As September ended with extraordinary scenes of an Indian Summer sweeping England, we were literally living in record-breaking times. Temperatures as high as 29.9 °C smashed records for four consecutive days, three of which had been held for over a hundred years. Britain’s newspapers printed front pages showing beach-goers sweltering in huge crowds, and summery scenes in parks nationwide – but though stories of the UK’s heatwave were being printed alongside news of extreme flooding in Cambodia and hurricane warnings over the Atlantic, none broached a difficult question: was this another example of an extreme weather event, and could it be attributed to climate change?
“Scientists are wary of attributing any one specific weather or climate event to climate change, although they are getting more vocal about the trends in temperature and rainfall changes and how those link to climate change,” says Rob Sassor, whose Conservation Leadership MPhil thesis focused on how environmental issues are reported in the media. “This issue is tricky because ‘climate’ and ‘weather’ are somehow synonymous in the minds of the general public, but it’s not that simple.”
Links between extreme weather events that occur over short periods of time and longer term changes in climate due to human influence have been stressed by activists such as Al Gore, but this approach has led to criticism from scientists such as Myles Allan, the head of the Climate Dynamics Group at the University of Oxford. The science behind quantification of the influence of humans on the risk of extreme weather incidents is complex, and while anthropogenic influence is heavily blamed in some instances, it is not implicated at all in others. According to studies, greenhouse gas emissions increase the likelihood of certain events, but decrease the probability of others, sending mixed messages to the public and creating a challenging environment for environmental campaigners.
As a County Councillor and intern at Fauna and Flora International, Sarah Whitebread has experience of the difficulties of communicating environmental issues to the public. “If whenever we have a heat wave we start saying “Look! It’s Global Warming!” then whenever we get a cold snap in spring all the climate sceptics say “Global Warming - what a load of nonsense.” We clearly can’t base our arguments on one offs like that.”
Analysis of data gathered by the University’s Weather Station suggests that the autumnal heat wave we have seen this October is indeed something of a “one off”, and not indicative of a pattern of increasing temperatures. Average monthly temperatures recorded in October for the past sixteen years show that while this month so far has been unusually hot, there has been no increase in average October temperatures from 1996. Similarly, peak summer temperatures also show no pattern of increase, with July averages fluctuating around a mean of 18 °C.
October’s spike in temperature may have been an anomalous weather phenomenon, but this month’s heat was preceded by an unusually dry summer. 2011 will go down as a year of drought in the UK and many other countries, suggestive of longer-term changes in climate that may be cause for concern. After Britain saw the driest March in fifty years, no-one was more affected than the UK’s farmers. Roland Randall runs Monach Farm near Hilton, Cambridgeshire, a traditional livestock farm stocking cattle, pigs, sheep and poultry, as well as internationally renowned pedigree dairy goats. He estimates that this year’s drought cost him around six thousand pounds. “We had to take livestock off pasture 3 months earlier than normal, so feed cost more as we had to buy in concentrates. We could not source our winter hay locally so had to buy in from Bristol at 50% more than last year, plus haulage.”
Furthermore, Randall noticed changes in the flora and fauna on his farm. “We noticed breeding birds were out of sync with the main phase of insect abundance and several species including owls had a later brood once conditions improved in July.” The effects of such warm spells on animal and plant life may be severe. However, although reports such as Randall’s have suggested that bird breeding times may be affected, and migratory birds are being sighted after their normal period of departure for warmer climes, Dr Michael Brooke, Curator of Ornithology in the University Museum of Zoology, is sceptical that the heatwave will have long-lasting impacts.
“In so far as the English October record was broken, the weather was certainly unusual,” he says. “But frankly, a week of warm weather isn’t beyond birds’ physiological tolerance, so in terms of whether it will affect bird populations – probably not.” However, work conducted by his students has detected changes in the first appearance dates of hoverflies in conjunction with warming trends. Insects have first appeared earlier as the Springs have become warmer, trends that match those seen in a number of other species, and that strongly suggest long-term changes in the UK’s seasonal temperatures.
Although the British media largely chose not to invoke climate change arguments in their coverage of the October heatwave, do students find their attitudes to global warming altered by the unseasonable heat? “I do think the heat is related to global warming – and my conviction is strengthened due to other recent uncharacteristic weather patterns,” says Kathryn Noonan, a student from Massachusetts. “When I was younger we prayed for snow and it hardly ever came - now there are multiple blizzards. Summer is also hotter, so hot that it was nearly unbearable the whole time I was there in September, when by rights it should be cooling down, not maintaining heat wave standards.”
Dr Ben Phalan from the Department of Zoology’s Conservation Science Group again draws the key distinction between individual weather events and changes in climate patterns in his summation of what the heatwave means. “As an individual event, it doesn’t make much difference to my belief that climate change is a real and important problem. Extreme weather happens. It’s when such events stack up into long-term trends that we should pay attention to them.”
article here (page 24)