It’s not just the UK that has experienced extreme weather in recent months. Now the southern Japanese island of Kyushu has joined the club of locations experiencing wild weather this year. Over the weekend, parts of the island received 100mm of rain per hour, experiencing a whole year’s rain in one weekend, flooding from which killed at least 28 people. Rescue teams are searching for six people reported missing. Add to this, the record breaking spell of hot weather and drought that has hit the US over recent weeks and the some of the wettest weather in recorded British history and you have yet more evidence of our changing climate. And it’s not just a question of miserable or uncomfortable weather. The US Department of Agriculture has forecast a spike in food prices as farmers struggle to maintain typical yields from their parched fields. The warnings have already led to a 30% increase in the price of corn, that staple of Midwest farms and whose cost impacts on the price of meat, bread and breakfast cereals. Farmers in the UK are increasingly reporting that they are losing the battle against the persistent and heavy rains that have fallen on the UK for four straight months. Whole crops have been lost through flooding and waterlogging with entire crops of potatoes, spinach and chard ploughed back into fields. Those crops that haven’t been ruined are mostly late and patchy with imports making up the shortfall in produce that would normally be supplied domestically. Fruit hasn’t fared much better with many of the UK’s traditional growing areas experiencing the feared late cold snap that inhibits the setting of the blossom required for the fruit to form. The heavy rains are already causing cherries to split, lowering their value. On top of the double-dip recession, UK businesses and households have had to contend with the wettest April ever together with the wettest April-June quarter ever. Now it seems certain that food inflation will soar through the second half of 2012. So now we can add farmers to the tourism industry on the list of business badly affected by the UK’s rains.
So what is causing this? Traditionally, climate scientists have been reluctant to pin the blame for individual events or runs of extreme weather on climate change but some are now coming out and saying that this year’s record-breaking weather is likely to be the result of climate change. A neat analogy that I heard recently though helps to explain the influence of climate change. It goes like this “Imagine that a top baseball player begins taking steroids. He hits many more home runs than usual but it’s impossible to say whether any individual home run was hit because of his use of steroids.” So it is with our climate. The increasing emission of greenhouse gases is leading to more frequent and more severe extreme weather but it’s still very difficult to say that any individual event was caused solely by climate change.
At Original Carbon, we have been saying for several years now that the UK has developed a summer Monsoon season. Each July for the past 6 years (including this one already) has produced more rain than the long-term monthly average, some by more than 100%, so a pattern is beginning to be set. Why is this? It is fairly well-known that the succession of wet summers the UK has experienced over the last 6 years is likely to be caused by a shift in the course of the Atlantic Jet Stream, a ribbon of high-speed, high altitude winds. These winds demarcate regions of warm and cold air. In the case of the Atlantic Jet Stream, regions to the south of the Jet Steam tend to have more settled, dry, anticyclonic weather than the cooler, wetter areas to the north. More typically, the Jet Stream runs to the north of the UK but in recent years, it has moved much further south, this year stationing itself over central France. One possible explanation for this comes from Dr Peter Stott, Head of Climate Monitoring and Attribution at the Met Office’s Hadley Centre. He postulates that major reductions in the quantity of Arctic sea ice may be causing the Jet Stream southerly move. Whatever the cause, the medium-term forecasts don’t show any relief from the rain in the UK.