Global warming – more complex than we thought

mehhl_fig1

Figure 1 | The external forcing and responses. a, The grey line shows the annual mean time series of effective radiative (solar and volcanic) forcing. The red line shows the 11-year running mean time series of solar radiation. The blue line shows volcanic radiative forcing. The black line shows the effective
radiative (solar-volcanic) forcing. The purple line shows the CO2 concentration (right axis). b, Shown are the global mean temperature (red), and the global mean precipitation intensity (blue) simulated in the forced run with the ECHO-G model. (p.p.m., parts per million.)

From the University of Hawaii ‑ SOEST, more modeling mania for the future.

New research shows complexity of global warming

Greenhouse gases versus solar heating

Global warming from greenhouse gases affects rainfall patterns in the world differently than that from solar heating, according to a study by an international team of scientists in the January 31 issue of Nature. Using computer model simulations, the scientists, led by Jian Liu (Chinese Academy of Sciences) and Bin Wang (International Pacific Research Center, University of Hawaii at Manoa), showed that global rainfall has increased less over the present-day warming period than during the Medieval Warm Period, even though temperatures are higher today than they were then.

The team examined global precipitation changes over the last millennium and future projection to the end of 21st century, comparing natural changes from solar heating and volcanism with changes from man-made greenhouse gas emissions. Using an atmosphere-ocean coupled climate model that simulates realistically both past and present-day climate conditions, the scientists found that for every degree rise in global temperature, the global rainfall rate since the Industrial Revolution has increased less by about 40% than during past warming phases of the earth.

Why does warming from solar heating and from greenhouse gases have such different effects on global precipitation?

“Our climate model simulations show that this difference results from different sea surface temperature patterns. When warming is due to increased greenhouse gases, the gradient of sea surface temperature (SST) across the tropical Pacific weakens, but when it is due to increased solar radiation, the gradient increases. For the same average global surface temperature increase, the weaker SST gradient produces less rainfall, especially over tropical land,” says co-author Bin Wang, professor of meteorology.

But why does warming from greenhouse gases and from solar heating affect the tropical Pacific SST gradient differently?

“Adding long-wave absorbers, that is heat-trapping greenhouse gases, to the atmosphere decreases the usual temperature difference between the surface and the top of the atmosphere, making the atmosphere more stable,” explains lead-author Jian Liu. “The increased atmospheric stability weakens the trade winds, resulting in stronger warming in the eastern than the western Pacific, thus reducing the usual SST gradient—a situation similar to El Niño.”

Solar radiation, on the other hand, heats the earth’s surface, increasing the usual temperature difference between the surface and the top of the atmosphere without weakening the trade winds. The result is that heating warms the western Pacific, while the eastern Pacific remains cool from the usual ocean upwelling.

“While during past global warming from solar heating the steeper tropical east-west SST pattern has won out, we suggest that with future warming from greenhouse gases, the weaker gradient and smaller increase in yearly rainfall rate will win out,” concludes Wang.

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Citation:

Jian Liu, Bin Wang, Mark A. Cane, So-Young Yim, and June-Yi Lee: Divergent global precipitation changes induced by natural versus anthropogenic forcing. Nature, 493 (7434), 656-659; DOI: 10.1038/nature11784.

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Full paper here: http://www.readcube.com/articles/10.1038/nature11784

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Volcanism, the unknown forcing. Nobody knows what the average flux is from the volcanic core out to space, how it varies temporally and spatially. It could easily equal other forcings but we have a paucity of measurements. Pity the PR release doesn’t go further on what they mean by volcanism.

Jens Bagh

Please provide proof temperatures today are higher than during medieval period 900 -1200 BP.

Peter Miller

“showed that global rainfall has increased less over the present-day warming period than during the Medieval Warm Period, even though temperatures are higher today than they were then.”
I can understand proxies for temperature during the MWP – a subject obviously beyond the grasp of Mann and his ‘maths’, but a proxy for rainfall? Rainfall records were not particularly good 800-1,000 years ago!
So, just make it up as you go along, just like most ‘climate science’.

Lewis P Buckingham

Are temperatures higher now than they were in the Medieval Warm Period?

Réaumur

“Using computer model simulations -” … “Our climate model simulations show -”
I feel sorry for climatologists.
The climate is big and slow, so they can’t test their theories with experiments on the physical universe like proper physicists do. Instead they have to live in “The Matrix” and do all their science in a made-up virtual world.
Now, if we could harvest their energy while they were in there…

Konrad

This will be the coming meme, “it’s more complex than we thought.”. The new strategy will be managing the walk back. Sceptics should turn and assault through. After this tiresome and sorry season of “The great global warming caper”, does anyone really want to sit through the same fellow travelers performing “Biocrisis! Biocrisis! ” or “Sence and Sustainability”? In the age of the Internet, the recommendation from Sun Tzu “always leave your enemy a path of escape” is not practical. A number of those that supported the “cause” are likely to experience significant upset in the coming year. I feel it is better to get it over quickly, than draw the end out.

steveta_uk

“Adding long-wave absorbers, that is heat-trapping greenhouse gases, to the atmosphere decreases the usual temperature difference between the surface and the top of the atmosphere, making the atmosphere more stable,” explains lead-author Jian Liu.

“Of course, I am not suggesting that a more stable atmosphere can in any way imply that more extreme weather events are less likely”, he forgot to add.

Lew Skannen

No! Not complex at all. David Attenborough explains it.

Basically the climate is modelled by a green line and a yellow line. The green line is the climate without human produced CO2 and that is a rather trivial model because all it requires is the input of volcanoes and the sun … and a few hundred other parameters available here.
( http://wattsupwiththat.com/2012/02/19/crowdsourced-climate-complexity-compiling-the-wuwt-potential-climatic-variables-reference-page/ )
You then add in the effect of CO2 to this simple model and you get the yellow line.
Simple.

Ronald

Thats the fun part of climate sciences they don’t understand. If you use false data tho make a model you can only get a false model. This one is all so heavy hockestickt by saying that now its warmer then in the MWP it’s simply not warmer so the hole thing is a peace of grape.

Rich

Confused. It says that the whole globe never gets more than 3mm of rain a day (in the figure). How is that possible?

Espen

I see one big problem here: They claim that the warming is stronger in the east Pacific than in the west – but as Bob Tisdale shows again and again – for several decades there has been no warming at all in the east Pacific.

As soon as GHG’s are mentioned we know that the rest is rubbish. The GHG theory is not built on science it violates both 1st and 2nd laws of thermodynamics so cannot happen. The sun is the ONLY heat input into the climate system.
Will the Hawaii ‘scientists’ explain why a desert, very dry, is far hotter than a rainforest at the same latitude. According to the GHG theory the reverse should be true.
It is about time these people got out of their cosy rooms and looked at reality.

wilt

As for warming: if you click on WUWT’s World Climate Widget, for UAH an anomaly of minus 0.01 degree Celsius is displayed for January 2013, another 0.2 degree down from December 2012.
I wonder if and how the modelists can link this to increasing CO2 …..

Alan the Brit

PocketOED1925:
Model, to fashion after, a representation of thing or object. to work into shape.
Simulation, to feign, pretend, wear the guise of, or act the part of, shadowy likeness or mere pretence, unreal thing.
Representation, work of art portraying something, calling of attention to something, place likeness before, make out to be.
Remember you Virginian Colonials et al, these are not my words, but theirs!!!! Just one tiny wee flaw in the paper, it is based on the somewhat arrogant presumption that they know all there is to know about climate science, what drives it, what influences are major or minor, etc.
(BTW just thought I’d ask, are you chaps & chappesses getting along alright in the colonies without us?)
Alan the Brit 😉

mem

But today the Sydney Morning Herald reported on yet another study from the University of Adelaide saying that rainfall intensity will increase with global warming…
http://www.smh.com.au/environment/climate-change/rainfall-intensity-to-increase-with-global-warming-study-20130201-2doro.html

William H

Is this another attempt by the Chinese, who seem increasingly to be the authors of these ‘studies’, to dumb us down to the point that we don’t know which way is up any more? In none of these studies is there any practical way to test their hypothesis (i.e. WAG, without the S for Scientific). Just the “computer model says so, so it must be so” scenario.
I can now say that I have lost what little ‘faith’ I had left in the pseudo-science of climatology.
On informing my bank manager that my computer (Excel) says I have more money than the monthly statement says, his response was “My computer says ‘No’!”. Turns out, the bank’s computer had made a serious error. It was contributing lots of warmth to the atmosphere while producing vast errors in output, due to errors in input. The climate modelers could learn a lot from my bank.

Quelgeek

So very many weak links it defies belief that any two hold together at all, never mind form a chain. My skept-o-meter is pegged.

John West

John Marshall says:
”Will the Hawaii ‘scientists’ explain why a desert, very dry, is far hotter than a rainforest at the same latitude. According to the GHG theory the reverse should be true.”
Actually, GHG “theory” predicts that the desert would cool faster than the rainforest and it does.
IMO, this “paper” is just laying the foundation of explaining away the failed predictions of massive positive feedbacks from warming. Basically, they’ll be able to say “we didn’t know GHG forcing and solar forcing were different wrt water vapor / clouds (precipitation)” and go on being alarmist on something else like ocean “acidification”.

Jimbo

…………global rainfall has increased less over the present-day warming period than during the Medieval Warm Period, even though temperatures are higher today than they were then.

Where did this snippet of information come from?
What could have caused the allegedly localized and very warm period in Europe and left the rest of the planet alone? Now, here are the ‘localized’ effects of this period from the Mann himself. I accuse temperature of several centuries of discrimination. 😉

Dr. Michael Mann – [Medieval Warm Period]
Agriculture was possible at higher latitudes (and higher elevations in the mountains) than is currently possible in many regions, and there are numerous anecdotal reports of especially bountiful harvests (e.g.,documented yields of grain) throughout Europe during this interval of time. Grapes were grown in England several hundred kilometers north of their current limits of growth, and subtropical flora such as fig trees and olive trees grew in regionsof Europe (northern Italy and parts of Germany) wellnorth of their current range. Geological evidence indicates that mountain glaciers throughout Europe retreated substantially at this time, relative to the glacial advances of later centuries (Grove and Switsur, 1994)…………………
Some of the most dramatic evidence for Medieval warmth has been argued to come from Iceland and Greenland (see Ogilvie, 1991). In Greenland, the Norse settlers, arriving around AD 1000, maintained a settlement, raising dairy cattle and sheep. Greenland existed, in effect, as a thriving European colony for several centuries. While a deteriorating climate and the onset of the Little Ice Age are broadly blamed for the demise of these settlements………..
Although Lamb (1965) did not argue for a globally synchronous warm period, his characterization has often been taken out of context, and used to argue for global scale warmth during the early centuries of the millennium comparable to or greater than that of the latter 20th century.”
http://www.meteo.psu.edu/holocene/public_html/shared/articles/medclimopt.pdf

Just another climate model study. No basis in reality.

Here is the longest instrumental precipitation record fro England&Wales since 1766:
http://climexp.knmi.nl/data/pHadEWP_monthly_qc_mean1a.png
Please show me any foot print of “greenhouse gases forcing” in it. These are hard local data, no questionable proxies or, alas, computer models.

steveta_uk

Wilt, I think you read the Jan 2011 figure, Jan 2013 isn’t out yet.

Village Idiot

“Global warming – more complex than we thought”
[snip . . when commenting try and include some useful content . . mod]

Elizabeth

OT but maybe relevant. Has anybody noticed that lately a “Global Warming” search in Google news is getting less and less biased towards the AGW fanaticos? ie more skeptical stories appearing on MSM etc…

wilt

Correction: Steveta_uk you are right, the number on the climate widget refers to January 2011 (by the way it might be time to update the data that are displayed when clicking on the widget). Sorry for the mistake.

Both Arctic and Antarctic ice isotopes say the Medieval Warming Period was warmer than the present. The greatest heat at present seems to be between the ears of tax-and-reg types.

Tom in Florida

John West says:
February 1, 2013 at 3:26 am
“Actually, GHG “theory” predicts that the desert would cool faster than the rainforest and it does.”
Yes, but don’t forget to mention that the GH gas in this case is water vapor, or the lack there of.

Richard M

Let’s see .. they claim the atmosphere will produce less rain and be more stable. That completely refutes the claims of extreme weather. From now on when anyone tells you that climate change creates more extreme weather simply point them at this study and tell them they are denying peer reviewed science.
If they can use junk science to make claims we can certainly use junk science to refute them.

Patrick

At “Using computer model simulations,…” I stopped reading. Why don’t these people just say “We don’t know.”?

oldfossil

My knee-jerk reaction to this story is not to heap scorn on it. It suggests a plausible mechanism for the climate stability of the last decade. In addition the study contradicts the alarmist predictions of catastrophic increases in rainfall, and favors the skeptic cause.
I would like to see how Liu et al account for the lack of a “fingerprint.”

peterg

Perhaps there is some subtle message here. Climate models with positive feedback would have to have enhanced evaporation and precipitation, and if this isn’t in the records, would have to be explained somehow. This study would suggest that CO2 does not create extra H2O vapor, so less positive feedback?
For mine, 300 hundred watts/m2 long range radiation from the atmosphere raises the surface temperature by 30 degrees K, so an extra 2 watts isn’t going to do enough to be noticed outside the measurement noise.

michael hart

Here we go again. If the authors of the article wish someone to take their assertions and their model seriously then I am sure they will be willing to give us their global precipitation predictions.
If I was feeling generous then I might initially even accept some “projections” in lieu of predictions.

SAMURAI

“Using an atmosphere-ocean coupled climate model that simulates realistically both past and present-day climate conditions….”
My eyes rolled so hard, my ocular muscles cramped and I’ll be seeing double for a week.
Climate Models are based on inaccurate and manipulated assumptions of chaotic systems not well understood, by grant-funded scientists that are paid to adjust the parameters to get a predetermined result so they can keep their jobs.
What could POSSIBLY go wrong with scenario?…

Bob Tisdale says:
February 1, 2013 at 3:48 am
Just another climate model study. No basis in reality.

Ah, but “Using computer model simulations, the scientists . . . showed that global rainfall has increased less over the present-day warming period than during the Medieval Warm Period . . . ” See? It was evidence! It’s better than present-day “reality”; it’s a time machine! With a little tweaking, it will doubtless show us Will Shakespeare subcontracting out his plays to . . . Well, we won’t give it away; that’s for next week’s PR^ 2 (Peer-Revealed Press Release).
/Mr Lynn

markx

At least they made a point of mentioning it is all a modelling exercise…
“…For the same global surface temperature increase the latter pattern produces less rainfall, notably over tropical land, which explains why in the model the late twentieth century is warmer than in the Medieval Warm Period (around AD 1000–1250) but precipitation is less…..”
And of course, Mann is the main source of the MWP being cooler than today, based on his weighted proxy sourced models…..
Science 2009 Vol: 326:1256-1260. DOI: 10.1126/science.1177303
Global signatures and dynamical origins of the little ice age and medieval climate anomaly
Mann, M. E.

Global temperatures are known to have varied over the past 1500 years, but the spatial patterns have remained poorly defined. We used a global climate proxy network to reconstruct surface temperature patterns over this interval. The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally.

Intriguing to see how few proxies are available stretching back to the the MWP, and how they are weighted, and how much ‘modeled cooling’ there is in areas where proxies aren’t available … http://www.sciencemag.org/content/suppl/2009/11/25/326.5957.1256.DC1/Mann.SOM.pdf

And the solar forcing has the usual problem that recent values are assumed to be significantly higher than around 1900, although solar activity now [and recently] is on par with what it was a century ago.

A C Osborn

Any Study starting with the premise that current warming is GHG based is GIGO before it starts.

michael hart

William H says:
February 1, 2013 at 3:04 am
“Is this another attempt by the Chinese, who seem increasingly to be the authors of these ‘studies’, to dumb us down to the point that we don’t know which way is up any more?”

Two of the institutions named are Hawaii University and Columbia University, so I’m inclined not to believe that explanation. If I was looking for a conspiracy theory I would more likely guess it to be an attempt to influence China and their fossil fuel consumption, rather than the other way round.
Or possibly an attempt to ingratiate themselves with influential people in China.
That said, my pet theory, and null-hypothesis, remains one of gross general incompetence.

Joe Public

@ John Marshall February 1, 2013 at 2:54 am
Will the Hawaii ‘scientists’ explain why a desert, very dry, is far hotter than a rainforest at the same latitude.
But a desert cools significantly at night, giving it a large Diurnal Temperature Range. So whilst its daytime temperature will be warmer (than a rainforest), its daily mean temperature may not be.

Bruce Cobb

“Global warming from greenhouse gases”. Proof? It’s like assuming the earth is flat, and writing a paper based on it.

Tim Clark

[ Konrad says:
February 1, 2013 at 2:36 am
This will be the coming meme, “it’s more complex than we thought.”. ]
My initial reaction exactly.
It’s more complex than we thought, and it’s going to be worse than we think.

Chuck Nolan

Alan the Brit says:
February 1, 2013 at 3:02 am
(BTW just thought I’d ask, are you chaps & chappesses getting along alright in the colonies without us?)
Alan the Brit 😉
———————————
Actually Alan we could use some help but I don’t think your leader’s ideas are any smarter than Lisa Jackson’s.
She must have sold all of her oil stocks and invested in carbon credits or like your leaders invested in marine hazard bird thrashers.
I wonder if all the major pension plans in the world are heavily invested in a “green future”?
cn

Berényi Péter

“we suggest that with future warming from greenhouse gases, the weaker gradient and smaller increase in yearly rainfall rate will win out”
Okay, fine. And what do they predict?

“Adding long-wave absorbers, that is heat-trapping greenhouse gases, to the atmosphere decreases the usual temperature difference between the surface and the top of the atmosphere, making the atmosphere more stable,” explains lead-author Jian Liu.
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Rubbish. That directly contradicts the atmospheric “hot spot” predicted by all climate models. Nowhere is it predicted that AGW will cause the surface to warm faster than the atmosphere.
One of the main predictions of AGW is the GHG warms the atmosphere first, then the surface warms as a result of the lapse rate tying the atmosphere to the surface.
In contrast, it is solar heating that heats the surface first, then the atmosphere warms. Thus one way to detect if warming is due to GHG or solar influences is to study if the atmosphere lags the surface of the surface lags the atmosphere.

beng

****
showed that global rainfall has increased less over the present-day warming period than during the Medieval Warm Period, even though temperatures are higher today than they were then.
****
Mule-fritters. Tell that to the Vikings and many others…

And they know how much rain fell around the world during the MWP how?

markx

It is really worth going back to assess Mann’s original contention that the MWP was ‘cooler than the present’ (of course, he has to rename it the MCA, the Medieval Climate Anomoly, as otherwise the whole thing would fail the Orwellian test).
Available here: (needs a log in – no cost) Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly. Michael E. Mann, Zhihua Zhang, Scott Rutherford, Raymond S. Bradley, Malcolm K. Hughes, Drew Shindell, Caspar Ammann, Greg Faluvegi, Fenbiao Ni
http://www.sciencemag.org/content/326/5957/1256.short
http://www.sciencemag.org/content/326/5957/1256.full.pdf
Note Figure 2 – the top figures showing the temperature anomaly map of the world for the MCA (compared to the 1961 to 1990 period) ..and the weighted proxies on the right…to me it is an incredible construct: Note all the blue (cooler than recent times) on the map.
Starting in northern America we see a cluster of proxies – by the temperature anomaly map, all apparently warmer than now, except for one cooler site. Down to the Caribbean … neutral, but heavily weighted..
Peru, Ecuador, looks like it was warm there…. back up to Greenland … a very warm spot…, across to Europe, only two proxies, one heavily weighted, but both warmer, across to northern Russia …one isolated proxy with an isolated warmer spot … to central China, there is a cooler spot …then head a bit east in China..another very hot spot…then all the way down to Tasmania and New Zealand – Tasmania is cooler, NZ is warmer than now…… Back to Africa, 3 proxies, one cooler (and heavily weighted) and one very lightly weighted and warmer, and one neutral…
Then look at all the modeled cooling on the map … right across central Asia, based on 4 proxies (!!), all of which were warmer except one… ALL of the Southern Ocean, the southern Indian Ocean, and southern Atlantic oceans were supposedly much cooler, (based on Tasmania, and three proxies in Africa?!!) All of the eastern Pacific is shown as cooler, … based on a string of proxies in the western Americas, which were mainly warmer, and perhaps eastern China ..warmer also?

Fig. 2. Reconstructed surface temperature pattern for MCA (950 to 1250 C.E.) and LIA (1400 to 1700 C.E.). Shown are the mean surface temperature anomaly (left) and associated relative weightings of various proxy records used (indicated by size of symbols) for the low-frequency component of the reconstruction (right). Anomalies are defined relative to the 1961– 1990 reference period mean.

Now I do appreciate the vast effort and detailed measurements and complicated science which have gone into this effort, but to me it is rather like building an intricate full scale model of a Boeing 747 with Lego blocks (a truly mighty effort indeed) and then selling flight tickets to London.

Joe Public says:
February 1, 2013 at 5:46 am
@ John Marshall February 1, 2013 at 2:54 am
Will the Hawaii ‘scientists’ explain why a desert, very dry, is far hotter than a rainforest at the same latitude.
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But a desert cools significantly at night, giving it a large Diurnal Temperature Range. So whilst its daytime temperature will be warmer (than a rainforest), its daily mean temperature may not be.
=========
As well, the rainforest air contains significantly more energy than the desert at the same temperature due to water vapor. Thus it is meaningless to talk about temperature without also talking about humidity. 100F at 0% RH is much different than 100F at 100% RH. Something that makes something called “average global temperature” completely meaningless.
You cannot average the temperature between two places with different relative humidity and arrive at a meaningful result. This is especially true when considering land temperatures. Ocean temperatures are somewhat more meaningful because the humidity is more constant.

Pamela Gray

So when the Sun heats thangs up without the aid of greenhouse gases, the air is cranky, but when greenhouse gases fouls that process up, the air becomes nice’n peaceful like. Dang. Can’t be have’n that now can we, cuz it be opposite of the current talk’n points for political action. But then I s’pose Ph.D. types don’t much worry ’bout us flat Earthers notice’n the contradiction.

lsvalgaard says:
February 1, 2013 at 5:31 am
although solar activity now [and recently] is on par with what it was a century ago.
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And temperatures have not increased for 16 years and counting, in spite of massive increases in CO2 as China and India have industrialized.
Coincidence? Maybe. But it certainly indicates that CO2 is not the main driver of temperature. We should have seen a massive increases in temperature over the past 10 years due to industrialization and land use changes. It hasn’t happened, contrary to the predictions of the majority of climate scientists. Hansen, Mann, Jones, the IPCC, they got it dreadfully wrong and billions in taxpayer money have been wasted in the process.
When a theory fails to predict correctly, it is a failed theory. All that is required is a single contradiction to disprove a theory. This is the very heart of science and the scientific method. Any example that contradicts the theory is proof the theory is wrong.
This is completely Ignored by consensus climate science because climate science is not a science any more than political science is a science. Climate science is the political process of collecting confirmations for a belief, while ignoring contrary evidence.