BBC: Forget CO2 – Here Is the Real Cause of Climate Change

The movie has this, that, and some other things wrong with it.

In places I wish they had made the wording more precise.

For some of the political parts, they descended into, say, the style of just news reporting, e.g., the parts on Africa. Maybe the African claims are true, maybe less than fully true.

The evidence presented in the graphs was really easy to understand and, for a movie, well done. But for science, the graphs had some biggie problems, e.g., didn't make clear the units on the vertical axes.

In the Wiki piece, Carl Wunsch was not happy. Apparently about all he was unhappy about was what he took as an implication from the placement of his interview. I'd tell him to calm down -- his point was that the oceans have one heck of a store of CO2 and take in CO2 when cool and expel it when warm. Okay -- interesting.

His claim that with warming the CO2 expelled would be dangerous seems to need more details since no doubt at times in the past the oceans have been significantly warmer than now. In that case, the oceans expelled CO2. Then, how much CO2? What were the effects?

The movie essentially claims that CO2 in the atmosphere has at most a trivial warming effect and that the CO2 from human activities is such a small fraction of the total compared with CO2 from volcanoes and biological activity that it is just trivial. They did give some numbers, but more numbers presented more carefully would be welcome.

The biggies for me were:

(1) In the Vostok data, the CO2 rose 800 years after the temperature rose -- same for going down. So, CO2 didn't cause the temperature; instead something else caused the temperature (the movie claims sub spots) and the temperature caused the CO2. Seems pretty solid.

(2) Since year 1000, through The Little Ice Age and during the cooling from 1940 to 1975 or wherever it was, I could take seriously the sun spot explanation and not believe the CO2 explanation.

For cosmic rays going back hundreds of thousands or millions of years, they were not clear on just how they measured that. We have suspect some isotopes and their decay products. It would have been better to have been clear on that.

For me, the main point was that CO2 is essentially irrelevant. That's important. That the sun spots make a better explanation is clear from the graphs, but that stuff about the solar wind blocking the cosmic rays that would create water droplets and, thus, clouds could use a lot of detail.

Also, for people who do understand the greenhouse effect, their presentation was maybe correct if put a lot of weight on just one word they used at one point, but, really, their graph missed a biggie point: The visible sun light can reach the ground and heat it, and, then, the ground radiates like a Planck black body in the infrared, and it's that infrared that CO2 can absorb. That is, the CO2 can't absorb the visible. E.g., to see this, just exhale and observe that the CO2 is invisible. But it's not invisible in the infrared. That is, if look at their diagram, one could ask how the light was able to get through the atmosphere and to the ground but, then, bounce off the ground and get captured by CO2 on the way out? Well, the light didn't really bounce off the ground. Instead the visible light warmed the ground which radiated in the infrared. Okay.

My ugrad physics prof was big on infrared radiography, and I took his course. Arguing the details of the greenhouse effect could be a lot of work. Given that the CO2 levels don't fit the temperature levels well, to heck with working so hard on those details.

The Wunsch remark does seem to lead to a clarification of the rising CO2 concentration: That is, since CO2 from humans is such a tiny fraction of CO2 sources, how come more human activity has led to significantly higher levels of CO2? Well, apparently the answer would be that the warming was caused by sun spots; the ocean warmed; and CO2 was not from humans but from the warmer ocean. Some numbers would be nice to have.

It's is good to see an explanation that doesn't require us to solve the Navier-Stokes equations each picosecond for each cubic nanometer for decades into the future!

At this point, an awful lot of people for various reasons will have a heck of a time accepting that CO2 has nothing to do with climate change and then a harder time accepting that sun spots are really the answer, from the present, going way back, millions of years. But the issue is very important.