Manmade Global Warming Has Increased Monthly Heat Records By A Factor Of Five, Much Worse To Come

Monthly temperature extremes have become much more frequent, as measurements from around the world indicate.

Potsdam Institute for Climate Impact Research News Release

On average, there are now five times as many record-breaking hot months worldwide than could be expected without long-term global warming, shows a study now published in Climatic Change. In parts of Europe, Africa and southern Asia the number of monthly records has increased even by a factor of ten [full graphic in the study]. 80 percent of observed monthly records would not have occurred without human influence on climate, concludes the authors-team of the Potsdam Institute for Climate Impact Research (PIK) and the Complutense University of Madrid.

“The last decade brought unprecedented heat waves; for instance in the US in 2012, in Russia in 2010, in Australia in 2009, and in Europe in 2003,” lead-author Dim Coumou says. “Heat extremes are causing many deaths, major forest fires, and harvest losses – societies and ecosystems are not adapted to ever new record-breaking temperatures.” The new study relies on 131 years of monthly temperature data for more than 12.000 grid points around the world, provided by NASA. Comprehensive analysis reveals the increase in records.

The researchers developed a robust statistical model that explains the surge in the number of records to be a consequence of the long-term global warming trend. That surge has been particularly steep over the last 40 years, due to a steep global-warming trend over this period. Superimposed on this long-term rise, the data show the effect of natural variability, with especially high numbers of heat records during years with El Niño events. This natural variability, however, does not explain the overall development of record events, found the researchers.

Natural variability does not explain the overall development of record events

If global warming continues, the study projects that the number of new monthly records will be 12 times as high in 30 years as it would be without climate change. “Now this doesn’t mean there will be 12 times more hot summers in Europe than today – it actually is worse,“ Coumou points out. For the new records set in the 2040s will not just be hot by today’s standards. “To count as new records, they actually have to beat heat records set in the 2020s and 2030s, which will already be hotter than anything we have experienced to date,” explains Coumou. “And this is just the global average – in some continental regions, the increase in new records will be even greater.”

“Statistics alone cannot tell us what the cause of any single heat wave is, but they show a large and systematic increase in the number of heat records due to global warming,” says Stefan Rahmstorf, a co-author of the study and co-chair of PIK’s research domain Earth System Analysis. “Today, this increase is already so large that by far most monthly heat records are due to climate change. The science is clear that only a small fraction would have occurred naturally.”

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31 Responses to Manmade Global Warming Has Increased Monthly Heat Records By A Factor Of Five, Much Worse To Come

  1. Superman1 says:

    Articles like this convince me we are not being told the full story by those who are taking and analyzing copious amounts of relevant data, and are not releasing the results to the public. My concern is similar to Sherlock Holmes’ in The Hound of the Baskervilles: why was the hound not howling? We have a ‘black’ community who I’m sure is gathering tremendous amounts of data relative to climate change, especially in the Arctic given its history, and, with its banks and banks of supercomputers, must be generating models that provide some approximation of the positive feedback impacts. One would expect them to inform the President of what needs to be done, and in turn the American people would receive some sort of message. There has been absolute silence!

    Has the ‘black’ community concluded ‘game over’ and, like the Doctor with the Stage 4 Pancreatic Cancer patient, the President decided not to deliver the bad news? We know the situation is at least as bad as that portrayed by the unclassified literature, which even with its feedback-free models, is still pretty horrific. Predictions of 6 C by century’s end mean ‘game over’. We also know it is worse when positive feedbacks are added, and it could be much worse. I am getting the uneasy feeling the situation is even far worse than anyone has projected, especially seeing these once-’extreme’ events starting to pile up with ‘only’ 0.8 C.

  2. Byron Smith says:

    “in Australia in 2009”
    Out of date already. Australia’s 2013 heatwave has smashed previous records. Of the 20 hottest days (national average temps) in the entire Australian temperature record, 7 of them have come in 2013.

  3. Superman1 says:

    Given the rapid rate at which these records are being broken, we need to use parallel legal, economic, socio-political, and technological remedial approaches as soon as possible to prevent the worst case from happening, if that is still possible. There is a serious legal issue here that I have not seen addressed. Fossil fuels are weapons of mass destruction. They use the atmosphere as a transmission medium. Their combustion unleashes these weapons against the USA (and all other countries), and will eventually destroy their populations. Does not our Constitution tell us the government’s job is to “provide for the common Defence and general Welfare” of the USA? Are we not constitutionally-bound to take whatever action is necessary to eliminate these weapons and protect out collective security?

  4. Guy Marsden says:

    It’s nice to sit around an pontificate about the societal/legal/govenmental impacts of Climate Change, but that accomplishes nothing. My strongly held belief is that the solution lies with individuals in civil society. Here’s what I’m personally doing:

  5. Paul Klinkman says:

    We need to move beyond “Yes it’s happening”, especially for the now anxious crowd that gets it. Somewhere in America there are voters pulling up the rear who naturally expect the earth to always be normal, as it was when they were kids. For them, tailor the message, but that’s not this crowd on this site. If anything, tailor the message on this site to what we tell the voters pulling up the rear.

    For example, these voters understand the outright lying of the tobacco industry. Not one of these voters would ever offer their own kid a cigarette, even though the cigarette ads try not to ever mention lung cancer unless they are forced to. Well, that’s how the fossil industry is going to act. Buy, buy, buy and lie.

    We need to have an energy morality in our communities. Nobody in any community is to kill the earth for our children, no extinct species for pleasant luxuries. Everything can be done the better way, usually the solar way, rarely the geothermal way, and so on.

    We will establish community standards, and then we expect every business in America to agree to adhere to those standards.

    This is the anxious crowd on the climateprogress site. Which one of you volunteers to start the forum, website or wiki that puts the standards together? Today is a pretty good day to make that decision. Put up a flag, start advertising, see who you get.

    Myself, I have to drive down the price of solar heat right now (and could use help doing THAT!)

  6. Nancy Sharp says:

    My computer won’t let me get to that website.

  7. Niall says:

    This had occurred to me as well. The reason I think not is that it would require a major international cover-up, not just at, say Goddard, which is credible, but at the Hadley Centre and so on as well. There are just too many opportunities for leaks.

    I’m sure many climate scientists are having sleepless nights. I do think the political class knows intellectually that it is game over for much of humanity, but I also think there is a *major* problem with cognitive dissonance. The only means of tackling the problem mean abandoning beliefs that are very deep rooted – in terms of economics and so on. It goes to the root of the sense of self. I was never attached to growth economics to begin with, so that came relatively easy to me. It’s harder if you come from the sort of background that allows you to become a top-level politician.

  8. Geez, we can even get much more basic by simply adopting a vegetarian diet. This can make a huge difference. For instance, producing a half pound of hamburger for someone’s lunch a patty releases as much greenhouse gas into the atmosphere as driving a 3,000-pound car nearly 10 miles. More info at

  9. fj says:

    Kind of suspect these stats are indicative of rapidly accelerating unstable equilibrium

  10. Jeb says:

    No, it is NOT too late. But, we only have 5 to 7 years to slow GHG emissions, before the 20-some self-perpetuating cascading feedback loops of global warming pass their irreversible tipping points and begin the release of of trillion of gigatons of methane that woujld turn the planet into an oven within only two decades afterward…

  11. Jeb says:

    Here is a link to info on the 20-some feedback loops mentioned >>> link

  12. climatehawk1 says:

    I urge jettisoning the term “manmade.” It is sexist and unnecessarily antagonizes one of your audiences. Please use “human-caused” or something similar.

  13. Mulga Mumblebrain says:

    Whatever your Constitution says about common defence and general welfare is irrelevant. Even supposing that the rich men who drew up the Constitution were really concerned about the rabble, their descendants today are not. For today’s elite, the proles are mere ‘moochers’ and ‘the Rights of Man’ are registered in dollar notes not mere existences. The absolute intensity of elite denialism, the concerted inaction of their political stooges, the scarcely credible machinations of the anti-scientific and anti-rational denialist industry and the complicity of the Rightwing MSM in the denialist Crusade all indicate one thing, to my mind at least. That the ruling capitalist elites in the West want climate catastrophe to occur, for reasons that also seem plain to me. To cause a great Malthusian cull of billions of ‘surplus’ human beings for whom they have no use, but bottomless contempt mixed with intense fear.

  14. James says:

    We have a bunch of craven cowards for so-called leaders. They would throw in the towel rather than to fight the good fight to save the world, or at least to go down trying. Scoundrels. The whole lot of them.

  15. Joe Romm says:

    For headlines, there is nothing wrong with it. Anything else is inapt. The main folks it antagonizes are deniers.

  16. Mulga Mumblebrain says:

    They are not leaders, they are followers, followers of the orders that they receive from the real global power, that of money. One that broke ranks would either be undermined economically, overthrown in a coup, see his country sanctioned then invaded or be assassinated.

  17. wili says:

    Sup, you’ll “enjoy” this piece.

    Guy McPherson on our current predicament.

    Has the right tone, even if a couple of the claims may be a bit off.

  18. Martin Hanson says:

    Yes, it was Sherlock Holmes, but it was ‘Silver Blaze’, not ‘The Hound of the Baskervilles’.

  19. Superman1 says:

    I’m no lawyer, but there may in fact be a legal argument based on the Constitution that those who are charged with protecting the common defense and general welfare are not doing their job. Fossil fuels as used today are the ultimate chamical weapon, and our government is doing exactly zero to protect us. If Clinton was almost impeached for his diversions, should not Obama and Boehner be impeached for their allowing this citizenry to be extinguished in a few generations?

  20. Superman1 says:

    First, what evidence do you have that it’s not too late? Do you have climate models with feedbacks that show minimal and reversible effects? I thought not!

    Second, one feedback omitted is damage cleanup after extreme events. These events are increasing drastically, as Hansen showed, and the cleanup and rebuilding are today very fossil fuel intensive. If NYC has to be relocated, think about the fossil fuel expenditures that will be required.

  21. Superman1 says:


    I’ve seen that video before, and one or two others of his as well. Without models that contain all the feedbacks, it’s hard to say yeah or nay on the accuracy of his predictions. I suspect he’s overly pessimistic about the time frame, based on his dependence on Malcolm Light’s results on Methane release.

    But, we can almost bound the problem. Some of the recent model-based studies are predicting on the order of 6 C by century’s end, given our present path of fossil fuel use. Books and articles have concluded that 6 C is essentially end of most species on Earth, including ours. To think that we could continue our present fossil fuel use to the end of the century without positive feedbacks kicking in strongly is truly wishful thinking. So, under present use, somewhere between mid-century and end of century for extinction of life is a good guess. This all pre-supposes that these positive feedback loops are not operating in strong self-sustaining mode already. Where is that evidence?

  22. Superman1 says:

    “My strongly held belief is that the solution lies with individuals in civil society.”

    Yes, if there are about six billion of those individuals following your lead. If there are a few thousand, game over! That’s why we need some top-down mandates to enforce strict rationing, and the sooner the better.

  23. Superman1 says:

    All the species were placed on this Earth with a minimal resource requirement footprint sufficient for self-sustainability. All but one species have continued to follow this footprint. The sooner this one outlier species adheres more closely to the original plan, the more self-sustainable we will become.

  24. wili says:

    Yeah, he should have left out the Malcolm Light stuff. Plenty strong without it.

    Did you see the piece in Nature (iirc) a few weeks back that had a graph that suggested that, for climate sensitivities over anything greater than 3 degrees per doubling, we are already in runaway GW, just from modeling the feedback from CO2 from the top 3 meters of terrestrial permafrost. MacDougal was the lead author, if I recall correctly. The response at a number of sites–tamino and climatesight at least–was “Oh Sh!t!”

    I try to remind myself that this is just one study, but the few studies that seriously try to account for carbon feedbacks do seem to be coming back with rather…disturbing results, to say the least.

  25. wili says:

    Has the ratio of record highs versus record lows for the US in 2012 been computed yet?

  26. OH says:

    We can conserve, we can skip a war, we can use technology to get us every 1% closer to where we need to be, we can get Americans those green jobs, we can start building those 144,000 windmills. The worthless rich are going to reap nothing but vengeance the longer they stand in the way and refuse to help. Let the squeamish work hard now to talk to these brick-wall-headed idiot science-deniers, or stand aside if it comes to doing it the hard way.

  27. wili says:

    Ah, found it in the “By The Numbers” piece from the 11th. It’s 5:1 for heat vs. cold records for 2012. This in an La Nina year with low solar activity.

    So we had:

    1 : 1 essentially forever before about 1970
    1+ : 1 from ’70 to 2000 steadily rising
    2 : 1 in the first decade of the century
    3 : 1 in 2011
    5 : 1 now in 2012

    Does anyone see a pattern here? Anyone want to graph it? What should we expect next? This looks beyond exponential when you consider the change in time frame (though as it is, it looks rather Fibonacci!).

    Perhaps this will suddenly crash down this year or revert to some more linear-looking trend, but right now it is looking ominously like things are getting a lot worse a lot faster than most anyone is talking about.

    Do we have figures for the Northern Hemisphere as a whole?

  28. Bernd says:

    Denialism will not help any more this study appeared yesterday as well in many of Germany’s TVs and newspapers.

    Yesterday the joint worldwide study of well known institutes in Spain and Germany were announced to the media in several European States, from the Universidad Complutense de Madrid and the Potdam Institute für Klimafolgenforschung and came to a joint conclusive result of climate change.

    All German print media and TV-stations like the 24 hour news station N-TV, reported on the study.

    N-TV reported (translated freely from myself):

    “Hotter than everything what we ever experienced”
    Number of heat records increase

    Even today heat-record-months, worldwide monitored, are experienced five times more often than it would be without climate change. This shows a study on basis of NASA data. Continues the global warming than the results will be fatal: It will not only be more often hot, it will be also much hotter.

    Monthly temperature extremes are clearly more common, this show global meter readings. In average global record-heat-months are today five times more common than it would be without the global warming. This proves a new study which is published in the magazine “Climatic Change”.

    In parts of Europe, Africa and southeast Asia the number of monthly heat records are even ten times higher. 80% of the observed monthly heat records would not have occurred without the influence of the human on the climate, explained the Author-Team of the Potsdam-Instituts für Klimafolgenforschung (PIK) and the Universidad Complutense de Madrid.

    Data from more than 130 years

    “In the last ten years unprecedented heat waves happened like those in 2012 in the USA, 2010 in Russia, 2009 in Australia or 2003 in Europe”, said Dim Coumou, head author of the study. “Heat extremes caused deaths, large forest fires and crop loss, societies and ecosystems are not adapted to such reoccurring new record temperatures”. The released study is backed up by monthly temperature data of 131 years from more than 12.000 locations worldwide, data which was compiled by NASA. Because of the comprehensive statistic analysis the increase of records was established.

    ….. ETC.

  29. BelleIslander says:

    Given the known facts that the we’ve already passed peak oil production, the globe’s impossible to solve economic mess, the sure to be coming riots and famines due to the prevailing drought-like conditions in North American, Eurasia , and Australia, occurring amidst an unfortunately extremely overcrowded world that is already armed to the teeth with both nuclear and biological weapons; I can only conclude that most of us will probably be dead within only 3 to 5 years from now. Awful times are surely coming and there’s not really a damn thing that any one of us can hope to do about it. It is over. No matter how rich or powerful they may presently think they are, no one can possibly hope to survive all the cataclysmic changes which are rapidly coming to this world. All I can advise is for one to try to learn how to nurture one’s own soul during whatever little time might still be left to us whilst preparing ourselves for our total extinction both as individuals and as a species. It’s been nice knowing you.

  30. Eshu says:

    I’m in a position to affect some policy change and budget allocations at a potentially federal level THIS WEEK. I need to pass on the latest, absolutely most up-to-day information on flood/heat/weather scenarios, preferably NYC as its coastline affects the jerks responsible for funding Big Bad Energy, and Sandy is providing a moment of attention fixed in time and space to the eastern seaboard.
    Please, for the love of humanity, gather and post as many links to data for worst-case scenarios for flooding, temperature increase and the like, preferably with map data. I seem to be the only one at these meetings aware of the runaway feedback mechanisms in the arctic permafrost/Siberian shelf/methane hydrates and how ice melting within the next few years will radically affect the temperature gradient in the far north, ripping and copying and sending storms far more frequently into North America. We have so much on our plate every hour and are grossly understaffed. If you wanted a way to help via article comment, this is it.

  31. wili says:

    Check out Hansen and Sato’s latest. Kevin Anderson is good, too:

    And Guy McPherson (if you avoid the AMEG/Malcolm Light stuff)

    Lots of further ref.s there, too.