A scorching heat wave in Europe and a spate of forest fires has re-ignited the debate over whether global warming can be blamed for an apparent increase in the world鈥檚 weird weather.
快猫短视频s agree that no one yet knows the answer to this question, but they point out that an increase in the number and severity of extreme events is exactly what their models of a warmer world predict.
鈥淭he weather we鈥檝e seen over the last few days is entirely consistent with what we鈥檙e likely to see over the next few decades,鈥� says John Turnpenny, at the Tyndall Centre for climate change research in Norwich, UK. 鈥淲e鈥檙e likely to see such a heat spell in London every year.鈥�
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Extreme weather conditions are affecting all parts of Europe.
- In the UK, meteorologists predict a fair chance that the country will record 100掳F (37.8掳C) for the first time this week, beating the previous record of 98.8掳F (37.1掳C) from August 1990.
- In Portugal nine people have been killed in the worst wave of forest fires in recent history. Western North America is also facing another bad year for burning forests.
- In Switzerland, melting ice has contributed to a record number of climbing accidents in the Alps.
- The heat in Germany has already cost agriculture more than 2002鈥檚 disastrous floods, while in Spain the price of chickens has soared as the heat reportedly killed more than a million birds.
Such weather events fit in well with climate models that predict the effects of global warming driven by rising levels of atmospheric carbon dioxide. The UK鈥檚 meteorological office, for example, says the UK is set to get warmer and drier.
By 2080 there will be, at worst, 50 per cent less rain than there was in the 1990s. Average summer temperatures are set to rise by up to 3.5 degrees, while temperatures swings will be wilder, with the top 10 per cent of daily highs soaring as much as 7 degrees.
Cause and effect
But scientists caution that just because extreme weather fits with model predictions, that does not prove that global warming is the cause.
鈥淧eople lump extreme events into one basket and use it to strengthen their arguments about climate change. But you can鈥檛 do that,鈥� says Simon Brown, a climate change expert at the UK鈥檚 Hadley Centre in Bracknell, Berkshire. 鈥淲e can鈥檛 say that one causes the other. We鈥檙e not at that point yet.鈥�
In July, the World Meteorological Organization warned that 鈥渆xtreme weather events might increase鈥�. But Ken Davidson, director of the World Climate Program and a contributor to the statement, says media reports linking such weather to climate change were overblown. 鈥淚t certainly isn鈥檛 clear at this point,鈥� he told 快猫短视频. 鈥淲e were very careful to use the word 鈥榤ight鈥�.鈥�
It is even difficult for researchers to say that there are more extreme events now than there were in the past, because there is no agreed-upon definition for the word 鈥渆xtreme鈥�, notes Brown. This makes it hard to compile reliable statistics.
Davidson adds that drawing up a list of weird weather events may look impressive, but must be carefully done to be meaningful: 鈥淭here鈥檚 always strange weather.鈥�
