David R. Henderson  

Cook vs. Cass on Global Warming

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I wouldn't have even noticed the National Review debate between Oren Cass and John Cook, if a creepily worded article title at Vox hadn't caught my attention. The title: "Scientists are testing a 'vaccine' against climate change denial." The author is Michelle Nijhuis. It would be bad enough for someone to have an actual vaccine against denial of anything. One thing makes the article less creepy than the title: Ms. Nijhuis is not referring to an actual vaccine but to a way of arguing that reduces people's defenses. One thing, though, makes the article more creepy. She doesn't seem to distinguish between climate change denial and disagreement with specific claims about climate change. So it seems that, if she had her way, she would have people on her side of the issue use the "vaccine" on anyone who doesn't agree with some of the most extreme proponents: those who think humans are causing 100 percent of global warming.

Why do I make that last claim? Because she approvingly cites John Cook, whom I have posted about earlier, as someone who uses the vaccine. And the item she cites by Cook is his claim that 100% of global warming is caused by humans. Cook writes:

There is a consensus of evidence that human activity is causing all of recent global warming. Not some of it. Not even most of it. All of it.

I would give you the blow by blow, but it's more edifying if you read the debate in order: first Cass, then Cook, then Cass.

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COMMENTS (15 to date)
Aaron W writes:

I find this particular debate on this issue to be extremely mind numbing. Regardless if humans are causing most or all of climate change, the current science is that humans are extremely likely (99%) to be the dominant cause of climate change. Whether the current amount caused by humans is 75% or 100% not particularly illuminating in terms of thinking of possible cost-effective solutions (if any exist.) Even if that number were say 70% today, as humans emit more greenhouse gases, their "responsibility" for the problem will grow.

I think the issue is that the proponents of "doing something" perceive that saying "humans are not causing all of it!" is a dodge to avoid accepting certain public policy interventions. In some cases, their suspicion is not entirely unfounded, either. A better way to engage would be to talk about the costs versus the benefits of particular public policies.

In my mind, something like a carbon tax (or any of the myriad equivalents) is preferable to ham-fisted regulations or nothing at all; however, it still is woefully inadequate to actually addressing the issue. Huge breakthroughs are required in basic research fields in any of the following: battery materials, fuel cells, solar fuels, biofuels, nuclear, etc. Furthermore, entrepreneurs and businesses need a free hand to get such technologies to commercial stages. Here, I think those on the right could offer a valuable perspective on addressing climate change that would be a much more viable and workable alternative than a mere carbon tax. Instead, though, we're stuck in a debate about whether humans are causing 70% or 100% of climate change that in reality will never be resolved by science.

Marc writes:

I also find it mind-numbing. Cass seems to be arguing that Cook is ignoring consensus by stating that 100% of climate change is human caused, when the consensus never addressed those positions, and then using that to cast doubt on the actual consensus. Cook corrects his impression of the actual consensus numbers, and then shows where the studies that estimate the percentage of natural and human global warming components, and he is right--no one is showing any significant natural contributions that can explain the available data on global warming. Cass' response? Going back to the 97% consensus number and much older data. At the end, I find Cass demonstrating, ironically, many of the five elements of denialism Cook speaks about as he attacks Gook. I find this sort of thing one of the main reasons why I believe National Review has lost all credibility in the global warming debate. The questions of science are not best debated or reported in a journal with a political axe to grind, and Cass illustrates that with spades.

And to amplify what Aaron is saying above: if you focus on the consensus exact numbers and use it to dodge the hard debate, you are using denialism, obstructionism, and abdicating your place at the table when it comes down to arguing for solutions that are more politically palatable. Which is a shame, because there are certainly free market components of potential solutions to the AGW-related issues, but if the Right spends all of its time denying instead of debating the policy merits, we all suffer.

Radford Neal writes:

Debating what fraction of recent warming is due to human activity is absurd, for several reasons:

1) Humans engage in all sorts of activities. Knowing that humans are responsible isn't specific enough.

2) The amount of recent warming is uncertain. Two people could agree that 100% of recent warming is due to human activity, but disagree quite a bit on how much the earth has warmed due to human activity, which is what matters.

3) The fraction of recent warming due to human activity is going to be quite sensitive to the definition of "recent".

Regarding point (3), it is pretty obvious from looking at the data that there is substantial natural variability in temperatures, on scales of a decade or more. Considering that points (1) and (2) above make saying "100% of recent warming is due to humans" pretty pointless, the obvious conclusion is that the people who say this, rather than something more meaningful, are trying to deceptively imply that natural variability is negligible.

MikeP writes:

When I engage in the climate change debate, I accept for the sake of argument the IPCC statement of the scientific consensus as far as global warming and the effect of humans on warming are concerned. While they don't say it's certainly 100% human caused, I am fine accepting that it's 100%.

I don't argue the science because the economic case for extensive government enforced subsidies, mandates, or taxes to solve climate change is so phenomenally weak.

Pay attention to the economic thinking of those upset by Trump ripping up the piece of paper Obama signed in Paris. It is fraught with fallacy, models that find gains in redistribution solely due to propensity to consume, and outright Marxism at the far end.

When serious economists such as William Nordhaus do the full studies, they find that the optimal carbon tax does yield the greatest net benefit, but that it is only a modest improvement over delaying 50 years before the optimal tax or indeed over doing nothing. More importantly, these studies find that targeting CO2 levels or temperatures costs far more than it benefits.

But what does the Paris Accord target? A temperature. And those who support it have absolutely no concept of how much their parochial desire for that temperature will cost their grandchildren -- and especially the developing world's grandchildren.

So, yes, I find fighting over scraps of scientific claims to be damaging, giving ammunition to the activists that they then use to paint more people deniers.

Andrew_FL writes:
Whether the current amount caused by humans is 75% or 100% not particularly illuminating in terms of thinking of possible cost-effective solutions (if any exist.)

You're missing some steps here. You've leapt from "70%" to "solutions" without skipping a beat.

Mark Bahner writes:
But what does the Paris Accord target? A temperature.

It's important to understand that implementing the Paris Agreement will not result in the world meeting any of the temperature targets of the Paris Agreement (i.e. below 2 degrees Celsius warming from pre-industrial temperature, and hopefully 1.5 degrees Celsius warming from pre-industrial temperature).

In fact, it's a very defensible statement that there is nothing realistic that humanity can do at this point to keep the global average surface temperature below 1.5 degrees above the pre-industrial average temperature.

P.S. The reason this is important is that people are mistaken if they think those who worked on the Paris Agreement will be satisfied if Paris Agreement targets are met.

Roger McKinney writes:

Anyone can google it and find out that humans only contribute 5% of all new CO2. Besides, CO2 is the least damaging greenhouse gas. Water vapor and methane are much greater problems and humans have little to do with either.

I first got interested in global warming in the late 1980s when it was a real science and people could debate it. There was no consensus. Then in the 1990s a97% consensus appeared even though none of the facts had changed. It became clear that socialists had hijacked the issue. Recently I read Robert Heilbroner the economist who lamented the collapse of communism in the USSR and Eastern Europe. He wrote that socialists had lost the economic debate and the future for them was in the environment.

IronSig writes:

Roger Care to point the directions to your Google sources?

Sean writes:

david's global warming opinions seem to be based on a combination of mood affiliation (progressives believe one thing, must be wrong) and results based reasoning (one belief leads to opposing taxes, i guess that must be the correct one then).

every climate related post here reduces the credibility of all his other more reasonable posts.

Procrustes writes:

So, Sean, you write that "every climate related post here reduces the credibility" reduces David's credibility.

From that, does that mean you consider that the statement that humans are causing 100% of global warming is credible? And that anyone who disagrees should be metaphorically vaccinated or labelled a denier?

Mark Bahner writes:
From that, does that mean you consider that the statement that humans are causing 100% of global warming is credible?

That humans are causing 100% of "recent" warming--roughly, warming since the middle of the 20th century--is not merely credible, it represents mainstream scientific thinking. That is, mainstream scientific thinking now is that, absent human influences, the average global temperature would actually have decreased since the middle of the 20th century.

MikeP writes:

Anyone can google it and find out that humans only contribute 5% of all new CO2. Besides, CO2 is the least damaging greenhouse gas. Water vapor and methane are much greater problems and humans have little to do with either.

The 5% may or may not be true, but it is certainly no refutation of climate science. If the current natural mechanisms for converting CO2 to O2 or new carbonates balance out 95% of the "new" CO2, but not 100% of the "new" CO2, then humans are causing an increase of CO2 in the atmosphere.

And as far as the damage from CO2 goes, the theorized mechanism of warming is that slight increases due to increased CO2 result in more water vapor in the atmosphere, and that water vapor causes the actually interesting warming. Yes, increased water vapor means increased clouds, and clouds have both warming and cooling effects that are poorly modeled. But CO2 being a minor contributor to warming is again not a refutation.

Jeff writes:

My admittedly limited understanding of most of the climate models is that the direct effect of CO2 on temperature is logarithmic. This means that if doubling the CO2 concentration from the 270 ppm (parts per million) concentration it was at before the Industrial Revolution to 540 ppm resulted in a 2 deg C temperature rise, you'd have to double it again to 1080 ppm to get an additional 2 deg C rise. Currently we are thought by many to be approaching peak fossil fuel burning, and the concentration is around 410 ppm.

That doesn't sound very scary. Why then are people so exercised about CO2? It's because they assume in their models that there are other positive feedback effects that amplify the warming that started with higher CO2. Clouds are the most important one. No one doubts that warmer temperatures mean more water evaporation and presumably more clouds. But what kind of clouds and how they circulate within the atmosphere could mean that more clouds either cool the Earth by reflecting away solar radiation, or they might warm the Earth by blocking some of the heat that would otherwise radiate away at night. Some of the skeptics think the climate models have the wrong sign on the water vapor effect. If they're right, we really don't have much to worry about.

Models with strong positive feedback effects predict that small peturbations away from equilibrium have explosive effects. But the Earth has seen much higher CO2 concentrations than we're seeing now, and the system didn't blow up then. If there are all these positive feedbacks just lying in wait for us, why hasn't Doomsday arrived already? How has life on Earth survived all these millenia? Isn't it far more likely that the climate is actually inherently stable?

Dale Courtney writes:

Back in 2009, NRO columnist Kevin Williamson broke down the global warming claims as follows:

"The planet is getting warmer, human activity is a main factor, the consequences will be catastrophic, and some U.N.-style climate policeman is going to be able to manage a mitigating response — in an economically efficient manner that also is consistent with our political liberties and national sovereignties."

He said that we need to divide the issues (and that paragraph) up into what we agree with:
1. The planet is getting warmer
2. Human Activity is the main factor
3. The consequences will be catastrophic
4. UN climate cops are going to be able to manage the mitigating responses
5. That will be done in an economically and efficient manner
6. That will be done without violating our political liberties and national sovereignty.

The Paris Agreement forces us to swallow that entire paragraph whole.

Does anyone actually believe that Paris will accomplish steps 4-6? And at what cost to us?

Mark Bahner writes:
Currently we are thought by many to be approaching peak fossil fuel burning...

The problem is that the scientific community has systematically hidden this fact--that we are approaching peak fossil fuel burning--from the public.

The IPCC has various Reference Concentration Pathways (RCPs) of which they describe RCP8.5 as "business as usual." This is despite the fact that RCP8.5 has CO2 emissions rising throughout the 21st century, to nonsensical levels.

It's amazing to me how many people naively think that the IPCC actually cares about science, or claim without evidence that climate science is self-correcting.

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