Extreme weather is simply a weather condition which is significantly different from the usual weather pattern. The summer heat waves and cold winter spells over the last couple of months in Hong Kong are two examples of extreme weather. Other disruptive conditions across the globe include drought, flooding, massive tropical cyclones, etc.
Human-induced global warming has increased the number and strength of these extreme events. Heat-trapping greenhouse gases trigger droughts and wildfires. On the other hand, as our oceans get heated up, more moisture will be evaporated into the atmosphere. It increases the chance of massive downpour, leading to destructive floods. Global warming also creates more frequent and intense tropical cyclones, which are formed when high temperatures and high humidity meet.
Cold snaps in winters are in fact caused by global warming too. This may sound counterintuitive but scientists have discovered that melting ice has weakened the polar vortex, which is a large pocket of very cold air over the polar region. As a result, cold blasts break through the polar vortex, all the way down to the temperate and even sub-tropical regions of the Earth.
| JPC Monthly Newsletter | |
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