> For example, the greenhouse effect is a piece of well-established science. Climate change is even less scientific. To what extent humans contribute to the problem is even less scientific.

I've run into conservatives who believe that, and invariably it turns out they have only looked at a small part of the evidence.

For example, they might dismiss the extent of human contribution to rising CO2 levels as mere correlation, claiming that scientists are just noting that the CO2 curve matches some other human activities and are assuming that those activities are responsible for the CO2. Maybe it is just coincidence and the rising atmospheric CO2 comes from natural sources.

If that was all scientists had, that would be a good point. But that isn't all scientists have. CO2 from burning fossil fuels has a different isotopic composition that CO2 from natural sources so scientists can directly distinguish "our" CO2 from "natural" CO2.

Then there is atmospheric oxygen levels. Burning fossil fuels should not only release CO2 into the atmosphere. It should also take oxygen from the atmosphere. Guess what? The atmospheric oxygen levels have been doing just what they should be doing if scientists are right about how much of the atmospheric CO2 comes from us.

The point is that the questions I outlined become increasingly less scientific. There are genuine scientific questions, but there are lots of others that are kind-of scientific, and others that are not scientific at all.

Climate activists won't admit that.

This shuts down the possibility for a reasonable discussion because one party (the activists) is overwhelmingly guilty of acting and arguing in bad faith.

What does it mean to be less scientific?

For instance, I believe that there are fewer experiments that confirm general relativity than there are that confirm quantum mechanics, so does that mean GR is less scientific than QM?

Does this mean GR-skeptics are on firm scientific ground? No, it does not. The evidence for GR is overwhelming. That QM may have even more evidence does not cast doubt on GR. Both GR and QM have overwhelming evidence, and there is no meaningful sense in which one can say that one is less scientific than the other.

> This shuts down the possibility for a reasonable discussion because one party (the activists) is overwhelmingly guilty of acting and arguing in bad faith

No, what shuts down the possibility for reasonable discussion is people discarding 90% of the experiments and measurements, and then claiming that there is no evidence. It's not the activists that are doing this.

When you start to enter the realm of modelling, especially of complex systems with feedback loops, you aren't really conducting science any more.

Unfortunately the brand of science is used to promote these models, which is disingenuous. These models aren't like physics models, they are like economic models.

Unlike economic models, however, the climate systems have boundary conditions and underlying assumptions based on real science -- physics.

> What does it mean to be less scientific?

I'm not a fan of the "less scientific" phrasing, but the point of science is to be convincing to even a skeptic. That's why reproducibility (try it yourself in your own lab!), statistical analysis (there's basically no chance this is a coincidence!), control groups (it's not just an endemic property of the lab), random sampling (it's not selection bias) and other things are so important.

In some kinds of inquiry, it becomes difficult or impossible to apply certain standards. It's flat out unethical and immoral to not treat a man's syphilis just to have better quality evidence. So if you're studying syphilis, you need to find other ways to be convincing. It's impossible to have a statistically significant sample of Earths or a control group of Earths, so the bar for convincing is also higher in climate science.

"Less scientific" probably means "doesn't have access to many standard scientific techniques, so stronger evidence in other ways is essential to be convincing".

Wait, no, it's not "the point of science" to be "convincing to even a skeptic". Scientific reasoning is not a vote, or a talent show.

> Scientific reasoning is not a vote, or a talent show.

Sure it is. It evolved from "natural philosophers" showing off their work to each other. People have always been able to convince themselves of things, but scientific rigor is about convincing other people (i.e., being objective).

The hallmark of scientific objectivity is not convincing other people, but making correct (and testable) statements about reality.

Why is testability important? How do we know if something is correct?

The point is to be convincing to a rational mind. It's not a persuasion contest, no. The evidence should speak for itself. But it needs to speak to an audience.

Otherwise it would be a self indulgent exercise and not a corporate one.

So far I have yet to see a climate change denier who has looked at any of the IPCC reports [0] -- they operate on the same scale of evidence as religious fanatics. It was actually fascinating to see the improvement comparing AR5 with the AR4, and they are only 6 years apart!

>For example, the greenhouse effect is a piece of well-established science. Climate change is even less scientific.

Even looking at this sentence, which is the foundation of your arguments, the way you express yourself is that the greenhouse effect itself is not scientific! The actual science part of climate change is actually pretty great science, and very much scientific. You can check out the physical science IPCC report [1] for the starters. It contains many references to actual scientific articles, but by itself is a great piece of work.

The political part -- policies, denial of facts, media coverage, bribery by the fossil fuel industry representatives and continuous slander of climatic researchers is a problem, I agree.

[0] -- Here's the IPCC Synthesis report, a short summary, for starters: http://ipcc.ch/report/ar5/syr/

[1] -- IPCC Physical science report: http://ipcc.ch/report/ar5/wg1/

It's a question of risk mitigation. Would you say that a 5% risk of humans going extinct it worth it, for an oil company to collect an extra $50 billion in profits?

I would say no. An oil CEO might say yes.

Who should have a bigger say in public policy, the civilians facing the 5% possibility of human extinction and no extra paycheck, or the oil CEO weighing their paycheck against possible human extinction?

The current head of the EPA clearly thinks oil industry profits are more important. Trump clearly thinks oil industry profits are more important.

It's _not_ just about an oil CEO. It's about everyone who uses energy. Gas tends to be a high percentage of poor people's cost-of-living, and cheap oil tends to act as a progressive reverse-tax. In cold climates, heating one's house is also closely linked to energy prices.

When you hamper the economy, everyone loses a little. It weakens wealth creation slightly.

We're at a moment in history where we're pulling people out of poverty, through economic growth. So any actions that limit economic growth need to be judged with a high bar. https://www.economist.com/news/leaders/21578665-nearly-1-bil...

I'm not saying that we shouldn't do it, and if it is actually a 5% catastrophic risk then I think it would be prudent to take action at the cost of leaving millions of people in extreme poverty. But there is a trade-off, and it needs to be examined.

Your worries about the economy are purely hypothetical, and most likely wrong. Infrastructure spending generally stimulates economies and there is no reason to suspect that building clean energy infrastructure will be any different. Additionally, clean energy prices will most likely be cheaper and more stable in the long term due to decreased maintenance costs and lack of dependency on energy inputs from politically volatile regions.

And even if energy prices rise slightly, the reduction of externalities will more than make up for those increased costs. It is well known that pollution from fossil fuels causes a variety of health issues. I would gladly pay a few more cents per kwh if it reduces my chances of getting cancer or heart disease.

The chance that anthropogenic climate change will lead to human extinction is much less than 5%. There just isn't any plausible mechanism for this. The one exception is extinction due to climate change triggering a war in which extinction-causing biological weapons are used. Unfortunately for risk mitigators, the chances are about equal that such a war would be cause by an economic collapse resulting from attempts to prevent climate change.