The summary below is an abridged version of a National Academy of Science paper due August 6. The lead author, Dr. James E. Hansen, has been researching and writing about climate change for decades. His body of work qualifies him as our greatest or one of greatest living scientists. We will continue our walk off of a very high cliff until the threats of climate change are fully recognized and the subject of a massive effort to limit the damage. Hansen is a professor at Columbia University and directs NASA Goddard Institute for Space Studies. He has been a fearless advocate concerning the extreme dangers of climate change at a very real personal cost. Harassment and personal attacks are common for those who can’t handle the truth. We owe Hansen a profound debt of gratitude for his brilliance and personal courage. Michael Collins
The New Climate Dice: Public Perception of Climate Change
By James Hansen, Makiko Sato, Reto Ruedy ”” July 2012
The greatest barrier to public recognition of human-made climate change is probably the natural variability of local climate. How can a person discern long-term climate change, given the notorious variability of local weather and climate from day to day and year to year?
Figure 1. Fire fighters battle the Taylor Creek blaze, one of several fires which have burned over 75,000 acres in southeastern Montana in summer 2012. Image credit: USFWS/Gerald Vickers via InciWeb.org.
The question is important because actions to stem emissions of gases that cause global warming are unlikely until the public appreciates the significance of global warming and perceives that it will have unacceptable consequences. Thus when nature seemingly provides evidence of climate change it needs to be examined objectively by the public, as well as by scientists.
Therefore it was disappointing that most early media reports on the heat wave, widespread drought, and intense forest fires in the United States in 2012 did not mention or examine the potential connection between these climate events and global warming. Is this reticence justified?
In a new paper (Hansen et al., 2012a), we conclude that such reticence is not justified. The paper attempts to illustrate the data in ways that properly account for climate variability yet are understandable to the public.
We show how the probability of unusually warm seasons is changing, emphasizing summer when the changes have large practical effects. We calculate seasonal-mean temperature anomalies relative to average temperature in the base period 1951-1980. This is an appropriate base period because global temperature was relatively stable and still within the Holocene range to which humanity and other planetary life are adapted (note 1).
We illustrate variability of seasonal temperature in units of standard deviation (σ), including comparison with the normal distribution (“bell curve”) that the lay public may appreciate. The probability distribution (frequency of occurrence) of local summer-mean temperature anomalies was close to the normal distribution in the 1950s, 1960s and 1970s in both hemispheres (Fig. 2). However, in each subsequent decade the distribution shifted toward more positive anomalies, with the positive tail (hot outliers) of the distribution shifting the most.
Figure 2. Temperature anomaly distribution: The frequency of occurrence (vertical axis) of local temperature anomalies (relative to 1951-1980 mean) in units of local standard deviation (horizontal axis). Area under each curve is unity. Image credit: NASA/GISS.
An important change is the emergence of a subset of the hot category, extremely hot outliers, defined as anomalies exceeding +3σ. The frequency of these extreme anomalies is about 0.13% in the normal distribution, and thus in a typical summer in the base period only 0.1-0.2% of the globe is covered by such hot extremes. However, we show that during the past several years the global land area covered by summer temperature anomalies exceeding +3σ has averaged about 10%, an increase by more than an order of magnitude compared to the base period. Recent examples of summer temperature anomalies exceeding +3σ include the heat wave and drought in Oklahoma, Texas and Mexico in 2011 and a larger region encompassing much of the Middle East, Western Asia and Eastern Europe, including Moscow, in 2010.
The question of whether these extreme hot anomalies are a result of global warming is often answered in the negative, with an alternative interpretation based on meteorological patterns. For example, an unusual atmospheric “blocking” situation resulted in a long-lived high pressure anomaly in the Moscow region in 2010, and a strong La Niña in 2011 may have contributed to the heat and drought situation in the southern United States and Mexico. However, such meteorological patterns are not new and thus as an “explanation” fail to account for the huge increase in the area covered by extreme positive temperature anomalies. Specific meteorological patterns help explain where the high pressure regions that favor high temperature and drought conditions occur in a given summer, but the unusually great temperature extremities and the large area covered by these hot anomalies is a consequence of global warming, which is causing the bell curve to shift to the right (Fig. 2).
Yet the distribution of seasonal temperature anomalies (Fig. 2) also reveals that a significant portion (about 15 percent) of the anomalies are still negative, corresponding to summer-mean temperatures cooler than the average 1951-1980 climate. Thus people should not be surprised by the occasional season that is unusually cool. Cool anomalies as extreme as -2σ still occur, because the anomaly distribution has broadened as well as moved to the right. In other words, our climate now encompasses greater extremes.
Our analysis is an empirical approach that avoids use of global climate models, instead using only real world data. Theories for the cause of observed global temperature change are thus separated as an independent matter. However, it is of interest to compare the data with results from climate models that are used to simulate expected global warming due to increasing human-made greenhouse gases.
Indeed, the “climate dice” concept was suggested in conjunction with climate simulations made in the 1980s (Hansen et al., 1988) as a way to describe the stochastic variability of local temperatures, with the implication that the public should recognize the existence of global warming once the dice become sufficiently “loaded” (biased). Specifically, the 10 warmest summers (Jun-Jul-Aug in the Northern Hemisphere) in the 30-year period (1951-1980) were used to define the “hot” summer category, the 10 coolest the “cold” category, and the middle 10 the “average” summer. Thus it was imagined that two sides of a six-sided die were colored red, blue and white for these respective categories. The divisions between “hot” and “average” and between “average” and “cold” occur at +0.43σ and -0.43σ for a normal distribution.
Temperatures simulated in a global climate model (Hansen et al., 1988) reached a level such that four of the six sides of the climate dice were red in the first decade of the 21st century for greenhouse gas scenario B, which is an accurate approximation of actual greenhouse gas growth (Hansen and Sato 2004; updates are provided by a Columbia Univ. webpage). Observed summer temperature anomalies over global land during the past decade averaged about 75% in the “hot category”, thus midway between four and five sides of the die were red, which is reasonably consistent with expectations.
The relation between the bell curve and climate dice is illustrated in Figure 3. Extremely hot outliers already occur more frequently than unusually cold seasons. If the march of the bell curve to the right continues unabated, within a few decades even the seasons that were once considered average will cease to occur.
Figure 3. Frequency of occurrence (vertical axis) of local June-July-August temperature anomalies (relative to 1951-1980 mean) for Northern Hemisphere land in units of local standard deviation (horizontal axis). Temperature anomalies in the period 1951-1980 match closely the normal distribution (“bell curve”, shown in green), which is used to define cold (blue), typical (white) and hot (red) seasons, each with probability 33.3%. The distribution of anomalies has shifted to the right as a consequence of the global warming of the past three decades such that cool summers now cover only half of one side of a six-sided die, white covers one side, red covers four sides, and an extremely hot (red-brown) anomaly covers half of one side.
We have shown that the increased frequency of “hot” seasons is a result of global warming. The cause of global warming is a separate matter, but observed global warming is now attributed with high confidence to increasing greenhouse gases (IPCC 2007a).
Both attributions are important. Together they allow us to infer that the area covered by extreme hot anomalies will continue to increase in coming decades and that even more extreme outliers will occur. Indeed, we conclude that the decade-by-decade shift to the right of the temperature anomaly distribution (Fig. 2) will continue, because Earth is now out of energy balance, with more solar energy absorbed than heat radiation emitted to space (Hansen et al., 2011); it is this imbalance that drives the planet to higher temperatures. Even an exceedingly optimistic scenario for fossil fuel emissions reduction, 6%/year beginning in 2013, results in global temperature rising to almost 1.2°C relative to 1880-1920, which compares to a current level ~0.8°C (Hansen
et al., 2012b).
Figure 4. Wildfire frequency and spring-summer temperature in the western United States. Image credit: Westerling et al. (2006).
Practical effects of increasingly loaded climate dice occur mainly via amplified extremes of Earth’s water cycle. The broadening of the “bell curve” of temperature anomalies is related to interactions of warming with the water cycle. Hot summer anomalies occur when and where weather patterns yield an extended period of high atmospheric pressure. This condition is amplified by global warming and the ubiquitous surface heating due to elevated greenhouse gas levels, thus increasing the chances of an extreme anomaly. Yet global warming also increases atmospheric water vapor overall, causing, at other times or places, more extreme rainfall and floods, consistent with documented changes over Northern Hemisphere land and the tropics (IPCC 2007b).
The (Northern Hemisphere) summer of 2012 is still unfolding. A global map of the anomaly distribution will be provided on a Columbia Univ. webpage) once the data are complete; the data so far suggest that parts of the United States and Asia likely will be in the extreme (+3σ) category. One of the consequences of extreme summer heat anomalies is increased area and intensity of wildfires, as shown in Fig. 4. Updates of these data and other climate impacts after the 2012 data are complete will be useful for assessing impacts of continued global warming.
Related Articles
NASA News: How Warm was Summer 2010?
NASA Earth Observatory: Image of the Day, Aug. 9, 2010: Heatwave in Russia
NASA Earth Observatory: Image of the Day, June 29, 2012: Heat Wave Fuels Wildfires in the Rockies
NASA Earth Observatory: Image of the Day, July 17, 2012: Drought Grips the United States
Footnote
1 In contrast, we infer that current global temperature is above the Holocene range, as evidenced by the fact that the ice sheets in both hemispheres are now rapidly shedding mass (Rignot et al., 2011) and sea level is rising (Nerem et al., 2006) at a rate (more than 3 mm/year or 3 m/millennium) that is much higher than the rate of sea level change during the past several millennia. (Back to text)
References
Hansen, J., I. Fung, A. Lacis, D. Rind, Lebedeff, R. Ruedy, G. Russell, and P. Stone, 1988: Global climate changes as forecast by Goddard Institute for Space Studies three-dimensional model. J. Geophys. Res., 93, 9341-9364, doi:10.1029/JD093iD08p09341.
Hansen, J., and Mki. Sato, 2004: Greenhouse gas growth rates. Proc. Natl. Acad. Sci., 101, 16109-16114, doi:10.1073/pnas.0406982101.
Hansen, J., Mki. Sato, P. Kharecha, and K. von Schuckmann, 2011: Earth’s energy imbalance and implications. Atmos. Chem. Phys., 11, 13421-13449, doi:10.5194/acp-11-13421-2011.
Hansen, J., Mki. Sato, and R. Ruedy, 2012a: Perception of climate change. Proc. Natl. Acad. Sci., in press. Early draft posted as “Public perception of climate change and the new climate dice”, arXiv.org:1204.1286.
Hansen, J., P. Kharecha, Mki. Sato, F. Ackerman, P.J. Hearty, O. Hoegh-Guldberg, S.-L. Hsu, F. Krueger, C. Parmesan, S. Rahmstorf, J. Rockstrom, E.J. Rohling, J. Sachs, P. Smith, K. Steffen, L. Van Susteren, K. von Schuckmann, and J.C. Zachos, 2012b: Scientific case for avoiding dangerous climate change to protect young people and nature. Proc. Natl. Acad. Sci., submitted.
Intergovernmental Panel on Climate Change (IPCC), 2007a: Climate Change 2007: The Physical Science Basis. Solomon, S., et al. eds., Cambridge University Press, 996 pp.
Intergovernmental Panel on Climate Change (IPCC), 2007b: Climate Change 2007, Impacts, Adaptation and Vulnerability. Parry, M.L., Canziani, O.F., Palutikof, J.P., Van Der Linden, P.J., and Hanson, C.E. eds., Cambridge Univ Press, 996 pp.
Nerem, R.S., Leuliette, E., and Cazenave, A., 2006: Present-day sea-level change: A review. C. R. Geosci., 338, 1077-1083, doi:10.1016/j.crte.2006.09.001.
Rignot, E., Velicogna, I., van den Broeke, M.R., Monaghan, A., and Lenaerts, J., 2011: Acceleration of the contribution of the Greenland and Antarctic ice sheets to sea level rise. Geophys. Res. Lett., 38, L05503, doi:10.1029/2011GL046583.
Westerling, A.L., Hidalgo, H.G., Cayan, D.R., Swetnam, T.W., 2006: Warming and earlier spring increase western U.S. forest wildfire activity. Science, 313, 940-943, doi:10.1126/science.1128834.
Contact
Please address all inquiries about this research to Dr. James Hansen.
Published with permission, government document
the immediate density of the story and the difficulty of finding the part that related to the headline has meant that I have not read the story.
Yet the question is important and I would like to comment. I think that the issue is a classic “tipping point” case. My sense of the public, and here I think “acceptance” is a bad choice of words, my sense of the public understanding is that it is quite wide at this point. For instance I work with two people, one a professed tea partier and the other a defender of the 1%. The way they talk of “global warming,” of course since “climate change” is a word of consciousness, has shifted. One can almost feel their struggle at having to alter their relationship with the concept. There is the tug of the previous derisive stance trying to get out of the way of the weight of first perceived reality and then the shifting weight of social and peer pressure.
Bring to that the felt helplessness that we all share and the lack of sense that there is anything we can do, and you have your perceived “lack of public acceptance.” My sense is that the public very much gets it. They very much get that we are staring through the windshield headed for a cliff. And they very much wish that it was as simple as grabbing some single driver out of the driver seat and taking over. But it just ain’t that simple is it?
I have posted this thought on these comment boards before, but progressives need to re-frame this issue. The issue is not global warming or climate change, whatever you want to call it, the issue is that our continued burning of fossil fuels is polluting human beings and most other life on Earth to death! Period!
A warming climate is just one bad outcome. Others are acidification of the oceans, more respiratory diseases and asthmas, more cancers from exposure to oils and the chemicals used to extract oil, poisoning of groundwater from fracking, etc. When we limit the discussion to “it’s getting hotter” – every time we have a cold spell, conservatives say, “see, global warming is a bunch of bunk”. Or we have these dry, tedious discussions like these charts from Jim Hansen, which Mr. Wegerson rightly observes are boring and thick to wade through. Nobody but the most wonkish among us care about how many standard deviations from the norm our average temperatures are. This is all about pollution - plain and simple and we need to frame it that way. Conservatives don’t have a lot of wiggle room when you say our dependence on fossil fuels are polluting us all to death and walk through the litany of ills I cite at the beginning of this paragraph. It is irrefutable.
We breathe it out with every breath!
Posh!
i think it will too late before the “public” attitude catches up with the ability to get “our” leaders, lol, to do “something” anything” about global warning. the success of the Right in denying the reality of Global warming is still driving the discussion.
i frankly can’t imagine this changing anytime soon. all this talk about winning over the public and the efforts invovled to combat climate change is a futile effort. the Rich own the discourse on Global warning. when has truth succeeded in the Fox/Right wing era in leading to correcting the lies and innuendo. years of lies and deception are not erased overnight.
the Right and Fox News are going to have to lead the change. so don’t hold your breath waiting for them to start anytime soon . those damn liberals will have just wait for the rest of the population to get their reality “changed.”
just sitting back and watching the deniers “see” the reality of global warning is the only way any real efforts can be amassed and sustained. and that aint’ a pretty or a quick enough reality for those of us who have seen global warning coming for a long time now.
sad. the ignorant masses are what the Elites will have to respond to, if they respond at all. by then it will have been too far down the road for us to do anything but mitigate the worst effects global warning will have.
the Rich think they can avoid the effects of global warming. that is enough to keep us on the path we are on now and for the foreseeable future. maybe science can come up with something to counter global warming, otherwise we are just toast.
Hansen has done his job. He needs a translator/polemicist for the common man. This is what he calls the “simplified” version for the public. There’s great stuff in this piece, especially Figures 3 and 4. Highly persuasive but not the rhetorical structure to “grab” the general pubic to make the point.
I just got this email after I read your reply. This is from a good friend who is both a science nerd (Columbia grad;) and politically involved: “Do you think the simplified version is simple enough? Do you think a translation into even simpler language could be useful?”
I’m responding with a big yes and an invitation to collaborate on translating this into about 500 words that will make the case.
Here’s Hansen being a bit more concise:
That’s powerful but might better be said this way:
“Developing and using Canada’s tar sands oil resources would produce seven times the total CO2 pumped into our atmosphere over the past 150 years.”
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WaPo Aug 3
…(Suzuki being one); say it’s too late.
Shouldn’t we be using that as a base-line for action? It would seem that the collective we are operating on the assumption it can be stopped.
It can’t, it won’t; that seems the only logical position.
Find out just what any people will quietly submit to and you have found out the exact measure of injustice and wrong which will be imposed upon them,and these will continue till they are resisted with either words or blows,or with both~FDouglas
You’re absolutely right. Nothing is going to change in the US until the Republicans and their conservative supporters change their opinion about global warming, or until they are utterly obliterated as a political and intellectual force in this country. For even the first thing to happen, you have to get rid of their leaders, and in the climate change “debateâ€, none is more righteous and insolent than Sen. James Inhofe of Oklahoma.
His is a state which is in a second year of extreme drought. This summer Oklahoma has been setting temperature records as high as 114 degrees F. James Hansen in his editorial says “These weather events are not simply an example of what climate change could bring. They are caused by climate change. The odds that natural variability created these extremes are minuscule, vanishingly small. To count on those odds would be like quitting your job and playing the lottery every morning to pay the bills.â€
Sen. Inhofe likes playing those odds. His response to people like James Hansen can be found on his website.
Sen. Inhofe also has on his website a list of 700 scientists who do not believe mankind has or is even able to influence global climate. Many of them are like Dr. Christy; sometime in the past several hundred million years the earth was warmer than today, so no amount of scientific studies and statistical correlations can ever prove that any warming or climate change that exists today is anything other than the capriciousness of Mother Nature. Or, as Sen. Inhofe recently said, only God can change the climate.
Anyone who thinks otherwise is a liberal, hysterical, leftist/socialist/communist/godless alarmist. For people like Sen. Inhofe, this “debateâ€, which he insists is now over and which his side has won, is all about tribal identity as a Republican, which to them always boils down to obtaining and maintaining political power. Trash the economy in order to get Barack Obama out office? Why not – it’s all part of obtaining and maintaining power. Denigrate, ridicule, and ignore those who warn about climate change? That too is just part of the package of defeating the true enemies of America – the liberals. It is they who want to destroy the American way of life, not the oil companies or coal companies or the Koch brothers or any of the other corporate interests which fund the Republican party.
If summers routinely top out at 130 degrees F. in Tulsa, turning Oklahoma into the Sahara of the west, that won’t be enough to convince men like James Inhofe. If ocean acidification wipes out virtually all fish stocks, Oklahomans will simply take their business from Red Lobster to Chick-fil-A. There are about 50 million Americans who routinely vote Republican, again, more out of tribal loyalty, since to vote Republican requires you to accept a variety of fantasies like supply side economics, American exceptionalism, unlimited defense spending, and the United States founded as a Christian nation. It is hard to imagine any sort of climate change that would cause them to abandon their support for the fantasist half of what constitutes political debate in America. Oklahoma would have to be completely uninhabitable for people there to have an Inhofe Moment – a point in time when they realize James Inhofe is a highly dangerous cretin who should be drummed out of office once and for all.
Instead, they recently reelected him, and he is now the ranking member on the Senate’s Environment and Public Works committee. Which means, according to almost all polls which show the Republicans taking over the Senate in November, that he will be the new chairman of the Environment committee in the Senate. The damage he can do is only just beginning.
and financial skullduggery, our civilization (and I use the term loosely) is going over the cliff and it’s already too late to stop it.
The most sensible suggestion I’ve seen comes from John Michael Greer @ Archdruid Report.
[paraphrased] “You’re going to become poor. Learn how live poor while it’s still relatively painless.”
Strip your life down to bare essentials and master basic skills of living.
The hardest thing will be to accept that the American Dream is really a fantasy that has become a nightmare. It’s time to abandon it.
Poetry is the only way we can talk about what is beyond language.
…that we’re going to have to live with the consequences. But most of us just don’t know what that means, or how to do that if they do understand.
As usual, we are in denial and still are focused on the impossible, because we’re told (and believe) it can be stopped.
People need to understand; it’s not going to get better, but rather, catastrophically worse.
The vetting process has already begun, me thinks…
Find out just what any people will quietly submit to and you have found out the exact measure of injustice and wrong which will be imposed upon them,and these will continue till they are resisted with either words or blows,or with both~FDouglas
Saying that CO2 is not a pollutant because we exhale it, is about as good an argument as saying a tsunami isn’t dangerous because we drink water. The levels of CO2, in addition to sulfur dioxide, benzene, arsenic and other toxins, coming out of the tailpipe of your car are extremely dangerous! If you don’t believe me, I have a simple experiment for you: Hook a garden hose to the tailpipe of your car and bring the other end into your living room. Let your car idle for a half hour or so and tell me that car exhaust is not a problem. Multiply that exhaust by several hundred million vehicles and tell me honestly that this doesn’t represent a dire threat to human existence. I friggin’ dare you!
sarcasm alert
Sorry Skriz, I should have used sarcasm tags.
I’m with you that the issue is continued burning of fossil fuels. I’m not sure I agree with you about changing the approach from speaking about global warming and acidification to solely pollution. We can at least observe the warming and acidification. The air, though, is fine – it’s a beautiful day here, not a cloud in the sky!
That was an undeniable retort.
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it’s nothing short of a tinderbox.
I drove across the state Friday and Saturday. It took two days because the tollway was closed on account of the Luther fire. Driving east into OKC I saw five fires burning to the north, and searching for info I fortunately found a radio station that reported that I-44 was closing down and the area being evacuated. The DJ also announced that the governor put in a statewide burn ban that day.
Watching the news coverage on TV you could tell the responders were unequipped and unprepared for all this. It felt like watching Katrina, wondering why on earth has no one called out the National Guard.
Got up early on Saturday in order to get the hell out of there, as I-44 had been re-opened and it was only 90 degrees at 7am. Drove through the burned mile or two of the tollway, with nothing but black and smouldering tree trunks, and a blanket of gray ash on the ground. I decided then that buying “The Road” on audiobook the week before maybe wasn’t such a bad purchase. I remember Agonist contributors praising it, but I found it to be repetitive and kind of flat. But after seeing the area around Luther, I realized that there isn’t much new or different to say when there’s nothing left.