If you're an ordinary person trying to make sense of what's happening with the Earth's climate, in some ways this is a very confusing time.
On one hand, climate researchers continually are releasing new studies, some of which - at least to a non-scientist reader - might seem to complicate the basic premise that the burning of fossil fuels and other human activities are driving global warming and altering the climate. This recently published study in Nature, for example, uses modeling to see whether the seeming slowdown of the rise in global surface temperatures over the last decade and a half might last until as long as 2030. That comes after another study, published in Earth's Future, a journal of the American Geophysical Union, which concludes that there really was no hiatus in global warming at all, because the energy simply was absorbed by the planet's oceans.
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And to add to the noise level, people also are being bombarded by the claims of climate-change deniers, which increasingly are echoed by people in high places. Last week, the U.S. House Science, Space and Technology Committee - chaired by Rep. Lamar Smith, R-Texas, who doesn't believe that human activity is driving global warming - tweeted a link to an article from Breitbart News, with the headline "Global Temperature Plunge, Icy Silence from Climate Alarmists." The article recycled claims made by a British tabloid, including that record high global temperatures actually had been caused by El Nino, a mass of warm water in the Pacific, and were unrelated to climate change. (The New York Times and the Washington Post both published articles debunking the assertions, and the Weather Channel actually ran a detailed rebuttal in which it asked Breitbart to stop using one of its videos.)
So what's an ordinary person to think? According to Jeff Dukes, director of Purdue University's Climate Change Research Center, the basic story on climate change hasn't really been changed either by recent studies or by the denialists' claims.
"The fundamental bones of the science haven't changed in the past year," Dukes said.
The important thing to remember is that climate scientists' conclusion that the Earth is rapidly warming as the result of human activity is based upon decades' worth of studies and data. Even if a new study has a finding that could alter one part of the basic story line, that change has to be confirmed by additional studies.
If anything, Dukes said, recent information seems only to further substantiate scientists' existing conclusions. "The studies that are coming out are interesting, but they don't change the overall message that's been consistent for decades," he said.
"I would say the most striking thing over the past year has been the temperatures themselves. We've seen incredibly warm temperatures and drops in ice that suggest there is a real urgency to taking action on this front," he said. "We still see unequivocal evidence of warming, and incredibly strong evidence for a dominant human influence on that warming."
"We see a complication in the public dialogue from misleading information, misleading tweets, but the science is really clear on this," Dukes said. "What's muddying it is political in nature."
Indeed, surveys have found people's views about climate change tend to be shaped by their political leanings, and that they reinforce those views by getting their information from media sources that tend to agree with their existing beliefs.
Dukes dismisses the assertion that El Nino alone caused those record temperatures, or that any recent temperature data has discredited climate science. "El Nino was a big part of what we've been experiencing in the past year, but it coming on top of this massive amount of greenhouse gases injected into the atmosphere," he said.
Beyond that, he emphasizes, climate change is a long, uneven process. "We're going to see lots of year-to-year variability," he said. "What's the significant question to me is: 'How do we expect the climate to change over the course of the coming decades and centuries?'"
Image: The six-month period from January to June was the planet's warmest half-year on record, according to NASA scientists. Credit: NASA WATCH VIDEO: Why Do People Still Deny Climate Change?