Where did English summer go?

August 22, 2007

What is a proper English summer? Should we really expect unfettered sunshine and months spent in the garden with our barbecues? Is it time to admit our climate is variable and the weather is hard to predict?

An expert in environmental change at The University of Nottingham says our knowledge is improving exponentially but there is still a long way to go. Teleconnections and feedbacks are critical in determining the operation of the climate system and the challenge for climate scientists is to understand the nature and scale of past natural variability - only then can we tease out what impact humans have had on the climate system and what the implications might be.

Professor Michele Clarke, from the School of Geography, points out that in April the U.K. Met Office published its summer forecast predicting that we could experience warmer temperatures than normal and warning that “periods of very hot weather” have “implications for people's health”. It has been warm, she says, but it has also been very wet and the Met Office admits that it could not have predicted the record breaking rainfall in June and July.

Professor Clarke said: “I don't blame the forecasters for getting it wrong but there is an important lesson here. The climate system is complex and varies at a range of spatial and temporal scales making predictions very difficult. If we have difficulties predicting the weather for tomorrow how can we realistically predict future climate? In order to improve our predictive abilities we need to improve our understanding of how the climate system works and how the feedbacks between the oceans, complex land surfaces and the atmosphere operate”.

We now know that our wet summer was caused by changes in the Pacific. It's all the fault of La Niña (part of the natural El Niño Southern Oscillation) in which abnormal cooling of Pacific ocean temperatures influences atmospheric circulation systems, deflecting the Atlantic jet stream southwards bringing low pressure systems and rain to us (instead of Iceland).

Professor Clarke suggests: “Citizens demonstrating against climate change at power stations and airports this summer could be premature in their concerns but the residents of Tewkesbury, who are campaigning against new housing developments on their floodplain, have a better case”.

Source: University of Nottingham