SOURCE: Washington Post
DATE: February 14, 2018
SNIP: A draft United Nations climate science report contains dire news about the warming of the planet, suggesting it will likely cross the key marker of 1.5 degrees Celsius, or 2.7 degrees Fahrenheit, of temperature rise in the 2040s, and that this will be exceedingly difficult to avoid.
The draft document states that there is a “very high risk” of the planet warming more than 1.5 degrees above the temperature seen in the mid-to-late-19th century. Maintaining the planet’s temperature entirely below that level throughout the present century, without even briefly exceeding it, is likely to be “already out of reach,” it finds.
The document finds that a warming of 2 degrees Celsius (3.6 degrees Fahrenheit) would pose substantially larger risks in many respects than 1.5 degrees C — but it also finds that some severe risks will be present at 1.5 degrees, too.
What’s most striking is the radical nature and rapidity of the changes that would be required to somehow preserve a world below 1.5 degrees.
The document finds that the world has only 12 to 16 years worth of greenhouse gas emissions left, from the start of 2016, if it wants a better-than-even chance of holding warming below 1.5 degrees.
Two of those years have already elapsed, as of this writing. A third will have nearly elapsed by the time the draft report is finalized and released in October.
And once this “carbon budget” for 1.5 degrees Celsius is used up, emissions would have to plunge to zero to preserve the 1.5 degree goal — something that would almost certainly never happen, as it would sharply impair the world economy.