The Freak Weather That Won’t Be Denied Global Warming Has Everyone Guessing When & Where The Next Extreme Weather Event Will Happen

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These are trying times in Pendleton Harbor, Texas. During what government scientists say is the worst drought since the Dust Bowl of the 1930s, the water level in Toledo Bend Lake has sunk to its lowest level since it opened in 1969, leaving this subdivision, built on its manmade shores, high and dry.

“Where you once were able to drive your boat, you can now mow the grass,” says John Miller, a former park ranger who retired to this relatively verdant spot on the Texas-Louisiana border with his wife Rita five years ago. The couple began visiting the area as the Toledo Bend hydroelectric dam was built half a century ago, a process that created the South’s largest lake and more than 1,000 miles of shoreline filled with rustic cabins, mobile homes and ample fishing.

But as the drought drags into a second year, the couple’s two boats are parked in their yard. And Pendleton Harbor’s taps could soon run out of water.

Across Texas and Oklahoma, record low rainfall and intense heat have taken a heavy toll on water supplies. The 109 reservoirs that supply nearly all of Texas’ water had lost nearly a quarter of their total combined capacity by the end of 2011, says Ruben Solis, director of surface water resources at the Texas Water Development Board.

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Throughout last fall and into the new year, Pendleton Harbor sat near the top of a state watch list of cities and towns with six months or less of water supplies. Dozens of other communities around Texas have been forced to enact water-rationing measures as forecasters expect the drought to continue into the spring.

But is climate change to blame for the Texas drought?

Assessing the Stormy Weather

What individual weather events such as mega-droughts and extreme storms can tell us about climate change is a question attracting increased attention from scientists and policymakers. Until recently, climate scientists have spoken mostly in generalities. While hotter temperatures and more extreme storms and droughts were consistent with global warming, natural variations and related factors had made them reluctant to connect the dots between individual blasts of weather and a slow moving global trend. But that’s changing as extreme weather has proliferated—along with the human, habitat and economic costs. Scientists are improving their understanding of how greenhouse gases impact the weather. The old stock refrain—that a single weather event cannot prove or disprove climate change—is no longer reliable.

And scientists—including many caught up in 2009 “Climategate” scandal that fueled skepticism about the scientific consensus—are striving to talk about what is already widely understood and in language that’s easier for non-scientists to understand.

“We are just trying to say to people who don’t realize it: The climate is going to change. People need to know,” says climate scientist Richard Somerville, a member of the world’s foremost authority on the matter, the Intergovernmental Panel on Climate Change (IPCC) and science director of Climate Communication, one of the newly formed initiatives aimed at getting the peer-reviewed mainstream scientific view before the public.

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Though climate gets the marquee billing in this debate, it’s weather people really care about. It’s where the rubber meets the road in terms of how global warming will shape the future. Despite everything we have yet to discover about the consequences of our high carbon dioxide lifestyle, we’re bound to notice drastic changes in the weather: freak storms, record setting droughts and unusually long spells of 110+ degree days in Chicago or Washington, D.C.

In fact, scientists say climate change is already altering the weather. And non-scientists have taken notice. Last November nearly four in ten people interviewed by pollsters from Yale University said they had experienced climate change firsthand; possibly a sign, says Anthony Leiserowitz, director of the Yale Project on Climate Change Communication, that the public has begun to see global warming as a problem here and now—not one awaiting action by future generations.

Stormier Weather?

The world scientific community painted the most complete picture yet of how global warming is changing the weather in a flurry of reports and studies issued around last December’s United Nations international climate talks in Durban, South Africa. A few weeks before the talks, IPCC put out its first-ever special report on the subject. In typically cautious, scientific language, it concluded that global temperatures and sea levels are likely increasing as a result of global warming, and intense droughts and storms are going to exact more harrowing tolls on people as well as on economic “sectors with closer links to climate,” such as “water, agriculture and food security, forestry, health, and tourism.”

The report also pointed out what remains unknown. It noted that too little is understood about tornadoes and tropical cyclones, for instance, to say with certainty what impact rising global temperatures have on their frequency and severity. In the U.S., the Texas drought was just one extreme in a record-setting year. The National Oceanic and Atmospheric Administration (NOAA) reported in early December that 2011 had been either a remarkably dry or excessively wet year for 56% of the country.

The report cataloged spring flooding along the Mississippi River, historic wildfires in the West, an unusual number of tornadoes and the deadly Hurricane Irene that cut a swath from the Caribbean up the East Coast all the way to Vermont and southeastern Canada, killing more than 50 people and causing more than $10 billion in damages to buildings, roads, bridges and other infrastructure. In all, 2011 saw a record 12 weather events that cost the country $1 billion or more each to clean up. That’s a big jump over the annual average from 1980 to 2010, when there were a total of 99 billion-dollar weather events, an average of just 3.3 a year, according to NOAA’s National Weather Service.

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“Extreme weather and associated societal impacts have increased in recent years. With our changing climate, the nation must be prepared for more extreme weather in the future,” National Weather Service director Jack Hayes said in a web video that accompanied the report.

“Freak weather” even made Time magazine’s list of the top 10 U.S. news stories of 2011. The insurance industry, meanwhile, doled out more than $100 billion in claims related to the 2011 natural disasters, Insurance Journal reported in January 2012.

Climate extremes also unfurled across just about every other continent last year leaving people dead, homes damaged and livelihoods destroyed. While the U.S. recorded a dozen events that packed $1 billion or more in devastation, Jeffrey Masters, the meteorologist and co-founder of the website Weather Underground, tallied up 32 such $1 billion events worldwide in 2011. They included flooding in Thailand that alone caused an estimated $45 billion in damages. Masters noted on his blog that five countries—Thailand, Australia, Colombia, Sri Lanka and Cambodia—suffered their costliest weather-related natural disasters on record last year

And 2011’s freakish weather followed a blockbuster 2010 for extreme weather, which featured a Russian heat wave and ensuing forest fires that caused an estimated 56,000 deaths; epic flooding in Pakistan that displaced 20 million people; and one of the busiest Atlantic hurricane seasons on record. The Amazon rainforest weathered its second 100-year drought in five years. Twenty countries set records for extreme heat, while it was the wettest year ever recorded over the Earth’s land areas, to name just a few of the extremes chronicled exhaustively by Masters on the blog he frequently uses to call attention to the weather-climate change connection.

“I’m a hurricane scientist, so I think in terms of hurricane terms,” Masters says. “We are starting to see the outer spiral band of the storm. It’s going to hit us and there will be a large degree of destruction. But we can still act now. How bad it gets is up to us.”

Déjá vu All Over Again

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For scientists, it has been eerie to watch today’s headline-making extreme weather events track so closely with what computer models predict for a warming world. It’s like a bad case of déjà vu, says Somerville, distinguished professor emeritus and research professor at Scripps Institution of Oceanography at the University of California, San Diego, who has been studying climate change for decades.

So far, as the IPCC points out in its special report, the vast majority of fatalities have occurred in poorer developing countries, but the U.S. and other rich Western nations are racking up enormous losses to roads, ports, factories and other costly infrastructure. And in a globalized world, many impacts reach across borders and public tragedies and private sector losses intertwine. For instance, the flooding in Thailand was “virtually certain” to lead to an industry-wide shortage of disk drives, Apple Inc. CEO Tim Cook warned last fall. The same floods also gutted auto parts manufacturing operations in Thailand that supply Toyota, GM, Ford and Honda.

That’s just a taste of what’s to come, says Joseph Romm, a senior fellow at American Progress, who writes a blog, on climate issues.

“The most important thing for people to understand is that the planet has only warmed a little over 1 degree Fahrenheit in recent years,” Romm says. “We are on a path to warm five to 10 times that much this century. So if people think we’ve seen extreme weather, we ain’t seen nothin’ yet.”

For several years now, world leaders have talked about capping emissions soon enough to keep global temperatures from rising more than 2 degrees Centigrade (3.6 degrees Fahrenheit). There are, in fact, precise measurements of what it would take to reduce emissions to rein in warming in the 2°C range—as little as 3.7% of global gross domestic product a year if we had started in 2011 but 9% a year if we wait until 2020, according to one estimate, though a growing number of researchers have begun to question whether it’s not already too late—in political if not technological terms—to maintain warming in such a relatively modest range

Currently, the world is on course to warm by three times that amount—6°C (10.8°F) by the end of the century, according to the International Energy Agency. That could be very bad news for food and water supplies. A 4°C increase could reduce global crop yields by 40%, according to researchers, while global warming will push more than a third of all counties in the lower 48 states toward water crises by 2050, according to a study published by the Natural Resources Defense Council.

In many places across the world, experts warn, hotter, drier conditions may be the new normal, spreading famine, sparking food riots and destabilizing governments. And climate change will take a toll on production of such luxuries as coffee, wine, tea and maple syrup. Even durum wheat use to make pasta is under threat as Italy’s Mediterranean climate shifts northward ushering in hotter, drier weather more akin to Northern Africa. These are just a few of the anticipated culinary tragedies—though such losses seem trivial compared to the millions currently starving in the Horn of Africa

And humans, by many accounts, will fare better than other species, which scientists say may already be entering the world’s sixth mass extinction, the first since the Cretaceous mass extinction that ended 65 million years ago, marking the end of non-avian dinosaurs. Data from the International Union for the Conservation of Nature indicates that in the last 500 years, 21% of mammals are currently threatened with extinction (1% are already extinct), 28% of reptiles (1% already extinct), 31-42% of amphibians (1% already extinct), 43% of snails and slugs (13% are already extinct), 19% of crustaceans known as decapods which include lobsters, crabs and shrimp and 17% of jawed fish including sharks, rays and skates. But these numbers don’t tell the whole picture: In many cases, as with reptiles, snails and slugs, very few species have been assessed. Officially, a mass extinction means the loss of three-quarters of the planet’s species in a short interval. As changing temperatures and human demands threaten wildlife habitats, and carbon dioxide accumulating in the Earth’s oceans bleach coral reefs and wreak havoc on aquatic ecosystems, such massive losses are rapidly drawing closer to reality.

Better Communicating

With those kinds of stakes, some of the most eminent experts have banded together to improve their communications skills and take a more active role in explaining the emerging reality in layperson’s terms.

One such initiative, the Climate Science Rapid Response Team was conceived in response to 2010 testimony before a U.S. Congressional committee by Chris Monckton, a British public figure, whose unscientific contentions that climate change is neither manmade nor catastrophic has frustrated the scientific community. The team launched in September 2010 with 39 scientists and has since grown to include 145 experts and to field hundreds of inquiries from media outlets and government agencies, according to Scott A. Mandia, who helps coordinate inquiries from news outlets and government agencies from his post as a physical sciences professor at Suffolk County Community College in Selden, New York. Team members have also participated in public speaking seminars held a few times a year and at major scientific meetings, often in concert with the Union of Concerned Scientists and Climate Communications, where Somerville is the science director.

They practice speaking in shorter sentences, leaving out scientific jargon. They are urged not to frontload every sentence with a long list of “buts” and unknowns. In the intensely competitive field of science, where skepticism is ingrained and theories must be peer reviewed, such caveats are stated upfront. But for the rest of us, Somerville acknowledges, they “create the impression that there’s no connection” between climate change and weather, which simply is not the case.

“We are trying to be more effective. The screamer side of the debate [over climate change] has been very noisy and drowns out the climate scientists,” says Somerville, one of the scientists whose e-mails were stolen by hackers and released to the public in 2009 in an effort to discredit the overwhelming body of research indicating that global warming is real and human-caused.

Scientists are also relying on better metaphors. By adding so much carbon dioxide and other greenhouse gases to the atmosphere, we have “loaded the dice,” the idea being that all the natural variations that go into particular weather events are still present but warmer temperatures increase the odds of extreme events. In recent years, for instance, the world has been breaking high-temperature records twice as often as low-temperature ones, with the ratio of highs to lows now moving closer to 3-to-1, a clear sign that the world is warming.

“People can relate to that. It’s plausible and intuitively clear,” says Somerville, who also likes comparisons to baseball statistics that any sports fan can grasp.

In one variation on that theme, Major League Baseball star Barry Bonds is a stand-in for the weather and steroids represent climate change. A jury convicted Bonds of illegal steroid use in 2011, but he was hitting home runs before he started taking steroids. The tricky part is determining how much the steroids contributed to his home runs and how much Bonds’ natural talent—aka natural weather variations such as cold fronts or El Niño events—came into play. While it may not be possible to link a particular home run to steroids, the steroids raised the odds that he would hit balls out of the park. Similarly, climate change is making weather extremes more likely.

More Scientific Assessments

Meanwhile, scientists are getting better at understanding exactly how much climate change may already factor into the weather—or, to continue the Barry Bonds analogy, to pinpoint how much climate change factors into particular weather events.

It’s an evolving field known as “climate attribution” but scientists often deploy tested approaches that they’ve used for decades to examine the severity of hurricane seasons and other events such as El Niño and La Niña weather patterns. El Niño refers to warming waters in the Pacific Ocean and is tied to rain and floods on the Pacific coast and tornadoes and storms in the southern U.S. La Niña refers to cooling Pacific waters and is associated with snow and rain on the west coast, warmer-than-usual weather across the rest of the country, drought in the southwest and hurricanes in the Atlantic.

Last year Republicans in the House of Representatives blocked a planned reorganization at NOAA that would have provided more resources for climate-weather studies, but the agency’s Earth System Research Laboratory has already carried out several climate attribution assessments since 2007, including issuing opinions on the causes of the Russian heat wave and the mid-Atlantic “Snowmageddon” storms that blanketed the mid-Atlantic in 2009 and 2010.

Similar efforts are underway in Europe, South Africa and elsewhere. The new work adds to the body of research financed by insurance companies that—in the face of increasingly large natural disaster payouts—have been in the forefront of examining the link between climate change and weather extremes.

Different Opinions

One day the computer models may be robust enough to warrant litigation against oil companies or power plants over emissions-induced weather extremes, but today researchers rely on inexact science. Disagreements abound among the scientists trying to isolate human-induced global warming (often called “anthropomorphic forcing”) from already erratic natural variables such as high- and low-pressure systems and El Niño. Harold Brooks, a climate scientist at NOAA’s National Severe Storms Laboratory in Norman, Oklahoma, likens the process to detecting a faint radio signal amid a lot of static.

Take the 2010 Russian heat wave that led to raging peat bog fires and killed an estimated 56,000 people: NOAA researcher Randall Dole issued a report concluding that a stationary high-pressure system was the cause. But a couple of German researchers, Stefan Rahmstorf and Dim Coumou at the Potsdam Institute for Climate Impact Research, published another report concluding that there is an 80% chance that the record-breaking temperatures would not have been reached without climate change. A third, Myles Allen of the University of Oxford, told New Scientist that both were right, because even if most of the variables that led to the heat wave were natural, increases in temperatures in western Russia over the last three decades, likely caused by climate change, may have pushed the natural variability into the danger zone.

Brooks says that’s largely his reading of the two seemingly contradictory reports, as well. Indeed, rather than causing new weather events, climate change appears to exacerbate them—making heat waves hotter, droughts drier, tropical storms wetter and gale force winds stronger, according to scientists.

In a paper released just before the IPCC report last November, James Hansen, an outspoken climate scientist at the National Aeronautics and Space Administration, made a similar argument that global warming made both the Moscow and Texas heat waves more extreme. It was “nearly certain” that both the Moscow and Texas heat waves would not have occurred without global warming, the paper stated. Hansen rejected meteorological explanations of the cause, such as blaming La Niña for the recent Texas warming, by saying those other well understood meteorological events are now often amplified or otherwise influenced by warming and that more climate extremes could be expected if emissions are not soon brought under control.

Other assessments of the Texas drought reached similar conclusions about how rising temperatures play into otherwise naturally occurring events. A team of scientists from NOAA, the Lawrence Berkeley National Laboratory, and the Lawrence Livermore National Laboratory also found climate change “fingerprints” on the drought after analyzing 19 climate models. They concluded that the severe drought that has gripped Texas and Oklahoma in recent years may be the new normal for the continent by the middle of this century, thanks to climate change. The results were published last December in the American Meteorological Society’s Journal of Hydrometerology.

Meanwhile, Texas State Climatologist John Nielsen-Gammon, a professor of atmospheric sciences at Texas A&M University did his own study and found climate change was a minor factor in the record Texas temperatures, adding only about one degree to what would have happened anyway.

“For most people the extra degree was no big deal,” Nielsen-Gammon wrote on his blog. “For the rancher who’s managed to hang on until September but whose stock tank is going to run dry just a week or so before it would have been replenished by rain, or for the family whose house was just on the wrong side of the edge of the wildfire, a degree makes all the difference in the world.”

Is Climate Change Impacting All Weather Today?

One obstacle to exactitude is that extreme events, by their very nature, are infrequent and leave few clues for scientists to follow, says Kevin Trenberth, senior scientist at the National Center for Atmospheric Research. Trenberth caused a stir last year by suggesting that the time had come to flip the burden of proof and assume climate change plays a role in all weather today.

“Of course there is large weather and natural variability. And even with climate change, most of the time it falls within the bounds of previous experience. But increasingly it doesn’t, and records are being broken that are consistent with a human influence of warming,” he wrote in an e-mail exchange

It’s a controversial idea that has attracted criticism from other climate scientists and has been assailed by climate deniers and a few prominent bloggers like Roger Pielke, Jr.

“It’s more of a rhetorical question than anything scientific,” says Pielke, a professor of environmental studies at the Center for Science and Technology Policy Research at the University of Colorado at Boulder.

Pielke, a darling of the denialist community for his criticism of Al Gore, Trenberth and others, has accused climate scientists of overreaching to make weather-climate change connections, allegations that have annoyed Somerville and other top scientists who consider Pielke, a political scientist, an unqualified gadfly on matters of climate science.

Nevertheless, questions of overreach have roiled the climate science community before. Perhaps the most memorable round of recriminations followed Hansen’s testimony before Congress in the late 1980s, the first time climate change made international headlines. Many in the science world felt Hansen had strayed from the rigors of science into the layman’s land of the educated guess, though such criticism has lost much of its bite as ensuing decades have shown his analysis to be sound.

Public Awakening

Now, the recent spate of extreme weather may be convincing the public where climate science has not.

In a poll conducted by the Yale Project on Climate Change Communication last November, about two-thirds of those interviewed said they believe global warming is affecting weather in the U.S. And 38% said they had personally experienced the effects of global warming.

“So much of the country was hit with extreme events. We were surprised at the number of people who connect weather and climate change and see it impacting them,” says Anthony Leiserowitz, director of the Yale project, a multi-year, in-depth effort to assess what Americans think about climate change.

After the 2009 Climategate scandal, for instance, his team documented a 12% decline in belief in climate change. By last November, public opinion had started to rebound, and was holding steady with about two-thirds of respondents saying they believed the world is warming and half of them agreeing that humans are causing the change, up three percentage points over the previous survey. But the number of people who said addressing climate change cannot wait for the economy to improve showed an even bigger jump—rising to 57% from the 49% of just a few months prior.

Leiserowitz says those results may signal “a shift in consciousness for the American public” as climate change begins to break out of the “frames” of science, environment and politics that have confined it to date, feeding political polarization and stymieing bipartisan efforts for climate legislation and other government action. Such a shift toward the warming trend as a threat to public health, private property and our very way of life appears to bode well for the prospects of eventual action to rein in emissions.

Don’t Mess With Skepticism

Even if, as Leiserowitz points out, “the climate system doesn’t care if you are a Democrat or a Republican,” there’s still a great deal of skepticism in hard-hit places like Texas, a state helmed until recently by Republican Gov. Rick Perry, who made denying climate change central to his failed presidential campaign.

John Miller, the retiree in Pendleton Harbor, says he does not believe climate change has much to do with his community’s water shortage.

Also skeptical is John Jacobs, mayor of Robert Lee, a Texas town that ran out of water last year and was forced to build a pipeline to a neighboring town, a fix that has just about doubled local water bills

“Personally, I have my doubts” that climate change is involved, says Jacobs, but he admits a debate is raging among his constituents. “You can go to any beauty shop or coffee shop in town, and there’s that debate going on,” he says.

CHRISTINE MACDONALD is the author of Green, Inc.: An Environmental Insider Reveals How a Good Cause Has Gone Bad (The Lyons Press). Her work has also appeared in The Boston Globe, Los Angeles Times, Dallas Morning News and Chicago Tribune.