James Hansen Is Correct About Catastrophic Projections For U.S. Drought If We Don’t Act Now

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

The response by NOAA’s Martin Hoerling to James Hansen’s recent op-ed does not reflect the scientific literature.

I’m traveling, so let me focus first on Hoerling’s incorrect statements — posted on this blog and DotEarth — about drought. As readers know, the journal Nature asked me to write a Comment piece on the threat posed by drought after they read one of my posts examining the latest science on prolonged drought and “Dust-Bowlification.”

The Nature article, which is basically a review of recent drought literature, is here (subs. req’d). Most of the text is here.

The research I did for that article — along with the comments of the expert reviewers I sent it to — is why I know Hoerling is quite wrong. Hoerling begins by quoting Hansen’s recent New York Times Op-Ed piece:

“Over the next several decades, the Western United States and the semi-arid region from North Dakota to Texas will develop semi-permanent drought, with rain, when it does come, occurring in extreme events with heavy flooding. Economic losses would be incalculable. More and more of the Midwest would be a dust bowl. California’s Central Valley could no longer be irrigated. Food prices would rise to unprecedented levels.”

Hoerling then asserts:

He doesn’t define “several decades,” but a reasonable assumption is that he refers to a period from today through mid-century. I am unaware of any projection for “semi-permanent” drought in this time frame over the expansive region of the Central Great Plains. He implies the drought will be due to a lack of rain (except for the brief, and ineffective downpours)….

But facts should, and do, matter to some. The vision of a Midwest Dustbowl is a scary one, and the author appears intent to instill fear rather than reason.

That’s a very serious attack on Hansen — if it were true. But it isn’t, and it should be retracted.

The fact is that the recent literature examining warming-driven drought in America could not be clearer in warning about a “semi-permanent” (or worse) drought in both the South West and the Central Great Plains and “More and more of the Midwest.” Here are two studies that lay things out starkly:

I would also add the 2010, Environmental Research Letters article “Characterizing changes in drought risk for the United States from climate change.”

And that’s not even counting the Journal of Geophysical Research study that Hansen himself co-authored in 1990, “Potential evapotranspiration and the likelihood of future drought,” which projected that severe to extreme drought in the United States, then occurring every 20 years or so, could become an every-other-year phenomenon by mid-century.

As an important aside, contrary to what Hoerling states, Hansen was not implying the drought will be due to lack of rain (by itself). Everyone seriously writing about warming-driven drought knows we are talking about a combination of factors, ones that I laid out in my Nature article:

Precipitation patterns are expected to shift, expanding the dry subtropics. What precipitation there is will probably come in extreme deluges, resulting in runoff rather than drought alleviation. Warming causes greater evaporation and, once the ground is dry, the Sun’s energy goes into baking the soil, leading to a further increase in air temperature. That is why, for instance, so many temperature records were set for the United States in the 1930s Dust Bowl; and why, in 2011, drought-stricken Texas saw the hottest summer ever recorded for a US state. Finally, many regions are expected to see earlier snowmelt, so less water will be stored on mountain tops for the summer dry season.

Obviously, since Hansen coauthored an article titled, “Potential evapotranspiration and the likelihood of future drought,” we know he understands the drought conditions are driven by more than precipitation changes. The whole point of that 1990 paper was to examine the impact of warming-driven evaporation on soil moisture and drought.

It is quite surprising that Hoerling doesn’t appear to know the drought literature given that, as Revkin notes, he “runs an effort by the National Oceanic and Atmospheric Administration to assess the forces contributing to extreme weather events!”

Hoerling says it is reasonable to assume Hansen means “a period from today through mid-century.” Hansen says the “semi-permanent drought” will develop “over the next several decades.” That would clearly seem to mean that these conditions will evolve by just after mid-century, the 2050s and 2060s. This is also the first period of time where aggressive action to reduce emissions today could substantially change the projected climate.

Dai’s analysis does indeed project drought conditions over the Great Plains and Midwest. He is in the process of revising his analysis, but the figure below (which had been his 2030s projection in his original version) is a rough representation of where his analysis projects things will be in Hansen’s time frame for the U.S.

The PDSI [Palmer Drought Severity Index] in the Great Plains during the Dust Bowl apparently spiked very briefly to -6, but otherwise rarely exceeded -3 for the decade (see here).

And this isn’t just Dai’s finding. Michael Wehner et al. find the drying has the same signature. The study is behind a firewall, but you can see a PDF of a  PowerPoint presentation here.

Of course, just because several models project this future doesn’t make it a certainty.  As I note in the article, “drought models need to be improved. They successfully chart the hydrological changes seen in the US Southwest and the drying seen at the global level7, but regional predictions can be disturbingly variable.”

On the other hand, these models most certainly are not the worst-case scenario. Dai is modeling A1B (720 ppm), whereas we are on track for worse than that. A  plausible worst-case scenario is here (and below):  Royal Society Special Issue on Global Warming Details ‘Hellish Vision’ of 7°F (4°C) World — Which We May Face in the 2060s!

Hansen’s use of the term “Dust Bowl” is justified since that is the term widely used in the drought literature (see below). We are talking conditions that become as bad as the original Dust Bowl by mid-century and then get much, much worse for a long, long time. The Nature editors made repeated use of the term “Dust-Bowlification,” and I was particularly delighted that one of the leading experts in the field that I sent the piece to, Jonathan Overpeck, also liked the term.

Indeed, Hoerling’s critique is really only about whether the semi-permanent drought conditions will extend outside the U.S. SW to include most of Northern U.S. Great Plains. The literature is very clear that the Southwest is very likely headed for Dust Bowl conditions:

The serious hydrological changes and impacts known to have occurred in both historic and prehistoric times over North America reflect large-scale changes in the climate system that can develop in a matter of years and, in the case of the more severe past megadroughts, persist for decades. Such hydrological changes fit the definition of abrupt change because they occur faster than the time scales needed for human and natural systems to adapt, leading to substantial disruptions in those systems. In the Southwest, for example, the models project a permanent drying by the mid-21st century that reaches the level of aridity seen in historical droughts, and a quarter of the projections may reach this level of aridity much earlier.

… the climate change that is taking place because of increases in carbon dioxide concentration is largely irreversible for 1,000 years after emissions stop….   Among illustrative irreversible impacts that should be expected if atmospheric carbon dioxide concentrations increase from current levels near 385 parts per million by volume (ppmv) to a peak of 450-600 ppmv over the coming century are irreversible dry-season rainfall reductions in several regions comparable to those of the “dust bowl” era

So again, the ‘debate’ such as it is, is how far into the northern US Great Plains and Midwest these Dust Bowl conditions will extend — and that’s without even considering the impact of the increasingly early loss of the winter snowpack, which most of these studies don’t even model. Since the recent literature suggests the droughts will extend that far, Hansen’s warning is justified by the literature.

And Hansen’s use of the phrase “semi-permanent” is fully warranted.  Given that the drought conditions just keep getting worse and worse as long as we keep warming –  and are “largely irreversible for 1000 years” (according to a NOAA-led paper), “semi-permanent” seems like a rather mild word.

Bottom Line: Given how catastrophic it would be to the nation and the world if our breadbasket were indeed hit by these conditions, Hansen’s warning seems fully justified and Hoerling’s response does not.

Finally, it’s always worth repeating that much of  human behavior and government policy is driven by the desire to avoid it worst-case scenarios, which is why we have fire insurance and catastrophic health insurance — and a military budget equal to that of the next 16 countries combined.

If we look at the plausible worst case for climate, we get both continuing high levels of emissions and high carbon-cycle feedbacks.  That possibility was discussed in a Royal Society Special Issue on a 7°F (4°C) World, which notes “In such a 4°C world, the limits for human adaptation are likely to be exceeded in many parts of the world, while the limits for adaptation for natural systems would largely be exceeded throughout the world.”

This would be the worst-case for the 2060s, but is in any case, close to business as usual for 2090s:

This is 13-18°F over most of U.S. and 27°F in the Arctic. The drought conditions that would be created by such warming over most of the central and western U.S. are beyond imagining.

And there is every reason to believe that the earth would just keep getting hotter and hotter:

Indeed, Steve Easterbrook’s post “A first glimpse at model results for the next IPCC assessment” shows that for the scenario where there is 9°F warming by 2100, you get another 7°F warming by 2300.  Of course, folks that aren’t motivated to avoid the civilization-destroying 9°F by 2100 won’t be moved by whatever happens after that.

So if folks want to quibble about whether the semi-permanent Dust Bowl that the U.S. Southwest is headed to by mid-century might not spread to the northern U.S. Great Plains for, say, another few decades after that, well, I must say they are rearranging deck chairs on the Titanic.

How many major scientific articles have to be published before people realized that on our current emissions path we are simply headed towards self-destruction of modern civilization, where feeding 9 billion people will be exceedingly problematic to say the least?

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46 Responses to James Hansen Is Correct About Catastrophic Projections For U.S. Drought If We Don’t Act Now

  1. Mike Roddy says:

    Some of us were waiting for someone to set the record straight, Joe, and knew that you would be the best person to do it. Thanks.

    Hoerling is clearly an extreme outlier, [snip], whose claims are clearly false, and whose motivations are unknown.

    Of more concern, perhaps, is Revkin once again setting up a “debate” between the peer reviewed science- summarized so well here- and a person with apparent credentials but little scientific evidence.

    This pattern has gone way beyond how it affects the reputation of the New York Times, or parsing whatever Revkin’s motivations might be. This obvious example of false balance and fake controversy is having major toxic effects on our future, through its negative impact on public understanding. The Times needs to cancel that blog, and find someone who actually knows the subject. Maybe it can be called Vast Earth, replacing the “Dot” that so clearly represents the depth of the text.

    • Mulga Mumblebrain says:

      In Australia the entire Murdoch swamp is entirely denialist, and increasingly so. One favourite tactic is to report on some new study by scientists, outlining the horrors to come, then refute it with some local dim-wit, with no scientific standing, who will state something like, ‘I’ve been swimming here for fifty years, and I ain’t seen no sea-level rise’. The contrast between the lying, ‘watermelon’, scientists (hated by the rabble as ‘smart-arses’ and ‘know-it-alls’)and the common folk with their commonsense, is unsubtle.
      The other media empire, Fairfax, is slightly less hysterical, but the Financial Review has unearthed a real zealot, called Lawson (small world, eh?)who delights in smugly denying everything. Today he was sneering at the biodiversity crisis, allegedly another example of environmental extremism, because, apparently, no-one can name any species that has lately become extinct. The genius of MSM journalists, and their predictability never ceases to amaze. And, believe me, it will either never change or only do so when it is way too late, whereupon the reptiles of the MSM will find some way to blame the Greenies for it.

  2. SecularAnimist says:

    Thanks Joe — I think this is one of the best and most important and most compelling articles you have ever written.

  3. climatehawk1 says:

    Not the first time Mr. Hoerling has popped up. Here is a quote from him on the Great March 2012 Heat Wave: “Why wouldn’t we embrace it as a darn good outcome,” Hoerling said. “This was not the wicked wind of the east. This was the good wind of the south.”

  4. Rabid Doomsayer says:

    Grain production in particular requires very well behaved weather. Gentle soaking rains, a few weeks late, can be severely deleterious for a grain crop. Global warming will change weather patterns and reduce reliability. Our industrial Agriculture system is very heavy into grains and therefore vulnerable.

    Even without mega-droughts we could have serious problems.

    If we change the way we do things, move to poly-cultures then our resilience is improved. A food Forest can produce a huge amount of food in a small area, but is more labor intensive and does not produce industrial quantities of a single product.

    Where severe persistant drought occurs any agriculture becomes problematic. However we can change our food production away from grains and not be so vulnerable to ill timed weather.

    These sorts of changes cannot happen overnight. If we leave everything to the last moment then the production and distribution systems will not cope.

  5. AlaninAZ says:

    I am pleased Joe posted this fine reply to Revkin’s attempt to paint James Hansen as an alarmist. I would like to see the Times drop Revkin, but if not at least give voice to another blogger more committed to climate change action. A possible blog title is The Gathering Storm.

    • ltr says:

      Revkin is a sham and a disgrace for the NYTimes.

    • ltr says:

      The problem with Revkin is that he is not committed to truth, there is the problem the continual falseness of Revkin in attacking climatologists. Revkin changed immediately on leaving the NYTimes as a reporter, suddenly Revkin was an attacker of splendid scientists.

  6. Leif says:

    It might be beneficial to look at the number of climate predictions that Hansen has gotten basically correct since 1981 compared with the number any or even all of the denier sphere.

    Please Help: Stop individual Corpro/People from profiting from pollution of the commons! It is a stone stupid foundation to run an economy upon… IMHO

    • M Tucker says:

      Yep, I totally agree! Dr Hansen’s predictions have consistently been accurate for more than 40 years now. We ignore his warnings at our peril.

  7. kob6 says:

    The attacks on Hansen all skipped over its main point, which was: “Canada’s tar sands, deposits of sand saturated with bitumen, contain twice the amount of carbon dioxide emitted by global oil use in our entire history.”

    Hoerling is focusing on Hansen’s incidental claims and not the main point. Does Hoerling believe that mining the tar sands will be a bad thing for civilization? I suspect he does .

    I’ll pass on the debate about whether this or that drought is a direct consequence of climate change. But if it isn’t now a result of rising C02 it will be a consequence of it soon enough.

    Hansen’s “game over” point is clearly valid and informed critics, those who understand the risk of rising c02, are distorting Hansen’s essential message by fixating on in-the-weeds estimates of drought impacts.

    Fine, it’s great and interesting science to any weather event to climate change. But this debate, as interesting as it is, has to put in context to the mega issues.

  8. shannon says:

    I was just talking to a friend who was in a meeting with some climate experts in TX recently. All of these men were saying that Hansen has discredited himself by being too shrill and insistent and fear-mongering. They were eager to buy into Hoerling’s critique of Hansen, presumably b/c it’s too frightening to consider the possibility that Hansen is right. I’m amazed continually at the depths of people’s denial about the catastrophe we’re heading for. It’s as if they get on the Titanic, knowing full well it’s going to hit an iceberg, but they think they’ll be one of the ones to get in a lifeboat.

  9. David Lewis says:

    “If you want to know the scientific consensus on global warming, read the reports by the IPCC. But if you want to know what the consensus will be ten years from now, read Jim Hansen’s work”. – quote from Chuck Kutscher, NREL, on the back cover of Hansen’s “Storms of My Grandchildren”.

    People should take a look at the 1981 Science article Jim published.

    Hansen has a long track record of staking out a prominent position and being right, as opposed to some of these clowns who think they know more.

  10. fj says:

    This is a great post and more than ever it is necessary to pull out all stops to avoid the failed policy of climate pragmatism.

    Just like James Hansen has gone after Keystone XL as game over, it’s long overdue that he pulls out all stops to advocate rapid deployment of net zero mobility along with the likes of Bill McKibben, Lester Brown, and Mike Bloomberg.

    While New York City’s rollout for the first stage of its bikeshare system is impressive by conventional expectations — this is essentially an early-stage net zero transit system — it is embarrassing how anemic it is compared to what can be achieved with broad rapid design, development, and deployment of net zero and near net zero mobility technologies and systems, that on community levels, come with intrinsically rapid social change potential similar to that of cell phones.

    And, like Amory Lovins has said many times: “Something is not impossible if it already exists,” and with the current existence of 1/2 billion Chinese cyclists and bikeshare being rapidly deployed worldwide, net zero mobility and transit definitely exists.

  11. Daniel C Goodwin says:

    Thanks for finding the time to set the record straight on this one, Joe. “Permanent dustbowlification” may be the most dire immediate threat from global warming. I am very grateful for Joe Romm’s dedication to this issue.

  12. David F. says:

    I’ve got to agree with Dr. Hansen. Even if precipitation patterns were to remain unchanged, I would expect drought frequency to increase just from the 5-10F increase in mean temperature. The Texas drought from last summer was certainly intensified significantly from the record breaking late spring and summer heat. As we continue to experience greater warming, it seems likely that there will be increased frequency, duration, and extent of these sorts of catastrophic drought events.

  13. Ben C. says:

    Hear hear. I couldn’t have said it better myself. When will humanity wake up!!

  14. D. R. Tucker says:

    “Whether or not you have a child, grandchild, nieces or nephews in this world, you should know there is an all-out war underway to harm their future and the future of all life on the planet. If that sounds apocalyptic, well, it is, according to James Hansen, NASA’s top climate scientist. Dr. Hansen recently wrote a gripping op-ed piece about the Keystone pipeline signaling ‘game over’ for our climate. If presidential approval is given to allow oil to be extracted from Canadian tar sands and piped down to Texas oil refineries, the energy intensive extraction process will release enough greenhouse gases into the atmosphere to help move us into the danger zone. As you might guess, Hansen means “game over” not in any sports context but in terms of the ultimate American challenge: Will we do what is necessary to avert climactic disaster for generations to come? This reality is unfolding now but the drama will not be broadcast on any station near you: Our planet’s fate is a little TOO real for prime time.”

    http://www.huffingtonpost.com/betsy-rosenberg/a-motehrs-day-challenge_b_1511268.html?ref=green

  15. John Atkeison says:

    Thanks for another good one!
    I’ll be sharing it widely.

  16. PJMD says:

    Here’s my letter to the NY Times the day after President Obama revealed his “evolution” on the issue of marriage equality and James Hansen’s piece appeared:

    To the Editor:

    There’s an ironic juxtaposition between the attention being given to President Obama’s courageous decision about marriage equality (President Obama’s Moment, May 10) and the soporific response to Dr. James Hansen’s warning about what will happen to all of us without swift action to reduce greenhouse gas production (Game Over for the Climate, same issue).

    In the near future our civilization won’t have the luxury of debating who can marry, birth control, nor the marginal tax rates of millionaires. They’ll be worried about relocating cities from inundated coastlines, managing massive numbers of climate refugees, mitigating one disaster after another, feeding themselves and paying for it all.

    Let’s keep our eyes on the big issues — survival of our civilization — while celebrating this triumph for human rights. It’s time to stand up and take responsibility for our waste products — the carbon dioxide that has made us wealthy — by putting a price on it. Our nation hungers for action. That should be the President’s next move.

  17. ltr says:

    Andrew Revkin has turned into a complete sham, a denier of climate change by always finding false arguments to set along correct arguments and pretending there is no difference or the false arguments counter the correct. I see the name Revkin and I stop reading.

    • Spike says:

      Yes – reading Dot Earth one is left with a strange feeling that in that particular Universe there is never enough certainty to act, enough consensus to proceed, a near permanent state of indecision, and an epoch of time in which to ponder further and consider before….. calling for more research.

      I am reminded of Churchill’s speech on the lack of resolution of political leaders in the 1930s

      “So they go on in strange paradox, decided only to be undecided, resolved to be irresolute, adamant for drift, solid for fluidity, all-powerful to be impotent.”

      • Mulga Mumblebrain says:

        Such a position materially benefits Revkin’s owners, the 0.01%, who own the MSM and the fossil fuel industry. Revkin pleases his Bosses, and gets a pat on the head and a nice supply of dog biscuits. It’s a living.

        • Dennis Tomlinson says:

          Is it a living, or is it a killing. This is one of those times when I hope John Lennon was wrong, and there actually IS a hell below us. Some folks deserve a hellish place to hang out for all eternity, or until the Great Implosion reduces it all to nothingness once again. [No charge for the Cognitive Dissonance.]

  18. john atcheson says:

    Joe:

    Great job! Mr. Hoerling’s unfounded assault on Dr. Hansen’s Op ed needed to be taken on, and as usual you did it superbly.

    At the end you ask how many scientific papers need to be written before we accept reality …

    Well, maybe it’s not a question of scientific papers or facts — maybe it’s about changing our cultural experience of warming — bringing the remote future to the present on an emotional level, since that’s how we appear to operate.

  19. Alex Smith says:

    Hoerling’s denial of the coming drought contradicted the research of a dozen top climate scientists I have interviewed for Radio Ecoshock. For a layman’s view, try Robert Kunzig’s 2008 National Geographic article “The Drying of the West” (or radio interview here:
    http://archive.org/details/KunzigDryingOfTheWest

    At least Google for easily available speeches by Dr. Jonathan Overpeck of the University of Arizona. He lives there, he knows, he was an IPCC Lead Author.

    Revkin over-reacted, as he did after the Heartland Institute. He did not find the consensus of scientists, thus putting our descendants at risk. It’s very sad what happened to Andy Revkin.

  20. jyyh says:

    Just an inquiry, what the northernmost location in the Pacific northwest that maybe used for rice cultivation currently? I do not remember the topography of the Rocky Mountains now, but I’d imagine the projected droughts are in part associated with the storm tracks moving north to a range that’s got a higher elevation.

  21. Peter says:

    C02 last week at 397.17ppm- that’s up over 4ppm, from the same time last year. Will we pass 400ppm next year- very likely.

    http://www.esrl.noaa.gov/gmd/ccgg/trends/weekly.html

  22. BBHY says:

    The Canada tar sands industry claims that it’s ok because the increase in CO2 is “only” 12%.

    Well, even if it was that low, we are already dumping far too much CO2 into the atmosphere. Continuing at the same level is bad. Any increase is very bad. We need to decrease.

    Clearly, any way you look at it, the tar sands do not decrease CO2 emissions.

    So, even if we were to believe the industry’s own figures tar sands development is still very bad, and it should not be used.

    It is probably worse than what the industry claims, but that doesn’t really matter because we should (must!) already not be using it based on their own figures.

  23. Mike 22 says:

    It amazes me that a person in Dr. Hoerling position is apparently ignorant of the climate projections for the region he is supposedly an expert on. Hard to believe, actually.

    What’s Dr. Hoerling’s take on this century’s climate for the Great Plains? Cool with predictable precipitation? Everything back to normal? Bumper crops? Where are his projections?

    • Sasparilla says:

      Good questions Mike, unfortunately as a meteorologist he doesn’t know any of those things – he just knows Hansen is wrong and Revkin takes any opportunity to stick it to Hansen (and anyone else who says we need to deal with this now).

      Remember according to the Koch founded & funded Heartland institute – “…such as Revkin at DotEarth/NYTimes, who has a well-known antipathy for some of the more extreme AGW communicators such as Rornm, Trenberth, and Hansen”. You don’t earn those kinds of credentials from Heartland without doing what they want…

  24. EDpeak says:

    Good thing JR keeps the updates on drought coming.

    But why is New Zealand (and the southeastern tip of Australia) not shown on the first graph?

    I’d love to see the effects on those two regions (he says, looking at his passport ;-)

    Also is PDSI relative or absolute? In other words are those organge marks on the middle of Australia mean it will be only medium dry (between -1 and -2) on an absolute level, or moderately drier-than-they-already-are-today?

    Because those are relatively drier regions of Australia, already today (much of the top half, and must of Western Australia away from the Perth/coast, as seen here http://www.fas.usda.gov/pecad2/highlights/2004/06/crop_watch/w040618/Slide6.JPG are already dry)

  25. Sasparilla says:

    Excellent article Joe, absolutely needed to be written, which you have done so well.

    Was over on the NYTimes site looking at the comments – (I replied to a couple) but its tough to read through.

  26. Anne van der Bom says:

    Is Hoerling a NOAA scientist? Huh? When I read his comment, I thought he was a just a visitor from the WUWT parallel universe.

    On Hansen’s claim:

    “The global warming signal is now louder than the noise of random weather…”

    he had this to say:

    This is patently false. Take temperature over the U.S. as an example. The variability of daily temperature over the U.S. is much larger than the anthropogenic warming signal at the local, weather time scales. Depending on season and location, the disparity is at least a factor of 5 to 10.

    This raises so many red flags.

    It is typical WUWT reasoning. Cherrypicking peaks and troughs and comparing those to averages. Does he really think Hansen is so incompetent as to not know this? Has this Martin Hoerling ever done statistics? Clearly Hansen was talking about statistical significance and that the global warming signal was clearly detectable in the random weather noise.

    To detect a signal in the noise, it is not necessary for that signal to be larger than the largest amplitude of the noise. Any statistician knows this.

  27. Jim Baird says:

    Mr. Romm, the 1000 year irreversibility notion is predicated on the thermal inertia of the oceans, which have accumulated 90% or the heat attributable to global warming.

    It seems to me the conversion of this heat to energy using the ocean thermal energy conversion method would in fact reverse this process.

    It would also draw down CO2 levels because of the capacity of a cooler ocean to dissolve more gas.

    Sea level rise can further be mitigated by desalination and moving ocean volume to productive terrestrial use, such as desert irrigation. Capturing runoff before it reaches the ocean and relocating this to the deserts or electrolysis, which would produce hydrogen as a water/energy currency.

    With Constructive Capitalism I believe this problem is reversible, but if belief is flawed, I would be grateful for the edification.

  28. Lisa Boucher says:

    I know that three days is an eternity for the attention span of the internet, but I’m going to write anyway and hope that somebody sees this comment.

    While climate deniers of various stripes were busying themselves with the drought chairs on the TItanic, I noticed what seems to be an error of a much different kind in the New York Times op-ed that James Hansen wrote:

    “If we were to fully exploit [Canada's tar sands] … concentrations of carbon dioxide in the atmosphere eventually would reach levels higher than in the Pliocene era, more than 2.5 million years ago …”

    But three years ago, a team of UCLA researchers, led by Prof. Aradhna Tripati, found that the CURRENT (!!) levels of atmospheric CO2 have ALREADY exceeded those of the Pliocene Epoch (not “era”) and are equivalent to what was typical during the Miocene Epoch (which preceded the Pliocene).

    Here are excerpts from the press release that announced the publication of their research:

    “Tripati, before joining UCLA’s faculty, was part of a research team at England’s University of Cambridge that developed a new technique to assess carbon dioxide levels in the much more distant past — by studying the ratio of the chemical element boron to calcium in the shells of ancient single-celled marine algae.  Tripati has now used this method to determine the amount of carbon dioxide in Earth’s atmosphere as far back as 20 million years ago.”

    “Tripati’s new chemical technique has an average uncertainty rate of only 14 parts per million.”

    “You would have to go back at least 15 million years to find carbon dioxide levels on Earth as high as they are today …”

    To the best of my knowledge, these findings have not been refuted.

  29. Allan says:

    The vilification of Dr. Hoerling is probably misguided. As the head of US Climate Variability program he does carry some academic weight and I doubt is not unaware of the latest scientific papers. You should expect some rebuttle from the scientific community and in fact, welcome it. It refocuses our efforts to provide the best information available.