State of the Planet

News from the Columbia Climate School

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Connecting the Dots: Extreme Weather and Climate Change

Hurricane Irene. August 2011

Last winter, hundreds of people were stranded in their cars for over 12 hours as the third worst blizzard in Chicago’s history hit the city. The largest wildfire New Mexico had ever experienced burned from June 26 to Aug. 3, forcing the closure of the Los Alamos National Laboratory. Hurricane Irene washed away roads, houses and bridges in Vermont’s worst flooding in 84 years. Joplin, Mo. residents had 20 minutes’ warning before a tornado devastated their town. And thousands evacuated their homes to escape the largest and most damaging flooding of the Mississippi River in 100 years. These are just of few of 2011’s extreme weather events. The National Oceanic and Atmospheric Administration reported that “the United States set a record with 12 separate billion dollar weather/climate disasters in 2011, with an aggregate damage total of approximately $52 billion.”

Chicago blizzard. Photo credit: RRGPhotography.com

A new study by Yale and George Mason University found that 82 percent of Americans personally experienced extreme weather or a natural disaster last year. A majority of Americans believe weather in the United States is getting worse, and many also say that weather in their own area has become more extreme and damaging. Large majorities now believe that global warming was responsible for making some of these recent extreme weather events worse.

I asked Professor Ben Orlove, anthropologist and co-director of the Earth Institute’s Center for Research on Environmental Decisions, which studies environmental decision-making and climate change communication, about the connection between extreme weather and global warming, and his thoughts on changing the public’s perceptions about climate change.

How did your interest evolve from anthropology to climate science communication?

There’s a long tradition in anthropology of looking at human populations and the environments that they live in. The interactions go both ways because cultures are very much shaped by their environments, but also influence the environments in many ways. I’d done the bulk of my fieldwork in the Andes. My first research on climate there dealt with El Niño climate variability. And I’ve since continued from climate variability to climate change, with a particular interest in glacier retreat. The changes in water availability are already having a significant impact on local indigenous communities. And then to climate change communication, understanding it as very much a two-way street. Communication is often understood as getting the correct information out to the masses, but I think it’s important to see environmental issues, including climate issues, as a process of dialogue between experts and the public. The goal is to help experts understand what the public’s priorities are, how they conceive of the environment and climate, and what issues are relevant to them.

The new Yale/George Mason poll about people’s perceptions of extreme weather and global warming found that more people are now making the connection between extreme weather events and global warming. What is the difference between weather and climate?

Weather is the change on the short-term time scale—what’s going on in the atmosphere, the temperature, the precipitation. Climate is the long-term trend. Jason Smerdon, an associate research professor at Lamont-Doherty here at Columbia, says “weather” is what you need to know when you’re trying to figure out what to wear today. And “climate” is what you need to know if you’re designing a house. I think that puts it very well.

Are there legitimate links between extreme weather events and climate change?

There are many links between extreme weather events and climate change. We certainly know that the earth is warming. There are many lines of evidence: the temperature record, the records from thermometers around the world from 150 years, and indirect records that go back earlier point to the warming. It certainly stands to reason that as the world gets warmer we’re going to have more hot events.

Fire in New Mexico. Photo credit: Los Alamos National Laboratory

As you shift the mean temperature higher and higher, you’re creating an increased likelihood of extreme high temperatures. We also know that sea level is rising as the oceans grow warmer. As glaciers around the world melt, there’s more water going into the oceans. And as the oceans themselves are warming, they expand and raise sea level, maybe 6 inches. (According to the U.S. Environmental Protection Agency, sea levels rose 5 to 6 inches over the last century.) That doesn’t sound like a lot but it’s really quite significant as trends continue.

The Hudson River came very close to flooding the (New York City) subway system when Hurricane Irene came through last year. Part of that high water was due to the water pushed by the hurricane, some of it was due to the fact that the tides were high, some of it was all that extra water riding on top of a higher ocean. Also, as the world is warming, the warmer air can hold more water vapor, so it stands to reason that you might get more extreme storms. We know that hurricanes form when the ocean is warm.  In any case, the science has pointed generally to links between global warming and increased extreme events.

Joplin, MO. Photo credit: FEMA

People notice the events that are close to them. They’re much more aware of the weather in their area and perhaps where their relatives and friends live than they are of weather in remote parts of the world. And they may be over prone to say that this particular event is caused by climate change. But what the scientists say about extreme weather events is that the increases in frequency and overall intensity are due to climate change. That doesn’t mean that any one single event itself is directly linked to climate change.

Can you suggest a good way to illustrate this distinction between weather and climate, and increased risk?

This is also Jason Smerdon’s analogy. Think of different weather events, and let’s say you can divide them into 6 possibilities from the mildest to the most extreme. We know that in the past, weather was just like just rolling a die. You get some 1s, some 2s, up to some 6s. The temperatures in recent years have been like a die that gives 5s and 6s more often, and 1s and 2s less frequently, because we are seeing more record high temperatures and fewer lows. But with rainfall, we are getting 1s and 6s more often, with droughts and floods becoming more common. These shifts are in line with the predictions that climate modelers have made, so we are more confident in their models of future climate change. And the fact that this pattern is happening over so many areas, over such a wide area, is what leads scientists to say, yes, we see a strong association between climate change and extreme weather events. Some people think we’re even beginning to see some 7s—entirely unprecedented events like the forest fires in Russia (triggered by severe drought and heat) in the summer of 2010. They were on a scale that just hasn’t been seen before.

How can those who want to motivate the public to deal with climate change use extreme weather events to show how risks are increasing?

People have many different ways of processing information. I think if you throw a lot of numbers at people, it’s really hard to engage them. But if you can offer them vivid images, you can really get them more concerned, more engaged. So if you tell people that the mean winter temperatures in New England are increasing, that really doesn’t tell them very much. If you tell them that ski resorts that used to open by Thanksgiving now don’t even always open by Christmas—that really creates something vivid. Tell them that farmers who used to tap maple trees in Vermont have many more years each decade when the winter’s not cold enough to stimulate sap production, so the sap production is moving north into Canada—that’s also vivid. Talking about extreme weather events, linking extreme weather events both to climate change and to areas where people live, is very powerful and motivates people to action. It also motivates them immediately to take some kind of preparatory steps.

Damage in VT caused by Hurricane Irene. Photo credit Jim Greenhill

For example, if there’s a greater risk of flood in your area, you might want to buy flood insurance, think about what you store in your basement, or you might even think twice about where you choose to live. Those are all steps that people can take, and they get people engaged in thinking of climate change as a serious issue. Then when broader policy issues come forward, like questions of energy conservation, let’s say, they might add climate change to the mix of issues they consider when they think about energy. And there are certainly many energy policy issues right in front of us now: Do we support wind energy? Do we support solar energy? Do we support fracking to produce natural gas? These are all concrete decisions that people are called upon to make.

As people become more concerned about global warming, what do you feel is the most effective use of that concern?

I think it’s important for people to get engaged locally. A lot of response to climate change can take place at the city level, or the county and state level. Cities are often conscious of their vulnerabilities, and there are many steps the city can take, partly to manage this vulnerability to flooding and to heat waves. And then there are ways that people can support policies that are more climate-friendly. Sometimes taking one type of action can lead to another type of action. If people discover that it’s really quite simple—that there are many simple energy conservation steps that they can take, for example—that will lead them to take other forms of action and perhaps to take climate change issues more seriously when they’re choosing which candidates to vote for or which issues to write letters about. It might also lead them to take other kinds of steps wherever they happen to live. I live here in Manhattan, and my building is considering changing from a very polluting kind of heating oil to a lighter heating oil and to gas heating, and we can do that more effectively if we partner with other buildings on our block. That’s a simple step of coordinating at a very local scale.

Do you think it’s a good sign that people are starting to connect extreme weather with climate change?

I think it’s great news. The climate scientists and many people in the public agree that there’s a connection between climate change and increasing extreme weather events. The scientists define it and measure it in a more precise and rigorous way, so they would not agree with the public on every particular event, and on every particular association of a particular hazard in a particular area with climate change, but there’s a high degree of overlap in their perceptions. And I think that the changing perception of extreme weather events is a very encouraging sign that the American public is beginning to see that climate change is not just a question for the high Arctic and remote islands of the Pacific. It’s something that’s right here at home, right now. When there’s more flooding and more drought and more heat waves and more storms, that’s the connection that really grabs people’s attention. More importantly, it encourages many to start taking action.

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