Weather blowing hot and cold
Scientists blame climate change for extreme temperatures
SINGAPORE — Deep freeze, heatwave, flash floods: What on earth is going on with the weather?
The new year has barely started and already extreme conditions are making headlines.
Record cold in the United States, severe flash floods in Singapore, a blistering heatwave in Sydney, record low temperatures in normally balmy Bangladesh, plus a severe cold snap across large parts of China. And now blizzards in Hokkaido, while just to the south, Tokyo basks in unusually mild winter weather.
With each passing year, the weather seems to become more extreme, breaking records and generating major headlines. And scientists say climate change is increasingly to blame.
That is because the planet’s atmosphere and oceans are heating up. Warmer air holds more moisture, bringing more rain and snow. Warmer oceans provide more fuel to power storms.
In short, climate change is giving the weather an extra kick and affecting atmospheric circulation, such as high-altitude jet streams, in ways scientists do not fully understand.
Evidence
There is strong evidence that climate change caused by burning fossil fuels and deforestation is increasing the intensity of heatwaves, droughts and coastal flooding.
Extreme heat and longer droughts also mean more severe bushfires in places such as Southeast Australia and California.
Leading climate scientist Michael Mann, professor of atmospheric science at Penn State University in the US, explained the link simply last year during a presentation published by Climate Reality.
“There are various ways in which climate change can make weather more extreme. Some of them are fairly obvious — if you warm up the planet, you’re going to have more frequent and intense heatwaves. Warmer planet, you’re going to have more extremely hot days. You tend to see more flooding events, because a warmer atmosphere can hold more moisture, so when it does rain or snow, you actually get more precipitation. The rain and snow falls in larger amounts, and that’s something we’ve seen as well in recent years,” Mann said.
A 2016 study by the United Nations’ World Meteorological Organization noted strong links to climate change exacerbating a severe summer in Australia in 2013 and Britain’s extreme floods in 2014.
Although it’s an island country, Singapore, too, will face more extreme conditions as the world warms.
Fire and ice
Experts expressed the concerns for Singapore would be more droughts and flash flooding, due to increased rainfall.
Government statistics already show a trend of increasingly intense rainfall over the years. The annual maximum hourly rainfall was 80 mm in 1980, and 90 mm in 2016.
The hottest years in Singapore also took place in the past decade. The year 2016 was Singapore’s hottest year, with the annual mean temperature rising to 28.4 C.
Sea levels, too, are rising around the island, which is why the government is raising the height requirement for new reclamations.
But what about the bitter cold snap in the eastern US?
Some scientists say climate change and cold spells, which occur when cold Arctic air dips south, may be related.
The Arctic is not as cold as it used to be and studies suggest this is weakening the jet stream, which ordinarily acts like a giant lasso, corralling cold air around the pole.
“There’s a lot of agreement that the Arctic plays a role, it’s just not known exactly how much,” The New York Times quoted Marlene Kretschmer, a researcher at the Potsdam Institute for Climate Impact Research in Germany, as saying. “It’s a very complex system.”
One thing is clear. As the world continues to warm and as more heat-trapping greenhouse gases are pumped into the atmosphere, expect more weather extremes, scientists say. It’s the new normal.