Yet another study shows lower climate sensitivity

Global warming less extreme than feared?

Policymakers are attempting to contain global warming at less than 2°C. New estimates from a Norwegian project on climate calculations indicate this target may be more attainable than many experts have feared.

Photo: Shutterstock

The researchers have arrived at an estimate of 1.9°C as the most likely level of warming. (Photo: Shutterstock)

Internationally renowned climate researcher Caroline Leck of Stockholm University has evaluated the Norwegian project and is enthusiastic.

“These results are truly sensational,” says Dr Leck. “If confirmed by other studies, this could have far-reaching impacts on efforts to achieve the political targets for climate.”

Temperature rise is levelling off

After Earth’s mean surface temperature climbed sharply through the 1990s, the increase has levelled off nearly completely at its 2000 level. Ocean warming also appears to have stabilised somewhat, despite the fact that CO2 emissions and other anthropogenic factors thought to contribute to global warming are still on the rise.

It is the focus on this post-2000 trend that sets the Norwegian researchers’ calculations on global warming apart. 

Sensitive to greenhouse gases

Climate sensitivity is a measure of how much the global mean temperature is expected to rise if we continue increasing our emissions of greenhouse gases into the atmosphere.

CO2 is the primary greenhouse gas emitted by human activity. A simple way to measure climate sensitivity is to calculate how much the mean air temperature will rise if we were to double the level of overall CO2 emissions compared to the world’s pre-industrialised level around the year 1750.

If we continue to emit greenhouse gases at our current rate, we risk doubling that atmospheric CO2 level in roughly 2050.

Mutual influences

A number of factors affect the formation of climate development. The complexity of the climate system is further compounded by a phenomenon known as feedback mechanisms, i.e. how factors such as clouds, evaporation, snow and ice mutually affect one another.

Uncertainties about the overall results of feedback mechanisms make it very difficult to predict just how much of the rise in Earth’s mean surface temperature is due to manmade emissions. According to the Intergovernmental Panel on Climate Change (IPCC) the climate sensitivity to doubled atmospheric CO2 levels is probably between 2°C and 4.5°C, with the most probable being 3°C of warming.

In the Norwegian project, however, researchers have arrived at an estimate of 1.9°C as the most likely level of warming.

Manmade climate forcing

“In our project we have worked on finding out the overall effect of all known feedback mechanisms,” says project manager Terje Berntsen, who is a professor at the University of Oslo’s Department of Geosciences and a senior research fellow at the Center for International Climate and Environmental Research – Oslo (CICERO). The project has received funding from the Research Council of Norway’s Large-scale Programme on Climate Change and its Impacts in Norway (NORKLIMA).

“We used a method that enables us to view the entire earth as one giant ‘laboratory’ where humankind has been conducting a collective experiment through our emissions of greenhouse gases and particulates, deforestation, and other activities that affect climate.”

For their analysis, Professor Berntsen and his colleagues entered all the factors contributing to human-induced climate forcings since 1750 into their model. In addition, they entered fluctuations in climate caused by natural factors such as volcanic eruptions and solar activity. They also entered measurements of temperatures taken in the air, on ground, and in the oceans.

The researchers used a single climate model that repeated calculations millions of times in order to form a basis for statistical analysis. Highly advanced calculations based on Bayesian statistics were carried out by statisticians at the Norwegian Computing Center.

2000 figures make the difference

When the researchers at CICERO and the Norwegian Computing Center applied their model and statistics to analyse temperature readings from the air and ocean for the period ending in 2000, they found that climate sensitivity to a doubling of atmospheric CO2 concentration will most likely be 3.7°C, which is somewhat higher than the IPCC prognosis.

But the researchers were surprised when they entered temperatures and other data from the decade 2000-2010 into the model; climate sensitivity was greatly reduced to a “mere” 1.9°C.

Professor Berntsen says this temperature increase will first be upon us only after we reach the doubled level of CO2 concentration (compared to 1750) and maintain that level for an extended time, because the oceans delay the effect by several decades.

Photo: UiB

We used a method that enables us to view the entire earth as one giant ‘laboratory’ where humankind has been conducting a collective experiment through our emissions of greenhouse gases and particulates, deforestation, and other activities that affect climate, explains professor Terje Berntsen at UiO. (Photo: UiB) Natural changes also a major factor

The figure of 1.9°C as a prediction of global warming from a doubling of atmospheric CO2 concentration is an average. When researchers instead calculate a probability interval of what will occur, including observations and data up to 2010, they determine with 90% probability that global warming from a doubling of CO2 concentration would lie between 1.2°C and 2.9°C.

This maximum of 2.9°C global warming is substantially lower than many previous calculations have estimated. Thus, when the researchers factor in the observations of temperature trends from 2000 to 2010, they significantly reduce the probability of our experiencing the most dramatic climate change forecast up to now.

Professor Berntsen explains the changed predictions:

“The Earth’s mean temperature rose sharply during the 1990s. This may have caused us to overestimate climate sensitivity.

“We are most likely witnessing natural fluctuations in the climate system – changes that can occur over several decades – and which are coming on top of a long-term warming. The natural changes resulted in a rapid global temperature rise in the 1990s, whereas the natural variations between 2000 and 2010 may have resulted in the levelling off we are observing now.”

Climate issues must be dealt with

Terje Berntsen emphasises that his project’s findings must not be construed as an excuse for complacency in addressing human-induced global warming. The results do indicate, however, that it may be more within our reach to achieve global climate targets than previously thought.

Regardless, the fight cannot be won without implementing substantial climate measures within the next few years.

Sulphate particulates

The project’s researchers may have shed new light on another factor: the effects of sulphur-containing atmospheric particulates.

Burning coal is the main way that humans continue to add to the vast amounts of tiny sulphate particulates in the atmosphere. These particulates can act as condensation nuclei for cloud formation, cooling the climate indirectly by causing more cloud cover, scientists believe. According to this reasoning, if Europe, the US and potentially China reduce their particulate emissions in the coming years as planned, it should actually contribute to more global warming.

But the findings of the Norwegian project indicate that particulate emissions probably have less of an impact on climate through indirect cooling effects than previously thought.

So the good news is that even if we do manage to cut emissions of sulphate particulates in the coming years, global warming will probably be less extreme than feared.

About the project
Geophysicists at the research institute CICERO collaborated with statisticians at the Norwegian Computing Center on a novel approach to global climate calculations in the project “Constraining total feedback in the climate system by observations and models”. The project received funding from the Research Council of Norway’s NORKLIMA programme.The researchers succeeded in reducing uncertainty around the climatic effects of feedback mechanisms, and their findings indicate a lowered estimate of probable global temperature increase as a result of human-induced emissions of greenhouse gases.The project researchers were able to carry out their calculations thanks to the free use of the high-performance computing facility in Oslo under the Norwegian Metacenter for Computational Science (Notur). The research project is a prime example of how collaboration across subject fields can generate surprising new findings.
Written by:
Bård Amundsen/Else Lie. Translation: Darren McKellep/Carol B. Eckmann
h/t to Andrew Montford via Leo Hickman
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I cringe every time I hear about Bayesian statistics being employed. Such statistics amount to
educated (or not so educated) guesses about what someone thinks the values are, presumably
incorporating knowledge that he has, and weighted according to more educated guessing.

cmarrou

“According to this reasoning, if Europe, the US and potentially China reduce their particulate emissions in the coming years as planned, it should actually contribute to more global warming.”
Talk about damned if you do…

I still insist that future carbon emissions are going to be drastically reduced simply as a matter of advanced technology in personal vehicles (they’re going electric, just as fast as batteries can be reduced in price) and, hopefully, widespread nuclear power. Assuming heavy future carbon emissions is just plain dumb, in my opinion.

Ray Hudson

So in summary:
1) It is not worse than we thought.
2) It is not even as bad as we thought.
3) But pay no mind to the data that falsifies our predictions of doom. We are all still doomed and have to take drastic action.
4) Please keep sending us money so we can continue to study this dangerous problem.
Yeah. Right. Friggin crooks.

Keith Gordon

Seems to be part of an ever growing back tracking on Co2 sensitivity, if this come from an increase in temperature’s in the 1990s and a halt in 2000s what would a sustained drop in temperatures do to there projections, maybe we shall see soon enough.
Keith Gordon

john price

Very interesting that reducing particulates would lead to further warming not cooling. An. Obvious contradiction to the regulatory trend.

Henry says
How dumb can you be? What a waste of money, time and effort.
“But the researchers were surprised when they entered temperatures and other data from the decade 2000-2010 into the model; climate sensitivity was greatly reduced to a “mere” 1.9°C.”
Now, if they had asked me I could had given them this information in 2 minutes:
http://www.woodfortrees.org/plot/hadcrut4gl/from:2002/to:2013/plot/hadcrut4gl/from:2002/to:2013/trend/plot/hadcrut3vgl/from:2002/to:2013/plot/hadcrut3vgl/from:2002/to:2013/trend/plot/rss/from:2002/to:2013/plot/rss/from:2002/to:2013/trend/plot/gistemp/from:2002/to:2013/plot/gistemp/from:2002/to:2013/trend/plot/hadsst2gl/from:2002/to:2013/plot/hadsst2gl/from:2002/to:2013/trend
which shows/proves earth has been is cooling since 2002.
The results of my investigations prove that this cooling will accelerate, because we are on a curve, curling down. So the next two or three decades will become successively cooler.
For those interested in reading the truth about global warming and global cooling see here:
http://blogs.24.com/henryp/2013/01/24/our-earth-is-cooling/

coalsoffire

Wouldn’t it be easier to use chicken bones or even dice to come up with a totally random guess and then average it? But probably that sort of easy work is not as well paid.

Paul Matthews

The paper on which this is based (annoyingly the news release doesn’t say) may be
http://t.co/SAC5YSR5
If so, it says sensitivity is around 1.9C, see Fig 6, and the news release is wrong to say that it depends so much on whether or not the last 10 yrs are included (compare fig 6 a and c)

Matthew R Marler

Let a thousand models bloom. Let a hundred schools of thought contend.

Wamron

How exactly is this good news?
When amelioration was unobtainable this undermined the drive to impose restrictions on us that would achieve nothing.
If this makes it seem ameliorations are attainable it only strengthens the hand of those who want to control our lives.
I dont give a fig for “the environment” or what happens when Im gone.I only care about surviving the present economic oppression.
This isnt going to help.

Ian E

Well, of course, it is essential to lower their estimates of climate sensitivity – otherwise it would be too late to stop 2 degrees of heating and politicians could no longer coerce the public to accept further direct and indirect taxes by scaring them with mention of tipping points. Now they can go back to their mantra of 2 decades/2 years/2 months/etc to save the Earth!
Still, it is nice to see that the science has been so completely settled all along.

RobW

Sorry a tad OT but Mr. Watts would you please add a page to the reference pages on ” Ocean Acidification”. It is clear the warmists have lost the temperature scare and are moving in droves to the CO2 cause the oceans to die meme. I have had several debates but require better inform ation to continue to be successful in public forums. Thanks

The part where it is stated “Regardless, the fight cannot be won without implementing substantial climate measures within the next few years.” seems rather weird especially when the latest science appears to confirm that we should be trying to double the CO2 concentration for a better world.

RMB

You can not heat water from above. surface tension blocks the heat very emphatically and very convincingly. Thats why there is no climate sensitivity.

Eliza

Being sarcastic:
We need money to continue in our jobs so we added the following paragraph to our report which really shows that it’s better to do nothing:
“Climate issues must be dealt with Terje Berntsen emphasises that his project’s findings must not be construed as an excuse for complacency in addressing human-induced global warming. The results do indicate, however, that it may be more within our reach to achieve global climate targets than previously thought. Regardless, the fight cannot be won without implementing substantial climate measures within the next few years.”
LOL

Pathway

Burn more coal. Yea.

mason

I find it hard to believe that only carbon dioxide is the sole forcer of temperature change..when there are so many other gases such as methane and water vapor that are equally or more important and forget the input by the sun and ocean currents

cedarhill

Perfect timing! Declare victory, impose taxes and whatnot to keep it “stable” and move on to the next bonfilre to light so the sun will come back in the Spring.

kim

Well darn, I guess there just isn’t going to be enough carbon dioxide to prevent the next Ice Age. Mother Gaia is such a tease.
===========

Policymakers are attempting to …

‘Policymakers’ used to be my elected representatives (who wrote the law, enacted legislation, etc.) … who are they now?
Elected representatives are accountable to the people (to varying degrees, obviously) who elected them (voted on every 2, 4 or 6 years depending on the office) … how are today’s policymakers held accountable, or responsive to the people and THEIR desires?
Are we talking about the bureaucrats who infest -er- inhabit the various federal (and state, etc) agencies that carry out enacted legislation, or somebody else?
Just seeking clarification on that point …
.

Mark Bofill

“Burning coal is the main way that humans continue to add to the vast amounts of tiny sulphate particulates in the atmosphere. These particulates can act as condensation nuclei for cloud formation, cooling the climate indirectly by causing more cloud cover, scientists believe. According to this reasoning, if Europe, the US and potentially China reduce their particulate emissions in the coming years as planned, it should actually contribute to more global warming.”
Priceless.
It’s a darn good thing the science is settled, otherwise studies like this one might upset a lot of political apple carts.

FrankK

More model Monte Carlo alchemy. Just watched a new series of ‘Yes Prime Minister’ (G.O.L.D. TV UK) and the PM summarised it succinctly:
[Climate] “Computer models are no different to fashion models: seductive, unreliable, easily corrupted and they lead sensible people to make fools of themselves”
[] My addition.
Cheers.

davidmhoffer

They used a method that allows them to view the entire earth as a giant laboratory? What did they think the rest of the methods use? A single thermometer on the back of a donkey wandering around Afghanistan?
Then with all the data up to 2000 they come up with sensitivity of 3.7 but then they add in the data post 2000 it drops to 1.9
Interpretation? Their model is wrong. It gets before 2000 wrong and adding post 2000 data to it produces a radically different number. When adding in less than 10% of the data cuts your model estimate in half, it is a good sign that your model is trash.

How many angels can dance on the head of a pin? Until we know, in detail, all the characterisitcs of natural variations of global temperatures, it is impossible to estimate climate sensitivity in this manner. Until we have an actual way of measuring climate sensitivity, these guesses merely recognize that the previous estimates, which were claimed to be accurate by the IPCC, are merely only guesses. No-one has the slightest idea what the value for climate sensitivity is. My estimate that, since there is no CO2 signal in any modern temperature/time graph, the value of climate sensitivity is probably indistinguishable from zero, is a much simpler way of doing the estimations, and is probably as good as any other guess.

pochas

We must create a World Climate Control Commission with the power to Tax The World!

rgbatduke

The really, really amusing thing about this is the enormous impact that a tiny timespan has had on the estimate (which is absolutely on the right track). And that timespan is not “finished”. Every year with basically neutral temperature at this point shaves another 0.1 C off of the overall expected sensitivity, at least down to the 1-1.4C expected from CO_2 only, at least 0.3 to 0.4 of which we’ve already experienced as CO_2 went from 300 to 400 ppm.
Indeed, that’s the pace — 1.2 C total warming by the time CO_2 gets to 600 ppm. Maybe. But we really have only a tiny segment of good, tamper-proof data (RSS or UAH, take your pick). If they remain flat for another decade, or go down, that will completely alter the predictions. If they go up, or sharply up, that will completely alter the predictions.
Doesn’t sound particularly settled, but then, our ignorance is profound. It isn’t settled, as this study clearly shows.
Note well, if the climate remains flat, AR6 is going to reduce sensitivity to less than 2 C just as AR5 is dropping it well below 3C — nobody believes the extreme predictions any more. The IPCC simply is unwilling to face how meaningless all of these predictions are, given their extreme statistical sensitivity to new data as it comes in.
rgb

policycritic

Is there a link? The one you give is to an email address. Thx.

Rex

“The Earth’s mean temperature rose sharply during the 1990s.”
‘Sharply’ ? Fractional increases in temperature that humans
would not be able to discern without the aid of instrumentation.

DirkH

“These results are truly sensational,” says Dr Leck. “If confirmed by other studies, this could have far-reaching impacts on efforts to achieve the political targets for climate.”

The rent seekers are queuing at the exit.

mpainter

A new tinker toy contraption that is going to show us how things do not work. How many global climate models does this make so far?

James Ard

Off topic, but this morning on cspan they had a Reuters reporter taking questions on the drought. When the question of whether global warming has any influence, the reporter mentioned droughts in the 50s and the 80s and pretty much blamed cycles. I nearly fell out of my chair. I believe the ship jumping is becoming an epidemic.

Kev-in-Uk

I dunno, is it just me, or does this seem yet more of the ‘gradual climbdown’ over recent months?
Their hypothesis of CO2 being the primary driver has been fairly clearly falsified due to lack of warming despite significant CO2 increase and that hurts them!
or – if they want to claim this current lack of warming is due to natural variability, then the previous warming could also be due to natural variability – and that hurts them too!
it just strikes me they are desperate to find something they can turn too – but the simple fact remains, that the data (even fudged data) is not showing what they need it to show.
Now would be a good time to record the names of all the alarmists, along with any screencaps of their actions – as in due course, they will all be reversing course and claiming they were misled, etc, etc.
What if the economy still doesn’t recover after all that wasted money on AGW ? – I can well imagine Jones, Hansen et al being physically forced to eat their words in a few years time by the impoverished folk they have ‘created’! The sounds of several hundred million cold starving folk, baying for blood must be beginning to haunt their dreams!

DirkH

arthur4563 says:
January 25, 2013 at 7:12 am
“I still insist that future carbon emissions are going to be drastically reduced simply as a matter of advanced technology in personal vehicles (they’re going electric, just as fast as batteries can be reduced in price)”
No Moore’s Law for batteries.

DesertYote

More Post-Normal thinking, OY! If the methodology used to derive the so called “Climate Sensitivity” was valid, then it would be independent on the set of data used, as long as the size of the domain is greater then zero. So what happens to the derived figure when data from 2010 to 2013?
These jokers are just trying to keep CO2 reduction a viable tool in the Marxist war against prosperity by explaining away the failure of temperatures to raise as expected. They showed their hand in these paragraphs:
‘“These results are truly sensational,” says Dr Leck. “If confirmed by other studies, this could have far-reaching impacts on efforts to achieve the political targets for climate.”’
and
“Terje Berntsen emphasises that his project’s findings must not be construed as an excuse for complacency in addressing human-induced global warming. The results do indicate, however, that it may be more within our reach to achieve global climate targets than previously thought.
Regardless, the fight cannot be won without implementing substantial climate measures within the next few years.”

banjo

“Less extreme than feared”? or `It`s milder than predicted…how wonderful`
Well, at least we know what they were hoping for, and what they actually fear.

Oscar Bajner

Sometimes I truly wish I could time travel:
Circa 2020 — Climate Scientists announced today that they have updated their model with
data from the period 2010 – 2020 and are very surprised that the model outputs a climate
sensitivity of 1.4125.
Scientists were reportedly very excited that the lower sensitivity implied that emissions
control policies were now even closer within reach, but cautioned that we should not become
complacent, and that further study was necessary.
/sarc

Jan P Perlwitz

davidmhoffer wrote in http://wattsupwiththat.com/2013/01/25/yet-another-study-shows-lower-climate-sensitivity/#comment-1208754

When adding in less than 10% of the data cuts your model estimate in half, it is a good sign that your model is trash.

It’s not often that we agree. I am not going to jump to the conclusion that is was “trash”, but such a result is suspicious at least.

DesertYote

_Jim says:
January 25, 2013 at 7:56 am
Policymakers are attempting to …
###
“Policymaker” is standard term from the Marxist lexicon that encapsulates a concept that exists within the Marxist world-view. Like most Marxist jargon, what it appears to mean and what it means to the Marxist are different. In this case, the term is used to identify those pressure points that the Marxist activist can target in order to achieve their goal of the enslavement of mankind.
Whenever you read such terminology, you can be pretty sure that you are reading something embedded within the Marxist world-view. Even if the writer is not aware of it. Marxist have had such an influence on our society that even conservative thought is polluted with this non-sense.

DCA

I saw this today at bishop-hill re: CS
Uniform priors and the IPCC
http://www.bishop-hill.net/blog/2013/1/25/uniform-priors-and-the-ipcc.html

Phil's Dad

But the researchers were surprised when they entered temperatures and other data from the decade 2000-2010 into the model; climate sensitivity was greatly reduced to a “mere” 1.9°C.
I know others have already commented on this but…seriously? They were surprised by this?!
(And for Jim who wanted clarification at January 25, 2013 at 7:56 am. Let’s be absolutely clear about this; it depends.)

the1pag

It would seem that Norway, being at fairly high latitudes, should be more concerned about the prospect of oncoming global cooling as indicated by the odd current behavior of sunspot cycle 24. Of course CO2 assists the sun in warming us in a minor manner, so in 30 or 40 years will Norwegians be welcoming all the CO2 that can be economically produced?

jae

Ho hum. Another day, another climate model…

“If confirmed by other studies, this could have far-reaching impacts on efforts to achieve the political targets for climate.”
Political targets… nuff said.

Gary

Who would have thought using a model sensitive to recent temperatures would produce such a result? Amazing, simply amazing. /sarc

John Peter

“arthur4563 says:
January 25, 2013 at 7:07 am
I cringe every time I hear about Bayesian statistics being employed. Such statistics amount to
educated (or not so educated) guesses about what someone thinks the values are, presumably
incorporating knowledge that he has, and weighted according to more educated guessing.”
I wonder if the discussion between learned statisticians at Bishop Hill has any bearing on the use of Bayesian statistics in this study.
http://bishophill.squarespace.com/blog/2013/1/25/uniform-priors-and-the-ipcc.html
Nick Lewis and Steve Jewson chime in with advice on why not to use flat prior, but Jeffreys’ Prior instead.

D.B. Stealey

Each new ‘study’ ratchets down the climate sensitivity estimate. In fact, sensitivity to 2xCO2 is statistically zero. This shows why. Any effect from adding more CO2 is lost in the noise. It is simply too small to measure. Thus, the “carbon” scare is falsified.

Eric H.

I am listening but I can’t make out the sound of any apologies…Nope, in fact Lindzen, Spencer, and others that have been estimating sensitivity at less than 2C are still being denigrated by the consensus. Of course the politics haven’t changed…

geo

Yawn. Mostly what this confirms is that for all their insisting climate models are fancy and robust, they’re really just “we expect what’s been happening will keep happening”, and aren’t truly independently predictive at all.

they determine with 90% probability that global warming from a doubling of CO2 concentration would lie between 1.2°C and 2.9°C.
Luke warmers.
And sensitivity to 2x c02 cannot be zero. If it were then changes in solar input would be zero.