BBC: Finding the elusive "smoking gun"

Apologies for the delay on this article. We’ve now fixed the weblog issue

The BBC reports on yet another discovery of the "Smoking Gun" of anthropogenic global warming.

The Earth is absorbing more energy from the Sun than it is giving back into space, according to a new study by climate scientists in the US.

They base their findings on computer models of climate, and on measurements of temperature in the oceans.

The group describes its results as "the smoking gun that we were looking for", removing any doubt that human activities are warming the planet.

The results are published in the journal Science this week.

The study attempts to calculate the Earth’s "energy imbalance" – the difference between the amount of energy received at the top of the atmosphere from solar radiation, and the amount that is given back into space.

Rather than measuring the imbalance directly, the researchers draw on data from the oceans, in particular from the growing global flotilla of scientific buoys and floats, now numbered in the thousands, which monitor sea temperature.

And it’s co-authored by our friend from realclimate, Dr Gavin Schmidt:

"Measuring the imbalance directly is extremely difficult, because you are looking for a very small number on a background of very large numbers," Gavin Schmidt, one of the research team from the US space agency’s (Nasa) Goddard Institute for Space Studies in New York, told BBC News.

Yes, we’ll come back to you on that one. So, how long is the baseline for these measurements?

"But we know how much energy is going into the oceans – that has been measured and over the last 10 years confirmed by satellites and in-situ measurements – and from our understanding of atmospheric physics, that has to be equal to the imbalance at the top of the atmosphere."

Yep, a whole ten years. Not even one solar cycle. The satellite record is 26 years long, but they looked at ten.

Bob Park in his latest "What’s New" newsletter showed exactly the length of the ocean measurements used:

A week ago, an important editorial in Science by Donald Kennedy
called attention to NASA’s recent decision to delay or cancel
planned Earth science missions and terminate orbiting spacecraft
to feed the pointless Moon/Mars mission. A report in this week’s
Science shows how just short sighted that is. An international
monitoring effort, Argo, has deployed 1,800 instrumented floats
in oceans around the world since 2000
. A NASA team led by James
Hansen collected data from the floats and precisely determined
ocean levels from satellite observations. They found that Earth
is absorbing more energy than it’s radiating back into space, an
imbalance large enough to raise temperatures 1 F this century,
even if greenhouse gas emissions are capped tomorrow. "There can
no longer be genuine doubt that human-made gases are the dominant
cause of observed warming," Hansen said. "This energy imbalance
is the ‘smoking gun’ that we have been looking for."

A whole four-and-a-bit years of ocean observations.

Back to the BBC article:

So data gathered from the oceans is plugged into a computer model representing the Earth’s complex climate, including the atmosphere, oceans, winds, currents, greenhouse gases and other "pollutants". What emerges is that at the top of the atmosphere, our planet is absorbing 0.85 watts more energy per metre squared than it is emitting into space.

So the energy is out of balance in the short time frame considered and no solar variation is mentioned at all. Any chance of some wild extrapolation?

"The normal state of the atmosphere is that pretty much the same amount of energy that comes in leaves; and only when there are very large changes is that going to change.

"Historically, those changes have happened very slowly; but what we are doing now is we are changing that imbalance at a rate which appears to be unprecedented over at least a thousand years and possibly longer."

From ten years to a thousand. Of course, proof of Gavin’s statement about it being "unprecedented over at least a thousand years" is strangely absent from the report published in Science, but maybe I’m not reading between the correct lines. Could Gavin be trying to throw another lifeline to the Hockey Stick?

Next comes the traditional BBC Online climate skeptic sandwich. This week, the lucky winner is William Kininmonth:

Not everyone agrees with these conclusions. One scientist who disagrees is William Kininmonth, a former head of Australia’s National Climate Centre and a member of Australia’s delegations at various rounds of United Nations climate treaty negotiations.

"The paper implies that it is possible to estimate quite accurately the global radiation imbalance," he told BBC News; other researchers, he says, have "explained why it is not possible to measure the imbalance with an accuracy better than several watts per metre squared".

Like other "climate change sceptics", Dr Kininmonth believes too much reliance is placed on computer models rather than hard data.

"I do not believe this research team has made a compelling case to suggest that their computer models are sufficiently realistic to justify the implications of anthropogenic (human-induced) global warming that they make," he said.

Oh don’t be such a wet blanket, William. Don’t you know that climate models can find signals much smaller than the resolution of the measurements? Yes, I know that even the IPCC warns that climate models are "unfalsifiable in the strict Popperian sense", but that’s the genius: no-one can prove them wrong.

Back to the cheering:

But Damian Wilson, manager of clouds and radiation parameterisation at the UK’s Meteorological Office, was more enthusiastic.

"The computer model matches temperature changes at the Earth’s surface quite well – but that alone doesn’t prove it’s right," he said.

"Having a model that also matches ocean heat uptake well suggests that the model is doing a pretty good job. I wouldn’t like to say the research proves that 0.85 watts per metre squared is the right figure, but it does give us more confidence that the models are doing a good job of producing a reasonable simulation of the energy imbalance."

Well that’s a half cheer, actually. Not that enthusiastic.

Has it occurred to anyone that that the Earth must be out of radiative balance by small smounts at some stages because the feedbacks and secondary responses are not instantaneous? Or that the cooling of Antarctica over the last 50 years and the growth of the icesheets practically everywhere except the tiny Antartic Peninsula represent a large sink sucking heat out of the atmosphere? Since the report excluded the poles from the analysis, is it any wonder they failed to mention this?

Personally I wonder what the gun is smoking, but that’s just me…

16 Comments

  1. Louis Hissink
    Posted May 5, 2005 at 6:00 AM | Permalink | Reply

    Earth is out of radiative balance?

    Put in standard English this can be re-stated as “earth is not in thermal equilibrium”.

    Only dead things are in thermal equilibrium.

  2. John A
    Posted May 5, 2005 at 6:48 AM | Permalink | Reply

    If the earth is out of radiative balance, it begs the question as to whether it is out of energy balance, since there are many processes in the earth’s climate system which are not represented in these models.

  3. Dave Dardinger
    Posted May 5, 2005 at 8:00 AM | Permalink | Reply

    Since I assume most people here also follow RealClimate to see the other side of the picture, you’ll have noticed I asked Gavin about the article which did the actual measurements of the .85 w/m2 +-.15 w/m2 and that he kindly gave a link for it. If everyone would be so kind as to go look at figure 6 and contemplate it for a bit it shouldn’t be hard to work up some fresh skepticism that the heat balance measurements can be accurate to that small figure with that small error.

    As I said there, if large patches of the ocean can switch from +80 w/m2 to -80w/m2 in a year, how can we get to +.85 w/m2 for 10 years and have it as anything but a coincicence?

  4. John A
    Posted May 5, 2005 at 8:51 AM | Permalink | Reply

    Re: #3

    What I want to know:

    1. During the time period considered, the solar cycle had a double-peaked maximum. Does this mean that the time period considered is atypical for the 20th Century?
    2. In his explanation regarding Lubos’ response, Gavin makes the following analogy:

    There are two different things here. One is the error in any particular flux (which can be large), and the second is the error in the overall balance (which is very small). To see why these things are different, think of a lake which is fed by a number of streams of uncertain flow, and drains into a river. If the lake level is steady, I know that the inputs are balancing the outputs, even if I don’t know their exact magnitude. If I now observe the lake level change, I can calculate very exactly the net imbalance regardless of the error in my estimate of the individual streamflows

    Erm, no. Using the same analogy, Lubos pointed out that the error in the lake level change that you’re trying to measure is greater than the imbalance between inputs and outputs that you claim to be measuring. Further, you make the assumption that the key input, solar forcing, remains constant – which is clearly not true. Further down, you make the claim that 0.85 W/m^2 is the mean of the imbalance calculated.

    3. How does an observation over ten years get generalized to a hundred or even a thousand years?

    4. Does the ten year period studied have any bearing on what we would call climatic change? Other people would call it “weather” or a “decadal oscillation”

  5. Dave Dardinger
    Posted May 5, 2005 at 9:47 AM | Permalink | Reply

    John,

    Concerning your point 3, the problem with the lake analogy is that the wind has kicked up waves a meter tall and he’s trying to measure over-all lake rises of a few millimeters. And he doesn’t have one standpipe, where he can make one measurement, but instead tries to look through a telescope on a satellite 100 miles over the top of the lake.

    In that regard, I need to re-read John Daly’s old article on trying to measure sea heights via satellite. He was rather dubious, but I’ve never checked to see if the complaint was valid or not. Looks like a job for the Audit Team .

  6. Scot Wilcoxon
    Posted May 5, 2005 at 11:58 AM | Permalink | Reply

    Aren’t plants converting solar energy to chemical bonds, so that energy should no longer be part of the heat budget? Were such things taken into account?

  7. Ferdinand Engelbeen
    Posted May 5, 2005 at 3:45 PM | Permalink | Reply

    Already posted in the first discussion about the smoking gun:

    The ocean heat balance is covered by Levitus for the period 1955-2003. This shows a remarkable dip in heat content of the world’s oceans in the period 1980-1990. See http://www.nodc.noaa.gov/OC5/PDF/PAPERS/grlheat05.pdf figure 1.

    Levitus has some interesting comment:
    “However, the large decrease in ocean heat content starting around 1980 suggests that internal variability of the Earth system significantly affects Earth’s heat balance on decadal time-scales.”
    Thus as the decrease in heat content in the period 1980-1990 probably is entirely natural, the increase in the period 1993-2003 probably is entirely natural too.

    I have asked at Real Climate if the GISS model used by Hansen e.a. also has a good fit with the ocean data for the 1980-1990 period…

  8. Louis Hissink
    Posted May 6, 2005 at 6:57 AM | Permalink | Reply

    John,

    No, not possible, our energy balance model is complete – what on earth could we have missed!

    The one force in nature absent from astronomy and geology – electricty.

    More on SMERSH shortly.

  9. Jon
    Posted May 10, 2005 at 7:29 AM | Permalink | Reply

    One of the interesting aspects of this study, was table 1. Unless I’m reading it incorrectly, which is entirely possible, the variance for the cumulative effects of the “forcing agents” is 1.80 +/- 0.85 w/m^2.

    The entire net “out of balance” model shows 0.85 +/- .15 w/m^2.

    What am I missing here, that the variance for just one factor is equal to the net differential for the entire equation?

    I also like how the variance for GHGs at +/- .4 is substantially greater than the variance for the entire model – +/- .15.

  10. ET SidViscous
    Posted Jan 12, 2006 at 11:05 PM | Permalink | Reply

    What is up with these spam wankers. And why aint the Spam Karma cathing the yobs.

  11. Steve McIntyre
    Posted Jan 12, 2006 at 11:09 PM | Permalink | Reply

    I don’t know why those ones got through. But it’s a big help. We got about 50 spams today. It varies a lot.

  12. JPK
    Posted Feb 20, 2007 at 11:06 AM | Permalink | Reply

    A NASA team led by James
    Hansen collected data from the floats and precisely determined
    ocean levels from satellite observations. They found that Earth
    is absorbing more energy than it’s radiating back into space, an
    imbalance large enough to raise temperatures 1 F this century,
    even if greenhouse gas emissions are capped tomorrow

    I wonder if thier study picked up the 3.2 x 10^23 Joules of ocean heat loss between 2003 and 2005?
    That energy had to go somewhere.

  13. MarkW
    Posted Feb 20, 2007 at 11:44 AM | Permalink | Reply

    I thought the British had outlawed both smoking, and guns?

  14. Steve Sadlov
    Posted Feb 20, 2007 at 12:02 PM | Permalink | Reply

    RE: #12 – There seems to be a de facto ban on using post 2003 data within the AGW fanatic circle.

  15. David Smith
    Posted Jun 17, 2007 at 4:54 PM | Permalink | Reply

    A couple of new (for CA) plots on Pacific equatorial heat content, with a few comments, is given on the CA auditblog here .

  16. STAFFAN LINDSTRÖM
    Posted Jul 22, 2007 at 7:25 AM | Permalink | Reply

    Still the “h” in “USHCN” is for
    historical so whatever happens
    land-use wise…less than an H-bomb…
    The darn site must stay in place…
    So we now have the “climatic sport-bra effect”(CSBE)
    (I googled that and found not anything on 30 first
    results (391 so called “hits”)
    so all credit to me please if
    this gonna be another of MY
    hits…

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