How hurricanes, typhoons, and cyclones are impacted by climate change.
Typhoon Shanshan, one of the fiercest storms to hit Japan in decades, made landfall there.
In the meantime, US meteorologists have issued a warning regarding a potentially "extraordinary" hurricane season in the Atlantic that might occur between June and November 2024, peaking in September. The extremely high sea temperatures that are currently being experienced in several areas have the potential to intensify severe storms.
Hurricanes, What are they?
Strong storms called hurricanes form in warm tropical ocean waters. They go by the names of cyclones or typhoons in other regions of the world. These storms are collectively referred to as "tropical cyclones".
Storm surges, which are temporary elevations in sea level, intense rainfall, and extremely high wind speeds are characteristics of tropical cyclones. This frequently results in extensive floods and damage. The highest sustained wind speed of a hurricane can be used to classify them. Major hurricanes with velocities of at least 111 mph (178 km/h) are classified as category three and above.
How do hurricanes originate?
Typhoons, cyclones, and hurricanes all start off as atmospheric disturbances, such as tropical waves, which are pockets of low air pressure where clouds and thunderstorms form. The winds within the storm cloud start to rotate as warm, humid air rises from the ocean's surface. The mechanism is related to how winds in tropical areas slightly off the equator are impacted by Earth's rotation. The sea surface usually needs to be at least 27C to supply sufficient power for a hurricane to form and continue spinning, and the winds also need to not fluctuate significantly with height. Even though the precise origins of particular storms are complicated, a powerful hurricane can occur if all three conditions are met.
Has the severity of storms increased? Although long-term data is scarce in some areas, the regularity of tropical cyclones has not increased globally and may have even decreased. However, the UN's climate panel, the IPCC, states that it is "likely" that a greater percentage of tropical cyclones worldwide have reached category three or above, meaning they achieve the greatest wind speeds.
It states that there is "medium confidence" that the average and peak rainfall rates related to tropical cyclones have increased. It's possible that the number and size of "rapid intensification events" in the Atlantic have grown.
Maximum wind speeds can become particularly harmful at this point due to their rapid increase. Additionally, it appears that the rate at which tropical cyclones travel across the surface of the Earth has slowed down.
This usually results in increased rainfall at that particular place. For instance, Hurricane Harvey "stalled" above Houston in 2017 and dropped 100 cm of rain over the course of three days.
In certain regions, such as the western North Pacific, the typical spot of tropical cyclones at their strongest has moved poleward. New communities may be exposed to these risks as a result. Additionally, there is data to suggest that US hurricanes are becoming more intense and damaging more property.
Does Hurricane Climatic Change Affect Them?
It is difficult to determine the specific impact of climate change for each tropical cyclones. In any event, the storms can vary greatly and are comparatively localized and brief. But there are a number of quantifiable ways that rising temperatures impact these storms. First of all, hurricanes may absorb more energy from warmer ocean waters, which raises wind speeds.
The record high Atlantic sea surface temperatures are contributing to the prediction of four to seven major Atlantic hurricanes in 2024. The primary cause of the high temperatures is sustained greenhouse gas emissions. Second, heavier rainfall can result from a warmer atmosphere's increased capacity to hold moisture. One analysis suggests that the heavy rainfall from Hurricane Harvey in 2017 was approximately three times more likely due to climate change.
Sea levels are also increasing as a result of warmer water occupying additional room and the melting of glaciers and ice sheets. Additionally, there may be local considerations. This implies that storm surges exacerbate coastal flooding by occurring on top of already high sea levels.
For instance, water levels from one of the deadliest hurricanes to ever hit America, Hurricane Katrina in 2005, are thought to have been 15–60% greater than they would have been under 1900's climate.
Overall, the IPCC comes to the conclusion that there is "medium trust" that human activity has increased the likelihood of a tropical storm becoming more powerful and "high confidence" that human activity has increased the precipitation associated with tropical cyclones.
What future changes might hurricanes bring about?
The IPCC predicts that there won't be a rise in tropical cyclones worldwide. However, it states that it is "very likely" that they will experience increased rainfall rates and maximal wind speeds as the planet warms. As a result, a larger percentage would fall into the hardest categories, four and five. These changes tend to becoming more drastic as global temperatures rise. According to the IPCC, although precise figures are unknown, the percentage of tropical storms that become category four or five may grow by approximately 10% if global temperature rises are kept to 1.5C. This percentage would then rise to 13% at 2C and 20% at 4C.
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