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“Earth is likely to cross a critical threshold for global warming within the next decade, and nations will need to make an immediate and drastic shift away from fossil fuels to prevent the planet from overheating dangerously beyond that level, according to a major new report released on Monday.
The report, by the Intergovernmental Panel on Climate Change, a body of experts convened by the United Nations, offers the most comprehensive understanding to date of ways in which the planet is changing. It says that global average temperatures are estimated to rise 1.5 degrees Celsius (2.7 degrees Fahrenheit) above preindustrial levels sometime around “the first half of the 2030s,” as humans continue to burn coal, oil and natural gas.
That number holds a special significance in global climate politics: Under the 2015 Paris climate agreement, virtually every nation agreed to “pursue efforts” to hold global warming to 1.5 degrees Celsius. Beyond that point, scientists say, the impacts of catastrophic heat waves, flooding, drought, crop failures and species extinction become significantly harder for humanity to handle.
But Earth has already warmed an average of 1.1 degrees Celsius since the industrial age, and, with global fossil-fuel emissions setting records last year, that goal is quickly slipping out of reach.” . . . . .
David Lindsay: Excellent, but tragic report, thank you Brad Plumer. Here is a great comment, from one of my favorite commentors:
Many people are simply unaware of the scale of the threat which climate change poses to humanity. The carbon cycle for the last 2 million years was doing 180-280ppm atmospheric CO2 over 10,000 years and we’ve done more change than that in 100 years. The last time CO2 went from 180-280ppm global temperature increased by around 4 degrees C and sea level rose 130 meters. (graph of the last 400,000 years of global temperature, CO2 and sea level http://www.ces.fau.edu/nasa/images/impacts/slr-co2-temp-400000yrs.jpg ) One amplifying feedback alone out of dozens, loss of albedo or heat reflectivity from Arctic summer sea ice melt, over the last several decades has been equivalent to 25 percent of the climate forcing of anthropogenic CO2. And that will continue to increase as that ice largely disappears by mid century. The Titanic sank because by the time the lookout called the warning the ship had too much momentum to turn. The Earth has a lot more momentum, e.g. we’ve already likely locked in at least 6 meters of sea level rise from the marine sectors of Greenland and West Antarctica’s ice sheets, and decade to decade warming in the near term is also virtually locked in. That momentum is building and the higher we let global temperatures rise the greater the risk of them going really high as amplifying feedbacks strengthen.