A warm climate is more sensitive to changes in atmospheric CO2

November 9, 2016
Global mean temperature anomaly with respect to preindustrial reference level. Left panel: Reconstruction of last 784,000 yrs. Right panel: Global warming projection to 2100 based on newly calculated paleoclimate sensitivity. Credit: Friedrich, et al. (2016)

It is well-established in the scientific community that increases in atmospheric CO2 levels result in global warming, but the magnitude of the effect may vary depending on average global temperature. A new study, published this week in Science Advances and led by Tobias Friedrich from the International Pacific Research Center (IPRC) at the University of Hawai?i at Mānoa (UHM), concludes that warm climates are more sensitive to changes in CO2 levels than cold climates.

Increasing atmospheric CO2 concentrations cause an imbalance in the Earth's heat budget: more heat is retained than expelled, which in turn generates global surface warming. Climate sensitivity is a term used to describe the amount of warming expected to result after an increase in the concentration of CO2. This number is traditionally calculated using complex computer models of the climate system, but despite decades of progress, the number is still subject to uncertainty.

The new study, which included scientists from the University of Washington, the University at Albany, and the Potsdam Institute for Climate Impact Research, took a different approach in calculating : using data from the history of Earth. The researchers examined various reconstructions of past temperatures and CO2 levels to determine how the climate system has responded to previous changes in its .

"The first step was to reconstruct the history of global mean temperatures for the last 784,000 years, using combined data from marine sediment cores, ice cores, and computer simulations covering the last eight glacial cycles," said Friedrich, a post-doctoral researcher at IPRC.

The second step involved calculating the Earth's energy balance for this time period, using estimates of concentrations extracted from air bubbles in ice cores, and incorporating astronomical factors, known as Milankovitch Cycles, that effect the planetary heat budget.

"Our results imply that the Earth's sensitivity to variations in atmospheric CO2 increases as the climate warms," explained Friedrich. "Currently, our planet is in a warm phase—an interglacial period—and the associated increased climate sensitivity needs to be taken into account for future projections of warming induced by human activities."

Using these estimates based on Earth's paleoclimate sensitivity, the authors computed the warming over the next 85 years that could result from a human-induced, business-as-usual greenhouse gas emission scenario. The researchers project that by the year 2100, global temperatures will rise 5.9°C (~10.5°F) above pre-industrial values. This magnitude of warming overlaps with the upper range of estimates presented by the Intergovernmental Panel on Climate Change (IPCC).

"Our study also allows us to put our 21st century temperatures into the context of Earth's history. Paleoclimate data can actually teach us a lot about our future," said Axel Timmermann, co-author of the study and professor at UHM.

The results of the study demonstrate that unabated human-induced are likely to push Earth's out of the envelope of temperature conditions that have prevailed for the last 784,000 years.

"The only way out is to reduce greenhouse gas emissions as soon as possible," concluded Friedrich.

Explore further: Fewer low clouds in the tropics

More information: "Nonlinear climate sensitivity and its implications for future greenhouse warming," Science Advances, DOI: 10.1126/sciadv.1501923

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17 comments

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entrance
1 / 5 (5) Nov 10, 2016
It's allways the year 2050.

Have a look at the graph. 2050 will become critical. Then we will probably exceed the maximum warming (inc. uncertainty).

2050 is also a very significant year in another context. By 2050 we won't have enough food worldwide. Reasons are water and air pollution, overfishing, destroying our environment, bees decline, global warming and of course overpopulation. I beliefe, solving the problem overpopulation would automatically solve a lot of other problems.

I am ready to help.
antialias_physorg
5 / 5 (6) Nov 10, 2016

I am ready to help.

That means as much as saying "I'm ready to invent faster than light travel". In effect what you are actually saying is: "I am a self conceited idiot"
Stop it.
entrance
2 / 5 (4) Nov 10, 2016
@antialias_physorg

Sorry, i don't understand this "I'm ready to invent faster than light travel"-comparsion (but my english is not very good, maybe that's the reason). Do you think, that we are not capable solving our problems?
TheGhostofOtto1923
3 / 5 (2) Nov 10, 2016
2050 is also a very significant year in another context. By 2050 we won't have enough food worldwide
We already don't have enough food worldwide because of overpopulation. By 2050 the situation should be resolved one way or another.
antigoracle
1.8 / 5 (5) Nov 10, 2016
2050 is also a very significant year in another context. By 2050 we won't have enough food worldwide
We already don't have enough food worldwide because of overpopulation. By 2050 the situation should be resolved one way or another.

Yet, the fattest nation in the world wastes 30-40 percent of its food.
gkam
Nov 10, 2016
This comment has been removed by a moderator.
Protoplasmix
3 / 5 (2) Nov 10, 2016
We already don't have enough food worldwide because of overpopulation.
No, because of stupidity – they're growing lettuce on the ISS: anyone suggesting there's not enough sunlight or available space to grow things on the planet, or especially in the wide open solar system, is a backwards-looking crapitalist loon.
antialias_physorg
5 / 5 (6) Nov 10, 2016
Do you think, that we are not capable solving our problems

I'm saying that you're just making a baseless claim.

I am ready for...anything. So what? What help is that, exactly? To anyone? None whatsoever.


Either you solve a problem or you don't. But "being ready" to solve a problem doesn't help anyone. It just means you're a nacissist idiot.

It's like a fat guy who says "I am ready to go on a diet". But who doesn't go on a diet. What would _you_ think of such a person? Complete idiot, right?
antigoracle
1.8 / 5 (5) Nov 10, 2016
I am ready to help.

Hey entrance, if you are truly ready to help, let me show you to the EXIT. It's just a single step of a tall cliff.
Protoplasmix
1 / 5 (1) Nov 10, 2016
late edit, I'm not kidding: The Greatest Threat to Global Food Security: Capitalism

It's arguably too soon to tell, but the climate aboard the ISS appears stable over the long haul. Exceptionally fair skies.
entrance
1 / 5 (1) Nov 10, 2016
@antialias_physorg

But i am already doing something by telling the people that a problem exists.

First you have to recognize a problem before you can solve it. And in many contries many people even don't know this problem. For example in Austria noone is talking about it. In my whole life i have never heard a politican mentioning the problem overpopulation. And i also can't remember, whether i have ever read an article on an Austrian website or in an Austrian newspaper.

Fact is that Austrians are currently hardly affected by this problem. But we can already recognize the first signs. Something is temporarely unavailable, something becomes more expensive, something dissapears from our supermarket's shelves. Such events will occur more often in future, and they will affect us more and more.

I believe, it is better to care about a problem before it gets critical. Otherwise it could be too late one day to solve this problem. I think, what i do, is better than doing nothing.
philstacy9
1 / 5 (6) Nov 10, 2016
Funding for climate research and climate engineering is sensitive to which ideology was recently elected president. Expect big changes in the climate scientific "consensus".
antialias_physorg
5 / 5 (3) Nov 11, 2016
But i am already doing something by telling the people that a problem exists.

Wow. Really? A problem exists? And you're telling people?

(Hint: that was sarcasm: people have been aware that a problem exists for 40 years. You're basically the last person on Earth to notice.)

For example in Austria noone is talking about it

Austria is set to miss its climate goals (but one must also take into account that it already produces 65% of its electricity from renewables - which is far larger than many other nations. The climate goals are respective to 1990 levels where renewables were already in widespread use in Austria)

i have never heard a politican mentioning the problem overpopulation.

Then you haven't been listening.
TheGhostofOtto1923
5 / 5 (2) Nov 11, 2016
No, because of stupidity – they're growing lettuce on the ISS: anyone suggesting there's not enough sunlight or available space to grow things on the planet, or especially in the wide open solar system, is a backwards-looking crapitalist loon
Look, I know you're a crackpot, but in actuality few people really grasp the reproductive potential of the tropical human animal.

Any species will produce more offspring than can be expected to survive to maturity. Humans have perhaps an unnatural love for their offspring, and began finding ways of saving them from predation, disease, accident, and harsh environs.

And when as a result they began starving in ever greater numbers they began domesticating plants and animals in order to feed them.

Maltus gave voice to the sad equation that had been known for millenia; the more you feed the more you have to feed. And sooner or later, no matter what you do, you run out of ways to feed.
Cont>
TheGhostofOtto1923
5 / 5 (2) Nov 11, 2016
And as children begin to starve, the people will blame their rulers no matter how benevolent or well-meaning these rulers might be. This has always made the people the enduring enemies of rulers everywhere. The result has always been war or revolution.

The only possible sustainable solution to this horrible equation is to reduce the birthrate, and we have not been able to do this until very recently without having to resort to infanticide, pogrom, or wholesale human sacrifice.

Infanticide, pogrom, and wholesale human sacrifice can take many forms, some direct and some not so recognizable.

Engineered wars can be appreciated as indirect forms of these actions. Pops can be stressed, forced out, or slaughtered in place. Demographics is the science behind engineered conflict and it is an ancient discipline.
TheGhostofOtto1923
5 / 5 (2) Nov 11, 2016
The Greatest Threat to Global Food Security: Capitalism
Have you considered the more efficient methods of warlords and communists? You may want to learn more about mass starvation in Somalia and Sudan, or Holodomor. Or the engineered pogroms like the khmer rouge in Cambodia or those in Rwanda and Burundi which were precipitated by the church.
Uncle Ira
3.4 / 5 (5) Nov 11, 2016
First you have to recognize a problem before you can solve it.


There are a lot peoples writing really stupid stuffs on the physorg.

And I am ready to help.

I believe, it is better to care about a problem before it gets critical. Otherwise it could be too late one day to solve this problem.
It might be to late already, those stupid peoples seem to have become a fixture.

But I am ready to help.

I think, what i do, is better than doing nothing.


Since I was already ready, let me help you with that. Nothing is stupider than an idiot doing what he does while he is being ready to help.

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