FALSE: HURRICANES ARE TO AN EXTENT LINKED TO GLOBAL WARMING
Written by Odhiambo Shem on October 27, 2022
A twitter post claiming that hurricanes are not linked to global warming is false.
“Hurricanes aren’t linked to global warming. “According to the National Hurricane Center, storms are no more intense or frequent worldwide than they have been since 1850. Constant 24-7 media coverage of every significant storm worldwide just makes it seem that way.” (Paul Bedard)”, reads the claim.
A study of rapid intensification of Atlantic hurricanes finds an observed increase in the probability of rapid intensification (1982-2009) which is highly unusual compared to one climate model’s simulation of internal multidecadal climate variability, and thus is a possibly emerging detectable anthropogenic change. The increase is consistent in sign with the model’s simulated response to anthropogenic forcing.
Emanuel (2007) found a strong correlation, on multi-year time-scales, between local tropical Atlantic sea surface temperatures (SSTs) and the Power Dissipation Index (PDI) for data through 2005. PDI is an aggregate measure of Atlantic hurricane activity, combining frequency, intensity, and duration of hurricanes. Both Atlantic SSTs and PDI have risen sharply since the 1970s, and there is some evidence that PDI levels in recent years are higher than in the previous active Atlantic hurricane era in the 1950s and 60s.
Number of Hurricanes in North Atlantica, 1878-2020
Scientists have been warning since at least the late 1980s that higher sea surface temperatures can increase the destructive power of hurricanes. Hurricanes are fueled by warm, moist air that evaporates from the surface of the ocean, and more water evaporates from the surface when the temperature is high. The global average sea surface temperature has increased since 1860, so it’s reasonable to expect that hurricanes would also become more destructive.
But high sea surface temperatures aren’t the only ingredient for a “successful” hurricane. For instance, powerful hurricanes can churn up cold water from deeper layers of the ocean, lowering the sea surface temperature and reducing the chance that fledgling storms nearby will reach their full potential.
The full body of available evidence suggests the number of hurricanes may stay the same or decrease slightly. But the hurricanes that do form may get stronger and wetter by the end of the century, with a 2-11% increase in hurricane intensity and 20% more rainfall, on average.
These percentages may sound small, but consider that most of the damage and deaths from hurricanes come from flooding caused by rain or storm surges. (A storm surge is a wall of ocean water that gets pushed inland by a hurricane.) Hurricane Katrina, for instance, was the third deadliest and most expensive hurricane ever in the U.S. It also had the highest surge on record in the country. And because sea levels are rising as the world gets warmer, there’s a higher risk of coastal flooding during even a minor hurricane.
According to the Time, higher average temperatures lead to warmer ocean waters which in turn causes more evaporation. As hurricanes pass over, they absorb more moisture, leading to heavier rainfall. Warmer waters linked to climate change also increase the storms’ wind speed, and can cause hurricanes to undergo so-called “rapid intensification” more often.
We looked into this claim that hurricanes aren’t linked to global warming and found it to be false. It misleads the public.