But… there’s only been maybe 0.8C of warming since the pre-industrial era… if you get rid of the last decimal…
The Tribune (Jackson, County, IN) reports:
Now, new research has shown that the upward move may have been too hasty, and there’s a discussion in Stockholm over whether to bring the lower end back down to 1.5 C (2.7 F).
It may seem like a minor detail, but it makes a difference to governments, which want to know how much CO2 emissions need to be cut to prevent temperatures from increasing more than 2 C (3.6 F) compared to before humans started burning fossil fuels. That’s the limit they have agreed to in U.N. climate talks. Temperatures have already gone up about 0.8 C (1.4 F).
Reducing the lower range of climate sensitivity “would mean that we have a better chance of staying below 2 degrees than we thought before,” said Kaisa Kosonen, a Greenpeace climate activist. “But I wouldn’t bet on it because they are not lowering the higher end of the range.”
In leaked comments on a June draft of the IPCC report, the British government called climate sensitivity “a key issue of concern” that helps give policy-makers a sense of how big a threat climate change is.
The United States, Australia and Norway have called for the authors to provide a single value as their best estimate in addition to a range, to give policy-makers better guidance.
Meanwhile, EU climate commissioner Connie Hedegaard is downplaying the discussion.
“You don’t need to have the last decimal to see that the overall number isn’t looking good,” she said in a comment emailed by her spokesman.
Some scientists resist giving a single value because it could give the false impression that there’s more certainty than there really is about how sensitive the climate is to CO2. That doesn’t mean they doubt that CO2 serves as an engine of warming — the question is whether it’s a four-cylinder or a V8.
“We know a great deal of the mechanism by which CO2 causes warming,” said Field, the Carnegie scientist. “There is still uncertainty about how much a range of feedbacks either amplify or suppress that warming.”