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Christopher Majka

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Christopher Majka studied oceanography, biology, mathematics, philosophy, and Russian studies at Mount Alison and Dalhousie Universities and the Pushkin Institute in Moscow, and was a guest researcher at the Edward Gray Institute at Oxford University. He has written articles for many national and international publications. His scientific work includes over 150 scientific papers and contributions to five books. He is a review editor for four international publications, a research associate of the Canadian Centre for Policy Alternatives-NS, a recipient of the Tom Brydges Award from the Ecological Monitoring and Assessment Network, and was included as one of Canadian Geographic's Environmental Scientists of the Year in 2010. Majka is a member of the Project Democracy team.

Loaded dice in the climate change casino

| August 11, 2012
Loaded dice in the climate change casino

In June of this year over 4,000 daily high temperature records were broken in the United States. There were 159 record high temperatures for the month, and 42 all-time temperature highs. July has been even worse, the hottest month ever recorded in the United States since comprehensive weather recording began in 1895. July 2012 was the 328th consecutive month that global temperature exceeded the 20th century average. In Canada record-setting temperatures were recorded in July in many parts of the country.

In August there have been snowfalls throughout every district of South Africa, an unheard of event. Johannesburg has only recorded snowfalls on 22 days in the last 103 years. The great drought of 2010 in Russia caused massive wildfires that destroyed 25 million acres of crops. In 2010 China recorded its second highest temperatures ever, and India recorded its hottest year on record.

Is there a pattern here?

The weather is not the climate. Weather happens all the time, everywhere all around us. Hot days, cold days, rain, sunny weather, hailstorms, tornados, ice storms, snowfalls, hurricanes … everyone's experienced at least a subset of the above. It changes day to day, hour by hour, sometimes even faster than that. Weather is what is happening now. Climate, on the other hand, is the season-by-season synthesis of weather patterns over a longer period and wider area. We experience weather moment by moment, but our individual understanding of climate is shaped from knowledge of atmospheric conditions over the long term. Nevertheless, despite the more intangible nature of climate, we all have a very tangible sense of what it is. Everyone knows the differences between a tropical, desert, Mediterranean, and tundra climate.

Is there a way we can determine if the extreme weather events we have been witnessing are indicative of a changing climate, or are we simply witnessing variable weather? The answer is yes.

Perception of climate change

James Hansen of NASA's Goddard Institute of Space Studies, one of the foremost climatologists in the world, and his colleagues Makiko Sato and Reto Ruedy have provided an emphatic demonstration of how climate is changing. In a strikingly elegant publication entitled Perception of climate change that utilizes a colossal dataset of temperature measurements from throughout the globe gathered over the last sixty years, they clearly demonstrate that the kind of extreme weather patterns that are affecting the globe are consistent with, and illustrative of, how the climate has been changing over the last several decades. We're going to see a lot more of such weather - and worse.

While demonstrating this scientifically involves some number crunching and statistical sophistication, the overall approach is easy to understand and puts to rest any lingering doubts about the reality of climate change that anyone might have harboured. In their analyses, Hansen and his colleagues established a reference period of 1951-1980. During this time the climate was stable and similar to the climatic regimen during the entire Holocene (i.e., the last 12,000 years). Moreover, it is also recent enough that people of the baby boom and older generations actually remember what the climate was like back then. They then compared this "base" period to what has happened between 1981-2011. What did they find? A great deal, but before we go there, there's one mathematical concept we need to clarify -- standard deviation.

Standard deviation

We all know that weather varies. Not only does it change on a seasonal basis, but it also varies from day to day. Some days a little warmer or cooler, rainier or dryer, the barometric pressure changes, the relative humidity rises or falls. However, at each time of year it tends to change within what is normally a narrowly defined range. So, for instance, in mid-summer, if the average (or mean) temperature in your area is, say, +18ºC, days when it gets up to + 24ºC or only to +12ºC are not that unusual. Temperatures of -4ºC or +40ºC would be extremely unusual. The standard deviation (in mathematics represented by the Greek letter sigma) shows the distribution of values around that mean.

Bell curve

Most people are familiar with the "bell-curve" (or normal distribution) which represents the distribution of values around a mean. The rule is that 68.27 per cent of values lie within one standard deviation unit of the mean (half on either side); 95.45 per cent lie within two standard deviation units; and 99.73 per cent (i.e., almost all) lie within three standard deviation units. The name "bell-curve" represents the shape of this distribution, and the fact that under normal circumstances the bell is symmetrical, i.e., it tails off in the same way on both sides. So, in normal circumstances if there is a variability in temperature, it is as apt to be cooler as it is warmer 

The temperature anomaly

So, with the math out of the way, let's examine at what Hansen found. The graphs below show the summer (June-July-August) temperature anomaly in 1955, 1965, and 1975 (three representative years from the 1950-1981 reference period) compared with 2006-2011 (the most recent years). The "anomaly" is the difference between the mean temperature of the 1951-1980 base period, and what actually happened that summer. The colour represents the temperature anomaly; the darker the red, the warmer it was; the deeper the blue, the cooler it was. The small numbers at the upper right of each graph are the global mean for that year, that is to say the average over the entire planet.

from Hansen et al. (2012)

We can see that in 1955, 1965, and 1975 temperatures throughout most of the globe were normal and the global mean anomaly was small: -0.09, -0.11, and -0.08 ºC. The situation between 2006-2011 is completely different. The maps are dominated by orange, red, and brown (temperature anomalies from +1.0 ºC to as high as +6.8 ºC) with very little green or blue. In other words, most of the planet was experiencing warmer than normal temperatures and very little was experiencing cooler than normal ones. Indeed the global means (+0.46, +0.42, +0.37, +0.52, +0.54, +0.45) are more than five-times the values in the earlier period, and they are all warmer.

The extent and scale of these temperature anomalies and the clear difference between the 1950-1981 reference period and recent years, is a strong indication that something may be rotten in the state of Denmark. However, this information by itself isn't enough. So, it's been warmer in the last three decades than it has been during the previous three. So what? The weather varies all the time; even the climate naturally varies to very small degree. There are periods of cooling and of warming. Could we be witnessing this? How pronounced is this heating? This is where standard deviation comes in.

The standard deviation anomaly

The maps below show the same areas, the same years, and the same time period as above. However, this time the colour doesn't indicate the temperature anomaly, but rather the anomaly in standard deviation (sd) units. The numbers above each map are the percentage of the area of each of the categories in the colour bar (± 0.0-0.43 sd, ± 0.43-2.0 sd; ± 2.0-3.0 sd; ± >3.0 sd -- we'll get to why 0.43 is the first number rather than 1.0 in a moment). This might sound arcane and mathematical, but stay with me.

from Hansen et al. (2012)

What do we see? In 1955, 1965, and 1975 there are substantial areas of white (±0.43 sd) and most of the rest of the world is either light blue or yellow (± 2.0 sd). From the bell-curve distribution, we know that 95.45 per cent of all values fall within two standard deviation units, so this looks normal. In 2006-2011 the situation is very different. We see much less blue (i.e., cooler areas), large areas of red (+ 2.0-3.0 sd), and substantial areas of brown (>3.0 sd). Indeed, the red category which comprised only 1, 0, and 1 percent of the planet in 1955, 1965, and 1975, now comprises 13, 15, 10, 17, 18, and 14 per cent in the years between 2006-2011. The brown category (more than three standard deviation units), which was completely absent in 1955, 1965, and 1975, now comprises 5, 5 ,4, 6, 13, and 8 per cent in the years between 2006-2011 -- a dramatic increase. Again, going back to the bell-curve, in a normal distribution only 0.27 per cent of the land area should be hotter than three standard deviation units from the mean. However, between 2006-2011 an average of 6.83 per cent of the planet's surface was that much hotter -- an area over twenty-five times greater than should normally be the case. Now, this smells really rotten, and not just in Denmark, but all over the world. The emergence of this category of extremely hot summers is a new, and troubling, phenomenon.

Below is another way of looking at some of this information. These are the temperature anomalies (cold, very cold, extremely cold; hot, very hot, extremely hot -- as above, in relation to the normal mean temperature for the areas) over land areas (i.e., not over the oceans) in the Northern Hemisphere (NH) summer (top row) and winter (second row), and Southern Hemisphere (SH) summer (third row) from 1950 to 2011. The graphs show what proportion of the land areas were covered by temperatures in each of these categories. What do we see? In northern and southern hemispheres in winter and summer, areas of very cold (dark blue) and extremely cold (violet) are very low for the entire time period (the left series of graphs). There are occasional increases of very cold areas to 10 per cent for a year or two. Cold areas (light blue), while very variable in extent from year to year, hover mostly around 33 per cent (the dotted line) from 1950-1981, and thereafter begin to decline to approximately half that amount of land area by around 2000.

from Hansen et al. (2012)

In terms of hot anomalies (the right set of graphs), very hot (dark red) and extremely hot (brown) areas in both hemispheres and both seasons are almost non-existent between 1950-1981. Thereafter they begin to increased markedly to encompass 25 to 35 per cent of the land area by the year 2000. Hot areas (orange), while very variable in extent from year to year, hover mostly around 40 per cent between 1950-1981, and thereafter begin to increase, reaching approximately 66 per cent (the second dotted line) by 2000. These are very dramatic changes in the world's temperature regimen.

The loaded dice

Imagine for a moment that we have a die (one of a pair of dice) coloured as follows: two sides white for normal temperature, two sides blue for colder than normal, and two sides red for hotter than normal. The area of the bell-curve between -0.43 to +0.43 standard deviation units encompasses a third of the entire distribution (the reason for the ±0.43 category in the above graphs). In a normal climatic situation, if we were rolling the dice to determine if the temperature (for a day, a month, a season, or any time period) was normal, colder, or hotter than normal, you would expect to roll a white face a third of the time, a blue face a third of the time, and a red face a third of the time. If you kept rolling the die and it kept coming up red over and over, and almost never blue, you would soon reach the conclusion that something was wrong -- the dice were loaded.

That's precisely what James Hansen and his colleagues have determined. Hot summers (i.e., those in which the seasonal mean temperature is greater than 0.43 sd units from the normal mean) are now being rolled 67 per cent of the time rather than a third of the time. Cold summers, on the other hand, are down to approximately 10 per cent rather than a third. The dice are loaded. The bell-curve is no longer symmetrical, but has been squashed and pushed towards the higher temperature end of the spectrum.

[Note: the change in winter is not quite as extreme because of higher variability in winter temperatures. Winter temperature varies more widely than does summer because the latitudinal differences between temperature in the winter hemisphere are greater from polar to tropical regions. So the temperature at any given latitude varies depending on whether the wind is blowing from the north or south.]

The loaded gun

The loaded dice mean that humanity has a loaded climatic gun pointed to its collective temple. Anyone who was alive and paying attention before 1981 can perceive the difference in climate that has occurred subsequently, and the analysis of huge datasets of environmental information clearly and unequivocally confirm this change. The emergence of a new category of extremely hot summers over ever larger areas of the earth's land surface (from 0.27 between 1950-1981 to 6.83 percent now -- a twenty-five fold increase) is a dangerous and troubling phenomenon. It makes it clear that the extreme weather (heat, wildfires, droughts, floods, tornados, hail storms, hurricanes) that has been afflicting the world over the last several years is not a fluke -- it is the new norm caused by climate change.

In nationwide polls in the United States conducted by the University of Texas in July 2012 the proportion of people who believed in the reality of climate change climbed to 70 per cent from 65 per cent in March, 2012 and the proportion of disbelievers fell from 22 per cent to 15 per cent. This confirms Hansen, Sato, and Ruedy's observation that "… public opinion about the existence and importance of global warming depends strongly on their perceptions of recent local climate variations." Despite this, climate change remains off the political radar in the 2012 United States presidential election.

In Canada belief in the reality of climate change is even stronger. Polling conducted last year by the Public Policy Forum and Sustainable Prosperity found that:

  • 80 per cent of Canadians believe there is solid evidence of global warming;
  • 91 per cent of this group believe it is a serious problem;
  • 73 per cent per cent of Canadians indicated a willingness to pay at least $50 per year in extra energy costs for more renewable energy to be produced.

Despite that, climate change policy in Canada is a hollow shell of bogus goals, phony targets, unrealized promises, blatant disassembling, and a lack of tangible action.

The environmental audit released in May, 2012 by Canadian federal environment and sustainable development commissioner, Scott Vaughan, is a damning indictment of the Harper Government's policies and practices. The absurdly low and inadequate greenhouse gas (GHG) reduction targets of 17 per cent below 2005 levels by 2020 (compared with the Kyoto Protocol targets which mandated 6 percent reductions below 1990 levels) will not be met. The government's own documents estimate that GHG levels will be 7.4 percent above 2005 levels with existing policies -- and those policies are incomplete themselves. There is a lack of critical cost-effective analyses, and regulations for key areas such as the oil and gas sector, are completely lacking. Commissioner Vaughn's assessment that the Canadian government is "unlikely" to be able to meet its own climate-change goals is a charitable interpretation at best.

The loaded gun of climate change isn't even a game of Russian Roulette. All six chambers are loaded and yet governments like Canada and the United States are still squeezing the trigger.

Christopher Majka is a biologist, environmentalist, policy analyst, and arts advocate. He conducts research on the ecology and biodiversity of beetles. He is a research associate of the Canadian Centre for Policy Alternatives and a member of the Project Democracy team.

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Comments

1. There are many scientific periodicals and many variations on the rules that govern peer review. I see nothing untoward in regard PNAS Contributed Submissions. The rules are very exacting in regard to conflict of interest, disclosure, full documentation of the review process, no collaborations in the past 24 months, etc. And finally manuscripts and the review process are evaluated by the PNAS Editorial Board that can reject them summarily if it finds anything wanting. "Narcissistic" is your choice of words. 

2. The terminology of "Climate Change" versus "Global Warming": my comment related to your remark:

Hadji Ramjet wrote: "AGW causes drought AND floods, does it also cause warming AND cooling?

3. The focus of the paper is not on drought. This rebuttal relates to your comment:

Hadji Ramjet wrote: "Hansen claims that global warming is associated with increased drought in the US."

I previously responded:

"Hansen et al. do not only discuss extreme heat  as causing drought, but also note that it can cause extremely heavy precipitation and flooding. They write: "The other extreme of the water cycle, unusually heavy rainfall and floods, is also amplified by global warming. A warmer world is expected to have more extreme rainfall occurrences because the amount of water vapor that the atmosphere holds increases rapidly with temperature, a tendency confirmed by observations. Indeed, rainfall data reveal significant increases of heavy precipitation over much of Northern Hemisphere land and in the tropics and attribution studies link this intensification of rainfall and floods to human-made global warming."

Thus, there is clearly no confusion between the concepts of heat and drought.

4. Hadji Ramjet wrote: "The empirical method involves data collection and analysis without a preconceived notion of significance or conclusion, or even a null hypothesis."

Complete nonsense. No science in the real world is conducted in this way.

5. Hadji Ramjet wrote: "Five published studies referenced, and your only critique relates to an NYT opinion piece?"

I previous responded: "The comments section to my survey article isn't the place where the detailed science of climate change will be decided."

The validity of Hansen et al.'s work isn't decided on the basis of how many articles you or I cite here. As I previously wrote: "There are surely some studies and researchers, such as Martin Horeling, who will disagree. There are then scientists who disagree with Horeling."

In my view the science in Hansen et al.'s work is well presented, well documented, well developed, well argued, and convincing in every regard. All the credible climate scientists I have consulted with concur. If others have different views let them publish them and we'll see how the scientific community adjudicates such claims.

Chris,

In no particular order of importance:

1. Hansen et al was a Contributed Submission, in which the author includes two reviews from persons selected by himself, in this case Andrew Weaver and Tom Karl. I cannot find a single reputable journal from Geophysical Research Letters, Journal of Geophysical Research - Atmosphere, Society of Experimental Test Pilots, the eight Journals of the Society of Automotive Engineers, the 12 Journals & Periodicals of the American Meteorlogical Society, Environmental Law Review, or any other that allows this sort of narcissistic process. The guidelines you copied here do not apply to Contributed Submissions. If you're going to admonish someone to "read the guidelines," it behooves you to first read all of them yourself.

2. If it's Climate Change vice Global Warming (your point 2), it follows that the former should be the focus of the paper at issue here; yet the former is mentioned 22 times while the latter 39 times. Clearly Global Warming is more relevant in this paper. In light of that, it's hypocritical to call Hoerling pedantic. To which, one example hardly constitutes a "pedantic fixation."

3. ...the focus of Hansen et al.'s paper is not on drought... (your point 5), yet your Joe Romm reference (your point 1) is specifically about drought. Assuming that Romm is correct and Hoerling is wrong about drought, and Hansen et al is not about drought, where is the linkage between Hoerling's position on drought and Hansen's positions on an entirely different issue?

4. Your second reference at point 1 is an extremely odd choice, given that it states, "There is zero evidence that “climate change” has increased the probability of setting temperature records," in complete contrast to Hansen et al. If "stephengoddard" is correct in his criticism of Hoerling, then Hansen is also incorrect in his claim of temperature anomalies shifting toward higher temperatures. It's incongruous that you would use a reference from a "denier" to support Hansen et al.

5. ...superlative example of empirical research... (your point 1). The empirical method involves data collection and analysis without a preconceived notion of significance or conclusion, or even a null hypothesis. Contrast that with Hansen et al: “…we were motivated in this research by an objective to expose effects of human-made global warming as soon as possible…” Commencing research with such a stated objective is the antithesis of the empirical method, saying it is does not make it so.

6. Five published studies referenced, and your only critique relates to an NYT opinion piece? 

 

Hadji Ramjet writes:

1."The body of research that does not support your view is growing."

The comments section to my survey article isn't the place where the detailed science of climate change will be decide. There are surely some studies and researchers, such as Martin Horeling, who will disagree. There are then scientists who disagree with Horeling:

• "James Hansen Is Correct About Catastrophic Projections For U.S. Drought If We Don’t Act Now" by Joe Romm. 

• "Martin Horeling needs to check his facts"

Let them publish their dissenting studies and scientists will debate and discuss. The out-of-context quote from IPCC Special Report on Extremes you refer to says, "but their work is in the nature of reviews and commentary rather than empirical research." I've no idea what this refers to, however Hansen et al's paper is a superlative example of empirical research.

There's nothing to be gained by just throwing references pro and con around willy-nilly. I'm a scientist and as I wrote earlier, "In my view this statement is fully supported."

2. Hadji Ramjet writes: "I do not understand your comment here." Read again more attentively. This phenomenon is not called "Global Warming": it is called "Climate Change." Climate changes increases climatic variability.

3. Yes it is properly peer-reviewed. You have either mis-read or mis-interpreted the Proceedings of the National Academy of Sciences submission guidelines. The review is not supervised by the author and the author does not get to select the reviewers. Read the guidelines themselves:

"Authors must recommend three appropriate Editorial Board members, three NAS members who are expert in the paper's scientific area, and five qualified reviewers. The Board may choose someone who is or is not on that list or may reject the paper without further review. Authors are encouraged to indicate why their suggested editors are well qualified to handle the paper. The editor may obtain reviews of the paper from at least two qualified reviewers, each from a different institution and not from the authors' institutions. For Direct Submission papers, the PNAS Office will invite the reviewers, secure the reviews, and forward them to the editor. The PNAS Office will also secure any revisions and subsequent reviews. The name of the editor, who is to remain anonymous to the author until the paper is accepted, will be published in PNAS as editor of the article."

I am a review editor for four international journals and the process above is consistent with the policies of all of these and of the 20 or more journals that I have published in.

4. Hadji Ramjet writes: "Dr Michaels produced the afore-mentioned scattergram."

So what?

5. I wrote, "In any event, the focus of Hansen et al.'s paper isn't on the hydrological cycle..."

To which Hadji Ramjet replied, "So why did you bring it up?"

Because the focus of Hansen et al.'s paper is not on drought (i.e., the hydrological cycle).

6. I wrote, "Finally, a pedantic fixation on the title of the paper..."

To which Hadji Ramjet replied, "The title hasn't been mentioned once in the comments section, relevance of this comment?"

Yes it has. You provide the following quote:

“This isn’t a serious science paper,” Dr. Hoerling said. “It’s mainly about perception, as indicated by the paper’s title. Perception is not a science.”

1. Hansen et al. write.. we can say with a high degree of confidence that events such as the extreme summer heat in the Moscow region in 2010 and Texas in 2011 were a consequence of global warming."

In my view this statement is fully supported ...

NOAA disagrees: http://www.noaanews.noaa.gov/stories2011/20110309_russianheatwave.html and http://www.agu.org/news/press/pr_archives/2011/2011-10.shtml

This Russian study disagrees: The dynamics of solar activity and anomalous weather of summer 2010: 2. Relationship with the active longitude zone; effects in the west and east. (Geomagnetism and Aeronomy, Volume 52, Number 1, pp. 1-15, February 2012)- K. G. Ivanov, A. F. Kharshiladze

American Meteorological Society disagrees: http://dx.doi.org/10.1175/MWR-D-11-00249.1 http://dx.doi.org/10.1175/2011JCLI3523.1 and http://dx.doi.org/10.1175/BAMS-D-12-00021.1 (...some extreme events are becoming less likely due to climate change.)

UCAR disagrees: https://www2.ucar.edu/atmosnews/features/5282/blocking-way

IPCC Special Report on Extremes disagrees: "Some authors suggest that a (natural or anthropogenic) climate change signal can be found in the records of disaster losses... but their work is in the nature of reviews and commentary rather than empirical research."

Comments from NOAA scientist Martin Hoerling (http://www.esrl.noaa.gov/psd/people/martin.hoerling/): "The claim in the Hansen NYT piece that the Midwest would be a dustbowl in coming decades thus runs contrary to peer reviewed literature and recent assessments by the U.S. Global Research Program that emerged from the synthesis of current understanding by an expert team of scientists."

“Published scientific studies on the Russian heat wave indicate this (Hansen's) claim to be false.  Our own study on the Texas heat wave and drought, submitted today to Journal of Climate, likewise shows that that event was not caused by human-induced climate change. These are not de novo events, but upon scientific scrutiny,one finds both the Russian and Texas extreme events to be part of the physics of what has driven variability in those regions over the past century.  Not to say that climate change didn’t contribute to the those cases, but their intensity owes to natural, not human, causes.”

The body of research that does not support your view is growing.

2. Hansen et al. do not only discuss estreme heat  as causing drought, but also note that it can cause estremely heavy percipitation and flooding. They write: "The other extreme of the water cycle, unusually heavy rainfall and floods, is also amplified by global warming. A warmer world is expected to have more extreme rainfall occurrences because the amount of water vapor that the atmosphere holds increases rapidly with temperature, a tendency confirmed by observations. Indeed, rainfall data reveal significant increases of heavy precipitation over much of Northern Hemisphere land and in the tropics and attribution studies link this intensification of rainfall and floods to human-made global warming."

So, there is clearly no confusion between the concepts of heat and drought.

I do not understand your comment here. Hansen is trying to link global warming with both increased AND decreased rainfall, but you make a conclusion about heat & drought? 262 record LOW temperatures occured in the US on 27-28 June 2012, is there a correlation, ie if AGW causes drought AND floods, does it also cause warming AND cooling?

3. Hansen et al.'s paper is properly peer-reviewed.

No, sadly it isn't. Until 2010 PNAS Members submissions were not subjected to ANY sort of review, and most recently the submission review is "supervised" by the submitting academy member WHO GETS TO SELECT THE REVIEWERS. This policy is NOT consistent with proper peer-review, hence the term "pal-review."

4. Hansen et al.'s data is drawn from the databases of NOAA and NCDC. If Patrick Michaels thinks that he has data that say something different, he should publish them and see if they survive peer-review, and then see how the scientific community appraises them.

Cherry-picking one critic? Dr Michaels produced the afore-mentioned scattergram.

5. In any event, the focus of Hansen et al.'s paper isn't on the hydrological cycle...

So why did you bring it up? The Palmer Hydrological DI is only one of four indices that show the same trend (or lack thereof).

6. Finally, a pedantic fixation on the title of the paper...

The title hasn't been mentioned once in the comments section, relevance of this comment?

 

1. Hansen et al. write (in the discussion section of their paper): "The increase of these extreme anomalies, by more than an order of magnitude, implies that we can say with a high degree of confidence that events such as the extreme summer heat in the Moscow region in 2010 and Texas in 2011 were a consequence of global warming."

In my view this statement is fully supported given Hansen et al.'s evidence that areas of extreme heat (> 3 sd units from the mean) now cover at least 25 times the land area on the earth that they ought to under a normal distribution.

 2. Hansen et al. do not only discuss estreme heat  as causing drought, but also note that it can cause estremely heavy percipitation and flooding. They write: "The other extreme of the water cycle, unusually heavy rainfall and floods, is also amplified by global warming. A warmer world is expected to have more extreme rainfall occurrences because the amount of water vapor that the atmosphere holds increases rapidly with temperature, a tendency confirmed by observations. Indeed, rainfall data reveal significant increases of heavy precipitation over much of Northern Hemisphere land and in the tropics and attribution studies link this intensification of rainfall and floods to human-made global warming."

So, there is clearly no confusion between the concepts of heat and drought.

3. Hansen et al.'s paper is properly peer-reviewed.

4. Hansen et al.'s data is drawn from the databases of NOAA and NCDC. If Patrick Michaels thinks that he has data that say something different, he should publish them and see if they survive peer-review, and then see how the scientific community appraises them. 

5. In any event, the focus of Hansen et al.'s paper isn't on the hydrological cycle, but on variations in global temperature over the last 60 years. There's no reason they should explore testable hypotheses in relation to the hydrological cycle; that's not the subject of their paper.

6. Finally, a pedantic fixation on the title of the paper misses the reason why Hansen et al. titled it as they did. They write: "A recent survey in the United States confirms that public opinion about the existence and importance of global warming depends strongly on their perceptions of recent local climate variations. Early public recognition of climate change is critical." 

Hey Hadji Ramjet - if you want to be taken seriously in any discussion about global warming please don't quote Patrick Michaels. He has as much credibility in this discussion as a steaming pile of dog shit. It should be pretty obvious to anyone who is not legally brain dead that these weather conditions are exactly what is going to happen under global warming.

I apologize if I have offended anyone with my language, but I am fed up with these ignorant deniers who are doing nothing but delaying necessary responses to something that is going to make life miserable for millions of people in the world who are already struggling. If you don't have anything constructive to say, then get out of the way.

Yet the NCDC raw data shows annual average contiguous US preciptitation on an upward trend, and flat over the summer months. The claim that precip is down due to drought is not supported by the data.

Palmer Drought Severity Index is flat; US Modified Palmer DSI shows no trend as well; Palmer Hydrological Drought Index is essentially flat, in fact shows a slight upward trend in the divisional plots suggesting less drought; shorter-term Palmer Z Index is also flat.

Scatterplot gauging correlation between Hansen’s own GISS temperature data (GISTEMP) and the U.S. Palmer Drought Severity Index with annual data through 2011 shows NO correlation.

A 2,129-Year Reconstruction of Precipitation for Northwestern New Mexico, USA,” Henri D. Grissino-Mayer, University of Tennessee, suggests that what New Mexico experiences today, isn’t really any different from what it has been experiencing in the past, when CO2 levels were far lower. In fact, for the most recent period, New Mexico has had greater rainfall.

 

The warmer the atmosphere, the more moisture it can contain.  The relationship between a warm atmosphere and drought on land seems obvious to me.

 

NOAA scientist Dr. Martin Hoerling is panning it. Dr. Hoerling contended that Dr. Hansen’s new paper confuses drought, caused primarily by a lack of rainfall, with heat waves.

“This isn’t a serious science paper,” Dr. Hoerling said. “It’s mainly about perception, as indicated by the paper’s title. Perception is not a science.”

 

Dr Patrick Michaels, former Virginia State climatologist:

"Hansen is simply wrong. Hansen claims that global warming is associated with increased drought in the US. This is a testable hypothesis which he chose not to test, and, because PNAS isn’t truly peer-reviewed for Members like him, no one tested it for him.

I have [examined] drought data [that] are from NCDC, and the temperature record is Hansen’s own. His hypothesis is a complete and abject failure."

 

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