October 08, 2008 | Graham

Oceans drive climate



Climate skeptics are frequently incredibly bad at arguing their case. I’ve been following the greenhouse issue since I was a kid back in the 60s, so I should have heard all of the persuasive arguments by now. But I read a very persuasive one today that I had never seen before. If the skeptics were doing their job that shouldn’t be the case.
This argument is actually eight years old. In the Summer 2000 edition of 21st Century, Dr. Robert E. Stevenson gives a run-down as to why it is oceans, not atmosphere, which control climate. Stevenson is an oceanographer and the truncated version of his argument runs like this:

Water retains heat better than earth or air. Water and earth are heated by direct exposure to the sun’s radiation which mostly passes through air. The heat is returned relatively quickly by the earth, so that in areas remote from the sea minima are lower and maxima higher than areas closer to the sea. Air is heated by the infrared radiation, but its re-radiation of energy in this spectrum cannot significantly heat water.
Transfers of heat from the ocean to the atmosphere follow a relatively predictable cycle. When the sea is hotter, the atmosphere is hotter, but as the air cannot be the source of this heat, it is the oceans that drive the temperature of the air rather than the other way around. The contribution of CO2 to global warming is therefore relatively trivial.

This view of the world fits in neatly with one of my most recent posts. Douglass and Christy, taking aerosols and the ENSO into account, argue there is no evidence for the greenhouse effect being enhanced by forcings. The corollary of this argument is that the ENSO and aerosols are capable of significantly masking the effect of CO2, and everyone seems to agree that it was the El Nino event in 1998 which made it the hottest year in the last century. What’s more, AGW proponents are now predicting cooler years because of ocean temperatures until next decade.
In the same post, noted climatologist Henderson Sellers is quoted::

Until and unless major oscillations in the Earth System (El Nino-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), North Atlantic Oscillation (NAO) and Atlantic Multidecadal Oscillation (AMO) etc.) can be predicted to the extent that they are predictable, regional climate is not a well defined problem. It may never be. If that is the case then we should say so. It is not just the forecast but the confidence and uncertainty that are just as much a key.

The ABC’s Science Show carried a story the other day about GOCE, a project to measure earth’s magnetic field which will allow us to more accurately measure sea levels. Marek Ziebert, Professor of Space Geodesy at University College London, explains:

It is that big, and the reason for it is because what this mission in particular enables us to do is to understand what the energy transport mechanisms are in the ocean. The ocean carries huge parts of the energy budget of the planet around the ocean, and so as that changes, as climate changes, then it’s going to affect everybody. Here in the UK everyone is aware of climate change these days and our climate is very affected by changes in the Atlantic. Most of our weather is driven by the moisture and the winds and the energy transport mechanisms from the Atlantic.
The difficulty we have at the moment is that although we know the shape of the surface of the ocean from space, what we don’t know is the physics of it. We can’t model the physics of it because we haven’t got a reference surface against which to measure these changes in height in the ocean. What this mission will enable us to do is to define that reference surface very clearly. So then we can say because that reference surface is at such a height, then the water is flowing in such a way and it’s driven by such forcings and such energies.

So the models may not only be flawed, but they may very well be trying to understand the wrong part of the earth system, and as yet we may not have enough information to model that more important part of the system, the oceans, properly.



Posted by Graham at 9:26 pm | Comments (4) |
Filed under: Environment

4 Comments

  1. Graham,
    As I said in the late post (8/10) to your 6/10 response about the flawed state of climate modelling, I think it’s a foregone conclusion that the models are indeed flawed. Indications are from my reading are that the complexity of climate dynamics is like the search for TOE, GUT worthwhile but beyond our currently existing science.
    Therefore all predictions are still based on incomplete/imprecise information.
    • Logically one can’t prove a negative (something doesn’t exist) only a positive. It is however valid to suggest that the explanation doesn’t fit the facts/observations/science. Then comes the argument what then does fit the facts etc. Some nay sayers simply point to natural causes and if true there isn’t a case to answer. Where this falters is that while there is precedence in geologic history for similar events what is new is that there is no definitive evidence for all factors happening at the same time? The answer to that is at best unclear. Therefore the nay argument is as flawed as ACC. Prudence then dictates that (as previously stated) “business as usual” is not an option until a more plausible alternative can be demonstrated. Especially in the light of current observations.
    • The article is eight years old at the current rate of technological change (knowledge) I find it hard to believe that someone else hasn’t already considered its implied impact. Again it isn’t a law of science only a paper. How definitive is it?
    • My reading of the article doesn’t sufficiently offer a plausible alternative explanation for all the events or can it say that there is no link i.e. that both the water heat absorption potential should be included in an improved model. The big provisor and my big worry is again the statistical aggregate methodology as they do say there are gaps in continuity the measurement series.(inbuilt flaw)

    Comment by examinator — October 9, 2008 @ 11:20 am

  2. Just look at the reality,the world has been cooling in times of expodential CO2 emitions.Is there a disconnect here between the scientific method and tax payer funding or heaven forbid,a direct correlation?

    Comment by Arjay — October 10, 2008 @ 8:33 pm

  3. Arjay,
    What you appear to be focusing on is weather V Climate. The problems we face aren’t year by year issues or even sun cycles but the long term issues.
    The time lag is the the 4 tonne Diprototon in the corner.

    Comment by examinator — October 11, 2008 @ 2:27 pm

  4. Examinator,the world has been cooling since 1998.Would you define a 10 yr period,a climate pattern or a weather pattern?I thought weather was a daily or seasonal term.
    Surely if there is expodential growth in the prime evil contrubutor CO2,then temps must increase at a corresponding rate,or are there other forces at play here?

    Comment by Arjay — October 11, 2008 @ 8:51 pm

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