Energy

Scientists Issue ‘Absurd’ Doomsday Prediction, Warn Of A ‘Hothouse Earth’

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• The media claims the planet was “dangerously close” to reaching a tipping point that would set off “unstoppable” warming.
• However, actual scientists disagree. One scientist called the “hothouse Earth” prediction “absurd” and not science.
• Let’s not forget climate models have regularly over-predicted temperature rise.

A group of scientists published a doomsday paper warning that if humans do not stop emitting greenhouse gases in the near future, parts of Earth could become uninhabitable.

The new warning of a “hothouse Earth” made waves in the media, with outlets reporting the planet was “dangerously close” to reaching a tipping point that would set off “unstoppable” warming.

At least one study author admitted to CNN she hoped the summer heat would mean “people may be more receptive to the urgency of the situation,” the outlet reported Tuesday.

“People getting a taste of the heatwaves, this is what climate change is all about,” co-author Katherine Richardson of the University of Copenhagen told CNN.

Overall, the tone of the paper and the media coverage is that Earth’s in imminent danger of reaching a climate tipping point that would result in 197-foot sea level rise and global temperatures between 7 and 9 degrees Fahrenheit.

But are we really close to catastrophe? There are at least a few reasons to be skeptical.

Veteran climatologist Roger Pielke, Sr. lambasted the doomsday paper and its accompanying news coverage. Pielke tweeted ” … [s]uch absurd claims [harm] actual effective policies with reducing risks from extreme weather and other threats.” He added the doomsday claims were “[s]peculation not robust science.”

“Hothouse Earth: Runaway global warming threatens ‘habitability of the planet for humans'” https://t.co/edJgL8d2qq Such absurd claims harms actual effective policies with reducing risks from extreme weather and other threats.

— Roger A. Pielke Sr (@RogerAPielkeSr) August 7, 2018

Climate scientist Bob Kopp took to Twitter to tone down the media hype around the new paper. Kopp also noted the paper offers no new evidence of when a “tipping point” might be reached, or what will cause it, though he agrees there is such a thing.

That said, it’s important to bear in mind that it is a comment. There is no *new* science in the piece to argue that the transition to a Hothouse will be completed rapidly (indeed, they – I think accurately – label this as a millennial transition) 4/n

— Bob Kopp (@bobkopp) August 7, 2018

The #HothouseEarth is likely real, but we don’t know what will trigger it, and the transition will take centuries. The need for active, flexible planetary stewardship is real, immediate, and certain. 12/12

— Bob Kopp (@bobkopp) August 7, 2018

Indeed, warming of 7 to 9 degrees Fahrenheit is consistent with the Intergovernmental Panel on Climate Change’s most extreme scenario, RCP8.5, that’s increasingly been called “exceptionally unlikely” by researchers because of unrealistic assumptions about future energy consumption.

The paper’s authors put the tipping point at 2 degrees Celsius — the goal of the Paris agreement. The authors call for “fundamental societal changes” to create a “stabilized Earth” at below 2 degrees Celsius, according to a press release.

That means no fossil fuels, planting more trees, reducing consumption and a whole host of other activities. Moreover, the scientists decried nationalist sentiment in the U.S. and other countries that could undermine the Paris accord.

In RCP8.5, the Earth crosses the 2-degree threshold around 2050. That threshold is pushed back in later scenarios that depend on future emissions, which are highly uncertain.

There’s another problem too: climate models have been running hot, predicting more warming than has actually occurred.

The new paper, for example, says the warming trend has been about 0.17 degrees Celsius per decade. Climatologist Judith Curry wrote in a 2017 report that climate models overestimated observed temperature trends by a factor of about two.

For satellite-derived data, climate models predict around 2.5 times more warming in the lower troposphere than has been observed.

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