IPCC says they don’t know if the climate is becoming more extreme

There has been much speculation and many headlines about the relationship between global warming and extreme weather.  For example, see this recent alarmist story from the AP in the Arizona Daily Star: “World warned to prepare for extreme weather.”  The first line of that story says, “Global warming is leading to such severe storms, droughts and heat waves that nations should prepare for an unprecedented onslaught of deadly and costly weather disasters, an international panel of climate scientists said in a new report issued Wednesday.”  Apparently the story authors got their information from alarmist press releases and interviews rather than the report itself.  (They got the page count wrong too.)

The basic conclusion of the Intergovernmental Panel on Climate Change’s (IPCC) new report on the subject of extreme weather is: “While there is evidence that increases in greenhouse gases have likely caused changes in some types of extremes, there is no simple answer to the question of whether the climate, in general, has become more or less extreme.”

While storm damage makes the news, the damage is largely an artifact of our propensity for building infrastructure in the areas subject to extreme weather rather than any imagined increase in such weather.

IPCC: “There is medium evidence and high agreement that long-term trends in normalized losses have not been attributed to natural or anthropogenic climate change.”

Some other interesting quotes from the IPCC report:

“The statement about the absence of trends in impacts attributable to natural or anthropogenic climate change holds for tropical and extratropical storms and tornados.”

“The absence of an attributable climate change signal in losses also holds for flood losses.”

“Some authors suggest that a (natural or anthropogenic) climate change signal can be found in the records of disaster losses (e.g., Mills, 2005; Höppe and Grimm, 2009), but their work is in the nature of reviews and commentary rather than empirical research.”

You can download the 582-page report here: http://www.ipcc-wg2.gov/SREX/  That page allows you to download either the Summary for Policy Makers (11.8 Mb) or the full report (44 Mb).

See also:

The Storm Over Tornadoes

Media pawns in IPCC extreme weather hype

Pained Earth’s summer to forget: the rest of the story



  1. I presented this to a different post a while back. This does a statistical portioning of the earth  and measures how it changes in temperature. More energy is what drives the extremes. I believe the conclusion written by the SKS author is a valid one. If you decide to take the time to see a different view of Hansen’s work the cold and extreme cold have decreased and the hot and extreme hot have increased.

    By doing an analysis of the entire globe at once, Hansen has gotten around the problem of attribution of a single event.  Global data, averaged over several months, allows Hansen to conclude that most of these events would not have happened without AGW.  Extremely Hot events, even for a single summer, kill established trees, permanently damage ecosystems and cause severe economic distress.  Praying for rain (as recommended by the Governor of Texas) is unlikely to correct the problem as long as we continue to emit large amounts of climate changing gasses.


    1951 to 1980 baseline. James Hansen is comparing the world regions anomalies to 2003 to 2011. I have read over this several times and get something new out of it each time.

    1 sigma events occur 33% above and below a mean (or central point)
    2 sigma events occur 2.43% above and below
    3 sigma events occur .13% above and below

    if you look at fig 3 up in the rt hand corner are the percentages of the points lieing in the sigma ranges.
     ………-3. -2…-1 ….0 …. +1…+2..+3 
    1955   0… 2… 45…32…. 20…1…..0
    2010  0….1….15….18….34…18.. 13

    The near normal distribution expected is close to what 1955 is. If you go back and look at 1965, and 1975 you will see similar numbers provided by Dr. James Hansen. +3 sigma is the very hot category. THe -sigmas are decreasing and the + sigmas are increasing all through the last decade which is the hottest decade in instrumentaltemperture history.
    Below is an update for more information.

    From Hansen’s paper we are in the more extreme temperature now.

    1. I looked at Hansen’s paper in your reference.  Frankly, I don’t understand sentences like these from the abstract: “These extremes were practically absent in the period of climatology, covering much less than 1% of Earth’s surface.  Now summertime extremely hot outliers, more than three 
      standard deviations (s) warmer than climatology, typically cover about 10% of the land area.”

      Hansen obfuscates the argument by assuming CO2 is responsible for the warming without presenting any evidence to back up that claim.  I notice also that he used the cooling period of 1950-1980 as a basis of comparison.  Looks like statistical malfeasance to me.

      And I glad to see you no longer believe the IPCC.

      1. Jon, I’m glad to see you finally DO believe the IPCC.

        Page six of the SPM, under “Climate Extremes and Impacts”, will give you the relevant sections in the full report that further elaborate on the subject RenewableGuy is explaining. JP

      2. Frankly, I don’t understand sentences like these from the abstract: “These extremes were practically absent in the period of climatology, covering much less than 1% of Earth’s surface.  Now summertime extremely hot outliers, more than three standard deviations (s) warmer than climatology, typically cover about 10% of the land area.”


          Hansen who has the temperature records at his finger tips is examining the surface area of the earth that lies in his statistical categories. SKS does a nice job describing what this means.

        3 sigma events in 1950 to 1980 covered about .13% of the earth varying from year to year.

        Those rare 3 sigma events of the past 1950 to 1980 time frame in 2010 cover 13% of the earth.

        If you go back to the sks article which is describing Hansen’s work, go to fig  3 and you will see all the 3 sigma events labeled in the upper right hand corner.


        2010 is 100 times the surface area of the earth compared to the average of 1950 to 1980.

        2003 40,000 people died in Europe. The plants studied in Europe actually expelled co2 that year rather than aborb it.
        2010 700 hundred people died in Russia due to the heat.
        In 2012 US had heat wave in March. Our lilacs that don’t bloom till may are blooming now on April 1st. The fruit farmers of Michigan are worried that with this early heat wave with blooming fruit trees, their crops may be damaged because a hard freeze at this time of year is still possible. We had heat records typically shattered by 10 degrees. typically records are set by tenths of a degree.

      3. “2003 40,000 people died in Europe. The plants studied in Europe actually expelled co2 that year rather than aborb it.”

        RG see

        “2010 700 hundred people died in Russia due to the heat.”

        “In 2012 US had heat wave in March.”

        Sorry RG, but that was simply a REGIONAL one time WEATHER event. The global temp anomolies for feb were actually abnormally low, exceeding the 2011 cold spell (although I doubt you’d have heard that from SkS any time soon)

      4. Sorry Adam,
        See my posting above again. The weather is on steroids now. Besides all weather is a one time event. But when a one time rare events no longer are rare, then the statisticians pay attention. Take a simple statistic such as warm to cold records. In the year 2011 which is a La Nina year the warm records outnumbered the cold records 2.8 to 1. What do you think will happen in an El Nino year?

        Look at the year in2010 in total. What was rare from 1950 to 1980 now is one hundred times more common. All the years listed above show a much higher frequency of what used to be rare events. There is a shift going on in our weather and it is getting hotter.

        russian heat wave


        One month?


        taking into perspective the whole world, 3 sigma events have expanded including the european heat wave. A greater percentage of the earth is covered in warmer temperatures than 30 to 60 years ago.

  2. Climate Extremes and Impactshttp://www.ipcc-wg2.gov/SREX/images/uploads/SREX-SPMbrocure_FINAL.pdf

    There is evidence from observations gathered since 1950 of change in some extremes. Confidence in observed changes in extremes depends on the quality and quantity of data and the availability of studies analyzing these data, which vary across regions and for different extremes. Assigning ‘low confidence’ in observed changes in a specific extreme on regional or global scales neither implies nor excludes the  possibility of changes in this extreme. Extreme events are rare, which means there are few data available to make assessments regarding changes in their frequency or intensity. The more rare the event the more difficult it is to identify long-term changes. Global-scale trends in a specific extreme may be either more reliable (e.g., for temperature extremes) or less reliable (e.g., for droughts) than some regional-scale trends, depending on the geographical uniformity of the trends in the specific extreme. The following paragraphs provide further details for specific climate extremesfrom observations since 1950.


    I’m just popping out the first instance that contradicts Jon’s thesis about the IPCC.


    It is very likely  that there has been an overall decrease in the number of cold days and nights,3 and an overall increase in the number of warm days and nights,3 at the global scale, that is, for most land areas with sufficient data.  It islikely that these changes have also occurred at the continental scale in North America, Europe, and Australia.  There is medium confidence  in a warming trend in daily temperature extremes in much of Asia. Confidence in observed trends in dailytemperature extremes in Africa and South America generally varies from low to medium depending on the region.  In many (but not all) regions over the globe with sufficient data, there is medium confidence that the length or number of warm spells or heat waves has increased.


    This is the language used by the IPCC to talk about the different levels of uncertainty in the data.I’m wondering if you are confusing the language that the IPCC uses to communicate their uncertainty levels. They are talking about the basis of increasing temperature which increases extreme weather.


  3. http://www.salon.com/2012/04/02/inside_the_republican_brain/

    The weakness of the contrarian argument is overwhelming and yet they cling to every thread there is of why AGW isn’t true or isn’t bad. Chris Mooney has been writing on this subject for some time now. Jon Duhamel is doing this for political reasons rather than science. Authoritarian thinkiing does not like uncertainty, which is what the republican party leans towards. Science is all about the uncertainty. If you don’t include the uncertainty in your peer reviewed science paper, you can be flagged for it and the papaer has to be rewritten. Climate science has enough uncertainty in it to give all kinds of room to argue against the main stream science. Climate science is certain enough to know that the future will be warmer and will change the world around us. This kind of uncertainty about the future drives the authoritarians wild with their money tied up in the trillions in the fossil fuel infrastructure.

    1. “The weakness of the contrarian argument is overwhelming and yet they
      cling to every thread there is of why AGW isn’t true or isn’t bad.”

      What complete and utter nonsense. On the thread on CCD I gave you a link to over NINE HUNDRED peer reviewed papers refuting dangerous human caused global warming and it’s related claims.

      And RG do you know how many papers the working list has gone up too? I’m not going to tell you, but I’m going to give you a link to it, so you can see for yourself
      But once again, I doubt that would have been reported from your precious skeptical science website.

      “Jon Duhamel is doing this for political reasons rather than science.”

      That is a cheap and baseless accusation. You know absolutely nothing about Jon. You should be treating him with respect since your the one commenting on HIS website. Not the other way round

      1. Adam

        The same scientists that refuted tobacco and cancer are also in your 900 list. Bring up  a single paper and lets discuss it. I will let you summarize what it says.

        A list of 900 papers does not refute what I am saying. YOu must show that.

        “Jon Duhamel is doing this for political reasons rather than science.”

        That is a cheap and baseless accusation. You know absolutely nothing about Jon. You should be treating him with respect since your the one commenting on HIS website. Not the other way round


        So many published conclusions presented on Jon’s site have been shown to be false. And yet Jon has an acedemic background that should of caught those mistakes before they were published. It’s either very sloppy or political.

      2. To renewableguy:

        You speak of motives.  My motive for this blog is to educate, entertain, and to counter all the blatherskite of CAGW proponents.  From your screen name I surmise that you have a vested interest in promoting CAGW in the hope of selling more solar or wind energy systems.  From your email address, I know your name.  A person with that same name is a board member of the Illinois Renewable Energy Association which seems to be an environmental activist group.  Is that you?

      3. Do you seriously imagine that RG comments here in order to promote sales? I know that conspiracies abound in your worldview, Jon; but you really have slipped a cog this time. JP

      4. You have violated some kind of rule here. If you publish in a controversial area expect to be criticized. I don’t sell renewable energy comercially but support it fervently.

        THe politics of this is there are a large group of conservatives who just cannot accept the science. Your group is being studied to be understood why this is such a stubborn issue.

        I get tired of the same old denial of science and get down to the real issue. Its your world view getting in the way of what the world is really doing. Printing easily debunkable articles made up for confusion of AGW is interesting to me. It isn’t based on truth. I think you are smart enough to understand the weakness of these articles before you ever print them. It leaves purposely confusing people about AGW.


        Chris Mooney has been studying why with such an obvious danger ahead, the group you are a part of refuses to get it. You aren’t going to like it, but where else are you going to get a view other than those that reinforce your point of view.


      5. I have never even introduced the topic of RE on this site. But you have brought it up. Just in solar electricty alone Arizona could provide all of California’s electrical energy. A good conservative should be able to see those business oportunities. Photovoltaics requires very little water which would be perfect for the Arizona desert. It would have the least disruption to the desert environment.

        If you are a good follower of the authoritarian side of the Republican Party, you will resist all renewable energy because it is threatening to the their wealth empire. Koch brothers for example.

        But if follow the wealth, Arizona and North Africa will be the renewable Meccas of the world. That is where there is the best sunshine on earth for renewable production.

        Eventually you are going to have to drop your love affair with carbon. Its just going to get too expensive.

      6. Look at the WryHeat archives, Adam, and tell us again that RG’s accusation is baseless. Tell us, after that review, that Jon has no political agenda. JP

      7. Amazing John, you are credulous enough to believe AGW but can’t imagine that someone would promote a position to make money!

        And how about you? You hide behind anonymity.

      8. “To promote a position to make money”, sure. To do so at WryHeat…THAT strains credulity. Your treatment of RG makes a good case for anonymity. JP

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