Summary of “The Dire Warnings of the United Nations’ Latest Climate-Change Report”

Since the 2009 United Nations climate talks, in Copenhagen, the consensus among scientists and policymakers has been that two degrees Celsius should be the limit; any further temperature increase would be catastrophic.
As a result, the final Paris Agreement declared that, while warming shall not surpass two degrees Celsius above pre-industrial levels, countries should pursue “Efforts to limit the temperature increase to 1.5 degrees C.” The Alliance of Small Island States also asked the Intergovernmental Panel on Climate Change-the scientific body that informs the climate policies of the United Nations’ member states-to prepare a special report on the specific impacts of global warming of 1.5 degrees, along with ways the world could feasibly keep the temperature from rising further.
The summary tells a nightmarish tale-one much worse than any of those in the I.P.C.C.’s previous reports-surveying the climate-change impacts we’re already experiencing with one degree of warming, and the severity of the impacts to come once we surpass 1.5 degrees of warming.
With two degrees of warming, three times as many insects, and twice as many plants and vertebrates, will lose their geographic range, when compared with warming of 1.5 degrees.
To keep warming at 1.5 degrees, governments and private businesses must make unprecedented changes-on a sweeping global scale-in energy systems, land management, building efficiency, industrial operations, shipping and aviation, and city-wide design.
“Human activities,” the report’s authors note, have already caused the global mean temperature to increase as much as 1.2 degrees Celsius above pre-industrial levels, with greater warming in certain regions, and particularly in the Arctic.
If warming continues at its current rate, it could reach 1.5 degrees by the time a child who is now a toddler starts high school.
The rate of sea-level rise accelerates once the West Antarctic Ice Sheet hits its tipping point-likely set to occur somewhere between 1.5 and two degrees of warming, if it hasn’t occurred already-when physics demands the whole sheet will irreversibly disintegrate.

The orginal article.