The worst rainstorm since 1884

Overnight, Hong Kong suffered through the heaviest rainstorm since 1884. Just last week, the city was blasted by a Tropical Cyclone rated locally as a level 10 Typhoon, the strongest and most dangerous signal in terms of public safety.?

So what’s going on? Physics. Here's how it works:?

• As the atmosphere warms, it can hold more water vapor. This means that tropical storms have more water to draw on, which can lead to heavier rainfall and flooding.
• Warmer sea temperatures keep the air directly above it warmer too, which encourages the movement of air, especially in low atmospheric pressure environments (wind is essentially the movement of air).
• Warmer air is also less dense, which allows storms to develop and intensify more easily.

In a nutshell, The Earth's warming atmosphere is leading to more intense and frequent tropical storms.?

The impacts of more intense and frequent tropical storms cannot be ignored.

Typhoon Mangkhut which ripped through Hong Kong in 2018 caused damage estimated at US$590 million. 2022’s Hurricane Ida caused at least 100 deaths and billions of dollars in damage in the USA. Additionally, sea level rise is making coastal areas more vulnerable to storm surge, which is the flooding that occurs when a storm pushes water onto land.

As global warming continues, we can expect to see more extreme weather events, including more intense and frequent tropical storms. The scientific evidence for the link between global warming and tropical storms is strong. A study published in the academic journal Nature found that the frequency of Category 4 and 5 hurricanes in the US has increased by 30% since the 1970s. Another study, published by the National Center for Atmospheric Research forecasts continued weather extremes, resulting in greater geo-social inequities as a result of intensifying storms.

This is a serious threat to human health and safety, as well as to the environment.

What can we do about it?

We need to take individual and collective action. There are a number of things we can do to reduce our impact on global warming and help to mitigate the risks of more intense and frequent tropical storms. These include reducing our reliance on fossil fuels and transitioning to clean energy sources, and finding ways to plant more trees and other vegetation in a sustainable manner to help increase absorption of carbon dioxide from the atmosphere.

As social animals, we must also act to help protect those most at risk in our communities - and that includes our future generations - from the devastating impacts of more intense and frequent tropical storms.