【】

Most polar bear populations are in okay shape today, and this comes with a problem: Climate change deniers, often in the form of bloggers, employ this fleeting reality to promote skepticism about the idea that the planet is warming.

The broad argument is that if polar bears -- who largely depend on Arctic sea ice to find food -- are doing okay, then there must be doubt about the effect that fossil fuel emissions have on the global climate.

Yet, observable evidence of human-caused global warming's impact is abounding, especially when it comes to Arctic sea ice. The last four winters have seen the four lowest maximum sea ice extents on record.

SEE ALSO:Thawing chunks of Arctic sea ice trapped and sunk boats in the Atlantic Ocean

So, climate deniers use polar bears as a tool.

"The magnitude of evidence would overwhelm these bloggers, so they focus on polar bears," Jeffrey Harvey, a population ecologist and senior scientist at the Netherlands Institute of Ecology, said in an interview. "You pick one or two topics when the evidence is not in your favor."

Harvey, along with 13 other researchers, including polar scientists and climatologists, published a report in the journal BioScienceon Tuesday, illustrating how internet bloggers have denied the impacts of human-induced global warming on polar bears to cast doubt on climate change science. This, the researchers argue, presents freely-available and easy-to-access distorted science to millions of readers.

A polar bear on Arctic sea ice.Credit: Kathy Crane/NOAA Arctic Research Program

The researchers looked at 90 blogs that covered polar bears and Arctic sea ice. Exactly half of these blogs were categorized as "science-based," and the other 45 were broadly defined as "climate-denier" blogs.

The differences were stark.

An analysis of the "science-based" blogs showed that 44 statements about Arctic sea ice extent were made, and every one of these blogs concluded that Arctic sea ice is declining.

In contrast, "science-denier" blogs included 85 references to Arctic sea ice, and less than 3 percent said the ice was in decline. Instead, these blogs concluded that the ice is either not in decline, or might be in decline today but this might simply be due to natural climatic swings.

The researchers also analyzed how both categories of blogs assessed the threat to polar bears from human-induced climate change. The numbers were similar.

The notion that sea ice isn't in decline, however, is wildly erroneous.

"Arctic sea ice is melting faster today than at any point in the last 1,500 years," Jeremy Mathis, the director of the National Oceanic and Atmospheric Administration's (NOAA) Arctic Research Program, who had no role in the study, said in an interview.

Mashable Light SpeedWant more out-of-this world tech, space and science stories?Sign up for Mashable's weekly Light Speed newsletter.By signing up you agree to our Terms of Use and Privacy Policy.Thanks for signing up!

Via Giphy

As expected, the greatest melting happens during the summer. Arctic scientists expect this sea ice to be completely gone during the summer sometime this century, though Mathis said predictions range from around 10 to 40 or 50 years.

Even so, the trend is undeniable.

"If everything stays the same, I imagine that we’re going to be much closer to those early estimates for seeing an ice-free Arctic during those summer months," said Mathis.

Polar bears, then, may not be hit hard by starvation now, but it's almost certain many populations will plummet when their historic habitat disappears.

"The climate change skeptics play the 'so far, so good game'," said Harvey. "At some point something has got to give. It's a simple habitat issue. As ice continues to melt, polar bears will be in big trouble."

The future vulnerability of polar bears is a "complicated story," said Mathis, because different populations will be affected by sea ice loss in different ways. And that's being studied now. But polar bears that are farther from land, exposed on the open sea, will almost certainly see declines, said Mathis.

The research team's critique of the "science-denier" blogs quickly generated angry responses. Of note, the zoologist Susan Crockford, who writes the blog "Polar Bear Science" found the critique in BioSciencetantamount to "academic rape," as she wrote in a tweet.

On her blog, she called the study "a smack-talk response" to a previous blog pointing out that polar bear populations didn't plummet in 2007 as some biologists predicted. (Harvey noted Crockford misunderstood and then mischaracterized this prediction).

A curious polar bear standing up to get a better look at NOAA scientists on a research cruise in 2003.Credit: Kathy Crane, NOAA Arctic Research Program

Harvey called these retorts "brutal" and "desperate," noting that scientists regularly scrutinize the work of other scientists.

"She thinks she has impunity of criticism by writing blogs," said Harvey. "The paper wasn’t about her. She’s a symptom."

Scientists traditionally challenge other theories or research in a formal, somewhat private manner, through publication in peer-reviewed journals, noted Harvey.

This allows other experts not involved in the research to scrutinize and provide possible edits for a study before it is published in a scientific journal. More public forms of debate -- like a Twitter argument -- serve to fuel public notions that the science of climate change, for example, is in doubt.

Still, Harvey said that some science denial must be countered in public.

"We are viciously attacked," said Harvey. "If more scientists in critical mass stood out against these people distorting science, we would overwhelm them in sheer mass."

Harvey appears to be doing his part, but maintained he's committed to being a scientist, not an aggressive spokesperson.

"I’m not an activist -- I’m a scientist," he said. "I don’t chain myself to trees."

---

Featured Video For You

---

---

(责任编辑：娛樂)