Here is an article I wrote for the December edition of the Dorset-based Marshwood Vale Magazine considering whether the recent awful summer weather could be a reflection of climate change.
Summer this year was the wettest for a century and Dorset experienced some particularly heavy downpours early in the season. Rainfall at Portland and at Hurn in the first ten days of July was nearly three times the normal monthly average. Several rivers burst their banks and towns were flooded including Bridport and Burton Bradstock. Devon was also badly affected and Modbury, Ottery St Mary and Yealmpton were inundated. The torrential rain in Dorset caused a landslip at the Beaminster Tunnel where two people died. The rain also undermined the cliffs on the Jurassic Coast leading to a 400 ton rock fall that killed one person near Hive Beach.
Our notoriously changeable weather depends on many factors but this summer it has been dominated by the Jet Stream. This is a band of fast moving winds running eastwards across the Atlantic high up in the atmosphere separating cooler northerly air and warmer southerly air. The Jet Stream is important for our climate as it guides Atlantic weather systems bringing rain and unsettled conditions. In a typical summer the Jet Stream lies to the north of the UK shielding us from these weather systems and bringing milder, settled conditions. This summer, the Jet Stream lay below the UK so the weather was cooler and wetter and because it did not move, this pattern persisted for several months.
The position of the Jet Stream could simply be a result of natural variation and most of us will shrug our shoulders and blame the awful summer of 2012 on “bloody British weather”. We do, however, live in a world where changes in conditions in one part of the globe may affect the weather in another part. Some climate scientists are beginning to wonder if the weather in Europe is being influenced by changes in sea ice many miles away in the Arctic.
At the North Pole there is a large mass of pack ice formed from sea water in this very cold part of the world; this is the Arctic sea ice. The size of this ice pack varies by season, partly melting in the warmer months and then refreezing as the cold returns. There has been a long term trend towards less ice in the warmer months and this reached a record low in September 2007. Slightly more summer ice was seen in subsequent years but in 2012 the record was broken again; the level of Arctic summer ice was the lowest since records began. This had not been expected and scientists were surprised and shocked by the extent and speed of Arctic sea ice loss. If, as seems likely, the loss continues, summer sea ice will disappear altogether from the Arctic some time this century. This represents a major change to the planet that should concern us all.
One of the principal drivers of this major change in the North Polar ice cap seems to be global warming; as the sea temperature increases so the ice melts more. Much of this effect on the polar ice can be attributed to human activity; burning of fossil fuels (e.g. coal, gas, petroleum) raises levels of the greenhouse gas, carbon dioxide, causing warming. Loss of such a large amount of sea ice has major effects on the planet. Most importantly, loss of the ice accelerates warming of the sea; the sun’s rays are no longer reflected away by the ice and the heat is absorbed by the sea. This is very serious for the stability of the climate.
There is also an indication that loss of the sea ice affects the position of the Jet Stream and makes it stay in one place longer. In consequence, weather patterns are maintained for longer; periods of wet weather may lead to floods and periods of dry weather may generate drought. These changes are compounded in that a warmer atmosphere holds more moisture leading to heavier rain. The loss of Arctic sea ice may, therefore, have contributed to our poor summer and we may now be experiencing the effects of climate change in the UK.
The unexpectedly large and continuing loss of the polar ice cap should be a major wake-up call to governments that the planet is changing. We are all beginning to feel the effects. The solution is clear, we must reduce use of fossil fuels; this will not reverse the changes but may slow them down. Unfortunately, governments still look on with disbelief and do nothing. It is a disgrace that climate change did not feature at all in the recent US presidential debates, especially when the US is one of the major users of fossil fuels. Perhaps the devastation wrought by Hurricane Sandy will make the US think again about extreme weather events.
But it gets worse. The response of industry to the melting of the Arctic ice has been to see opportunities for trade. Oil, gas, mining and shipping companies are rushing to expand operations in the Arctic as the ice recedes and new sea routes open up. This has the potential for environmental catastrophe as well as leading to greater emission of carbon dioxide and acceleration of climate change.
Let’s finish by quoting Bill McKibben, the environmental campaigner, on the loss of Arctic sea ice: “Our response (so far) has not been alarm, panic or a sense of emergency. It has been “Let’s go up there and drill for oil”. There is no more perfect indictment of our failure to get to grips with the greatest problem we’ve ever faced”.