Best and the Brightest May Finally Be Open To Considering Lower Climate Sensitivity Numbers

For years, readers of this site know that I have argued that:

  • CO2 is indeed a greenhouse gas, and since man is increasing its atmospheric concentration, there is likely some anthropogenic contribution to warming
  • Most forecasts, including those of the IPCC, grossly exaggerate temperature sensitivity to CO2 by assuming absurd levels of net positive feedback in the climate system
  • Past temperature changes are not consistent with high climate sensitivities

Recently, there have been a whole spate of studies based on actual observations rather than computer models that have been arriving at climate sensitivity numbers far below the IPCC number.   While the IPCC settled on 3C per doubling of CO2, it strongly implied that all the risk was to the upside, and many other prominent folks who typically get fawning attention in the media have proposed much higher numbers.

In fact, recent studies are coming in closer to 1.5C - 2C.  I actually still think these numbers will turn out to be high.  For several years now my money has been on a number from 0.8 to 1 C, sensitivity numbers that imply a small amount of negative feedback rather than positive feedback, a safer choice in my mind since most long-term stable natural systems are dominated by negative feedback.

Anyway, in an article that was as surprising as it is welcome, NY Times climate writer Andy Revkin has quite an article recently, finally acknowledging in the paper of record that maybe those skeptics who have argued for alower sensitivity number kind of sort of have a point.

Worse than we thought” has been one of the most durable phrases lately among those pushing for urgent action to stem the buildup of greenhouse gases linked to global warming.

But on one critically important metric — how hot the planet will get from a doubling of the pre-industrial concentration of greenhouse gases, a k a “climate sensitivity” — someclimate researchers with substantial publication records are shifting toward the lower end of the warming spectrum.

By the way, this is the only metric that matters.  All the other BS about "climate change" and "dirty weather" are meaningless without warming.  CO2 cannot change the climate  or raise sea levels or any of that other stuff by any mechanism we understand or that has even been postulated, except via warming.  Anyway, to continue:

There’s still plenty of global warming and centuries of coastal retreats in the pipeline, so this is hardly a “benign” situation, as some have cast it.

But while plenty of other climate scientists hold firm to the idea that the full range of possible outcomes, including a disruptively dangerous warming of more than 4.5 degrees C. (8 degrees F.), remain in play, it’s getting harder to see why the high-end projections are given much weight.

This is also not a “single-study syndrome” situation, where one outlier research paper is used to cast doubt on a bigger body of work — as Skeptical Science asserted over the weekend. That post focused on the as-yet-unpublished paper finding lower sensitivity that was inadvisedly promoted recently by the Research Council of Norway.

In fact, there is an accumulating body of reviewed, published researchshaving away the high end of the range of possible warming estimates from doubled carbon dioxide levels. Chief among climate scientists critical of the high-sensitivity holdouts is James Annan, an experienced climate modeler based in Japan who contributed to the 2007 science report from the Intergovernmental Panel on Climate Change. By 2006, he was already diverging from his colleagues a bit.

The whole thing is good.  Of course, for Revkin, this is no excuse to slow down all the actions supposedly demanded by global warming, such as substantially raising the price and scarcity of hydrocarbons.  Which to me simply demonstrates that people who have been against hydrocarbons have always been against them as an almost aesthetic choice, and climate change and global warming were mere excuses to push the agenda.  After all, as there certainly are tradeoffs to limiting economic growth and energy use and raising the price of energy, how can a reduction in postulated harms from fossil fuels NOT change the balance point one chooses in managing their use?

PS-  I thought this was a great post mortem on Hurricane Sandy and the whole notion that this one data point proves the global warming trend:

In this case several factors not directly related to climate change converged to generate the event. On Sandy’s way north, it ran into a vast high-pressure system over Canada, which prevented it from continuing in that direction, as hurricanes normally do, and forced it to turn west. Then, because it traveled about 300 miles over open water before making landfall, it piled up an unusually large storm surge. An infrequent jet-stream reversal helped maintain and fuel the storm. As if all that weren’t bad enough, a full moon was occurring, so the moon, the earth, and the sun were in a straight line, increasing the moon’s and sun’s gravitational effects on the tides, thus lifting the high tide even higher. Add to this that the wind and water, though not quite at hurricane levels, struck an area rarely hit by storms of this magnitude so the structures were more vulnerable and a disaster occurred.

The last one is a key for me -- you have cities on the Atlantic Ocean that seemed to build and act as if they were immune from ocean storms.  From my perspective growing up on the gulf coast, where one practically expects any structure one builds on the coast to be swept away every thirty years or so, this is a big contributing factor no one really talks about.

She goes on to say that rising sea levels may have made the storm worse, but I demonstrated that it couldn't have added more than a few percentage points to the surge.


  1. MingoV:

    "CO2 is indeed a greenhouse gas..."

    Yes, if you quadruple the concentration of CO2 in an airtight greenhouse, it costs slightly less to heat it. However, planet Earth is not a greenhouse. It has no glass roof and walls separating inside from outside. Any solar photon that strikes a CO2 molecule and warms the air is ONE LESS photon to strike and warm the surface. Net heat is the same whether a solar photon strikes a lower atmosphere air molecule, a water molecule, or the surface. The entire greenhouse theory of Earth warming is a crock.

    -- A clinical pathologist and chemist who aced his physical chemistry course

  2. NormD:

    Heard an interview on NPR recently where an engineer from the Army Corps of Engineers repeatably made the point that areas protected by CoE seawalls or barrier dunes had NO damage.

    He also spoke of several communities where seawalls or barrier dunes were recommended and would have been built by the CoE but the locals launch vociferous campaigns to stop the construction to "preserve our beaches".

    These communities suffered grievous damage.

    And now we are expected to bail these clowns out.

  3. Gil:

    So a blanket can't warm you because the escaping heat from your body escaped into the blanket making you colder.

  4. herdgadfly:

    We have been told that CO2 follows warmth, not the other way around. It is indeed very likely that the complexity of the miracle that is our atmosphere is not well understood. Moisture suspended in the air, cloud cover influenced by cosmic rays from the sun, sun spot activity and our air purifying oceans that absorb CO2 and even convert some of it to limestone - all these things and more that I don't comprehend - are keeping us relatively comfortable. Long term, it is warming, but we have to understand that we cannot now nor will we ever control the earth's climate.

    I go with Michael Crichton on this one: "You think man can destroy the planet? What intoxicating vanity."

  5. LarryGross:

    my attitude has been to understand realize that models do have flaws and the science itself is still in flux but like Hurricane models have flaws and the science of hurricanes is still evolving - we do not deny the existence of hurricanes and we do realize that if one is predicted, it often does appear and it can cause even more damage than predicted, as well as less.

    But we do not deny the hurricane or it's potential to cause harm because the models are flawed and we still have disagreement about how they actually work.

    it just makes sense to NOT be a skeptic on the EXISTENCE of something just because the models are flawed or the science is not complete.

    We do, in fact, waste millions of dollars evacuating from an area thought to be hit and it does not happen. But how many people say that because the hurricane did not hit that it proves the scientists are engaging in a conspiracy to fool people or perhaps that the scientists will somehow benefit from false evacuations?

    If this sounds silly, I agree but it's sill for both hurricanes and global warming. they are both real even if we don't know every nook and cranny about how they work or how severe they might be.

  6. Angel Zachriel:

    Sorry, but that is incorrect. Without the greenhouse effect, the surface of the Earth would be a chilly ≈-18°C rather than the
    balmy ≈+15°C that it is.

  7. Angel Zachriel:

    Chief among climate scientists critical of the high-sensitivity holdouts is James Annan, an experienced climate modeler based in Japan who contributed to the 2007 science report from the Intergovernmental Panel on Climate Change. By 2006, he was already diverging from his colleagues a bit.

    While Annan believes the evidence now allows for rejection of very high numbers for climate sensitivity, he still believes it is at a dangerously high level of 2.5-3.0°C.

  8. bigmaq1980:

    I see a moral hazard in there somewhere?

    Climate change or not, it seems to me that markets were distorted by the implied and explicit "insurance" provided by government for people who live along these coastlines.

    Bloomberg claims that for years he's been "predicting" that climate change might cause a disaster like this. However, it seems his NYC disaster prevention expenditure for 10+ was minimal vs the damage done vs "social" expenditures. Yet, he is one of the first in line calling for State and Federal funds, to "recover" (including building protective infrastructure).

    Moral hazard, or ponzi scheme?

  9. LarryGross:

    you can always buy private insurance but private insurance for these areas hit by storms has skyrocketed. Houses built at grade in the Sandy-flooded areas are said to cost as much as 31K
    to insure with private insurance.

    The insurance companies are speaking volumes about future risk and they, unlike the "deniers" are not gambling. They want cash on the barrel head if they are going to insure homes in newly-defined flood areas. FEMA and Army Corps have more than doubled the area of likely flooding in NY/NJ since Sandy.

  10. Steve Walser:

    Your analogy is not a good one as we know that hurricanes exist as well as much about how they grow and die. We know little about the total life cycle effects of CO2 in the atmosphere. A more apt analogy would be that someone predicted that hurricanes were going to continue growing uncontrollably once they hit land and so we should evacuate Kansas the next time one headed for the Texas coast.
    We don't do this because it runs counter to our real life experience just as the basic theory underlying dramatic predictions of climate change ruin to come runs counter to our experience that complex natural systems do not suddenly go wildly out of balance due to minor changes but are, instead, remarkably stable.

  11. Steve Walser:

    Slowly, slowly the air will be allowed to leak from the balloon of AGW alarmism as reality intrudes. The many who disparaged all who doubted the theory will never apologize, the trillions being spent on useless attempts to mitigate a non existent problem will never be admitted and the millions of poor who have been starved to death by the policies directly resulting from such fanaticism will never be acknowledged.
    Life will go on but we will largely learn nothing from this decades long debacle.

  12. LarryGross:

    we know more about hurricanes than we used to but even now when a hurricane occurs, you can see a dozen or more different model tracks.

    re: Kansas - ... re: Sandy... have you noticed as of late the much more extensive damage that we are seeing ... and the wider evacuation areas as well as the virtual abandonment of some of those areas by the insurance industry? FEMA just re-drew the flood maps of NY/NJ and the new ones show twice as much area susceptible to flooding from expected sea level rise.

    Now they do not know just how much it will rise but they are pretty sure it's not zero. So what do you do?
    do you seriously underestimate it so that the next Sandy floods much more than thought or do you start thinking in terms of probable higher sea levels and the likely damage that will result if and when storms hit?

    what do you gamble on?

  13. HenryBowman419:

    Worse, once AGW has died away, a brand-new catastrophe will be ginned up, and there will be calls for urgent action to prevent planetary collapse. These are simply crises generated for the sole purpose of controlling other people (and their money).

  14. marque2:

    no kidding, and of course subsidized government insurance in flood zones and free money from FEMA grants keeps people in flood zones, when they should be building dikes, or moving elsewhere.

    But this has been happening long before the global warming became a hot issue. Government has been doing this at least since the very cold 1970's and insurance companies have been refusing to insure at least as long.

  15. marque2:

    Not to beat on the dead horse here. but CO2 can only absorb certain wavelengths of light. Those that come from the sun are not in the range as often as wavelengths that come from the earth. Also note that different molecules do absorb different wavelengths of light. CO2 and H2O have similar profiles for absorption.

  16. LarryGross:

    no.. the areas that are expect flood are increasing in size by large amounts... land that never before was classified as flood prone.

  17. marque2:

    Whatever the master tells you, you repeat. Good job, you win 1000 sycophant points today.

  18. LarryGross:

    the flood maps determine the type and extent of subsidized flood insurance as well as the price of private insurance.

  19. marque2:

    ;-) more points!

  20. LarryGross:

    In other words, they have REAL impacts on people.... just as rising sea levels do....

  21. FelineCannonball:

    There's a lot of apples and oranges involved in this. Any geological record of climate sensitivity is working on a much different timescale than anthropogenic CO2 release. It's like comparing bread cooked in an oven and bread cooked by the Hiroshima blast. A lot of feedbacks work at the scale of 100's to 1000's of years (ocean temperature, sea floor temperature, heat conduction through permafrost, glacial retreat, etc.). If you are only worried about the year 2050 you ignore them. If you're looking at the last 50 years you ignore them. If you're looking at the year 2500, they're relevant. So when you through all this up there that scientists disagree you really have to pin down exactly what they're talking about. There will always be uncertainty but the discussion becomes meaningless if you aren't talking about the same thing.