Droughts, Fires, Heat Waves and Hurricanes. Oh My!
As the devastation wrought by Hurricane Sandy, killing over 100 people and producing upwards of $50 billion in damage along the U.S. East Coast, has reignited a long dormant conversation on climate change in the media, it’s important to note that this is not the only weird and wild weather the U.S. has seen this year.
In fact, 2012 has been a year of record-breaking weather across the U.S.
The worst drought in decades, unprecedented heatwaves and monster forest fires.
While climatologists have long stated that it is not yet possible to blame a single extreme weather event on climate change, research is showing that rising temperatures are very likely increasing the chances of extreme weather events and worsening them when they occur.
In March, the U.S. suffered a truly bizarre extreme weather event. A heat wave that made early spring feel like the height of summer. The March heat wave shattered 15,272 day and nighttime records across the U.S. and made March 2012 the warmest March on record for the country.
Then came summer 2012 when a longer than usual heatwaves worsened forest fires, exacerbated drought, and led to a series of destructive wind and thunderstorms known as derechos. July 2012 set the record for the warmest month ever in the U.S., beating out past scorchers set during the Dust Bowl.
The link between such extraordinary heat waves and climate change is crystallizing. A recent study in the Proceedings of the National Academy of Sciences (PNAS) found that extreme heat waves have increased worldwide by at least 50 times during the last 30 years. The research, headed by James Hansen of NASA, concluded that anthropogenic global warming was the only explanation for the observed increase in heatwaves.
Heat makes fire more likely and 2012 was a record breaker for forest fires in the U.S. New Mexico suffered its largest wildfire yet with 289,478 acres (117,148 hectares) burned up in the Gila National Forest.
Another fire in New Mexico, however, proved to be the most destructive in the state’s history when it destroyed over 250 buildings.
Colorado suffered a particularly damaging wildfire as well. The Waldo Canyon Fire destroyed over 300 homes, killed two people, and prompted a visit from President Obama. It was the state’s second largest wildfire on record.
While several factors are leading to explosive monster fires, including the practice of suppressing small fires rather than letting them burn out, scientists are increasingly outspoken that there is also a climate factor in these conflagrations. Rising temperatures, droughts, and less snow pack are increasing prime fire conditions in some parts of the U.S., particularly the Southwest.
“I have no doubt climate change is playing a role in this,” climate scientist Kevin Trenberth, who heads the Climate Analysis Section at the National Center for Atmospheric Research (NCAR), told The Salt Lake Tribune in July. Located in Boulder Colorado, Trenberth’s NCAR lab was evacuated during the Waldo Canyon Fire.
A record drought hit the U.S. heartland this spring and then spread, impacting over half of the contiguous U.S. by the end of the summer. The government declared disaster areas in 1,692 counties across 36 states.
The combination of record heat and dryness decimated the nation’s globally important corn crop, with around 45 percent lost, fears for another global food crisis have risen for next year.
The price of corn, which is used to feed livestock and for biofuels, hit a record high in August. Even as the U.S. East Coast was hammered by rain, drought conditions still persist across much of the U.S.
A recent report in American Meteorological Society has shown that climate change is increasing the likelihood of such droughts. For example, it found that climate change had increased the chances of a major drought in Texas in 2011 by 20 times.
“This is what global warming looks like at the regional or personal level,” Jonathan Overpeck, climatologist with the University of Arizona, told the Associated Press over the summer. “The extra heat increases the odds of worse heat waves, droughts, storms and wildfire. This is certainly what I and many other climate scientists have been warning about.”
Notice that scientists do not say climate change has caused these extreme events, instead they argue that rising global temperatures have increased the likelihood of extreme events and increased their potency. A common metaphor to describe this phenomenon is that climate change has “loaded the dice” for extreme weather events.
So, what about Hurricane Sandy?
The connection between hurricanes and climate change has come under more debate than heatwaves and droughts. However, scientists still point several ways in which the storm may have been exacerbated by climate change.
Year after year of rising sea levels, caused by climate change due melting glaciers and the fact that warmer waters actually expand, certainly added to Sandy’s devastating storm surge, which hit 14 feet in some places.
A warmer ocean also results in increased evaporation, leading to heavier precipitation. Combining the sea level rise with more precipitation probably resulted in a double whammy for coastal flooding.
In addition, higher oceanic temperatures and more precipitation may increase the intensity of some hurricanes. In fact, recent science shows that while hurricanes in general may occur less often due to climate change, particularly intense ones, like Sandy, are expected to occur more frequently in upcoming decades. Temperatures over the Atlantic Ocean were three degrees C (5.4 degrees F) above average during the reign of Sandy.Hurricane Sandy’s track. Notice how it veers eastwards. Image by: Cyclonebiskit.
Finally, the hurricane’s route was pushed by a rare blocking pattern, an unmoving block of atmosphere pressure, near Greenland.
This blocking pattern, which pushed Sandy westwards into New Jersey and New York, may be connected to sea ice loss in the Arctic, according to recent research.
Usually a hurricane like Sandy would move out eastwards and perish over the ocean, but this one was steered directly into the coast.
Much more research on this theory is needed, but it may be that Arctic sea ice loss, which hit a new record low this year, could have helped form the blocking pattern that brought Sandy along its unusual course.
“I would be very cautious,” Stefan Rahmstorf, professor of physics of the oceans at the Potsdam Institute for Climate Impact Research, told Reuters. “But there is reason to suspect that there could be a connection between the record sea ice loss this summer and the path of this storm.”
Much more research on this theory is needed, according to experts. In fact, the research on how the warming atmosphere is impacting extreme weather is still in its infancy. Hurricane Sandy, itself, was a truly bizarre storm, a combination hurricane and snowstorm, that has not been studied widely by climatologists.
Still, scientists are beginning to see stark changes in extreme weather around the world, not surprising given that weather systems are not independent of our climate, and new research is showing that a warmer world is very likely a more extreme one.
It’s not going to get any better, experts say, until societies begin to dramatically cut greenhouse gas emissions while adapting to a more extreme atmosphere.
*Adapted from mongabay.com.
Mongabay.com provides news, information, and analysis on environmental issues, with a special focus on tropical rainforests. The web site features more than 70,000 photos and has a section about forests for children available in nearly 40 languages.
Editor: Olga Feingold