Did Global Warming Stop in January?

Lisa MooreThis post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense.

January 2008 was the coldest month in several years, according to the scientific groups that track global temperature. Is it true, as DailyTech concludes, that January’s cold "wipes out a century of warming"? Has global warming stopped?

In a word, no. A single month does not make for a climate trend. Let’s look at the data.

Monthly Average Global Temperature Variation

Source: Raw data from the U.K.’s Met Office Hadley Centre (see description of data).

This graph shows "temperature anomalies" – that is, the variation from a long-term average of temperatures between 1961 and 1990. A temperature anomaly of zero would mean the temperature is exactly equal to the long-term average – neither warmer nor colder. (For more on how scientists take the globe’s temperature, see our previous post.)

As you can see from the graph, temperatures are trending upward over time in a zigzag pattern, not unlike the stock market. A shallow dip is followed by an even greater rise. Short-term dips should not be mistaken for long-term trends – in the stock market, or in climate!

January 2008 (circled in red) is cooler than other months in the past decade, but still significantly warmer than previous decades. Global warming isn’t likely to have stopped in January 2008 any more than it stopped in March 1976, December 1984, November 1992, or February 1994. These are all short-term dips in a long-term trend.

Global warming is a process that occurs over decades. It can’t be proven or disproven by a single month’s temperature.

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  1. kenzrw
    Posted February 27, 2008 at 7:47 pm | Permalink

    True, global warming can’t be disproven by a single month’s unusually cold tempertures, but neither can global warming be proven by a single heat wave or hurricane (as many people tend to say). Trends are what we need to look at. In this case, however, we need to find out and explain why so much of the world has cooled in the past year, to see if there are other feedback systems involved which may have been overlooked in the climate computer models (more low clouds? less high cirrus clouds? less solar radiation? more albedo from more snow?, etc).

    It also bothers me that the southern hemisphere sea ice area has grown over the past 30 years when I would assume it would be shrinking like the Arctic sea ice did last summer. It appears that all of that Arctic sea ice has refrozen (yes I know open water freezes faster than if it had ice, but this winter the sea ice in the Artcie even gained in areal coverage as well as thickness – http://arctic.atmos.uiuc.edu/cryosphere/). It’ll be interesting to see if there’s another record Arctic sea ice melt in the summer of 2008, as many predicted last August.

  2. johnmashey
    Posted February 29, 2008 at 2:01 am | Permalink

    I know Lisa knows this, but while the graph of the stock market may resemble the graph of global temperature, and both are noisy time-series, only one of them is driven long-term by laws of physics.

    This fact is ignored by certain people who think economics forecasting is like physics models.

  3. Posted February 29, 2008 at 3:27 pm | Permalink

    Your graph is not temperature, it is the deviation from the past average. How far back is the moving average? Could you plot the moving average temp so we can see what it was? If the deviation is negative for 100 years per the graph, the moving average temperature will be going down. So if the temp then starts to go up, the deviation is from a LOWER average past temp, resulting in the increase in deviation as shown, which makes sense. That does not mean the temperature is increasing long term, but is just reverting to the long term mean (as the stock market often does). i.e. it was colder for 100 years, now it is warming up again. Once the mean gets back to normal, the deviation (or anomaly as they call it) will once again go negative. Just like the stock market.

  4. johnmashey
    Posted February 29, 2008 at 4:39 pm | Permalink

    Skeptic1: how’s your physics?
    Do you understand and believe in:
    1) First Law of Thermodynamics
    2) Second law of Thermodynamics
    3) Greenhouse Effect
    4) Adequate predictability of Earth’s orbital shape, precession, etc over the next few thousand years?

    One more time: the stock market and global average temperatures are *not* the same kinds of time series, and reasoning about the former doesn’t help much about the latter. Local noise may exhibit a “reversion to the mean”, but long-term moving averages are driven by physics.

  5. Posted March 2, 2008 at 9:52 am | Permalink

    I understand the thermo laws as I am a Mechanical Engineer. Greenhouse effect-yes but this is not a law at this point, just an effect. And what causes it and the degree is not well understood from what I’ve seen, and CO2 apparently is not a big driver contrary to the popular opinion here. #4- I assume these will continue to behave the way they have over the last few thousand years, for the most part. However it is proven that the earth is wobbling more because of the large amount of water dammed in the northern latitudes, that would normally be allowed to flow to the equator. I don’t know the details of what this could cause.

    Lisa used the stock market analogy so I did too. But I was referring more to variation about a moving average, a common stock market graph. But they don’t use “anomaly”, which I assume is the deviation from the mean. No? If not what is it a deviation from? Computer prediction? If it IS from the mean or moving average, it is behaving as expected because it was COLDER for the first 100+ years, which would lower the mean by a certain amount depending on how far back you go. So the anomaly would have to become less, even if temperature is constant. But temp is not constant over time. In the graph above the cold spell has stopped and now the temp is rising back to a more normal value, hence the “anomaly” rises above the mean, which was lowered because of the cold spell. And we’re only talking about 150 years anyway, so that’s a very short time.

    It appears the above is just another attempt to obfuscate the data, which show that the temp rise has stopped over the last few years (even though CO2 is rising) and we are facing a downtrend in temp, with more variation etc which was normal at previous times in our history when Man was insignificant. If the environmentalists can hang on for another 10 years or so, things will be much more clear. We can’t affect anything in that short time anyway, if ever. Let the scientists keep crunching the numbers and be honest and open about the results. In the meantime there are many more higher priority causes needing attention, such as mercury and fluoride in the environment, dangerous pesticides apparently killing the bees – unless you are a denialist- (how long will we live if the bees are gone???), estrogens all over the place, poisons in plastic effecting babies, drug companies putting out dangerous and practially ineffective drugs, etc etc. We won’t be around to worry about any climate change if these other issues aren’t addressed.

  6. Posted March 2, 2008 at 10:10 am | Permalink

    One more thing- the above graph is shown in the following paper going back to year 1000.


    I know you won’t like the title but it reflects a well documented alternative viewpoint worth considering.

  7. johnmashey
    Posted March 2, 2008 at 11:16 am | Permalink

    Well, I tried.
    If you think nzclimatescience.net is a credible information source … really, it’s not even a a *good* denialist site.

  8. Posted March 2, 2008 at 11:16 pm | Permalink

    You didn’t try very hard! You’ve completely avoided the subject at hand, trying to direct it to a WSJ article implying that somebody thinks that one month makes a trend. You say it takes decades. How about centuries? I’m afraid you are unable to address the issue I raise. Is anyone else out there? Funny how you simply say I’m a “denialist”. How ridiculous. Scientists look at the facts. All of them. Politicians only look at those that suit their needs and distort them.

    Children keep on dreaming if you think you can save the world.

  9. fred1
    Posted March 3, 2008 at 5:42 pm | Permalink

    So JM,

    are you saying that the earlier IPCC reports which showed graphs about the Roman Warming, the Medieval Warming, the Little Ice Age are not correct? why do you think the IPCC would have mysteriously have smoothed these warmer periods away? obviously we are coming out of the LIA so of course temps will increase.

    also check out this site which is by as weather guy who has done some research which shows that many of the weather sites / measuring stations in the U.S are out of spec, meanning that their temp readings are not accurate, many of the sites are now too close to things like AC vents and blacktop which lead to higher than what should be readings. this guy has no political agenda. so we can’t even trust the actual core temp data regarding warming…http://surfacestations.org

    also, China and India both just experienced / are experienced their coldest and snowiest winters in 50 years….i doubt they will be interested in carbon caps, etc. too busy trying to keep warm.

  10. johnmashey
    Posted March 6, 2008 at 4:27 pm | Permalink

    Fred1: I’ve seen all this stuff before. I spent many hours studying the surface stations years ago, when my list of concerns included possible disagreement of satellites with surface stations. I’ve read both of Fred Singer’s books, where the only real constant is “Never regulate CO2 emissions.” I of course have read the IPCC reports and a lot of other *scientific* sources. I’m a AAAS member, so I read Science. I’ve looked at lots of other things, and much of it is junk intended to confuse people, or just simply bad math, or echo-chambers of disinformation.

    My background is math/physics, followed by a PhD in Computer Science. I helped design and sell supercomputers used by a lot of petroleum geologists and climate scientists to do their simulations, which meant I spent a lot of time with senior people. Although half-retired, I still give invited talks about statistical analysis of data at places like Stanford, Princeton, Imperial College, UT-Austin, etc.

    When Nobel Physics winners give talks to local 30-person town meetings (which happens here), I listen to them and ask questions:


    The first third is on climate, and Al Gore could have used the same slides.

    Now, I’m lucky: I live just up the hill from Stanford, so almost every week I can hear IPCC authors, Nobel prize winners (Physics/Chemistry), members of the US National Academy of Sciences, senior researchers, etc and talk to them. This doesn’t mean I agree with everything they say and how they say it, but I’m nowhere near smart enough to simply ignore the world’s top scientists, and I’m lucky enough to have interacted with enough to know who is good and who is fifth-rate at best.

    If you live anywhere near a decent research university, consider seeing if they have useful public lectures. There is no substitute for listening to an expert and being able to ask questions face to face. If you’re not so handy, at least some places do outreach programs, or one can find websites by serious science places like NASA GISS, UK-met, etc.

    If you’re not quite so technical as to join AAAS and read Science, I’d suggest taking a look at William Ruddiman’s “Plows, Plagues, and Petroleum”, which is <$20 at Amazon:
    (I wrote one of the reviews – it’s beautifully and carefully written.)

    Skeptic1: we’ve got lots of other problems to solve, but so what? Everybody always has a range of problems that need solving, both short and long-term.

    I grew up on a farm that had been farmed more-or-less-sustainably for 120 years, and I care about bees and lots of other things, but why is that that *this* one problem (AGW) needs to be ignored or denied?

    Well, actually, we know a lot about how that got started, and it has nothing to do with science, as recounted in Naomi Oreskes’ 58-minute video:

  11. Posted March 8, 2008 at 1:15 am | Permalink

    I listened to Oreskes and it is interesting but not conclusive. There are always skeptics for everything but the science must settle it, and there are still many scientists that appear to me to be very well qualified to say that C02 is not the prime cause of global warming, based on more recent science. That is the key issue needing confirmed. And in just 5-10 years, the temp trend of the earth will probably confirm that (CO2 up, Temp down).
    There are many recent examples of poorly formed conclusions based on poor data or incorrect interpretation. That doesn’t mean the “denialist” is wrong. The field of health is full of them. Remember the consensus thought margarine was so good and healthy for you? Now it is shown to be worse than butter. If I was saying butter is good 20 years ago, I’d be labeled a “denialist”. “Everyone knows butter is bad for you”. But the consensus was wrong! And eggs too- they are in fact quite good for you, even though they contain cholesterol. They don’t raise cholesterol or cause heart disease. We were told diet has nothing to do with cancer for decades, but more experience and research overturned that bit of false wisdom. It is the most recent research that counts. The CO2 work of 50 years ago may be incorrect. Yet we are told over and over that carbon emissions cause global warming. Done deal. Settled. Let’s move on to shutting down the U.S. or at least tax the heck out of those greedy corporations. It all reeks of socialist propaganda. Nobody on NPR brings up the other side of the story- because there is no more Fairness Doctrine.

    We’ve got the time to let more research settle the issue with GW. But if the bees die, we’ve only got 5 years left according to Einstein. So we better get our priorities straight and get more resources on solving the bee problem. Not to mention the beekeepers losing their shirt.

  12. richferris
    Posted March 10, 2008 at 9:53 am | Permalink

    Can you please tell me who established the standards as to how much ice is suppose to be on the globe at one time? The ice caps have come and gone over the millenium and they will continue to come and go with or without human intervention. So what? People need to change and adapt.
    Who is it to say that the melting of the ice caps isn’t a natural process.

    Many of you environmentalists talk like ice cap melting, flooding and disasters caused by nature are going to occur overnight. As our environment changes around us, so will the people. They will adapt to natures way as we have in the past.

    I am getting tired of the government taxing me to change my habits and people telling how I should live my life just so they can feel good about themselves.

    Why not go out and make a difference in the world by teaching a kid how to read or becoming a “Big Brother or Sister” to a kid in need instead of whining about something you have absolutely no control over. You want change in the world, that would do it.

  13. Posted March 10, 2008 at 5:25 pm | Permalink

    > We’ve got the time to let more research settle the issue with GW. But if the bees die, we’ve only got 5 years left according to Einstein.

    Einstein never said that; it’s a myth. Google it – you’ll see. Google the rest of your misinformation and you’ll see that’s myth, too. We don’t “have time” to solve the global warming problem.

  14. Posted March 10, 2008 at 11:42 pm | Permalink

    Google it? What if I found that info using Google? Which one of us is right?
    OK let the bees die. We will be in very bad shape if they do. Common sense. But in china they have people do it instead of bees in some areas since the bees left. I guess we can try that.

    Please post some reputable rebuttal instead if posting more deceptive claims. You have to dig to get at the truth.

  15. fred1
    Posted March 12, 2008 at 5:22 pm | Permalink


    do you agree / admit that there have been times in the earth’s past million years where global temperatures were warmer than they are today and CO2 levels were lower than they are today?

  16. johnmashey
    Posted March 13, 2008 at 2:24 pm | Permalink

    Catching up.
    Skeptic1, March 8.

    Have you read both of Fred Singer’s books? and Fred’s SEPP website? (I had, and I was long puzzled by some of the motivations, until I talked to Naomi, whose talk cleared up a lot.)

    “many scientists that appear to me to be very well qualified to say that C02 is not the prime cause of global warming, based on more recent science.”

    So, who are they, and what are your qualifications for assessing their qualifications?” In general, on the Web, unsupported opinions by unidentified posters are worthless, at best, so give me something useful. Are they active researchers? Do they publish in credible peer-reviewed journals? Do you read those? Do they mean what you think, or are you going on secondhand descriptions?

    Anyway, I have a general interest in understanding why people believe they believe, so:
    What do you read, and who do you talk to?

    See comment #84 in http://tierneylab.blogs.nytimes.com/2008/03/06/global-warming-payola/#comments for the sorts of people I learn from.

    Nutrition advice is not physics, just as the stock market is not temperature. Neither is a good analogy.

    A large number of people who don’t understand the science (and a few who do) don’t like it’s conclusions don’t believe it for ideological / political reasons, and your last paragraph appears to put you in that camp, as was Robert L. in http://scienceblogs.com/deltoid/2008/03/monckton_reckons_gore_is_the_s.php#commentsArea
    See #6, and my comment in #20 about the difference between smart libertarians and those being scammed into acting against their *own* self-interest and especially those of their descendants.

    Physics doesn’t care about political viewpoint.

  17. johnmashey
    Posted March 13, 2008 at 3:55 pm | Permalink

    fred1: of course, and that matters only if you think CO2 is the *only* factor that affects the temperature, which no real climate scientist that I’ve talked to (a bunch) believes. Look at


    and the figures

    In the first figure, you may notice that the last 3 interglacials had sharp peaks on the CO2 (blue), temperature (red) and CH4 (green) curves. Those peaks also are a subset of the 65-degreeN insolation (sun) (orange) at the bottom. You’ll notice the insolation is on its way down. Under unmodified conditions, the temperature would be slowly (10s of thousands of years) doing a slow slide down into the next ice age.

    The last interglacial (the one we’re in), at the left, looks different: the CO2 and CH4 lines didn’t drop off, and the temperature didn’t either. The peak temperatures of the last 3 interglacials were slightly higher, and the CO2 was lower. The temperatures have not yet had time to fully respond to the human-created forcing, i.e., even if we stopped emitting CO2 today, we’d keep warming for decades.

    Without human-induced CO2+CH4+N2O+soot+land-use-changes,
    http://www.skepticalscience.com/argument.php is a useful website that lists commonly-heard arguments, with a pointer to a web page per argument, that gives an accessible, short discussion, laced with references to credible scientific papers. You might want to check:

    [change] 2
    [co2lag] 8
    [lowco2] 28

    There are lots of other online resources that explain this, so I won’t try to duplicate them. However, I really recommend William F. Ruddiman’s “Plows, Plagues, and Petroleum”: consider going to http://www.amazon.com/Plows-Plagues-Petroleum-Control-Climate/dp/0691133980/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1205437616&sr=8-1, read my review there, and spend <$15 for the book. It’s only 200 pages, but it puts a lot of issues together in a coherent way, and is very accessible whether one is very technical or not. See especially page 41.

    Anyway, CO2 is the highest it’s been in the last million years, and going up fast. The temperature is not quite as high as the short, highest peaks, found only when the Milankovitch Cycles yielded more light at 65degrees N. However, it’s rather likely that we’ll match those peaks, depending on policies.

    The “Eemain interglacial”, i.e., the one just before ours, 130Kyears ago, was slightly warmer than we are right now, and the sea level is believed to be about 4-7 meters higher than now, i.e., due to much of Greenland having melted. That of course is quite survivable, but rather expensive, given that 130Kya (or even 1Kya) we didn’t have 6B+ people, of whom many live near the coast.

    http://flood.firetree.net/ gives an interactive map in which you can set the sea level rise, and it grays out below-sea-level areas. Of course, as the Dutch know well, just because something is below sea level doesn’t mean it’s under water, but it does mean a lot of money gets spent to keep the water out.

    For instance, see http://flood.firetree.net/?ll=38.1432,-122.0142&z=8&m=6, which is Northern California at +6m, i.e., big chunk of Silicon Valley below water [we can do dikes for that], but the San Joaquin River Delta, one of the richest farm areas in the world, is gone, and Sacramento has issues. (CA has 1000 miles of dikes already, and much of the Delta is already below water.)

    If you don’t live out here, you may not understand how the entire West is dependent on snowpack-melt for water, and on dams, aqueducts, irrigation, and AGW helps none of this. CA alone grows half of the US fruits & vegetables right now. Expect them to get a lot more expensive.

    Now if you’re elsewhere in the US, you might not care about us out here, but you should, because CA has the largest net subsidy (about $60B in 2000) to the Federal government (& other states)… Other big subsidizers include NY and NJ, and you can look on the map for the +6m effects on them. So is FL, but you don’t want to look at that, nor at New Orleans.

    No one expects +6m overnight. On the other hand, if you understand Peak Oil, you’ll know that descendants 100 years from now may have to build big dikes and steel+concrete sea walls … but they won’t have much petroleum to do it with.

  18. fred1
    Posted March 17, 2008 at 7:36 am | Permalink


    so since livestock are a main source of methane emissions do we need to put a cap on them? obviously there are much more livestock in the world now then there would be if humans did not have a demand for meat, etc. perhaps limit the numbers of livestock allowed in the United States and push for a global cap? they are a significant portion of GHG emissions as well…would you agree?

  19. Posted March 18, 2008 at 4:28 pm | Permalink

    fred1 – Take a look at our post on Farm Animals and Methane for ways to deal with the problem.

  20. johnmashey
    Posted March 19, 2008 at 8:44 pm | Permalink

    I’d expect, at some point or other, there will GHG-emission charges attached to many areas of agriculture, since:

    – some methane comes from rice paddies [and there has been work on designing rice strains and/or different growing methods to lessen such).

    – Agriculture not only generates CO2 from land-use changes like cutting trees, but nitrous oxide is also generated, especially from over-fertilizing.

    UC Davis is excellent at such topics: see for example:

  21. Posted March 20, 2008 at 11:15 am | Permalink


    Thanks for the link. Here’s another.

    Check out Eric Holst’s post about emissions from California rice farms. We’ve teamed with researchers from Davis and other organizations in an effort to identify options for rice growers to reduce emissions.

  22. assman
    Posted January 12, 2010 at 11:18 am | Permalink

    There is no trend. 0.6 degrees over a century is not a trend. You are seeing patterns in noise. You are being fooled by randomness. There is no global warming phenomena. You people suck.

    And I know I am not an expert. Nor have I published in the peer review literature. But I am also not a complete idiot. You people on the other hand are morons. In the future people will wonder how scientists and morons like you could be so stupid. I often used to wonder that about communism. How could anyone be so stupid as to think that communism would work. The hilarious things is that you are the same morons. Marx saw the impoverishment of the working class based on the extrapolation of a short term trend. He was a moron and you people thought he was a genius. You are still dumb fucks.