Earth’s Changing Energy Budget

Every few years, I try and construct a climate computer simulation model. I never succeed. I usually end up going round and round in circles, and giving up. (Examples 1, 2, 3)

Recently I’ve begun another attempt. And part of the process has entailed getting hold of figures for Earth’s energy budget, to use as a target to aim for – how I want my model to work. Here’s a famous one from 1997:


And here’s another one from the same guy (Trenberth) in 2009:


And here’s an even more recent one in Nature from 2012:


The interesting thing is that the numbers have been changing quite a lot over just 15 years. In 1997 the incoming solar radiation at the top of the atmosphere was believed to be 342 Watts/m². But by 2009, this had fallen to 341 Watts/m². And in 2012 it was down to 340.2 Watts/m². And reflected solar radiation at the top of the atmosphere had also fallen from 107 Watts/m² in 1997, to 102 Watts/m² in 2009, and 100 Watts/m² in 2012.

At the same time the estimated long wave back radiation from the atmosphere had risen from 324 Watts/m² in 1997, to 333 Watts/m² in 2009, and 345.6 ±9 Watts/m² in 2012. And estimated latent heating of the atmosphere had risen from 78 Watts/m² in 1997 to 88 ±10 Watts/m², an increase of over 10%.

These are quite large variations. And also now include quite large error margins. And since the radiative forcing due to rising carbon dioxide in the atmosphere seems to be estimated to be about 3.4 Watts/m², it would seem that this could easily get lost in among all the changes in estimates of other forcings (e.g. the 21.6 Watts/m² change in back radiation). The 2012 paper seems to recognise this:

The net energy balance is the sum of individual fluxes. The current uncertainty in this net surface energy balance is large, and amounts to approximately 17 Wm–2. This uncertainty is an order of magnitude larger than the changes to the net surface fluxes associated with increasing greenhouse gases in the atmosphere.

Or as Jo Nova put it:

This paper rattles the whole table of key numbers, with empirical results. It puts core numbers into a new perspective, numbers like the 3.7 Watts per square meter that a doubling of CO2 is supposed to add to the surface budget.

The models are hunting for imbalances and build-ups in planetary energy. But according to the observations, the longwave (infra-red) energy coming onto the earth’s surface, the infamous back radiation, is 10 – 17 W/m² higher than in the famous Trenberth diagram from 1997. So the models are trying to explain tiny residual imbalances, but the uncertainties and unknowns are larger than the target. The argument that “only the forcing from CO2 can fill the gap in the models” is not just argument from ignorance rhetorically, but factually too.

Another major implications is that water is churning up and falling out of the sky faster than the experts thought. The Earth’s evaporative cooler is lifting more water, taking more heat, and dumping that heat in the atmosphere. At the top of the atmosphere heat is radiating off the planet to offset the radiation coming in. On the water planet, it really is all about water.

Or maybe “expert” climate scientists aren’t really experts at all.


About Frank Davis

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6 Responses to Earth’s Changing Energy Budget

  1. Tony says:

    I realise that you’re not trying to create a prediction or projection but merely looking at energy flow on the basis of other things being equal. But I’m inclined to believe that such models may be of little use because other things do not appear to be equal.

    A bit like trying to determine the causes of cancer from a few dodgy surveys without even acknowledging the germ theory of medicine (I had to work a little to shoe horn that in – lol)

    Svensmark: The Cloud Mystery:

    • Frank Davis says:

      other things do not appear to be equal.

      Like what, for example?

      • Tony says:

        I meant ‘other things’ in terms of outside influences such as cosmic rays causing cooling by creating low level clouds. Variable because of variations in the strength of the solar wind and galactic events.

        I’m not trying to say your models are meaningless, only that there is this important omission. Important for climate prediction/projection that is. And I wanted to crowbar in both the Svensmark video and the cancer causation folly.

        • Frank Davis says:

          I quite accept that. I’ve read repeatedly that cloud formation is not well understood. And I bought Svensmark’s Chilling Stars a few years back.

          One point of building a model is to get some idea for myself how much clouds are likely to affect outcomes. In my previous models, I found they were pretty decisive. No clouds = strong warming. Total cloud cover = strong cooling.

  2. garyk30 says:

    “Or maybe “expert” climate scientists aren’t really experts at all.”

    Since most of the really important discoveries have been made by and the most useful products created by ‘non-experts’, experts are over-rated.

    Ben Franklin and bi-focal glasses and lightning rods, or Faraday and his law of induction come to mind.

  3. Cecily Collingridge says:

    Expert = X-spurt…
    X is an unknown quantity; spurt is a drip under pressure.

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