As part of the White House “Open For Questions” video posted last week, Holdren was asked: “Do you know the rate of reduction in carbon emissions the world would have to achieve in order to prevent an unstoppable process of methane release from the Arctic areas?”
“No one knows for sure how much warming would be enough to produce this result, but it's thought to be considerably less likely to happen if the ultimate warming is less than 2 degrees Celsius, that is 3.6 degrees Fahrenheit above the pre-industrial value, than if the ultimate warming is greater than that,” Holdren responded.
“That was one of the reasons why the nations that are party to the United Nations framework convention on climate change have embraced a global goal of keeping the increase below the 2 degrees Celsius.”
“To have a better than even chance of meeting that goal would require global emissions of carbon dioxide to be about 50% below their 2005 value by 2050 and close to zero by 2100. That will not be easy, but with appropriate leadership from the United States, China and the other big emitters it can be done,” Holdren continued.
According to the Earth Policy Institute, in 2005 carbon emissions from fossil fuel burning reached 7.9 billion tons. It was approximately 4 billion tons in 1969 and was at 3 million tons in 1751, before the automobile.
“Similarly, there are large stores of methane frozen into ice crystals under the Arctic Ocean, some which could also be released if enough warming occurred. Release of any significant fraction of these carbon stocks would speed up the pace of global warming.”