Climate News: Climate Change and Tropical Storms
- Proud Raksriaksorn
- Oct 2, 2024
- 4 min read
Tropical storms, also known as hurricanes, typhoons or cyclones depending on where you live, are formed in areas of low pressure and have a minimum wind speed of 63 km per hour. Rising ocean temperatures due to climate change are increasing the frequency, intensity and pattern of these storms, highlighting the need for urgent action and adaptation.
For the past year, ocean temperature records have been broken on a daily basis. As tropical storms are fuelled by the ocean’s heat, rising ocean temperatures are causing them to behave differently, changing their speed, course and making them more unpredictable and therefore more hazardous as well.
The change in temperature patterns across the year are also affecting the tropical storm season. Former climate and atmospheric scientist from the US National Oceanic and Atmospheric Administration (NOAA) James Kossin says, "Hurricanes themselves just respond to the environment that they're sitting in. And so if you make the environment in June look like the environment that would normally be in August or September, then the hurricanes will simply behave as though it's August or September. They don't have a calendar."
It is possible that tropical storm seasons may start earlier and last longer, although, due to a lack of sufficient data and clear trends, it is still too early to say for certain. What is certain was this year’s unusually early start to the season with Hurricane Beryl. Another worrying anomaly was observed in Hurricane Lee, a category 5 storm that struck Bermuda, the Northeast of the USA and Eastern Canada in September last year. The storm formed under conditions that supposedly should have prevented it from forming: there was an El Niño in effect during this time, which should have weakened it due to an increase in wind shear and atmospheric stability. The fact that Hurricane Lee still reached category 5, the strongest category, is incredibly concerning as this suggests that the extremely high temperatures last September (it is currently the hottest September ever recorded) could have possibly overpowered the El Niño’s stifling effects. Scientists are not entirely sure how this happened, underscoring the severity of climate change. If these trends persist, the future holds some grim implications.
Climate change has also been found to increase the peak intensity of tropical storms (their maximum strength). The International Panel on Climate Change (IPCC) says that the proportion of tropical cyclones of category 3 or higher is likely increasing. According to Hugh Willoughby, a research professor in earth and environment at Florida International University, the ocean surface temperature below a tropical storm determines the maximum potential intensity it can reach, and, when all the conditions are right, tropical storms can intensify very quickly. Furthermore, according to Kossin, there is overwhelming evidence to support the fact that the rate of tropical storm intensification is rising with ocean temperatures. This rise in temperature is, of course, largely due to climate change. Additionally, the water in our oceans isn’t just warming at the surface - the warming is also extending deeper and deeper underwater. Tropical storms churn the water they pass over, bringing cooler water to the surface which helps slow them down. However, tropical storms are now churning up warmer water, which intensifies them even more instead of weakening them.
Furthermore, tropical storms also appear to be slowing down. This is believed to be caused by the uneven heating of the planet, with the Arctic warming around 4 times faster than the rest of the Earth. This is reducing the temperature gradient in ocean waters, which affects wind speed. This can lead to tropical storms “stalling”, which is when they move slower over an area, remaining there for longer. This makes them more destructive due to more rain falling over the area and strong winds blowing for longer periods of time.
Sea level rise is also worsening the damage of tropical storms by allowing them to move further inland where they are most destructive. On average, storm surge waves have been getting roughly 3% higher every decade. Kossin recommends limiting development in coastal regions and adapting buildings and infrastructure to minimise damage as well as natural solutions such as planting grass (increases soil stability) and oyster reef restoration (helps absorb wave energy before they hit the coast and slows the rate of coastal erosion). Early-warning systems can also help safely evacuate people out of high-risk areas. "Adaptation is so important, and you know, may ultimately turn out to be the most important thing," he says, "Because we can't suddenly turn off climate change and have everything go back to the way it was. There's an inertia to the system that we can't really get past. And so adaptation is going to be a big part of it."
Technical terms used in this article:
Wind shear - the change in wind speed and direction at different heights, which disrupts the structure of a hurricane and makes it more likely to break apart
Temperature gradient - the difference in temperature per unit length
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