A group of scientists has just published a new
estimate of how sensitive earth is to rising greenhouse gases.
Their value for 'climate sensitivity' is at the low end of what
scientists have previously suggested - but there's still a lot of
Importantly, the study shows slower surface
temperature rise over the past decade doesn't change scientists'
projections of how much warming we can expect in the long term.
What scientists call 'equilibrium climate sensitivity' is the
warming we can expect from a doubling of carbon dioxide in the
atmosphere, compared with pre-industrial levels. It's a number
scientists are still trying to pin down - and it's important,
because the higher climate sensitivity is, the more warming there
In its last report, published in 2007, the Intergovernmental
Panel on Climate Change (IPCC) estimated a likely range of climate
sensitivity of between
two and 4.5 degrees Celsius, with a best estimate of three
degrees. But it didn't rule out lower or higher values and since
then, scientists have continued to try to narrow the range of
uncertainty surrounding the number.
new study, published as a letter in Nature Geoscience, is based
on measurements of how much heat the land, ocean, ice and
atmosphere have absorbed between 1970 and 2009.