Hansen in NYTimes: I’m not Sayin’ “I Told you So”, but…

May 10, 2012


GLOBAL warming isn’t a prediction. It is happening. That is why I was so troubled to read a recent interview with President Obama in Rolling Stone in which he said that Canada would exploit the oil in its vast tar sands reserves “regardless of what we do.”

If Canada proceeds, and we do nothing, it will be game over for the climate.

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. If we were to fully exploit this new oil source, and continue to burn our conventional oil, gas and coal supplies, concentrations of carbon dioxide in the atmosphere eventually would reach levels higher than in the Pliocene era, more than 2.5 million years ago, when sea level was at least 50 feet higher than it is now. That level of heat-trapping gases would assure that the disintegration of the ice sheets would accelerate out of control. Sea levels would rise and destroy coastal cities. Global temperatures would become intolerable. Twenty to 50 percent of the planet’s species would be driven to extinction. Civilization would be at risk.

That is the long-term outlook. But near-term, things will be bad enough. 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 priceswould rise to unprecedented levels.

If this sounds apocalyptic, it is. This is why we need to reduce emissions dramatically. President Obama has the power not only to deny tar sands oil additional access to Gulf Coast refining, which Canada desires in part for export markets, but also to encourage economic incentives to leave tar sands and other dirty fuels in the ground.

The global warming signal is now louder than the noise of random weather, as I predicted would happen by now in the journal Science in 1981. Extremely hot summers have increased noticeably. We can say with high confidence that the recent heat waves in Texas and Russia, and the one in Europe in 2003, which killed tens of thousands, were not natural events — they were caused by human-induced climate change.

How accurate was Dr. Hansen’s 1981 paper compared to observations since then?  Skeptical Science took a look.

Projected Global Warming

Now we arrive at the big question – how well did Hansen et al. project the ensuing global warming?  Evaluating the accuracy of the projections is something of a challenge, because Hansen et al. used scenarios based on energy growth, but did not provide the associated atmospheric CO2 concentrations resulting as a consequence of that energy growth.  Nevertheless, we can compare their modeled energy growth scenarios to actual energy growth figures.

Figure 4 shows the projected warming based on various energy growth scenarios.  The fast scenario assumes 4% annual growth in global energy consumption from 1980 to 2020, and 3% per year overall from 1980 through 2100.  The slow scenario assumed a growth of annual global energy rates half as rapid as in the fast growth scenario (2% annual growth from 1980 to 2020).  Hansen et al. also modeled various scenarios involving fossil fuel replacement starting in 2000 and in 2020.

Figure 4: Hansen et al. (1981) projections of global temperature. The diffusion coefficient beneath the ocean mixed layer is 1.2 cm2 per second, as required for best fit of the model and observations for the period 1880 to 1978. Estimated global mean warming in earlier warm periods is indicated on the right.

Since 1981, global fossil fuel energy consumption has increased at a rate of approximately 3% per year, falling between the Hansen et al. fast and slow growth scenarios.  Thus we have plotted both and compared them to the observed global surface temperatures from GISTEMP (Figure 5).

The global surface temperature record has improved since 1981, at which time the warming from 1950 to 1981 had been underestimated.  Thus Figure 5 uses a baseline of 1971 to 1991 (sets the average temperature anomaly between 1971 and 1991 at zero), because we are most interested in how well the model projected the warming since 1981.  As the figure shows, the model accuracy has been very impressive.

The linear warming trends from 1981 through 2011 are approximtely 0.17°C per decade for Hansen’s Fast Growth scenario, 0.13°C per decade for the Slow Growth scenario, vs. 0.17°C per decade for the observed global surface temperature from GISTEMP.  Estimating that the actual energy growth and greenhouse gas emissions have fallen between the Fast and Slow Growth scenarios, the observed temperature change has been approximately 15% faster than the projections of the Hansen et al. model.

If the model-data discrepancy were due solely to the model climate sensitivity being too low, it would suggest a real-world climate sensitivity of approximately 3.2°C for doubled CO2, although there are other factors to consider, such as human aerosol emissions, which are not accounted for in the Hansen et al. model, and the fact that we don’t know the exact atmospheric greenhouse gas concentrations associated with their energy growth scenarios.

Predicted Climate Impacts

Hansen et al. also discussed several climate impacts which would result as consequences of their projected global warming:

“Potential effects on climate in the 21st century include the creation of drought-prone regions in North America and central Asia as part of a shifting of climatic zones, erosion of the West Antarctic ice sheet with a consequent worldwide rise in sea level, and opening of the fabled Northwest Passage.”

We can check off all of these predictions.

49 Responses to “Hansen in NYTimes: I’m not Sayin’ “I Told you So”, but…”

  1. omnologos Says:

    Enough of the SkS nonsense…check SREX instead

    • MorinMoss Says:

      Since when did you start trusting anything from the IPCC?

      • omnologos Says:

        MorinMoss – having make a point of freeing myself from ideology, I don’t fear changing my opinion, and in this case I have learned to understand how the IPCC is not the root of all evil, rather a set of policy-naive scientists who struggle to write something scientifically accurate.

        And in the nooks and crannies of SREX like of AR4, there is a scientifically accurate message, even if seldom if ever it’s passed on to press releases or summaries for policymakers.

    • Nonsense? Nonsense???

      Oh, STFU.

    • otter17 Says:

      I don’t get it. How is it nonsense if Skeptical Science is citing sources for the comparison between Hansen’s mid-range emissions prediction and actual temperature data?

      And where specifically should we check within the Special Report on Extreme Events (SREX)? It doesn’t cover global temperature models or predictions, and it tends to agree with the prediction of increased droughts, depending on region anyway since data isn’t adequate for some regions. Besides that, the IPCC provides information for policy makers since the stance is that some form of mitigation plan is required. The IPCC even devotes a special report to renewables.

      Special Report on Renewable Energy Sources and Climate Change Mitigation

      In any case, it seems you are close to accepting that some form of mitigation is necessary. You seem to accept the IPCC analysis on certain things, and the IPCC provides scenarios on mitigation where a reasonable small fraction of GDP growth can be attributed to investments in mitigation over the coming years. I think the roadblock comes in where policy is involved. From what I can tell, you have libertarian leanings, a mistrust of government in general, and possibly don’t like identifying culturally with “alarmists” or “greens”. Taking rational risk mitigation measures may be more difficult due to these roadblocks.

      But, I think a solution is there for you. Dr. Hansen has specifically noted that he doesn’t want government to manage climate mitigation funds either. His solution is a transparent carbon tax that gets fed back to people and businesses, rewarding those that find innovative ways to be more efficient, use alternative energy, or conserve energy (or any combination of the three).

      • omnologos Says:

        otter17 – it’s nonsensical to check SkS about Jim Hansen. One should check apples against other apples, and oranges against other oranges. If only as a matter of respect for the work of scientists, Hansen’s pronouncements should be checked against other scientists’, eg what SREX has to say about upcoming climate.

        SkS is just an amateurish site written by non-professionals. Whatever its efforts, it cannot compete with the Big Boys (and Girls).

        • otter17 Says:

          When they correctly cite sources, as they often do, that says something. Nobody should believe their own written words outright, but realize that they do base their work in peer-reviewed sources. Most all have the climate science academic qualifications to analyze the topic, too.

          • omnologos Says:

            “correctly cite sources”…not sure. In any case, my point was that it’s absurd to say “Hansen is right because SkS confirms it”.

          • otter17 Says:

            Well, sure. That is common sense. BUT, they cite peer reviewed sources, which are checkable. Plus, many of them are indeed qualified in degrees and training for climate science work. Also, their coverage of the major issues are generally in line with National Academy statements, and other scientific bodies.

            On the flip side, you have contributed to Watts Up With That, where it is common practice to take a peer reviewed paper, and discredit it via an opinion analysis from one of the writers, none of which that I know of have any climate science qualifications. Very few citations, many errors.

            The difference in quality of information is huge. One accepts the peer reviewed science, the other appears to believe that there is a conspiracy among scientists (or incompetence throughout the entire field).

        • MorinMoss Says:

          Let’s have a list of which sites are professional.
          But you’ll lose any credibility if you include Watt’s circle of jerks

          • omnologos Says:

            Uh?? Why would I be skeptical of some and non-skeptical of others?

            All blog sites are scientifically amateurish.

          • MorinMoss Says:

            I did not say blogs; I said sites. Are there no sites that are trustworthy?
            If so, one wonders why you waste so much time on the ‘net at all.

            Also, as far as I can tell, you don’t criticize the denialist point of view.
            If both their sites and AGW ones are “scientifically amateurish”, why do they get the kid gloves treatment?

            How does that fit into your freedom from ideology?

          • omnologos Says:

            If Watts or Bastardi or Monckton had the political power of an Hansen or a Pachauri, and they proposed wholesale changes to civilization for the sake of the grandchildren, rest assured I’d be blogging about them very often 😎

            That’s where the ideology bit kicks in…

          • otter17 Says:

            What you don’t see though is that Watts, Monckton, and others ARE proposing wholesale changes to civilization for their perceived economic safety of the children (and themselves). By proposing that we do nothing, they tacitly put forth the notion that the risks from a changed climate are worth taking, whether they are willing to acknowledge there are any risks or not. Their ideology is in conflict with the peer reviewed science and scientific bodies.

            Nobody wants to radically change civilization or crash the economy, either. That is a straw man that is all too often brought out to stifle mitigation policy debate. What most everyone wants from a mitigation policy is something that provides realistic targets where we can maintain similar conditions for the economy, temperature, climate, crops, water supply, sea level, etc. As a side benefit, putting forth an energy plan will help solve energy access for the poor and resource depletion as well. People are still able to work, we reduce global climate risks, and we put R&D towards energy sources that can last the long haul. What is not to like?

          • pendantry Says:

            @otter17 that is an excellent point, well made. A pity it’s buried so deep.

      • omnologos Says:

        Sorry otter17 – I had missed the second part of your comment.

        I said repeatedly, I’m all for mitigation as long as it’s shown cost-effective. It’s an almost impossible task, mind you, unless the mitigation effort is of very little cost.

        Given the history of all of that, it’d be IMNSHO far better to concentrate on adaptation and check out the mitigation people every once in a while. But the political process worldwide has been going the other way around 8-(

        As of Hansen’s Tax, perhaps a small nation somewhere will experiment with it and show it viable. Or even an island? Until then, it’s hard to imagine cash-starved governments eg in the EU really embrace the level of transparency needed.

        • otter17 Says:

          Well, heck! This is something.

          I recall before that mitigation was impossible, end of story. Maybe I interpreted wrong. In any case, the view is that there is a chance that mitigation is viable.

          Ok, so you disagree with where the political process is focused, but there is still focus on adaptation. Sure, ok, that’s fine. Still there are various opinions about the economics of mitigation. Ask Nordhaus or Stern, and there is a substantial economic net benefit in the long term to mitigation. Ask other experts, maybe not. Nevertheless, you do concede that there is a possibility for mitigation to fit in somewhere.

          I wouldn’t mind if the USA tried out the carbon tax concept. BUT, we already have individual states within the USA trying out a cap and trade program (California, eastern states, etc). They do not seem to have been negatively affected in a noticeable way, even within a country where other states would be at an “advantage” economically. Also, I don’t think Australia has seen much in the way of negative effects.

          So long as we follow the National Academy of Sciences recommendations and at least TRY mitigating the best we can, producing the most benefit overall for everybody.

          • omnologos Says:

            I don’t want to try mitigating the best we can. I want to try mitigating in a sensible manner that brings more advantages than disadvantages, without assuming all advantages magically appear decades from now.

          • otter17 Says:

            Ok, sure. That is part of what I’m getting at with “most benefit for everyone overall”. Still, some progress here.

            One thing though, nobody is assuming advantages magically appear. The advantages in the economic studies are based in best estimates to mitigate risk. Not perfect, sure, but not magic either.

        • MorinMoss Says:

          The only thing that would make it not viable is if the playing field is not kept level.
          I can’t speak for Euro govt’s but the US has too many politicians who are completely beholden to self-interested billionaires and influential corporations who have used their Congressional puppets to stack the deck in their favor over the course of decades.

          And the Citizens United decision by the SCOTUS will live on in infamy as the single largest step a court has ever taken to undermining “1 person, 1 vote”.

          By the way, did you note in that Revkin piece that Emanuel excoriated Hoerling while not specifically denouncing Hansen?

        • MorinMoss Says:

          Monckton has plenty of influence and his traveling roadshow gets great attendance.
          He’s appeared in front of Congress, the House of Lords and had a sellout tour of Australia last year.
          Watts’ site is HUGELY influential and is a forum and springboard for the contrarians & deniers.
          I believe his readership is greater than the entire AGW collective.

          Wait a sec – are you free of ideology or not? Your recent statements are conflicting.
          The problem with a stubborn ideology is that it leads to wrong conclusions and decisions.
          Recall that all the Republican leadership were once ( not very long ago ) convinced that AGW needed to be tackled.
          Even Inhofe himself was a believer but let’s look at what changed his mind – the science, er, no, – THE (apparent) COST.
          So to the ideologically bound, truth doesn’t matter; if it contradicts your world-view, it’s automatically wrong.

    • pendantry Says:

      OK, check SREX then:

      Low-probability, high-impact changes associated with the crossing of poorly understood climate thresholds cannot be excluded

      • omnologos Says:

        Neither the appearance of a massive asteroid in the sun’s glare, invisible to the last moment. Let’s build underground cities then!

        • otter17 Says:

          Building underground cities would be an adaptation. A much cheaper mitigation plan would be to bolster the detection and deflection capabilities of Apollo asteroids. This is a similar excuse as the earthquake argument. Climate change differs as a threat in key ways.

          First the cause is readily identifiable and man-made; AGW isn’t a random natural occurrence. Also, the projections based on models and paleo records offer data to support the odds of a particular effect due to climate change. There are some effects that are nearly guaranteed, based on a continuing our current emissions path. Finally, nobody is proposing solutions to climate change that cost nearly as much as constructing a functioning underground civilization.

          There are some things worth preventing, like the disappearance of glaciers at Glacier National Park, or the loss of farming viability in my nation’s heartland. There are many more likely effects, too numerous to mention here. The point is, we are knowingly opening a can of worms by changing the climate this fast.

        • MorinMoss Says:

          Please make up your mind if you believe SREX or not, otherwise you’re cherrypicking once again.

          • omnologos Says:

            Alas, my beliefs are immaterial (I find SREX much better than AR4, if you really want to know). My point is that Peter should compare Hansen’s work with other scientists’ (for example, SREX’s), not with a website run by non-scientists.

            IOW…one can say “SkS is good, it agrees with Hansen” but one should not say under any circumstance “Hansen is good, he agrees with SkS”.

            The Latin saying for this is: “ubi maior minor cessat”.

        • pendantry Says:

          I don’t think that underground cities would help in such an event. And I’m not surprised that you took my comment in the way you did: my point is that for every person shouting ‘fire’ there are far more people saying ‘all is well, return to your desks and continue praying to the God of Growth’. (I understand that the death toll would have been lower in a certain incident in New York some years back, had there been more realism and less complacency.)

          • omnologos Says:

            I was just pointing out that planning for “low-probability, high-impact changes” may bring about strange consequences.

          • MorinMoss Says:

            It never hurts to improve your basic infrastructure and processes.
            One reason for the swift recovery of operations of the companies and markets from the destruction of the World Trade Center was because of the planning, upgrades and policies that were implemented in preparation for Y2K, which many contrarians had said were a waste of time and money.

            Planning for disaster improves resiliency in both processes and people – and there’s never anything wrong with that.

  2. Peter Mizla Says:

    Another Great call from James Hansen to do something about our madness with fossil fuels. Lets hope the world wakes up from its sleepwalking toward catastrophe.

  3. we could bury our head in the sands ..but that would be very messy..

  4. Hansen et al. (1981) was pretty damn impressive. A relatively simple model, certainly by today’s standards, but very high predictive accuracy in terms of global surface warming. It just goes to show we’ve understood the main climate drivers pretty darn well for 3 decades now. Hansen has every right to brag about his track record (unlike, say, Richard Lindzen, who’s been wrong on just about every climate position he’s taken during that same timeframe).

    • MorinMoss Says:

      Perhaps Lindzen aspires to be the Edison of climatology.

      “I have NOT failed, but merely put forth 10,000 hypotheses that don’t work”

  5. […] Climate Crocks: Hansen in NYTimes: I’m not Sayin’ “I Told you So”, but… […]

  6. Concerning Hansen’s 1981 model predictions it may be worthwhile to at least consider another take:


    • owlbrudder Says:

      Ah, Pielke strikes again! Using the eyecrometer in his inimitable (because who would want to) style and not allowing comments to his post. Not really worthy of consideration, imho.

    • otter17 Says:

      From what I can tell from the short Pielke Sr. article, he is making a similar claim that Dr. Pat Michaels made in testimony to Congress several years back. Essentially, Hansen made several predictions based on CO2 emissions scenarios, and Michaels used the highest emissions scenario to present as a comparison with actual temperature measurements, despite the fact that actual measured CO2 emissions were lower than Hansen’s high end scenario.

      So it is a matter of confusing (possibly through bias) emissions scenarios. That is an unfair comparison.

      Aside from that, Pielke Sr. takes a view that is not shared by a vast majority of climate science organizations, as well as the National Academy of Sciences, which indicates that some form of promptly implemented mitigation solution is needed.

      Why do you feel the need to bring up a single viewpoint that is likely flawed, and not widely accepted? Is there a climate change mitigation plan that is acceptable to you?

  7. Guys,
    Please take off you Al Gore T-Shirts, and trash’em.
    Global Warming never was, isn’t, and will never be.
    But, the good news is you can keep your posters of Kari Norgaard taped to the ceiling above your beds, so heck, 1 out of 3 ain’t bad, and wouldn’t you know it 1 out of 3 is the number of degrees that the temperature MAY have actually risen in the last 200 years.

    Ya know, being CLIMATE CHANGE and all………..

    Hmmm, maybe you’re on to something??

    • otter17 Says:

      It seems from your confrontational and incoherent polemic remarks, that you have a deep seated emotional dislike towards Al Gore, environmentalism, and maybe liberals/liberalism in general. I may be wrong on this, so let me know if so.

      Anyway, take heart. While our culture does tend to have a certain view of environmentalism and climate change fixes, that doesn’t necessarily provide a rational reason to dislike associating with those concepts. There are groups like Republicans for Environmental Protection (I guess ConservAmerica is their name now), who want to put in place policies that will mitigate climate change, reducing the multitude of risks we may place on those living in the future, and ourselves.

      Think of it like the USA’s national debt. This particular “debt” known as climate change can potentially cost money in the way of infrastructure upgrades (potentially trillions worldwide for sea level rise adaptation alone). Lost lives and hardship are also likely outcomes of this debt considering some nations, regions, or tribes may not be able to adapt their agriculture patterns. So, there are risks of serious financial problems from carrying a monetary debt, as well as altering the radiation absorption patterns of the atmosphere. There is no reason rational people cannot figure out a plan to mitigate both.

    • otter17 Says:

      Plus, check out this review of work by economist Nordhaus, particularly just look at Figure 1 and Figure 2. Mitigating climate change can save money overall, as well as the benefits to risk reduction towards lost life and livelihood.


  8. Maurizio really needs to grow the fuck up.

  9. omnologos Says:

    Revkin has the NOAA’s Martin Hoerling write some harsh words about Hansen’s op-ed.

    There is also Kerry Emanuel, not spending a single sentence in support of Hansen.

    I’ll eagerly waiting for comments demonstrating Hoerling is an Exxon shrill, or Emanuel a worse commentator than SkS.

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