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National Academy calls on nation to “substantially reduce greenhouse gas emissions” starting ASAP

By Joe Romm  

"National Academy calls on nation to “substantially reduce greenhouse gas emissions” starting ASAP"


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Final report warns, “Waiting for unacceptable impacts to occur before taking action is imprudent because … many of these changes will persist for hundreds or even thousands of years.”

NAS 100

“The number of days per year in which temperatures are projected to exceed 100°F by late this century” on our current (high) emissions path, A1FI

Last May, the U.S. National Academy of Sciences released the first of its “America’s Climate Choices” reports (see NAS labels as “settled facts” that “the Earth system is warming and that much of this warming is very likely due to human activities”).  Today, they released their final ACC report.

The good news is that the Academy is clear about the need to start reducing greenhouse gas emissions “as soon as possible” (for some reason the acronym, ASAP, sounds stronger).   The AP story got that message:  “Panel Says US Must Act Now to Curb Global Warming.”

The bad news is that the report is otherwise rather bland and conservative in that classic NAS style.  If your house were on fire, the NAS would take three months to write a report that says you should put out the fire “as soon as possible” (and, of course, you should do some adaptation planning for the potential loss of your home).

Dr. Kevin Trenberth, distinguished senior scientist at NCAR, wrote in an email that, while he agrees generally with the findings, “my quick summary is that there is a lot here that is good but it doesn’t seem to go far enough.”

The NAS also makes a mistake that is emblematic of its conservative approach, as we will see.

The main flaw of this report (like all the IPCC reports) is that the authors simply refuse to clearly spell out what is likely to happen if we stay anywhere near our current emissions path — or if we only moderate our emissions but the carbon-cycle feedbacks turn out to be more serious than the models say.  The latter is a near-certainty since the models ignore most of the major decadal feedbacks, including the defrosting ‘perma’-frost (see NSIDC bombshell: Thawing permafrost feedback will turn Arctic from carbon sink to source in the 2020s, releasing 100 billion tons of carbon by 2100).

The report does include the figure above, which reveals that if we don’t get our act together soon, then sometime in the second half of this century most of the South will probably see summers that rarely drop below 100°F [see full figure on page 26].  But the 2009 NOAA-led report on U.S. climate impacts — the source of that figure — was blunter.  And while the NAS cites that report, it doesn’t bother to review the extensive literature from the last two years on what the U.S. Southwest faces (see “USGS on Dust-Bowlification” and “NCAR analysis warns we risk multiple, devastating global droughts even on moderate emissions path“).

In terms of an overall assessment of the report, it’s hard to say whether the glass is half full or half empty.  Of course nobody who matters in this town was going to drink from this cup of scientific knowledge anyway, certainly not the way the NAS was going to frame it (see WashPost: “The GOP’s climate-change denial may be its most harmful delusion”).  So you might say for the lessons in the report, the class is half empty.

The discussion of future impacts — the empty part of the cup of knowledge — is, well, almost too empty to bother reporting.  You will learn things like (p. 20):

“The IPCC’s assessment of future climate change projects that Earth’s average surface temperature will increase (in the absence of new emissions mitigation policies) between 2.0 and 11.5°F (1.1 to 6.4°C) by the end of the 21st century, relative to the average global surface temperature during 1980-1999.”

Wait. Stop the presses.  That is somewhere between untrue and exceedingly misleading.  The low end of 1.1°C warming by 2100 is in fact the low sensitivity end of the B1 scenario, which is stabilization at 550 ppm (see here).  Now technically the IPCC scenarios don’t model mitigation policies, but they effectively assume changes that require massive mitigation.  For instance, 550 ppm would probably require some 10 wedges — which is a staggering amount of clean energy deployment beyond business as usual (see “The full global warming solution: How the world can stabilize at 350 to 450 ppm“).

Indeed, the IPCC’s Special Report on Emission Scenarios (SRES) makes clear that while the SRES scenarios don’t technically have climate policies, they can and do have energy efficiency and decarbonization policies, which are the same thing.  Here’s what the IPCC says about the B1 scenario, which includes aggressive policies to limit total global warming:

Incentive systems, combined with advances in international institutions, permit the rapid diffusion of cleaner technology”¦. Land use is managed carefully”¦. Cities are compact and designed for public and non-motorized transport”¦. Strong incentives for low-input, low-impact agriculture. These proactive local and regional environmental measures and policies also lead to relatively low GHG emissions, even in the absence of explicit interventions to mitigate climate change.

So it is really absurd to say that the IPCC projects the Earth’s average surface temperature might increase as little as 1.1°C by 2100 “in the absence of new emissions mitigation policies.”

The more I think about it, the more problematic an error this seems to me because, again, it leaves the misimpression there is some plausible chance that, absent serious policies, we might have very little warming this century.  That sentence should not have gotten through a process reviewed by so many distinguished scientists.

This is neither an academic matter nor is it obscure.  Heck an excellent explanation of this matter is even hiding in plain sight in the Wikipedia’s entry on the IPCC emissions scenarios:

In a report published by the MIT Joint Program on the Science and Policy of Global Change, Webster et al. (2008) compared the SRES scenarios with their own “no policy” scenario. Their no-policy scenario assumes that in the future, the world does nothing to limit greenhouse gas emissions. They found that most of the SRES scenarios were outside of the 90% probability range of their no-policy scenario (Webster et al., 2008, p. 1). Most of the SRES scenarios were consistent with efforts to stabilize greenhouse gas concentrations in the atmosphere. Webster et al. (2008, p. 54) noted that the SRES scenarios were designed to cover most of the range of future emission levels in the published scientific literature. Many such scenarios in the literature presumably assumed that future efforts would be made to stabilize greenhouse gas concentrations.

MIT’s Joint Program famously published their own analysis of the “no policy” scenario.  It ain’t pretty (see “M.I.T. doubles its 2095 warming projection to 10°F “” with 866 ppm and Arctic warming of 20°F“).  Indeed while the NAS report goes on and on and on about uncertainty (and why it is no reason for delay), MIT put out a figure 2 years ago that is superior to the entire NAS report.


As Andrew Freedman explained at the time:

For the no policy scenario, the researchers concluded that there is now a nine percent chance (about one in 11 odds) that the global average surface temperature would increase by more than 7°C (12.6°F) by the end of this century, compared with only a less than one percent chance (one in 100 odds) that warming would be limited to below 3°C (5.4°F).

So the NAS should not be leaving anyone with the impression that the no-policy case (aka business as usual) leads to a plausible range of warming of 2.0 and 11.5°F.  A more realistic range would probably be something like 6 to 14°F.

In case you were wondering why we should reduce emissions ASAP, the report explains the multiple reasons:

  • The faster emissions are reduced, the lower the risks posed by climate change….
  • Waiting for unacceptable impacts to occur before taking action is imprudent because the effects of greenhouse gas emissions do not fully manifest themselves for decades and, once manifested, many of these changes will persist for hundreds or even thousands of years.
  • The sooner that serious efforts to reduce greenhouse gas emissions proceed, the less pressure there will be to make steeper (and thus likely more expensive) emission reductions later.
  • The United States and the rest of the world are currently making major investments in new energy infrastructure that will largely determine the trajectory of emissions for decades to come. Getting the relevant incentives and policies in place as soon as possible will provide crucial guidance for these investment decisions.
  • In the committee’s judgment, the risks associated with doing business as usual are a much greater concern than the risks associated with engaging in strong response efforts. This is because many aspects of an “overly ambitious” policy response could be reversed if needed, through subsequent policy change; whereas adverse changes in the climate system are much more difficult (indeed, on the timescale of our lifetimes, may be impossible) to “undo.”

Yes, we are in the process of screwing up this planet for possibly a thousand years or more (see NOAA: Climate change “largely irreversible for 1000 years,” with permanent Dust Bowls in Southwest and around the globe and 2009 Nature Geoscience study concludes ocean dead zones “devoid of fish and seafood” are poised to expand and “remain for thousands of years”).  But hey, once you apply a proper discount rate, the net present value of the suffering of those tens of billions of people hardly matter at all.

The NAS rightly says we should “Begin mobilizing now for adaptation” since even “Aggressive emissions reductions would reduce the need for adaptation, but not eliminate it.”  One can’t argue with this recommendation:

The federal government, in collaboration with other levels of government and with other stakeholders, should immediately undertake the development of a national adaptation strategy and build durable institutions to implement that strategy and improve it over time.

But, again, it ain’t gonna happen until the US scientific community, which the NAS stands at the forefront of, figures out how to deliver its scientific message to the hear-no-evil, see-no-evil, speak-some-evil crowd (see “Conservatives oppose adaptation, too“).

The report has an adequate review of the science for those who have been sleepwalking through the last decade (or watching Fox News, which is much the same thing).  If you were wondering what the science says about the change in America’s climate, here goes:

  • U.S. average air temperature increased by more than 2°F over the past 50 years, and total precipitation increased on average by about 5 percent;
  • Sea level has risen along most of the U.S. coast, and sea level rise is already eroding shorelines, drowning wetlands, and threatening the built environment;
  • Permafrost temperatures have increased throughout Alaska since the late 1970s, damaging roads, runways, water and sewer systems, and other infrastructure;
  • There have been widespread temperature-related reductions in snowpack in the northeastern and western United States over the last 50 years, leading to changes in the seasonal timing of river runoff;
  • Precipitation patterns have changed: heavy downpours have become more frequent and more intense; the frequency of drought has increased over the past 50 years in the southeastern and western United States, while the Midwest and Great Plains have seen a reduction in drought frequency; and
  • The frequency of large wildfires and the length of the fire season have increased

And yet the media continues to report on record-setting wildfires and record-setting drought, and record-setting deluges without hardly a word on climate change.  I guess they don’t read NAS reports, either.

The one other interesting tidbit I found was in the section on geoengineering:

Geoengineering, applied to climate change, refers to deliberate, large-scale manipulations of the Earth’s environment intended to offset some of the harmful consequences of GHG emissions, and it encompasses two very different types of strategies: solar radiation management and post-emission GHG management…..

Solar radiation management (SRM) involves increasing the reflection of incoming solar radiation back into space….  A much-discussed example is the proposal to continuously inject large quantities  of small reflective particles (aerosols) into the stratosphere….

The potential benefits of many SRM strategies are offset by potential risks. In the case of aerosol injection strategies, for example, significant regional or global effects on precipitation patterns could occur, potentially placing food and water supplies at risk. SRM alone would also do nothing to slow ocean acidification, since CO2 concentrations in the atmosphere and ocean would continue to rise. Thus, it is unclear if any of the proposed large-scale SRM strategies could actually reduce the overall risk associated with human-induced climate change.

Precisely (see Science Sunday: “The economics (or lack thereof) of aerosol geoengineering”).

Bottom Line:  This would be a good report had it been written, say, 5 or 10 years ago.  Now it is just a glass half full.  For a class that is half full.

Begin mobilizing now for adaptation


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29 Responses to National Academy calls on nation to “substantially reduce greenhouse gas emissions” starting ASAP

  1. Tim says:

    The map and caption at the top of this post don’t make sense to me. How can one map be “compared to the 1960s and 1970s”? Is there supposed to be a second map?

    [JR: My bad.]

  2. Joan Savage says:

    I’m not comfortable with a shifting baseline that always puts climate change into the future. “”Waiting for unacceptable impacts to occur before taking action is imprudent because…” does not acknowledge that unfavorable impacts have already occurred, and several are on the rise.

  3. Jeff Huggins says:

    The Last 72 Hours

    In the last 72 hours or so …

    * The National Academy of Sciences published the report discussed in this post, calling on the nation to substantially reduce GHG emissions as soon as possible.

    * The Pontifical Academy of Sciences, part of the Vatican, published the report discussed a day or so ago, calling on humankind to face and address climate change in order to preserve a healthy and just future and to avoid causing harms to billions of people presently living.

    * Top execs of the Big Five oil companies argued to Congress that it would be misinformed, discriminatory, and counter-productive to change their tax treatment.

    If President Obama, the Democratic Party, the leading climate change organizations, CAP, the leading science organizations, and the rest of us can’t utilize these facts (along with many others) to bring about effective change, there is something wrong — with us. After all, an excellent card player can win if he gets good cards: he doesn’t need to wait and hope for his opponents to completely disappear.



  4. Roger says:

    Great reporting on a valuable report, Joe. So, what are we waiting for?

    In a more rational world, akin to the twentieth century one in which I grew up, thrilled when our NASA scientists made it possible for America to place man’s first footprint on the moon, our government would have long ago begun steps to save its citizens from hell and high water.

    Now, sadly, we’re holding the rest of the world back, as they wait and watch, disbelieving their eye and ears, wondering: Will the US ever lead again?

    What happened? Respect for science has always been one of the bases for American success. Why have we abandoned it? Is too much money, in the wrong hands, indeed the ultimate root of evil? Is it the Kochs?

    Do those with the most money, and their ‘friends’ in government who allow them to make even more money, somehow ultimately win, simply by surviving for one more generation than the rest of us?

    With all the great things man has done, and all of the huge hurdles overcome by millions who have struggled before, should it all come to a pitiful end because of rampant human greed in a handful of families?

    NO, I say! It’s time to rise up and demand our right to continued human life on Earth, at least until things beyond our control ensue.
    Go to http://www.gothelimit.org to see how the aware few can impact the many who are confused, or unaware. It’s not only labor who have a lever.

  5. Richard Miller says:

    To my fellow 47,000 readers of Climate Progress,

    Here is a simple way to put pressure on our leaders.

    Joe posted a report from the Center for American Progress a month ago (see http://climateprogress.org/2011/04/14/export-coal-china/) about the Department of the Interior’s plan to lease public lands in the state of Wyoming that would provide big coal companies with 758 million tons of coal. Interior will also decide this year about leasing public lands that would provide coal companies with an additional 1.6 billion tons of coal to burn and pollute our atmosphere.

    I have created a petition to be sent to President Obama and Secretary of the Interior Salazar objecting to this destructive plan. I have used MoveOn.org’s new petition tool. As I understand it, if enough people sign the petition, then they will send the petition to their 5 million members for them to sign.

    This is an opportunity to draw upon MoveOn’s large email list to put pressure on our leaders and also to help push for climate change as a priority issue at MoveOn.org.

    Here is the link to the petition:

    Richard Miller

  6. paulm says:

    Do I detect a mild bit of panic.
    Panic can be good some times…..

  7. Lewis C says:

    U.N. climate chief predicts U.S. turnaround on warming

    By Charles J. Hanley

    Associated Press
    Posted: 05/12/2011 04:26:08 PM PDT

    NEW YORK — Washington’s inaction on climate legislation is a “very serious hand brake” on world efforts to combat global warming, the U.N. climate chief said Thursday.

    But Christiana Figueres said she believes the U.S. will eventually join the rest of the industrialized world in mandatory reductions of greenhouse gases.

    “I don’t think it’s a permanent state of affairs that the world will be able to live with,” she said of the failure of Congress to cap emissions of carbon dioxide and other gases blamed for global warming.

    Figueres, head of the U.N. climate treaty secretariat, met with Associated Press editors and reporters in New York as the National Research Council issued an authoritative report in Washington on “America’s Climate Choices,” urging the federal government to act to “substantially reduce greenhouse gas emissions.”
    . . . . . . . . .

    Figueres said she sees a “very remarkable dissonance” between the “political incapacity” in Washington and the United States’ technological potential to lead the world toward a future of clean energy and less dependence on polluting fossil fuels.

    “From an international point of view,” she said, it “puts a very serious hand brake on the whole pace of negotiations.”

    Faced with these obstacles, the Obama administration for two years has promoted a voluntary approach to emissions reductions. But Figueres said international negotiators increasingly realize this unreliable “bottom-up” approach will fall far short of what’s needed to keep temperatures from rising more than 2 degrees Celsius (3.6 degrees F) above preindustrial levels.
    . . . . . . .

    Because of that realization, she said, she believes the annual U.N. climate conference, in Durban, South Africa, late this year, might produce movement toward an eventual legally binding agreement of “predictable” emissions reductions.

    “The expectation is that the United States live up to its responsibility, to its historical responsibility” as the past single greatest source of greenhouse gases now filling the atmosphere, Figueres said.


    In the coded language of diplomatese these quotes are scathing of the US – and as such pretty much unprecedented from a senior UN official.

    So when will Americans dare to face the fact that their government is behaving disgracefully in their name ? Supposedly its conduct is in the national interest in awaiting the destabilization of the upstart rival China – but actually it is grossly incompetent and culpably negligent in failing to acknowledge that true national interest demands that the global interest in resolving global warming be addressed immediately.

    In saying:
    “I don’t think it’s a permanent state of affairs that the world will be able to live with”
    Figueres gives as clear a public warning as she can that the world will not continue to tolerate US backsliding and intransigence.

    If Americans choose not to listen, they’ll have only themselves to blame when their nation is left on the sidelines of global affairs and treated as a pariah for the exacerbation of the long-term genocidal climate damage that the inherited White House policy of wilful intransigence is now causing.



  8. Mulga Mumblebrain says:

    I remember hearing an engineer say that the glass not half empty nor half full, but twice as big as it needed to be. The truth is worse, naturally, because all the scientific authorities that ought to be marching in the streets, resigning their Government sinecures, or, Indian fashion, going on public hunger strikes, are not even telling the truth when they are, half-heartedly candid. As Mr Romm shows, the truth is already dire beyond belief, and disaster, total disaster, is almost unavoidable already. And still the Right deny everything. The Fundament ran a letter today from the unspeakable Bob Carter, who has joined the ‘Institute of Public Affairs’, a far Right propaganda tank associated with ‘Free Market’ mystification. He wanted somebody to prove that mankind was responsible for the measured rise in CO2 level, yet I believe he still holds a post in a University somewhere in the ‘Deep North’, Heaven help us!

  9. Not A Lawyer says:

    you left out my favorite part of the report:

    “Most people rely on secondary sources for information, especially the mass media; and some of these sources are affected by concerted campaigns against policies to limit CO2 emissions, which promote beliefs about climate change that are not well-supported by scientific evidence. U.S. media coverage sometimes presents aspects of climate change that are uncontroversial among the research community as being matters of serious scientific debate. Such factors likely play a role in the increasing polarization of public beliefs about climate change, along lines of political ideology, that has been observed in the United States.”

    [JR: I missed that. Will do a separate post.]

  10. paulm says:

    @8 forgot to mention setting yourself on fire…

  11. Diana says:

    All the scientific data states very clearly that our planet is experiencing global change that will effect everyone and everything. It is time to be honest and take a real stand for the whole ecosystem of Earth.

  12. Ed Hummel says:

    Mulga #8, I meet idiots like Bob Carter almost every day. There are a lot of them out there in our woefully uninformed countries and they are exactly what the deniers in chief (Murdock and Koch types) are banking on to push their extremely selfish agendas. Since most media types are just “doing a job” and collecting good paychecks, and not out to do any real reporting, the general public won’t be connecting the dots until it’s way too late. You had your unbelieveable floods during your summer and the US is on course to have something similar as we get into our summer with the stuck atmospheric circulation patterns that continue to plague most places in the world.

    From what I’ve been reading about Aussies, many of you still don’t make the connection because of what The Fundament has been spewing day after day. We have Fox “News” spewing out its garbage to 10 times your number with the other media outlets usually not mentioning climate change connections when reporting the continuing disasters as JR continues to point out. And even the few stories that do make a mention of climate change connections are usually quite timid and the timidity tends to flavor the whole story which I’m sure gets transmitted to the audience as a very weak connection because of all the “uncertainty” (I’m being extremely facetious when I say that!!).

    I just had a conversation with a fellow activitist here in central Maine who just can’t understand why President Obama doesn’t use his bully pulpit to tell the American people what the real story is since Chu and Holdren must be briefing him on the latest science on a regular basis. All we could come up with is that he’s being way too political and is still sidestepping controversy unless he’s calculated that he can benefit from it until after next year’s election. Maybe he figures that he’ll finally be able to come out strongly to the general public about what we really face and what we must do about it. That would be marginally acceptable if it were true, but I guess my cynicism and overall pessimism keep a big fat doubt sitting right in the middle of my brain. I can’t help thinking that he is indeed just another beliiver in a certainly discredited economic and social theory which looks at continuous economic growth as somehow being what human civilization is all about, even when all the hard evidence from nature points in the opposite direction. If sustainability or extinction applies to every other species, they it surely applies to us, even if we are supposedly the most intelligent one.

    Then of course Obama’s actions (or non-actions) are not even taking another year and a half delay in meaningful action into account when we might already have reached a point of no return in many important feedback mechanisms as well as taking the stored ocean warmth of the last few decades and the gradual reduction in global dimming into account to exacerbate the already precarious situation that we’re in. And of course there are also the political and social upheavals that the weather disasters are leading to as agriculture continues to be disrupted worldwide and all food stocks continue to hit dangerously low levels. I’ll ignore the disruptions caused by volatile energy supplies and financial malfeasance to global societies and economies just to keep things simpler (I’m being fectious there, too).

    Those who look to technological fixes seem to forget that technology only works in a calm, stable social situation with no shooting and explosions occurring all over the place to destroy that technology as well as progressively more infrastructure and eventually even research facilities and the funding institutions which support them. I hope Rupert Murdock, Bob Carter, James Inhofe, Dick Cheney, Roger Ailes, Charles and David Koch, and all the rest of them are proud of their accomplishments. Too bad we can’t really say the same (yet!?!?!) for their opponents.

  13. Adam R. says:

    The Republican fossil stooges in Congress are reacting predictably:

    “I see nothing substantive in this report that adds to the knowledge base necessary to make an informed decision about what steps — if any — should be taken to address climate change.” -Joe Barton, Texas

  14. Lore says:

    Joan @2

    The map is a snap shot. We will be in dire straits well before that. You’re looking at massive crop failures and dislocation from food and water shortages decades before this, literally, drop dead date.

  15. Adam R. says:

    This is certainly an ominous conclusion to the report. Alas, my hometown paper, the Houston Chronicle, has apparently seen fit to ignore the story, just as it has done since the first report. Indeed, a search for “National Research Council” at the Chronicle’s site returns no hits connected to climate at all.

  16. Joan Savage says:

    Lore (#14)

    Pakistan, Queensland, Texas, Namibia, Manitoba, Mississippi basin, are in dire straits at present time.

    I took issue with the ACC conclusion phrase, which by inference treats all those events as “acceptable.”

    ACC: ”Waiting for unacceptable impacts to occur before taking action is imprudent because…”

    Proposed substitution: “Enduring current serious impacts without taking action is imprudent because…”

  17. Don A in Pennsyltucky says:

    Too bad that the NAS doesn’t contribute to the campaign funds of Boehner and McConnell. If it did, someone might pay attention.

  18. Michael Tucker says:

    I’m sorry optimistic UN person (from Lewis C’s post #7) I think a chance of meaningful climate legislation getting through congress in the next 10 years is remote.

    The House will not draft a bill and the Senate does not have the votes to bring a bill to the floor.

    After President Obama I predict a Republican president. It always happens. So nothing will happen for the next 9 years at least. After that we might get a Democratic president or we might get stuck again for another 4. So I am thinking chances are pretty good that nothing will happen for at least another 13 years.

    My feeling is that getting a global agreement between the major polluting nations will be even harder.

    As long as these 100 year and 500 year weather catastrophes are not connected with rising GHG levels the public will remain tepid on the subject. As Joan Savage said (#2), “…unfavorable impacts have already occurred, and several are on the rise.” The general public needs to be acutely aware that they do not need to wait 20 or 40 or 90 years, the effects of global warming and catastrophic climate disruption are happening now.

  19. Richard Brenne says:

    Epic comments here, especially Ed Hummel’s at #12. Like Mulga’s and others they’re so dense with knowledge I read them multiple times.

    Ed, could you tell us more about how global warming encourages circulation patterns to become stuck? How is this related to the huge upsurge in 500 milibar high pressure ridges that can often be accompanied (air and water looking for equilibrium) by corresponding cut-off lows as the Weather Channel’s Stu Ostro has observed? What creates a “sluggish” jetstream and one that can dip from north to south over places like the U.S. more often than it used to on its west to east trajectory? How does the 1 degree rise F since 1970 and resulting 4% more water vapor (equivalent to 1.5 Lake Superiors) in the atmosphere and the energy equivalent to the output from 190,000 nuclear power plants in the system create these changes, and what are the effects?

    Just in case you’ve ever wanted to do a doctoral dissertation, or several. . .

    And your concern that almost no linear trend of the 20th Century will continue throughout the 21st is my primary concern as well.

    I’ve never heard anyone talk about the loss in home insulation due to bullet holes and broken windows, but maybe they should.

  20. Ed Hummel says:

    Richard #19, that’s a tall order! It’s really all basic meteorology and there’s no need for a doctoral dissertation to explain the basics, but it would take some knowledge of atmospheric physics which could fill up at least one whole course (I’ve actually taught such courses in local high adult ed classes; got 15 weeks?!) Actually, undergraduate meteorology students would cover the material in great detail over a few semesters and in many different courses each of which concentrates on certain aspects of the underlying physics. However, give me some time, and I think I can put some simple answers to your questions together that would fit on a CP post. I’ll be back.

  21. Merrelyn Emery says:

    Thanks for that Lewis #7. It is indeed interesting that USA ‘exceptionalism’ is now being explicitly noted in the run-up to Durban. This event could end up being some sort of inflection point and not yet another ‘sigh, wimper – well we tried’ step in the process, ME

  22. Richard Brenne says:

    Thanks Ed! (#20)

    Maybe Joe would consider making that a guest post. You can e-mail him with that proposal.

    Here’s the thing: Meteorology is taught for meteorologists at the undergraduate, graduate and all other levels but I think if anyone understands something sufficiently they should be able to teach it in such a way that the public understands it, or at least those that have sufficient education (like a good college or even high school education in any field) and a sincere desire to learn.

    You seem to have the education, training, background, talent and candor (I think not representing any large institution is huge and allows far greater candor than most are able to summon) to do that. (Your historical, philosophical and other big-picture insights are also most unusual, as are those of your fellow commentators here like Mike Roddy, Mulga Mumblebrain, Merrelyn Emery – and those are just the Ms – and many others.)

    Also, correct me if I’m mistaken but meteorology has always been taught in a very static sense when what I’m asking for is the “Meteorology of Climate Change.”

    Finally, academia and even most books typically go into too much irrelevant (to most of us) detail. All the physics and chemistry and fluid dynamics and other principles and all the terminology and all the history of the increase in understanding and all the ways things are measured and all the history of the tools used to measure everything aren’t of interest to everyone.

    But the answer to a question such as this one I think should be of interest to every truly caring and thinking person: “With the very conservative IPCC Report predicting up to 10 degrees Fahrenheit increase by 2100, what would the resulting 40% additional water vapor and the energy output equivalent to about 1,900,000 nuclear power plants’ output added to the system mean? What would it mean to all those with basements, all those living in flood plains, to global agriculture and infrastructure?”

    Some of the questions I asked in my previous comment at #19 might be relevant to answering that as well. Or take any other approach you want.

    Of course I’d love to hear sincere answers from anyone, but again I’d love to see a post on this from Ed. Ideally I’d love to hear answers from Kevin Trenberth, Tom Karl, Stu Ostro, Jeff Masters and Ed.

    Of course I’m grateful for anything and grateful most of all to Joe and CP for answering these kinds of questions better than anyone I know, it’s just that I’m missing a few of these connections, at least in my own mind.

    Also instead of a huge undertaking just the best answers to these questions off the top of your head would be hugely helpful. I’ll bet if someone had endless time they’d come to much the same conclusions you’d come to in half an hour off the top of your head because you’ve studied and thought about all this so much to date. So don’t wind up with a big intimidating effort – I’ll take what you’ve got off the top of your head, and know that would be immensely valuable, of course minus any dandruff.

  23. Ed Hummel says:

    This is for Richard Brenne. I took a break for supper and am now back with some answers for you. Here are what I hope are simple explanations to your questions about connections between a warmer world and the circulation patterns that lead to more extreme droughts and floods.

    I think everyone knows that the tropics tend to be warm all the time because they receive more direct solar radiation than any other place. At the same time, each pole receives very little solar radiation and most of that comes only around each hemisphere’s summer solstice. Because the atmosphere is a fluid, the air molecules are able to move freely and mix easily. On a global scale, the excess heat of the tropics is continually being transported away toward the poles by convection (similar to warm air moving up and away from a hot stove) while the much colder air of the poles is continually being transported away toward the equator (similar to colder air from the far end of a room rushing back along the floor to replace the hot air near the stove). In between, there is a lot of mixing going on, especially in the mid latitudes where migratory high and low pressure system are always traversing.

    The greater the contrast in temperature between equator and pole, the more force there is to move the air and the faster it flows. This large scale air movement is most apparant in the polar front jet stream which more or less parallels the boundary between warm tropical air and cold polar air. The polar front jet stream tends to be stronger and more zonal (west to east flow) when the temperature contrast between equator and pole is the greatest. It also tends to keep meanders north and south to a more well ordered and strong set of long waves that provide most of the mixing at all levels between the polar and tropical air. The jet stream tends to be weaker and more meridional (more north and south flow) when the temperature contrast is less. The meanders tend to move more north and south and get cut off as individual high or low pressure systems that isolate anomalous pockets of relatively cold or warm air and which don’t have much force to move them; they become stuck.

    Ordinarily, the zonal flow regime reflecting a big contrast tends to be more prevalent in the winter hemisphere and it’s also assumed that such regimes tended to be more common year round during the max glaciations when general conditions tended to be windier and drier. The meridional flow tends to be more common in the summer hemisphere as that pole has its relatively warm season.

    The polar jet stream is also the boundary between warm core sub-tropical high pressure systems and cold core polar high pressure systems. Warm core highs are very deep and extend right up through the entire troposphere (the layer where all our weather occurs and which is bounded on top by the ozone layer of the stratosphere). They also tend to remain stationary for long periods. On the other hand, cold core highs are very shallow with very dense cold air at their centers and they tend to move easily toward the lower latitudes. The boundary between the two types of high pressure are usually where mid latitude storms form.

    If there is less contrast between equator and pole and the polar front jet stream tends therefore to be weaker and more prone to a meridional flow pattern, it is much easier for a sub-tropical high pressrue system to bulge poleward for more than it usually would with a stronger jet. If it bulges far enough poleward (resulting in anomalous 500mb heights), it can form a very effective block and lead to the formation of big low pressure systems that become stuck and just spin in place because they can’t move with the blocking high in place downstream. Once these blocks set up, the area under the warm, wet side of the cutoff low tends to have near continous precipitation mechanisms dumping a lot of rain or snow on the same general location. Meanwhile, the areas on the dry side of the cutoff low and under the blocking high tend to have mostly clear skies day after day with no precipitation at all. If these patterns tend to linger and repeat during the course of a season, simultanous droughts and floods will result.

    Another thing that happens with warming temperatures is warmer air holds more more water vapor and more water vapor in turn can absorb more heat energy from terrestial radiation (water vapor is an excellent green house gas as Richard Lindzen repeatedly tells us!). But not only does water vapor absorb more long wave radiation, but it also releases an immense amount of latent heat when it condenses back into a liquid to form clouds and precipitation. In fact, a large part of the heat transport away from the tropics occurs when precipitation occurs to release all that stored latent heat. If this occurs during a convective mechanism which is producing thunderstorms and tornadoes, they will most likley become more intense as more latent heat is released to drive them as the water vapor content of the air goes up. The added moisture can also drive greater snowfalls wherever the temperatures are cold enough for snow production and this extra latent heat release can probably make up for reduced energy due to contrasting air masses. This latter point answers the paradoxical question that Jim Hansen hits in his book STORMS OF MY GRANDCHILDREN. In other words, even though the overall jet stream flow can become weaker and more sluggish with less contrast between the equator and pole, individual storms can still crank up into monsters because of all the extra latent heat being released with the added moisture. The mechanism becomes quite similar to what happens with tropical cyclones which don’t need contrasting air masses and which just rely on the released energy of latent heat to operate.

    I hope that answered your questions. If other meteorologists want to add to this and clarify anything that seems a little fuzzy, be my guest. I’m going to bed!

  24. Mulga Mumblebrain says:

    Ed Hummel, #12, I’m afraid that I more than share your doubts concerning Obama. In my opinion no-one can even think of being President (or Congressman) without being a servant of the money power, the real driving force on this planet. Nader summed it up for me, in regard to Obama, with his succinct observation, ‘Prepare to be disappointed’. We have had the same hideous experience here in Australia, with Rudd succeeding Howard, who led what, in my opinion, was by far the worst regime, morally and ethically, in our history, and then governing as if he was Howard, reborn. Then, after a couple of years of hollow and cynical PR gestures followed by policy utterly congruent with that of his predecessor (sound familiar?) Rudd was rolled by his own party when his inauthenticity, opportunism and dedication to his predecessor’s agenda began to undermine his approval ratings. He was succeeded by Julia Gillard, who has not just continued the Howard/Rudd policy agenda, but, in many ways, exacerbated it.
    And overseeing this hideous descent into policy idiocy and moral insanity has been News Ltd, Murdoch’s (I always see echoes of Moloch in this name)horrendous bullying, vilifying, hatemongering, deracinating propaganda apparatus. In Chomsky and Herman’s ‘Manufacturing Consent’ they quote some candid business klepto, boasting that the US public had not spontaneously ‘moved’ Right, but had ‘been moved’ Right by relentless media propaganda. As it has been my steadfast belief for years that Rightwing ideology, based as it is on greed and contempt for, (and often naked hatred of) other people, was antithetical to human welfare, I always believed that the triumph of the Right would usher in an age of hideous violence and destruction. I once thought that it would then produce such revulsion in humanity that we would reject such an inhumane ideology forever. I regret to say that I now think that I was thoroughly mistaken. ‘Intelligence’ such as that which we possess, when grafted on to more primitive impulses and instincts, then transfigured by generations of unnatural selection to empower the most greedy, violent and psychopathic amongst humanity (the triumph of market capitalism)has proven absolutely self-destructive. A society that empowers, enrichs and promotes the likes of Murdoch, the Kochtopus and all their ilk, is innately destructive, and that includes self-destruction. Capitalism’s ‘creative destruction’ has run out of indigenous populations to exterminate, unexploited lands to pillage or non-Western cultures to colonise and subjugate. It is now finishing the job of destroying the biosphere and turning the resultant detritus into money with which they hope to further inflate their egos and defy the laws of Nature. This debacle has probably been more or less inevitable since Man decided to do without the Earth Mother goddesses and spirits of the forests, seas, air and mountains as deities, and instead promoted Himself to Glory, in the patriarchal ego projection of monotheism.

  25. Ed Hummel says:

    Mulga at #24, AMEN!!!

  26. Richard Brenne says:

    Wow! Thanks Ed! (Comment #23) Sorry to keep you up writing that!

    Often an amazing thread needs to continue and jump from one post to another. I feel that this has never more been the case than with Meteor gist Ed Hummel’s two comments, especially this one at #23 (#25 is good, but shorter).

    My own weak synopsis (to make sure I understand, am not making mistakes and can communicate this to the public) about the mechanism of how global warming produces more extreme weather events: Basically the warming of the poles means the jet stream is less rigorous and less likely to be pushing storms and other weather systems across continents like North America from west to east.

    Instead the jet stream often becomes more sluggish, can dip from north to south and block storms or droughts in place for longer periods. With increased temperatures the droughts can become drier and longer because of increased ground soil evaporation. Increased temperatures also mean more water vapor that can cause more daily precipitation as well as longer storms because they’re stuck in one region for longer.

    A parrot could’ve come up with something similar (okay I admit it, one did). See Ed’s first great synopsis about this here:


    I also brought up these links in comment #30 on the Weekend Open Thread and why don’t we all meet to discuss this there!

  27. Leif says:

    Ed Hummel, @ 23: Thank you for your efforts. Of course another thank you to Mulga M, @ 24, and gosh just so many more of you that keep CP so relevant.

  28. Phil M says:

    Not a lawyer says:

    “you left out my favorite part of the report:

    “Most people rely on secondary sources for information, especially the mass media; and some of these sources are affected by concerted ”

    I could not find that exact reference, can someone point me to where that was found? That’s gold.

  29. Donald Oats says:

    To emphasise Mulga Mumblebrain’s point: A particular newspaper in Australia preaches “balance” but structures stories for a definite propaganda effect. I have been bitterly disappointed at how the one national broadsheet (we have another national paper, the Australian Financial Review, but as the name suggests, it specialises on financial markets) has steered the non-debate into polarised debating heads territory, but provides the most significant coverage to the talking head of severely sceptical status. They don’t even get challenged on some of the most outlandish claims, too numerous to document here (although checking Deltoid’s site for Aussie stuff, and obviously this site too, will reveal many of the themes we are subjected to by the likes of the Murdocracy). The mis-balance has put a number of Australian climate scientists right off from submitting articles to the particular newspaper, but that unfortunately just leaves more print-space available for the worst of the AGW-rejectionists, to coin Eli Rabbett’s word.

    In discussions with friends on the climate topic, I stick to referring to climate change as “Anthropogenic Global Warming” (aka AGW) quite steadfastly, for the simple reason that the moniker “climate change”, while intended to be shorthand for human-induced climate change (of which global warming is one aspect) has been deliberated skewed by our national broadsheet to be open to wider interpretation as meaning climate change is natural (well, doh! Most of the last 4.5 billion years, we obviously had nothing to do with it because we weren’t here, or weren’t in such numbers that our behaviour was in any way significant.), and by doing that they can shift goalposts in any article to one of ridiculing the whole notion.

    The classic goalshift (“equivocation”, in rhetoric) is demonstrated quite clearly Ian Plimer or Bob Carter lecture on how climate has changed greatly in the deep geologic past, and by implication, they hope the reader will take them to mean that the current period of global warming is also entirely absent of human causation. Climate scientists are tacitly assumed not to have done their homework in understanding previous periods of natural climate change, but of course climate scientists know about this; indeed, they study ancient periods in order to understand the mechanisms of climate generation and change, and these mechanisms do not explain the current period of change – and rapidity of change – anywhere near satisfactorily, which is really the point that an honest piece of journalism would make clear. Instead, particular individuals fuel a fake controversy over the supposed failure to take into account previous natural climate change, and by tacit implication this makes the opponent look dumb, which is an extra bonus of this method of argument – unfortunately, it brings us not one whit closer to understanding the facts (which are very scary, just as this blog post is stating, and the final NAS report is understating).

    If the current period of climate change had physical parameters changing independently of us, then this would just be another round of natural climate change. But it is not, for the simple reason that human’s massive release of CO2 (carbon dioxide) has “pushed” on the climate system as a whole, and this climate forcing is what sets in train the climate system’s response, ie transitioning to a new regime (probably). The human emissions of CO2 do not “clear” from the environment for decades, and while it is present it causes other effects to come into play – like the warmer atmosphere being able to carry a much higher load of water vapour, another potent greenhouse gas. It is in our interests to find ways of avoiding the problem of CO2 emissions in the first place, in order to avoid not only initial effects (since CO2 is a greenhouse gas) but also the knock-on effects like increased water vapour, storms and flood/drought scenarios, permafrost melting, etc. Obviously some areas of the globe might have countries that initially benefit from the direction of the changes to global climate parameters (like temperature, precipitation, etc); that is no excuse for accepting accompanying worse conditions for other countries, however.

    I wish it wasn’t like this, but unfortunately moola does buy serious power for an individual, and there is no accounting for some particular individual’s beliefs. Especially if you are the monopoly national broadsheet creator and supplier. Us Aussies get the raw prawn insofar as quality newspapers go.

    PS: I hope the Aussie spelling isn’t too jarring for US readers :-)
    PPS: Another debating point that is variously applied over here is that our CO2 emissions per year are miniscule compared to the annual emissions and reabsorptions happening naturally. The simplest way to see through such a vacuous comparison is to notice that the total CO2 mass in the atmosphere is like a visa account balance, the natural emissions are like adding grocery bills each week to the owed amount, and the reabsorptions are like paying off part of the account with salary each month. If spending matches repayments for the year, then the visa account balance remains roughly the same from year to year, a relatively stable situation. Our problem is that the emissions by humans are like spending a little bit more each month than is paid off; the debt accumulates and results in the visa card debt increasing year by year. The interest on the growing debt is also compounded into the debt, and additional burden. Eventually, the kneecappers are sent round!