Here’s what we know about how climate change is fueling hurricanes
When Hurricane Ian hits Florida, it’s American most powerful hurricane It followed two consecutive weeks of devastating storms around the world on record.
In the Philippines a few days ago, Typhoon Nauru It gave rapid intensification new meaning the next day when it burst from a tropical storm with 50 mph winds to a Category 5 monster with 155 mph winds. Hurricane Fiona Flooded Puerto Rico, then became Canada’s most intense storm on record. Typhoon Maybock Gained strength in the warm Pacific Ocean and ripped more than 1,000 miles off the coast of Alaska.
Big storm hits Philippines in western Pacific Canary Islands In the eastern Atlantic, Japan and Florida in mid-latitudes, and western Alaska and coastal Canada in high latitudes.
Many people are asking about the role of rising global temperatures in such storms. This isn’t always an easy answer.
very clear climate change intensifies This Hurricane Intensity Cap And rainfall rates, it also raises mean sea level and hence storm surge. The impact on the total number of hurricanes is currently uncertain, as is the case elsewhere. However, as hurricanes occur, we expect more of them to become major storms. Hurricane Ian and other recent storms, Including the 2020 Atlantic seasonProvide a picture of what it might look like.
our Research Focused on hurricanes, climate change and the water cycle for years. This is what scientists know so far.
Rainfall: Temperature has a noticeable effect
The temperature of the ocean and atmosphere is Critical to hurricane development.
Hurricanes release heat when water evaporated from the ocean’s surface condenses into storm rain.
Warmer oceans produce more evaporation, which means more water is available to the atmosphere. A warmer atmosphere can hold more water, which in turn produces more rain. More rain means more heat is released, and more heat is released means stronger winds.
These are fundamental physical properties of the climate system, and this simplicity gives scientists great confidence in what storm conditions to expect as the planet warms.The potential for greater evaporation and higher rainfall rates is generally real All types of storms, land or sea.
This fundamental physical understanding is confirmed in computer simulations of these storms in current and future climates, and recent eventleading to high belief in increased rainfall rates in hurricanes At least 7% per heating.
Storm intensity and rapid intensification
Scientists are also highly confident that in a warmer climate, wind speeds will increase and storms intensify to powerful proportions Category 4 or 5 storms will increase. Similar to rainfall rate, the increase in intensity is based on the physics of extreme rainfall events.
Damage is exponentially related to wind speed, so stronger storms can have a greater impact on lives and the economy. The damage potential of a Category 4 storm with 150 mph winds, such as Ian at landfall, is approximately 256 times that of a Category 1 storm with 75 mph winds.
Whether warming causes storms to intensify faster is an active area of research, and some models provide evidence that this could happen. One of the challenges is that the world has limited reliable historical data for detecting long-term trends. Atlantic hurricane observations date back to the 1800s, but only since the 1980s have they been considered reliable on a global scale and have satellite coverage.
That said, there is already some evidence that the increase in rapid intensification is distinguishable in the Atlantic.
In the last two weeks of September 2022, both Nouru and Ian showed a rapidly intensifying trend. In Ian’s case, successful prediction A warning of rapid intensification was issued several days in advance while the storm was still a tropical depression. They represent significant progress in intensity forecasting over the past few years, although improvements have not been uniform.
There are indications that, on average, where storms reach their maximum intensity moving poleward. This will have a major impact on the location of the storm’s primary impact. However, it is unclear whether this trend will continue in the future.
Storm Surge: Two Important Effects
Storm surge – the rise in coastal water levels caused by storms – is related to many factors, including storm speed, storm size, wind direction and coastal seafloor topography. Climate change will have at least two important impacts.
Stronger storms increase likelihood of higher surges, while rising temperatures cause sea levels to rise, which increases water levels, so storm surges are now higher relative to land than before. As a result, there is confidence in the possibility of higher storm surges being added.
Movement speed and stall probability
The speed of the storm can be an important factor in the total rainfall at a given location: a slower-moving storm, Like Hurricane Harvey in 2017providing a longer time for rainwater to accumulate.
Have Signs of a global economic slowdown At hurricane speeds, but the quality of historical data limits understanding of this, the likely mechanism is unclear.
Frequency of future storms unclear
How the number of hurricanes that form each year might change is another major question that is less clear.
Have no definite theory Explain the number of storms in the current climate, or how they will change in the future.
In addition to having the right environmental conditions to fuel storms, storms must also be formed by disturbances in the atmosphere.Currently there are A debate in the scientific community On the role of these pre-storm disturbances in determining the number of storms in the current and future climate.
natural climate change, such as El Niño and La Niña, also has a major impact on whether and where a hurricane develops. How they and other natural changes will change in the future and affect future hurricane activity is a subject of active research.
How much is climate change affecting Ian?
scientists conduct attribution research Individual storms are assessed to assess the extent to which global warming is affecting them, and Ian is currently conducting these studies.
However, individual attribution studies do not need to determine that storms occur in environments where anthropogenic climate change is more conducive to more intense, more rain, and higher surge hazards. Unless greenhouse gas emissions are rapidly and substantially reduced, human activity will continue to increase the likelihood of more severe storms.
Matthew Barlow is a professor of climate science University of Massachusetts Lowell and Suzanne J. Camargo is the Lamont Research Professor of Ocean and Climate Physics Columbia Climate School.
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