Quantcast

Michael Mann Counters Climate Denial With Simple Statistics

Popular

By Tim Radford

Each of the last three years has seen record temperatures worldwide, further evidence that climate warms the Earth, not mere chance. Each has been named the warmest year since records began.

The chance of this being pure co-incidence is little more than one in a thousand, unless human-induced or anthropogenic climate change is factored in. The chance of 2016 reaching the temperature it did, when it did, would have been one in a million, unless climate change was counted as a contributor.


And if anthropogenic global warming, driven by the profligate combustion of fossil fuels over the last two centuries, is fed into the calculations, then the probability becomes quite high: In fact there would be a 50 percent chance of three consecutive record-breaking years at any time since the beginning of the century, according to a new study in the journal Geophysical Research Letters.

Calculating the Odds

Michael Mann, the distinguished climate scientist at Pennsylvania State University, is at it again. He and colleagues have been calculating the odds on the recent run of high temperatures to see if they can be explained by any factors other than climate change.

He has done this before: At the beginning of the year he calculated the chance that 13 of the warmest 15 years ever had all occurred in the first 15 years of this century. The probabilities at their highest worked out at one chance in 5,000, unless climate change was taken into account. At their lowest, the probability was one in 170,000.

Prof. Mann, who first drew the "hockey stick" graph that shows a steep rise in global temperatures with ever greater levels of carbon dioxide in the atmosphere, also attracts considerable abuse from those who claim that climate change is not happening.

Relying on Statistics

But he prefers to counter denial with simple statistics. The run of record breaking temperatures from 2014 to 2016 would have a chance of no more than 0.03 percent without anthropogenic influence: that is, without all that extra greenhouse gas from fossil fuels.

"With climate change, this is the kind of thing we would expect to see. And without climate change, we really would not expect to see it," he said.

Since the late 19th century, the average surface temperature of the planet has risen by about 1.1°C. Most of this warming has been in the past 35 years. According to the U.S. space agency NASA, 16 of the 17 warmest years have all happened since 2001.

If natural and human events—these include cyclic natural weather phenomena such as El Niño and volcanic eruptions and of course the increasing emissions of carbon dioxide, methane and nitrous oxide in the atmosphere—are taken into account, and understood to overlap the three years in question, then the chance of 2014 to 2016 becoming the hottest consecutive years on record since 1880 rises to up to 3 percent.

This kind of statistical calculation delivers odds that professional gamblers, merchant bankers, stockbrokers and hedge fund managers would take seriously. The challenge is now to get the rest of the human race to take the hazards seriously.

The odds are shortening on increasingly destructive consequences. Even a modest further rise in temperatures will be accompanied by a series of dangerous extremes of rainfall and potentially lethal heat.

"The things that are likely to impact us most about climate change aren't the averages, they're the extremes," said Prof. Mann. "Whether it's extreme droughts, or extreme floods, or extreme heat waves, when it comes to climate change impacts ... a lot of the most impactful climate related events are extreme events. The events are being made more frequent and more extreme by human-caused climate change."

Reposted with permission from our media associate Climate News Network.

EcoWatch Daily Newsletter

Fred Stone holds his brown swiss cow Lida Rose at his Arundel dairy farm on March 18 after a press conference where he spoke about PFAS chemical contamination in his fields. Gregory Rec / Portland Portland Press Herald via Getty Images

By Susan Cosier

First there was Fred Stone, the third-generation dairy farmer in Maine who discovered that the milk from his cows contained harmful chemicals. Then came Art Schaap, a second-generation dairy farmer in New Mexico, who had to dump 15,000 gallons of contaminated milk a day.

Read More Show Less
Protesters attend the 32nd Annual Fur-Free Friday demonstration on Nov. 23, 2018 in Beverly Hills, California. Ella DeGea / Getty Images

California Governor Gavin Newsom signed into law a bill that that bans the sale and manufacture of fur products in the state. The fur ban, which he signed into law on Saturday, prohibits Californians from selling or making clothing, shoes or handbags with fur starting in 2023, according to the AP.

Read More Show Less
Sponsored
Watchfield Solar Park in England. RTPeat / Flickr / CC BY-NC-ND 2.0

By Simon Evans

During the three months of July, August and September, renewables generated an estimated total of 29.5 terawatt hours (TWh), compared with just 29.1TWh from fossil fuels, the analysis shows.

Read More Show Less
A demonstrator waves an Ecuadorian flag during protests against the end of subsidies to gasoline and diesel on Oct. 9 in Quito, Ecuador. Jorge Ivan Castaneira Jaramillo / Getty Images

The night before Indigenous Peoples' Day, an Indigenous-led movement in Ecuador won a major victory.

Read More Show Less
Protesters block the road outside Mansion House in London during an XR climate change protest. Gareth Fuller / PA Images via Getty Images

One week into Extinction Rebellion's planned two weeks of International Rebellion to demand action on the climate crisis, the London police have banned the group from the city.

Read More Show Less
Sponsored
Protestors marched outside the Prudential Center in Newark, New Jersey on Monday, August 26, during the MTV Video and Music Awards to bring attention to the water crisis currently gripping the city. Karla Ann Cote / NurPhoto / Getty Images

By Will Sarni

It is far too easy to view scarcity and poor quality of water as issues solely affecting emerging economies. While the images of women and children fetching water in Africa and a lack of access to water in India are deeply disturbing, this is not the complete picture.

Read More Show Less
Pexels
  • Mice exposed to nicotine-containing e-cigarette vapor developed lung cancer within a year.
  • More research is needed to know what this means for people who vape.
  • Other research has shown that vaping can cause damage to lung tissue.

A new study found that long-term exposure to nicotine-containing e-cigarette vapor increases the risk of cancer in mice.

Read More Show Less
Demonstrators with The Animal Welfare Institute hold a rally to save the vaquita, the world's smallest and most endangered porpoise, outside the Mexican Embassy in DC on July 5, 2018. SAUL LOEB / AFP / Getty Images

By John R. Platt

Six months: That's how much time Mexico now has to report on its progress to save the critically endangered vaquita porpoise (Phocoena sinus) from extinction.

Read More Show Less