Climate change and extreme weather from the UK to Greenland – some thoughts and surprises – and reflections on recent changes in the Greenland Ice Sheet. With Edward Hanna, School of Geography.
Climate Change Research Seminar, Wednesday 22nd November, 11am, Junxion Building JUN0003
Recently there has been a significant increase in some types of extreme weather over the UK and other northern mid-latitudes: for example winters 2013/14 & 2015/16 in the UK were exceptionally mild, wet and stormy, while a large part of winter 2010-11 was unusually cold and had record deep snows.
Snowmageddon hit the eastern seaboard of the USA in the last few winters. Meanwhile several recent summers, most notably 2007 and 2012, experienced record UK rainfall and widespread flooding. These extreme events are closely related to recently-observed shifts in the eastward-moving atmospheric jet stream over the North Atlantic, where the jet has at times become slower moving with more north-south meanders exchanging air masses between mid- and high-latitudes. For example, warm air moving much further north than normal over west Greenland in summer 2012 caused a record surface melt and mass loss of the Greenland Ice Sheet.
These changes may partly be driven by the major reduction in Arctic sea-ice cover and amplified warming that has occurred in high northern latitudes over the last decade. Global warming is not a uniform process – as is seen through recent erratic temperature rises in the UK, Iceland and Greenland – and is prone to spring surprises through some subtle but high-impact changes in mid-latitude extreme weather.
We will also review recent changes in the Greenland Ice Sheet mass balance, where the latter is a major contributor to Twenty First Century global sea-level rise.