respectively), whilst the arrival of autumn has been delayed (1.5-days decade) and the summer season lengthened (5.6 days per decade). This century, under a high-greenhouse-gas-emission scenario, current spring and summer temperatures will arrive even earlier (3.3- and 8.3-days per decade, respectively), autumn temperatures will arrive later (3.1-days per decade), and the summer season will lengthen further (12.1-days per decade).
While we may all welcome an early spring and a long warm summer, that reaction would be simplistic. The results can have catastrophic effects for the natural world. Within the lakes themselves, aquatic species respond to thermal cues triggered by the lake temperature. In a stable climate, seasonal events such as spawning will occur at the same time and coincide with other events, which might provide a food source for example.
Dr Iestyn Woolway of 亚洲色吧鈥檚 School of Ocean Sciences is a leading authority in this field and his latest paper builds on previous research by developing a new methodology to look at seasonal shifts in lakes worldwide. Similar work exists for air temperatures and for oceans, but this is the first to look at the world鈥檚 vital freshwater bodies which sustain the environment and provide for our own needs.