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CLAIM
Climate Change has no impact on hurricanes like Ian.
FACT
Climate Change supercharges hurricanes like Ian. In case of Hurricane Ian, climate change amplified rainfall by more than 10%.
WHAT THEY SAY
Climate deniers are saying that climate change has no connection with or impact on hurricanes like Ian. They claim that such hurricanes have occurred even in the past and Ian is no different. They further say that the claim of climate change impacting hurricanes like Ian is a hoax. These claims mostly come under the larger claim that climate change itself is a hoax. We found various such claims/posts on social media.
WHAT WE FOUND
Climate change no longer seems to be a distant thing to the world. It is getting manifested in various forms in an increasingly warming world. We are witnessing erratic rainfall patterns, unlikely droughts, heatwaves and wildfires because of climate change across the world. It seems now that hurricanes too are getting amplified because of climate change.
The recent hurricane ‘Ian’ has been now termed as one of the five most powerful hurricanes in recorded history to strike the United States. It has, in fact, tied with Hurricane Charley of 2004 as the strongest-ever hurricane to hit Florida’s west coast.
Climate Change amplified Ian’s rainfall by 10%
We found out that climate change has definitely amplified the impact of hurricanes like Ian. Keeping aside other impacts like strength, intensification and sea-level rise, even just from the angle of hurricane-induced rainfall, it was scientifically found that climate change made Ian’s most extreme rainfall about 10% worse than it would have been without climate change. Two US climate researchers, Michael Wehner of the Lawrence Berkeley National Laboratory and Kevin Reed of Stony Brook University, through an analysis, found this just after Hurricane Ian.
The researchers ‘compared peak rainfall rates during the real storm to about 20 different computer scenarios of a model with Hurricane Ian’s characteristics slamming into Florida in a world with no human-caused climate change.’ They found out that the real storm was 10% wetter than the storm that might have been without climate change.
Wehner and Kevin Reed published a study in Nature earlier this year on the hurricanes of 2020. They found that the rainiest three-hour periods of the hurricanes of 2020 were more than 10% wetter than in a world with no human-induced climate change. They have now applied the same attribution technique in case of Hurricane Ian to find out that climate change amplified Ian’s rainfall by 10%.
The Physics behind it
Simple physics tells us that for every degree Celsius rise in temperature, air in the atmosphere can hold about 7% more water vapor. So the amount of moisture that evaporates from the ocean into the atmosphere increases about 7% for each 1 degree Celsius of ocean surface warming. This phenomenon helps scientists to analyze how much hurricanes like Ian have got rainier because of warming by greenhouse gas emissions. What is crucial here is the fact that stronger storms can draw even more moisture into them.
Climate Change supercharges Hurricanes
Presidential Distinguished Professor in the Department of Earth and Environmental Science at the University of Pennsylvania, Michael Mann, said in an interview that there is no question of doubt in his mind or in the mind of most of the scientists that climate change supercharges hurricanes like Ian.
Professor Mann said, “The warmer these oceans and the deeper those layers of warm water, and that’s one of the things we are seeing with the warming of the planet, heat penetrates deeper into the oceans and when the hurricanes churn up those deeper water, they are still warm.”
The distinguished professor explained that with an increasingly warmer world, heat is penetrating deeper into the oceans which in turn is intensifying hurricanes and storms.
“They don’t dampen the hurricane as they used to. So, we are seeing more intense storms, we are seeing greater storms, as you allude to rapid intensification where these storms can balloon from a relatively weak tropical storm to a hurricane and then to a major hurricane in just a matter of one or two days,” Mann further said in the interview.
Hurricanes are moving slowly because of Climate Change
While the major focus in case of discussing and analyzing the impacts of climate change on hurricanes has been about the picking up of heat and moisture as they churn over the ocean, studies have now pointed out the fact that hurricanes are increasingly moving slower after making landfall because of climate change.
A slow-moving tropical cyclone or hurricane will dump much more rain in one place than a similar fast-moving one. The winds will also hit against structures longer and can do more damage. Scientists found that this is giving hurricanes a greater opportunity to strengthen and destroy.
According to a study published in Nature, a typical storm, 50 years ago, would have lost more than three-quarters of its intensity in the first 24 hours but now its intensity would only be half lessened causing them to weaken more slowly and remain destructive for longer.
The researchers of the study, Lin Li and Pinaki Chakraborty of the Okinawa Institute of Science and Technology Graduate University in Japan, analyzed data from North Atlantic hurricanes making landfall between 1967 and 2018. They found that warmer ocean temperatures because of global warming are causing the storms to weaken more slowly, even after moving away from the source of the moisture.
Another study published in Science saw a ‘marked slowdown of tropical cyclones as the world warms, due to a poleward shift of the mid-latitude westerly winds.’ The researchers ran about 100 high-resolution simulations about the behaviour of tropical cyclones in three types of conditions: between 1950 and 2000, the present and various future scenarios.
The study found that anthropogenic warming could slow down tropical cyclones near populated mid-latitude regions in Asia and North America.
[…] Also, read this in English […]