National Geographic News
The Columbia Glacier in Alaska, seen in 2006 (top) and 2012 (bottom).

The Columbia Glacier in Alaska, seen in 2006 (top) and 2012 (bottom).

Photographs by James Balog

Brian Clark Howard

National Geographic

Published September 25, 2013

The United Nations' Intergovernmental Panel on Climate Change (IPCC) is meeting in Stockholm, Sweden, this week to iron out the final details of a widely anticipated report on the current state of global warming science. There has been much speculation about how the report will address an apparent decrease in the rate of warming over the past few years, dubbed a "global warming pause."

Prominent climate scientists say that discussion misses the bigger picture. The suggestion that global warming has stopped, says Richard Alley of Penn State, is "nonsense."

A recent paper by climate modelers at the Scripps Institution of Oceanography argues that the supposed pause in global warming can be explained entirely by recent variations in the El Nino-La Nina cycle in the tropical Pacific.

On Friday the IPCC, which is made up of several hundred climate scientists from around the world, will release a roughly 30-page summary of its new report tailored to the world's policy makers. Some time in the near future, the panel will release the 1,000-page report itself. (See "Leaked Report Spotlights Big Climate Change Assessment.")

It will be the fifth time the panel has assessed the state of climate change science since it was founded in 1988. The reports have documented a steadily increasing certainty among climate scientists that global warming is a human-made problem. Yet some public scepticism has persisted, especially in the United States.

Global Warming Hiatus?

Although climate models have been predicting increasing average global temperatures over the next century or so, the past decade has not shown as much warming as most scientists had expected. The year 2012 was no warmer than 2002. The IPCC draft report acknowledges a "global warming hiatus," according to media reports.

"Governments are demanding a clear explanation of what are the possible causes of this factor," Arthur Petersen, chief scientist at the Netherlands Environmental Assessment Agency and part of the Dutch delegation that is reviewing the IPCC report, told BBC News.

The Associated Press reported that "several governments that reviewed the draft objected to how the issue was tackled." Der Spiegel online called the supposed global warming pause an "Inconvenient Truth for climatologists" —an allusion to the climate change movie made by former U.S. vice president Al Gore, who in 2007 shared the Nobel Peace Prize with the IPCC for his work on the issue.

Global warming skeptics have seized on the news of a potential pause. The skeptical blog Jammie Wearing Fools wrote, "Fifteen years, no warming, yet we've endured nonstop hysteria in that time, with skeptics derisively called deniers, among other pejoratives. We'll be waiting even longer for the apologies."

He's certainly right about the last point. Gavin Schmidt, a climate scientist with NASA's Goddard Institute for Space Studies, told National Geographic that focus on a global warming pause over the past 15 years is a "misplaced" distraction that misses the big picture. He said, "The IPCC and the issue of climate change is not about the weather next year or the next five years; it's about the long-term climate change that we are engendering."

Schmidt, who has not directly contributed to the IPCC report, added, "We know we're changing the climate. We're very confident in that, and not just temperature, but also pressure, rainfall, ice changes, shrinking of glaciers, and many other factors."

Judging by drafts leaked to the media, the new IPCC report will take the same view. According to the BBC, "The panel states that it is 95 percent certain that the 'human influence on climate caused more than half the observed increase in global average surface temperatures from 1951-2010.'"

What Could Cause a Pause?

Still, there's no denying that temperature has plateaued in the last decade. Why? Scientists have considered a number of theories: small differences in solar radiation; volcanic eruptions that spewed sun-blocking ash and gases into the atmosphere; or pollution from factories, power plants, and tailpipes, particularly in Asia.

Schmidt pointed out, however, that the real anomaly in the recent climate record is not the last decade but the year 1998, which saw a sharp spike in atmospheric temperatures. "If you take 1998 out, there is no pause," he said. According to NASA data, the ten hottest years since 1880 have all happened since 1998, with 2010 being the hottest of all.

In 1997 and 1998 there was a strong El Nino event in the equatorial Pacific, meaning that the surface water there was unusually warm. As Alley explained in an American Geophysical Union talk recently, the El Nino cycle has a strong impact on how much of the heat trapped by greenhouse gases spreads to the ocean. In 1998, a warm ocean absorbed less heat—which caused the atmosphere to heat up more.

Since 1998, however, the equatorial Pacific has tended more often to the cooler La Nina state. Because a cool ocean absorbs atmospheric heat more readily, that has partially offset the atmospheric warming caused by greenhouse gases. "In the last decade the system has dumped more of the heat in the ocean and less in the atmosphere," Alley said.

The modeling work by the Scripps researchers, Yu Kosaka and Shang-Ping Xie, supports this idea. So do measurements of ocean temperatures, which show that warmer temperatures are spreading into the deep abyss. According to the BBC, the draft IPCC report suggests that the oceans have been absorbing more heat than expected, in effect insulating global surface temperatures from greater change.

Too Much Noise

In his AGU talk, Alley demonstrated how the argument that global warming has stopped could have been made many times over the past half-century. There have been many intervals of 5, 10, or even 20 years in which the global average temperature has stalled—but inevitably the long-term warming has resumed. The problem is the intrinsic variability, or noise, in the climate system, of which the El Nino cycle is one example.

Schmidt said people should avoid getting distracted by such noise, and should instead focus on the bigger questions raised by the coming IPCC report. Chief among those is what policy makers will actually do with a document that voices concern over climate change with even stronger language than before, and with greater resolution on predictions about global sea-level rise. (See "Rising Seas" in National Geographic magazine.)

"The IPCC report is a summary of what we know. It's not going to be radically different than [the last report in] 2007, but it's another underlining of the seriousness with which the scientific community views this problem," he said.

Follow Brian Clark Howard on Twitter and Google+.

43 comments
k kramer
k kramer

Again ...please lol this was a big money maker and now people are not afraid that the world is going to die off and they are broke from all the donations they gave,,,,, that got no where cause everyone kept using aerosols...bad people. And now it is at a stall until they can put a new spin on it. People keep your money this world will purify itself it is an amazing eco system and very well balanced. What we do have to worry about is GMO and the chemicals that are being sprayed on our fields for profit.


Vishnu Shriram
Vishnu Shriram

Palpably speaking, weather seems to have become more extreme. In the coastal metropolis of Mumbai for instance, traditionally there never has been even a moderately chilly winter. Over the last few years however winter temperatures have dropped below 15 degrees centigrade. The same can be observed on the opposite coast of India in Calcutta where too winters and summers have become more extreme.

Kyle Smith
Kyle Smith

When will we learn that it is all right to say "we really don't know".   To me both sides of this debate are idiots.  We have only being recording weather for about 125 years and really only doing it well for the past 50 years.  We do not have a clue what the "big picture" is.  Let's just admit that instead of getting all extreme and saying if someone does not agree with us they are ignorant.  Just saying.

Ernest Barker
Ernest Barker

Does "Global Warming Pause" Debate Miss Big Picture?  Of course it misses the big picture. To get the big picture, one has to consider the earth's 4.5 billion climate time line. Some choose to consider the last 12 years. Others choose to consider the last 125 years. Very few take time to understand the big picture of the earth's 4.5 billion year climate time.

david auburn
david auburn

i am not writing to argue with the deniers since that would be a wasted effort. "There are none so blind as those who will not see."   I am writing to assure people that there are others willing to listen to the authorities who put a human on the moon, that are in charge of our national defense and that have spent years of scientific study backing up their arguments with facts.

Brian Anderson
Brian Anderson

I have a question.  If we are taking energy out of the wind to create electrical power, then we have taken entropy (heat) out of the system, even if that wind is now more turbulent than it was, and seems more chaotic.  Still energy has been taken out.  Could this reduce gobal warming?  If not, how does solar thermal affect global warming?  The heat from the solar thermal is still here, and it will become heat later through friction, but mirrors should be reflecting some small percentage back up into space.  Its just a point to ponder.

Conwaythe Contaminationist
Conwaythe Contaminationist

"Global Warming" and its ugly sister "Climate Change" are Goebbelsian contrivances promulgated to keep the elitists in power  - to further their aim of controlling the ignorant masses, and nothing more.

Andrei Bilderburger
Andrei Bilderburger

The big picture is criminal parasites have gotten in charge of something that should be done by scientists and are making up scary stories to advocate satanically evil policies.

What is happening with the climate, what the implications of warming and cooling are, etc. are interesting scientific questions which are being swept under the rug in an attempt to create an advocacy group to gain political power.

The first step towards truth is long prison terms for all the IPCC members.  Then have some legitimate researchers look into why the Sahara was Rome's bread basket - covered with verdant wheat fields - when the world was a bit warmer, and then died off leaving abandoned cities in the desert when the world cooled  a bit.

John T.
John T.

 You just have to love how the above photo of the glacier has been taken from two different angles, and locations to make it look worse than it really is.I wish Scientists would just tell us the truth, and leave all the political correct agenda behind. Global warming has become a “Scientific Religion” that does not allow anyone to question it.If you do question the assumptions made by the Global Warming elite, you are branded a heretic, worthy of only ridicule, insults and bullying.

Justin Case
Justin Case

You know what I would like? I would like a lot of these supranational organizations touting superagendas to just disappear and be replaced by a reasonable sense of decency among producers and consumers. I don't think we would have a messed up environment or a bleak future if people could just stop wasting so much of everything as they go about their business. 

Most of the people "denying" global warming are really railing against this headlong panic mentality that we have to make supreme sacrifices TODAY or we will be dead in a decade. Sheesh. Enough already. Let's move quickly to a middle ground instead of being contentious about everything, especially about results of models that nobody is really sure about anyway. If we could just agree that using less of our fossil fuel legacy is better than using more, and spent a few pennies in that direction every day, then we would not need to have "truth" crammed down our throats, and we could buy some more time to watch the trends. To me and most people in the world, it is pretty clear already that we are headed in a bad direction.

--sigh-- 

That "new responsible consciousness" isn't going to happen is it? Well, then, let's get back to our contentious name-calling discussion of right and wrong, etc. 

Mister Science
Mister Science

Do you know how to spot a scientific illiterate?  Science is always filling in details and making small corrections.  The public relations flack working for the industry that prefers the harm it does not be known lies about those findings, and the illiterate latches onto the lies and declares the entire body of science invalid.

Keith Cameron
Keith Cameron

NatGeo used to be a world class publication. But, once they got political and signed on the the scam of Global Warming they lost all credibility with me. Every year the only gift I would as for was a subscription renewal. I haven wanted one in ten years or more. Damned shame how a great publication has been ruined!

Scott Miller
Scott Miller

There is always debate among the informed, but a religion requires the skeptical to be silenced.  If there is no debate, than you probably aren't asking the right questions.  Science is a never-ending debate carried over the centuries, and to suggest the debate is over, is about the most unscientific thing you can utter.  

Phillip Noe
Phillip Noe

There's no debate among the informed.  Humans are warming the planet mainly with our CO2 emissions and deforestation.  This is well established science.  The upward temp trend was never expected to be unabated as there are many unknowns in this uncharted territory.  Surprises will happen.  The overall deterioration of our only habitat continues.  Contact your Congressmen/women and insist they work harder to reduce emissions.  Our future generations are at risk.

KK Aw
KK Aw

@Kyle Smith 

To see the big picture, at the least, the authors and editors of WG1 have to integrate 9000 reports and 54677 comments.  That is the information available to them.  There are still things that they know they don't know and also unknown unknowns.

Sandy Hawkins
Sandy Hawkins

@Kyle SmithWe know a great deal about past climate. There is an entire field of science called, "Paleoclimatology". 

Sandy Hawkins
Sandy Hawkins

@Ernest Barker 

We know a great deal about past climate. There is an entire field of science called, "Paleoclimatology". 

Robert Strahlendorf
Robert Strahlendorf

@david auburn You are willing to listen. After listening, will you be willing to let them confiscate a lot of your wealth over these hypotheses? 

Jack Wolf
Jack Wolf

@Andrei Bilderburger The members of the ipcc are volunteer scientists that review and compile other scientist's journal papers.

It is then reviewed by individual counties.  Every single word is gone over.

Why throw them in jail?  Silly statements like this are below you.

As to the Sahara, the same thing happened to Mesopotamia.  Farming.

Sandy Hawkins
Sandy Hawkins

@John T. There are several reasons that sea ice is increasing, including decreasing levels of ozone. However, the issue is that ice mass loss in Antarctica is increasing. Between 1992 and 2011, the Antarctic ice sheets lost 1350 giga-tonnes (Shepherd 2012). This trend has continued, and in February 2013 alone, the Antartica ice sheet lost 923 billion tons of ice. http://climate.nasa.gov/key_indicators

Brian Anderson
Brian Anderson

@John T. 

John,

Does it snow more when it is 0° F or when it is 28° to 31°?  The answer is that it snows more when it is warmer in the 28° to 31° range.  If it snows more you get more ice.  You've seen this around you.  Please try to apply what you know to the situation, and try to listen to others.

John T.
John T.

@Christine Blair

I read the article you attached to your comment.Finally some truth.

What people do not realize is that the environmental “Global Warming” movement is decimating our economy.We are talking about real people who are willing to work hard to take care of their families. But every direction they turn another big project is delayed or shut down.

There is also the fear factor this creates in the business community.Some companies will not even start a new project for fear of all the environmental hoops they need to jump through.

More good jobs lost every day….

John T.
John T.

@Justin Case

Just so you know, the earth was warmer during the Medieval Warming Period, than it is today.And guess what, it was a time of prosperity and plenty.The Global Warming organizations that have trillions of dollars riding on the fear of Global Warming have been trying very hard to get rid of this fact.The “Global Warming Armageddon” bill of goods; that has been sold to the public is bogus.

See Link:http://wattsupwiththat.com/2013/04/11/evidence-for-a-global-medieval-warm-period/

Tom Moran
Tom Moran

Yes I'm sure the good men and women of science are not interested in money or prestige and that's why their work is anonymous and not influenced by grant money.

Justin Case
Justin Case

@Keith Cameron I don't think a lot of people are going to be swayed one way or another by National Geographic. Actually, I don't think the article pushes one way or another. If anything, the article itself calls the IPCC paradigm into question.

Andrei Bilderburger
Andrei Bilderburger

@Phillip Noe The view you give is that of the uninformed.  Brainwashed by the IPCC and its fraudulently fabricated database that does not match historical records (e. g. the warming period and 'little ice age' in Europe).

Everyone who is actually informed knows that during those historical times that were warmer than today, civilization grew and fluorished because the world was far more verdant than it is today.

John T.
John T.

@Phillip Noe

Quick, run to your bomb shelters, the sky is falling.

Do any of the “Climate Believers” actually look at what “Climate Science” has put forward as fact?CO2 is the least of the greenhouse gasses in our atmosphere.

FYI it is water vapor that is the major greenhouse gas.Without water vapor we would be one big ball of ice.CO2 makes up 0.039% of the gasses in our atmosphere. That is measured in parts per million.How is a gas that makes up such a small part of our atmosphere drive the climate?Whenever a climate scientist is asked this question, they say that it is complicated.Laymen are just too unintelligent to understand.

Mister Science
Mister Science

@John T. @Justin Case WUWT is a coal company sponsored anti-science public relations site.  Try to learn to tell the difference between a research scientist and a PR flack wearing a lab coat over his Armani.

k kramer
k kramer

@John T.@Phillip Noe Has anyone ever wondered what the scientist use in their homes and do the drive cars and do they recycle, what they use for cleaning is it aerosol. LOL sorry. It's a money making hoax, we are all going to die and it's not going to be from global warming.

Graham Davis
Graham Davis

@John T. @Phillip Noe @The sky is falling'? Glad to see that you noticed. It's down to cooling
of the stratosphere - predicted by the CO2 science - and so the outer limit of the atmosphere is 'falling'.

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