Sunday, 6 August 2017

How I became a climate skeptic.

Once upon a time, about 4 years ago, I was a climate believer. I believed the mainstream (IPCC) projections for climate change, and blamed most of it on carbon dioxide.

It seemed reasonable to decarbonize the energy system. I became a bit of a nuclear power advocate. I read books on nukes. I did introductory online courses on nuclear power. I noticed how the energy issue was totally partisan and divided right down the middle.

On one side were pro-nukes, on the other side the 'greens'. The greens were united along several lines. They:

  • opposed nuclear power
  • supported green issues
  • worried about global warming
  • were keen to reduce human energy use

For them, the debate was not about saving the planet by stopping carbon dioxide emissions. It was about saving the planet from the scourge of humanity.

The other side: pro-nukes was split. It included eco-modernists, conservatives, nuclear industry people, liberals and lefties.

I could not help notice that the news sources worrying about climate change were doing two things:

  1. opposing nuclear power
  2. greatly exaggerating climate change effects, and engaging in a little war against people they called 'deniers'.

Early on, I wanted nothing to do with any of these 'deniers'. They were right wing. They must be wrong. Right?

It slowly dawned on me that the only reasonable people refuting this climate alarmism in the news sources were the 'deniers'. What about all the reasonable people - those who accepted the mainstream IPCC analysis? Where were they in this debate? How come they weren't refuting the obvious over-exaggerations in the media?

The answer is that the 'mainstream' believe the establishment can only be goaded into action by exaggeration. So they stand by and let the hard-core green movement exaggerate. That was my first wake up call. My second wake up call came when I noticed the greens blaming global warming on nuclear power. What kind of good, ethically upright person, has any truck with that kind of politics. No me. That's the point when my pro-humanism kicked in and I dared to think the unthinkable. What if carbon dioxide was not much at fault for climate change? Then I looked at the evidence. The more evidence I looked at, the longer the term for the evidence: thousands, and even millions of years - the more I too turned into a 'denier' too. I have to call myself a skeptic.

I think CO2 has some effect on climate. I think it should warm climate mildly, but only a quarter to a third what IPCC say. I expect 0.6C per doubling of CO2. Q: What about the warming which has already happened? I hear you say. Surely that proves CO2 guilty? A: No.

  • Because we've seen no real warming for 18 years now. If it's 90% the fault of CO2, there cannot be a hiatus, but there is.
  • When you tell me what caused the Medieval Warm Period, then I'll believe there's such a thing as climate science. Till then it's climatology again.

Saturday, 5 August 2017

Greenhouse gas effect (GHGE) is overwhelmingly caused by water vapour. Not carbon dioxide.

Claim: The greenhouse gas effect (GHGE) is overwhelmingly caused by water vapour. Not carbon dioxide.

The current "consensus" says: the GHGE is very important at the equator (so climate models say). Approximately between +20º and -20º latitude. This extra heat 'trapped there' rises and settles down at the poles thereby warming the planet. This extra trapped heat is due to more CO2 from burning fossil fuels. Models say 24% of the GHGE is due to CO2. That about 72% is due to water and ~ 4% to other gases (mostly Ozone).

Let us move away from assumptions and models (alarmism) to basic science (below), which no one can dispute:

  1. The sun angle controls water vapour content of the atmosphere. So the atmosphere in the equatorial zone is 80× to 90× more H2O than CO2. [see diagram below]
  2. Water is a much more powerful GHG than CO2 because the bonds in water have far more degrees of freedom so can undergo far more electron bond transitions. It's these bond transitions which cause infrared (IR) radiation absorption. CO2 can only absorb IR at 3 frequencies. Water absorbs at dozens of frequencies.
  3. A plot of GHG forcing against water vapour in the atmosphere shows "the upper limit to the back radiation of GHGs is approximately 420 W/m² at water vapour concentration of approximately 32,000 ppmv, or an H2O/CO2 ratio of 80:1; (2) the lowest back radiation is 97 W/m² at the South Pole" where the ratio H2O:CO2 is 1:1.

This Is The Clincher:

Consider at the South pole where CO2:H2O is 1:1 and GHGE = 97W/m². If that is 24% due to CO2, it means CO2 effect = 23W/m² (at the poles). Moving on to the equator: CO2 is well-mixed so it's also 23W/m² out of 420 W/m² there. That means only 5.5% of GHGE at equator (where it really matters) is due to CO2.

The GHGE is said to be responsible for warming the climate by 33ºC above what it would be with no GHGE. From -18ºC to +15ºC. (Averaged). The US state of North Carolina has an average temperature of about 15.3ºC. NC is located latitude 33° 50' N to 36° 35' N. On Average that's 34.2 °N Let's treat it as the average place on Earth. Assume the ratio of H2O to CO2 = 34:1 there. Implying GHGE ~ 345 W/m². Subtract the part due to CO2 then it is 345 -23 = 322 W/m² due to H2O and O3.

What's the maximum CO2 GHGE?

Let us do a basic maths back of the envelope calculation to give us a maximum for the CO2 GHGE. It can not be more than half of the polar effect. Because even at the poles there's as much water in the atmosphere as CO2, and water is a more powerful GHG [see the last diagram below for a comparison of water and carbon dioxide GHGE]. Let's say the upper limit of the CO2 GHGE is 33% (at the poles) = 33 W/m². Let's count squares in the diagram above. 7 × 33 ÷ 50 = 4.62 squares show CO2 GHGE. The diagram has ~ 49 squares. 4.62 ÷ 49 = 9.5%. That puts an upper limit on the CO2 GHGE of 9.5%. 9.5% of 33ºC = 3.1ºC. (given earth's surface is 33ºC warmer than it would be with not GHGE.)

Remember how the effect of more CO2 tails off logarithmically?

So the CO2 GHGE is already nearly maxed out at about 3.1ºC, and most of that was due to the first 20ppm of CO2 in that atmosphere. Doubling CO2, from 280ppm to 560ppm does not double the effect. It only increases by a fraction of a degree.