>> "Projecting forward 20 years that means that we expect gross world product to
>> increase 84%. If we go carbon neutral and the final gross world product ends up at
>> 2% less than this simple projection, it grows about 80.5% instead. Thus we'd
>> reduce the amount of total growth by about 4%."
>
> Hold on, that sounds nothing like what you originally said. I quote, "Spending
> about 2% of current world domestic product on CO2 mitigation seems perfectly
> justifiable to me."

They match perfectly, but you may have misunderstood what I was saying.

Several different studies have concluded that the cost of going carbon neutral would result in dropping future world domestic product by $1 trillion/year. As the world grows, it is reasonable to assume that that trillion grows in proportion. We would therefore suffer a permanent loss of 2% of production, on which you can superimpose otherwise normal growth curves. So contrary to your repeated claim that I want to have my cake and eat it too, I'm talking about a large, ongoing economic hit. However it is a small fraction of global product, and the hit is small relative to ongoing growth rates.

>> Thus we'd reduce the amount of total growth by about 4%. Take a 20th power and we
>> find that the amount of growth in the end is reduced by a factor of 0.2% per year,
>> compounding annually. Note that when I say 0.2% I don't mean that it would be 2.9%
>> instead of 3.1%. Instead I mean that it would be 3.0934..% instead of 3.1%.
>
> I don't follow your calculations here. When I plug in 3.09% into a compound
> interest calculator instead of 3.1%, after 20 years I get the same 184% answer. If you
> suggest we can have our cake & eat it too, I suspect your math is screwy somewhere...

I could have messed up, let's to the math together.

Through this decade growth has averaged 3.1%/year. So every year we have 1.031 times as much stuff produced as the previous year. 1.031^20 is 1.84150671005791. So in 20 years I'd expect us to see 84% growth in production. If we multiply that by 0.98 to account for the cost of mitigating global warming, we wind up with about 1.80467657585675 times as much production as today instead. When I take a 20th root of that I get 1.02995907626323. So we lost about 0.001% of growth/year, compounding annually. That is about 3 percent of annual growth lost.

Oops, I definitely did have a calculation error. Thanks for keeping me honest. However you can still see that, relative to overall growth, we're talking fairly small numbers.

Another way to look at it is how far behind we are timewise. And the answer is that at 3.1% growth we'll grow 2% in about 8 months. So in 20 years and 8 months with CO2 mitigation our production will be about what it would have been in 20 years without. Again a difference, but not that significant of one in the grand scheme of things.

Moving on, you're quoting figures from the IPCC about temperature and crop yields. Those figures say that in the middle of the projections for where we are a century from now, crop yields are likely to decrease. Furthermore we're not just talking higher temperatures. We're also talking changing weather patterns, which likely means increased drought in most mid-latitude areas. You might want to ask some of the farmers in California how drought is helping their crop yields these days, if you can find any in business. (Yeah, I know, there is also a court case feeding into that. But according to the climate models that business would have had to go away in the end anyways.)

(Skims forward.) I think you're underestimating the economic and lasting effects of war.

Ah yes, the pollution item. Carbon sequestration is popular because it doesn't harm any vested interests. However it has never been proven on a large scale, and current estimates have solar and wind being cheaper. If you generate the power on the grid with solar and wind, then replace cars with electric vehicles, it is amazing how much air pollution goes away.

Now you may say that electric vehicles aren't going to be adopted. If you think that, go read The Innovator's Dilemma and its follow-up The Innovator's Solution. One of the case studies is the car industry. Based on technology curves the prediction in the mid-90s was that hybrids would be brought out in this decade, and electric cars would become fully competitive with old cars around 2020 or so. Those curves have continued to hold, and so - even without any government intervention - the likely widespread adoption of electric cars is about a decade or so off. Therefore planning on that future isn't exactly pie in the sky dreaming.

(Reads further.)

Well your comment about not valuing millions of poor people very much speaks volumes about your ethical system. Likewise I'm guessing you don't really care about details like mass extinctions in the oceans. With such a big gulf in our mattering maps we're not going to see eye to eye on a lot of big topics.