Sunday, 1 March 2020

"The Science Is Settled"

No it's not. They can't address the most simple and obvious contradictions and omissions.

It is often repeated by sources such as the BBC that

Solar energy radiating back to space from the Earth's surface is absorbed by greenhouse gases and re-emitted in all directions. This heats both the lower atmosphere and the surface of the planet. Without this effect, the Earth would be about 30C colder and hostile to life.

1. Temperature increases with pressure, gas giants like Jupiter and Saturn get hotter the deeper you are into the atmosphere. Same goes for Venus. The temperature at the height where pressure = atmospheric pressure on Earth is roughly the same as the temperature on the surface of the Earth, having adjusted for distance from the Sun, regardless of what gases make up the atmosphere. Mars has a thin atmosphere and Earth's Moon none at all, which provide counter-examples.

So a large part of that 30C is due to this effect IMHO and only a small part due to the actual composition of the atmosphere (H2O and CO2), but let's go with the 'consensus' that's it's all of it.

2. Of that 'consensus' 30C, how much is due to H2O and how much to CO2?
a) On average, there is 50 times as much H2O as CO2 in terms of parts per million (400 x 50 = 20,000 ppm = 2%).
b) H2O appears to reflect/absorb at many more wavelengths than CO2. See see this table.
So CO2's contribution, relative to H2O, must be infinitesimaly small.

Nonetheless, most people seem to assume that CO2's contribution is about one-eighth of the total. So let's just accept that as well and see where it takes us.

3. One-eighth of 30C is just under 4C. Other sources say 3C.

4. Skeptical Science jumps the shark on this topic:

The question of how the climate would change in a completely CO2-free atmosphere was brought up recently in a testimony to the subcommittee of the House Science and Technology Committee. An answer was provided by MIT scientist Dr. Richard Lindzen, who suggested that such a hypothetical removal of all the CO2 in the air would translate into a global cooling of about 2.5 degrees, presumably in Celsius...

In the Lacis et al experiments, removing the CO2 from the atmosphere generates a cooling of around 30 C, an order of magnitude difference from Lindzen's answer.

5. Next, I think the logarithmic effect is also broadly accepted, it makes sense. Extreme sceptics say the effect is already saturated and extreme alarmists (e.g. some contributors on Skeptical Science) claim it is close to linear, they cancel each other out.

CO2 concentrations (just under 420 ppm) are 50% higher than pre-industrial levels (280 ppm, which we have to accept as being natural, normal and thus harmless).

So of that 3C extra warmth, considerably more than two-thirds is due to the background 280 ppm and less than one-third is due to the additional 140 ppm, so CO2's contribution to temperature increases over the last 150 years or so is less than 1C.

The figure for average temperature increase since CO2 was at pre-industrial levels (when we were coming out The Little Ice Age) is between 1C and 2C. The implication is that all of this 1C or 2C is due to CO2, rather than less than 1C, which would at least seem plausible (if you ignore all the above niggles).

(Skeptical Science side-step the logarithmic issue by fudging their Y-axis and setting 'radiative forcing' at zero for 280 ppm, which is meaningless. As their chart shows, if you fudge it like this, 'radiative forcing' at a lower CO2 level of 140 ppm would be negative, i.e. it would have a cooling effect.)

6. So you have to ignore several glaring contradictions and omissions to reach the conclusion that CO2 increases have pushed up average temperatures by even 1C , that is at the upper, upper range of the even remotely plausible. (If you factor in items 1, 2 and the logarithmic effect, the impact of CO2 is immeasurably small).
7. What if Skeptical Science is/are right and a) temperatures really are 30C warmer because of CO2 and b) the effect is close to linear? In that case, average temperatures would have increased by about 10C since the 19th century, which clearly they haven't, even if we pretend that The Little Age was somehow normal and a reasonable base line.

Do they not read what they write and think it through to the logical conclusion and realise how stupid they sound?


View from the Solent said...

0C is just an arbitrary value on the absolute temperature scale.
Any type of calculation based on 0C is being economical with the truth.

Bayard said...

Who needs logic when they have got belief?

Mark Wadsworth said...

Vfts, we could recalculate everything in degrees K, I've accounted for that.

B, I used to believe, until I started trying to really understand it.

Bayard said...

Mark, me too, until my father pointed out that the ice-core graphs clearly showed that increased temperature produced increased CO2, but that the IPCC et al were trying to say that it was the opposite. I did find a wonderfully convoluted "explanation" in the New Scientist showing how that, although the graphs looked like they showed that rises in temperature preceded rised in CO2, that actually it was the other way around.

Mark Wadsworth said...

B, they think they can talk their way out of that. See here.

Dinero said...

"temperature increases with pressure"
Is there more detail to that subject. For example car tyres are not warm.

Mark Wadsworth said...

Din, completely different. Just Google "why is it so hot in the centre of Saturn" or "why do has clouds ignite and become stars". There's your answer. It applies on a much smaller scale to any atmosphere.

Theo L said...
This comment has been removed by the author.
Theo L said...

My understanding has been that CO2 isn't responsible for the majority of climate warming - and your numbers suggesting below 1 degree seem reasonable. I thought that the key was that by increasing the temperature, it will lead to higher concentrations of water vapour, and that will be the cause of the majority of the actual temperature increase.

Further to this, would global temperature not be a lagging indicator anyway? It takes time for an insulating effect to lead to higher overall temperature. If so, we wouldn't expect the current level of warming to directly correlate to current CO2 (and H2O) levels?

I think there is legitimate concern that by artificially increasing the concentration of CO2 (and thereby causing some, although not excessive warming) we risk allowing the concentration of atmospheric H20 to increase, leading to more significant warming in the future.


Mark Wadsworth said...

TL, when all else fails, they play the H2O feedback card. Why does it make a big difference whether there are
- 20,000 H2O and 400 CO2 ppm, or
- 20,400 H2O and no CO2?

Clue, it doesn't. H2O can't feedback itself.

Bayard said...

Mark thanks for that. I read it carefully and, as I suspected, it doesn't actually disprove the CO2 lags temperature effect.

"While the orbital cycles triggered the initial warming, overall, more than 90% of the glacial-interglacial warming occured after that atmospheric CO2 increase (Figure 2)."

Well, that is exactly what you'd expect from a continuous system. The oceans start to warm, CO2 starts being given off, then the oceans continue to warm for the same reason that they started to warm, not because of the initial outgassing of CO2, which is what the Shithead Science idiots are trying to argue.

Mark Wadsworth said...

B, exactly. Nearly all their stuff is like that. If that's the best they've got, then I remain firmly sceptic.

Theo L said...

I think the point on H2O feedback isn't that it leads to a runaway feedback loop - but rather it shifts the medium-term equilibrium level.

My understanding, using purely hypothetical numbers:
We have an equilibrium temperature at 20,000ppm H2O, and 280ppm CO2.

If we increase CO2 to 400ppm we cause warming of 1 degree to a new equilibrium level.

This leads to increased H2O levels (as a warmer atmosphere can contain more water vapour), and further warming, until a new equilibrium level is reached - say a further 1 degree at 20,200ppm H2O.

This means that the end result of the increase in CO2 levels is a new equilibrium temperature of +2 degrees.

This isn't a claim that "H2O feedbacks itself", it just pointing out that the equilibrium temperature brought about by increasing CO2 levels needs to account for the increase in H2O levels that accompany the initial rise in temperatures.

Mark Wadsworth said...

TL, the 1C is almost certainly an exaggeration to start with. So it increases H2O short term, it just pushed H2O towards saturation point, and we either gets clouds or rain, which cool it down again. In the real world, it's negative feedback, albeit only very slight.

Dinero said...

Saturn and stars google search , had no mechanism of pressure itself causing temperature rise. What mechanism are we left with.
Regarding the ideal gas law, rearranged for temperature, T=(PV)/(nR). when V decreases, P increases and so the Temperature stays unchanged. Volume decreased and Pressure increased.

Mark Wadsworth said...



"The outer edges of Jupiter’s atmosphere are much cooler than the core region. Temperatures in the atmosphere are thought to be as cold as -145 degrees C.

The intense pressure on Jupiter contributes to temperature increases as you descend. Not far into the atmosphere the pressure can be ten times what it is here on Earth and scientists speculate that the temperature is 20 degrees C(average room temperature on Earth).

A few hundred km deeper into the planet and hydrogen becomes hot enough to turn into a liquid."

This is widely known and accepted. I'm surprised anybody would question it.

Dinero said...

It may be often repeated but if it is directly equating temperature to pressure it is just plain wrong. Look at the Gas Law for yourself. PV=nRT .Compared to an uncompressed gas , a compressed gas has a smaller volume a higher pressure and the same temperature. PV=nRT.

Mark Wadsworth said...

Din, don't argue with me. Go and chat to a physics professor and explain to him why Jupiter must be cold in the middle.

Bayard said...

Theo L, Feedback: If the Earth gets warmer, and there's more H2O in the atmosphere (uncontentious fact: the warmer the air, the more H2O it can hold) there should be a greater greenhouse effect, causing even more warming and a greater greenhouse effect until the entire earth is like a tropical rain forest, hot and humid. That this doesn't happen shows that there is no simple positive feedback effect, the mechanism is more complicated than that. However the infra red radiation doesn't know what it's hitting, so it can't tell the difference between one greenhouse gas and another (setting aside the fact that H2O absorbs a greater range of the IR spectrum than CO2). So it really doesn't matter what causes the Earth to warm, whether it be H2O or CO2 and the "greenhouse effect" or solar radiation, there is going to be no secondary warming, nor certainly any runaway warming, because if this was going to occur, it would have already happened, as soon as things started to get warmer after the Little Ice Age.

Bayard said...

Din, this isn't about the gas laws, they don't apply to steady state situations, this is some other effect.