Study discovers why global warming will accelerate as CO2 levels rise

November 29, 2017, University of Reading
Study discovers why global warming will accelerate as CO2 levels rise
Credit: University of Reading

Global warming is likely to speed up as the Earth becomes increasingly more sensitive to atmospheric CO₂ concentrations, scientists from the University of Reading have warned.

In a new study, published this week in the prestigious journal PNAS, the scientists explain that the influence of increasing levels of atmospheric CO2 on will become more severe over time because the patterns of warming of the Earth's will lead to reduced cloud cover in some sensitive regions and less heat being able to escape into space.

The findings are supported by observations, suggesting that forecasts made by climate models evaluated by the Intergovernmental Panel on Climate Change are realistic.

Paulo Ceppi, researcher at the University of Reading and lead author of the study, said: "This resemblance of computer simulations to observations increases our confidence in projections that the climate sensitivity to the progressive rise in will increase over time into the future."

Evidence suggests that the upper level of the Earth's atmosphere warms faster than the surface in response to CO2 levels. However, the new study shows that as CO2 levels increase further, the rate of warming in the upper levels slows in comparison with that closer to the Earth's surface.

Reduced contrast in temperature between the upper and lower levels of the atmosphere causes decreased low altitude cloud cover over some areas of the Earth's oceans, leading to more sunlight reaching the sea surface, and therefore a more rapid rise in .

These conditions also impede the loss of heat from the atmosphere into space, contributing to the accelerated surface warming in response to rising CO2 concentrations.

These results emphasise the importance of rapidly reducing human caused emissions of greenhouse gases to avoid the worst impacts from ongoing as discussed at the recent COP23 meeting in Bonn that builds upon the 2017 Paris climate agreement.

Explore further: Formation of coal almost turned our planet into a snowball

More information: Paulo Ceppi et al. Relationship of tropospheric stability to climate sensitivity and Earth's observed radiation budget, Proceedings of the National Academy of Sciences (2017). DOI: 10.1073/pnas.1714308114

Related Stories

Formation of coal almost turned our planet into a snowball

October 9, 2017

While burning coal today causes Earth to overheat, about 300 million years ago, the formation of coal brought the planet close to global glaciation. For the first time, scientists show the massive effect in a study to be ...

Fewer low clouds in the tropics

August 16, 2016

With the help of satellite data, ETH scientists have shown that low-level cloud cover in the tropics thins out as the earth warms. Since this cloud cover has a cooling effect on the climate, the two-degree warming target ...

NASA data suggest future may be rainier than expected

June 12, 2017

A new study suggests that most global climate models may underestimate the amount of rain that will fall in Earth's tropical regions as our planet continues to warm. That's because these models underestimate decreases in ...

Ocean temperature as a vital sign revealing Earth's warming

September 14, 2017

Human activities have released carbon dioxide and other greenhouse gases into the atmosphere, and the result is an accumulation of heat in the Earth's climate system, commonly referred to as "global warming." But how fast ...

New study confirms water vapor as global warming amplifier

July 28, 2014

A new study from scientists at the University of Miami Rosenstiel School of Marine and Atmospheric Science and colleagues confirms rising levels of water vapor in the upper troposphere – a key amplifier of global warming ...

Recommended for you

Amazon River pirating water from neighboring Rio Orinoco

August 16, 2018

The Amazon River is slowly stealing a 40,000-square-kilometer (25,000-square-mile) drainage basin from the upper Orinoco River, according to new research suggesting this may not be the first time the world's largest river ...

6 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

El_Nose
not rated yet Nov 29, 2017
How is this a new explanation. It is a new study, but same theory that i learned in grade school
aksdad
1 / 5 (3) Nov 29, 2017
The findings are supported by observations, suggesting that forecasts made by climate models evaluated by the Intergovernmental Panel on Climate Change are realistic.

Uh huh. Suuure they are.

And back on planet reality, there are no observations that show a trend of decreased cloud cover over the oceans. So all the claims are based on computer manipulated climate models which have not been verified against observations. Science: 1 Alarmist climate study: 0

Refer to the latest (2013) report from IPCC. Look at the chapter on "Observations". Nothing on reduced cloud cover over the oceans.
snoosebaum
1 / 5 (3) Nov 29, 2017
Ok. now i know this AGW is total BS insanity , just go look at Monthy Avg charts back as far as u can [if you can find them ] You may have to plot a few yourself and only white countries have them, BOM in aus are the easiest , Canada u have to compare month to month. pick any location , NO HOCKEY STICKs R SEEN ! all look flat .
aksdad
1 / 5 (2) Nov 29, 2017
On second thought, I'll do the work for you so you don't have to. But you can verify it yourself in the IPCC AR5 report (2013), Chapter 2, Observations: Atmosphere and Surface, section 2.5.6 Clouds (p. 208):

http://www.ipcc.c...ex.shtml

Satellite observations of low-level marine clouds suggest no long-term trends in cloud liquid water path or optical properties (O'Dell et al., 2008; Rausch et al., 2010).

And
there remains substantial ambiguity regarding global-scale cloud variations and trends, especially from satellite observations

You're welcome.

aksdad
1 / 5 (2) Nov 29, 2017
Oh, and one more thing. Here's how realistic the IPCC found the models in 2013, from the Fifth Assessment Report:

https://www.ipcc....S-14.jpg

That black line below all the squiggly colored lines represents global temperature observations. The squiggly lines above are the range of temperatures predicted by several models. They all predict much more warming than has been observed.

Accuracy of climate models as shown by the IPCC? Not accurate. QED
leetennant
not rated yet Dec 06, 2017
How is this a new explanation. It is a new study, but same theory that i learned in grade school


Yeah, it's not. It's just more evidence supporting the current model.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.