[Vision2020] Climate slowdown means extreme rates of warming 'not as likely'

[Paul Rumelhart]

Here is an article from the BBC on a paper describing how the rate of 
global warming has stalled for a few years, and how this is actually 
impacting their climate models enough that they have decided that they 
should actually try to factor it in.  I see this as a positive thing.  
Their climate models have always predicted higher temperatures than have 
been observed, yet in the past they have been content to let their 
models run on freely, with nary a concern for this disparity.

Of course, they have no idea what sort of climate forcing, strong enough 
to significantly slow down the rate of warming, has been interfering, 
but at least they have set aside a ledger item for it. They have 
acquiesced to the idea that this may push their expectations of doom and 
gloom out a few years, though they expect with confidence that it will 
get as bad as they say it will despite knowing next to nothing about the 
strength or duration of the forcing that is interfering.  Maybe someday 
they will get the idea that perhaps there are other things affecting the 
climate, and will study those with the same vigor they do CO2.  I have 
high hopes. Oh, but then  I read the last two paragraphs:

"Is there any succour in these findings for climate sceptics who say the 
slowdown over the past 14 years means the global warming is not real?

"None. No comfort whatsoever," he said."

Nuts.  Of course, climate skeptics say that it's the comparative size of 
the role of CO2 component, as well as the unknown strengths or even 
directions of the feedbacks that are at issue. Not many deny that it has 
gotten warmer.

Anyway, here's the URL: 
http://www.bbc.co.uk/news/science-environment-22567023

And here's the article:


  Climate slowdown means extreme rates of warming 'not as likely'

By Matt McGrath Environment correspondent, BBC News

Scientists say the recent downturn in the rate of global warming will 
lead to lower temperature rises in the short-term.

Since 1998, there has been an unexplained "standstill" in the heating of 
the Earth's atmosphere.

Writing in Nature Geoscience, the researchers say this will reduce 
predicted warming in the coming decades.

But long-term, the expected temperature rises will not alter significantly.

The slowdown in the expected rate of global warming has been studied for 
several years now. Earlier this year, the UK Met Office lowered their 
five-year temperature forecast.

But this new paper gives the clearest picture yet of how any slowdown is 
likely to affect temperatures in both the short-term and long-term.

An international team of researchers looked at how the last decade would 
impact long-term, equilibrium climate sensitivity and the shorter term 
climate response.

Transient nature

Climate sensitivity looks to see what would happen if we doubled 
concentrations of CO2 in the atmosphere and let the Earth's oceans and 
ice sheets respond to it over several thousand years.

Transient climate response is much shorter term calculation again based 
on a doubling of CO2.

The Intergovernmental Panel on Climate Change reported in 2007 that the 
short-term temperature rise would most likely be 1-3C (1.8-5.4F).

But in this new analysis, by only including the temperatures from the 
last decade, the projected range would be 0.9-2.0C.

"The hottest of the models in the medium-term, they are actually looking 
less likely or inconsistent with the data from the last decade alone," 
said Dr Alexander Otto from the University of Oxford.

"The most extreme projections are looking less likely than before."

The authors calculate that over the coming decades global average 
temperatures will warm about 20% more slowly than expected.

But when it comes to the longer term picture, the authors say their work 
is consistent with previous estimates. The IPCC said that climate 
sensitivity was in the range of 2.0-4.5C.

Ocean storage

This latest research, including the decade of stalled temperature rises, 
produces a range of 0.9-5.0C.

"It is a bigger range of uncertainty," said Dr Otto.

"But it still includes the old range. We would all like climate 
sensitivity to be lower but it isn't."

The researchers say the difference between the lower short-term estimate 
and the more consistent long-term picture can be explained by the fact 
that the heat from the last decade has been absorbed into and is being 
stored by the world's oceans.

Not everyone agrees with this perspective.

Prof Steven Sherwood, from the University of New South Wales, says the 
conclusion about the oceans needs to be taken with a grain of salt for now.

"There is other research out there pointing out that this storage may be 
part of a natural cycle that will eventually reverse, either due to El 
Nino or the so-called Atlantic Multidecadal Oscillation, and therefore 
may not imply what the authors are suggesting," he said.

The authors say there are ongoing uncertainties surrounding the role of 
aerosols in the atmosphere and around the issue of clouds.

"We would expect a single decade to jump around a bit but the overall 
trend is independent of it, and people should be exactly as concerned as 
before about what climate change is doing," said Dr Otto.

Is there any succour in these findings for climate sceptics who say the 
slowdown over the past 14 years means the global warming is not real?

"None. No comfort whatsoever," he said.

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