Follow-up to Bayard's post of Wednesday. For sure, some Climate Scientists exaggerate or make false claims, but that doesn't invalidate anything.
For example, nuclear power stations 'work'. They use uranium etc to produce electricity, fact. They also appear to be profitable. We can argue - quite reasonably - about pollution risks, safety, terrorism risks, nuclear proliferation, decommissioning and long term storage costs etc, but those are not science issues. Just because some politicians make outlandish claims like them producing "electricity too cheap to meter" does not invalidate the science.
My big bugbear with Climate Science is that it is based on the bald claim that Earth's surface is 33 degrees warmer than it should be based on incoming sunlight. Therefore, they say, something must be 'trapping' thermal energy in the atmosphere; and that something is Greenhouse Gases (which sometimes includes water vapour and sometimes doesn't, depending what point they are trying to make).
This claim was originally made, and the calculation explained by Hansen back in the late 1980s and has been Climate Gospel ever since, completely unquestioned, even by many Climate Deniers. Some Climate Deniers have put forward other explanations, but none of them seems watertight to me and a lot are pretty flaky.
So how do they calculate the 33 degrees? By comparing half an apple with an imaginary pear is how. Here are the workings (refer to Stefan-Boltzmann equation to convert between temperature and W/m2):
What are the obvious flaws here?
- They take clouds into account when calculating weighted average albedo of Earth's effective surface (which means that part of the surface that can absorb radiation FROM and emit it directly TO space - oceans/land under cloud cover simply can't and can be ignored here) , which reduces solar radiation IN to 238 W/m2, but then just ignore clouds from there on.
- They then assume that solar radiation IN is all absorbed by oceans/land. Nonsense, over half is absorbed by clouds, less than half by oceans/land.
- The actual question is: is the effective surface at the right temperature to emit this much (238 W/m2 on average) back to space?
- They skip these this question, come in at a tangent and say that a black body (an imaginary pear) would have to be 255K to emit as much radiation as the effective surface absorbs in solar radiation IN (this is true).
- They compare this with part of the effective surface (half an apple) which has an average temp of 288K (also true), discrepancy = 33 degrees (mathematically correct).
- They then put forward an explanation for the 33 degree difference - it's Greenhouse Gases, and the rest is all built on that - all the pseudo-scientific mumbo jumbo like "radiative forcing" and "fluxes" and "effective emitting altitude" and "atmospheric windows" and "computer models" until your head spins (I know what these all mean. They are all dead ends or working backwards from the wrong answer).
Why not compare a whole apple with a whole apple, and take all its physical properties into account, in particular the low emissivity of clouds? That seems to be a lot more rigorous to me, so you should consider clouds and cloud-free oceans/land separately when looking at solar radiation IN and LW emissions OUT.
The more scientific approach is this. For sure, it's all rounded and mid-points of estimates and so on, but it follows the general idea based on what information I can glean. I could keep digging and add more and more lines and home in ever closer to an even more robust answer:
If you do it properly, you find that Earth's oceans/land and the clouds above them are the right temperature to emit as much LW radiation as they absorb in solar radiation. Sure, the sea level surface is warmer than in the pseudo-scientific calculation, but so what? An aluminum frying pan in the sunshine gets warmer than the pavement it is resting on, that has largely to do with aluminium's lower emissivity (plus/minus dozens of other adjustments). Look at the whole of the real apple and all its physical properties, not just a part of it/them!
[Completely different sets of rules apply when considering the temperature difference between sea level and clouds - the gravity-induced lapse rate; latent heat of evaporation; reflection of LW between the two; dew points at different absolute humidity, temperature, density and pressure etc etc. I can't cover all that here, but it is irrelevant to the actual topic].
Therefore, I conclude - unless somebody can show why their approach is better than mine, I refuse to believe anything based on the 33 degree Greenhouse Effect, because there simply ISN'T ONE IN THE FIRST PLACE!!
Bonus: the above approach neatly explains the alleged Greenhouse Effect (or absence thereof) on Venus and Mars, regardless of the fact that their atmospheres are nearly 100% CO2 - it's the clouds (or absence thereof) wot dunnit.
Caveats:
- I have only been looking into this for two-and-a-half years and 'only' did O-level physics forty years ago, so clearly have plenty more to learn.
- There are lots environmental, economic and political reasons for using less fossil fuels, sure, but those are quite different topics. For example, I'm against nuclear weapons, but that does NOT mean that I don't accept the science of nuclear fission. I am, in fact, broadly in favour of reducing fossil fuel use for precisely those reasons, but that does NOT mean that I just blindly accept their pseudo-science. We bribe our kids withthe promise of Xmas presents for good behaviour; we don't waffle on about Santa's Naughty List. Treat people like adults and they might just behave like adults.
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