I've been talking with a friend and essentially the argument goes that limiting growth today (sacrificing GDP) instead of saving it at a higher discount rate over, say 60-100 years when the discount rate will lead to a significantly higher return on saved money, then most of these prognostications will come to fruition is better than sacrificing current GDP growth and then tackling the problem of climate change in the future. — Question
Your friend has zero reasons to be confident in his economic predictions for 60-100 years hence. I know nothing about your friend; he might be a genius, but he still doesn't know what is going to happen economically in 100 years. Nobody else does either. I personally would not bank on such advice.
Go back to 1917 and ask yourself, what predictions in 1917 bearing directly on the economy have proved true in the intervening century? Nobody predicted the great depression, World War II (or any subsequent war); nobody predicted the immense importance of radio or automobiles or TV to the economy; nobody anticipated the manned landing on the moon or the absurdly expensive and wasteful Star Wars initiative of the Reagan Administration; nobody predicted antibiotics, the elimination of smallpox or polio, the 1918 worldwide influenza epidemic (only 1 year later) that killed between 20 and 40 million people in about a year. Nobody predicted AIDS, Ebola, or Zika either.
The human ecology and human economy is far more complicated than global weather. The range of predictions about global warming or climate change, whatever term you like better, is based on comparatively straightforward climate models which are based on physics, chemistry, and accumulated data. It's much easier to confidently predict what will happen to climate over 50 years with a doubling of CO2 methane in the atmosphere than it is to say what GDP will be 25 years from now.
You know, the Great Recession of 2008 was not predicted 15 minutes before it began.
Another point worth mentioning is if coal and natural gas, which are the cheapest available sources of power are abundant, then we ought to utilize them to achieve the maximum amount of growth possible. Then, when the resources run out or there are other cheaper options, then move onto utilizing those options. — Question
Have you learned nothing about the real world?
Look, at the time of the carboniferous epoch (359.2 to 299 million years ago) the world was very warm and humid and had high levels of CO2 in the atmosphere. The ancient forests, and animal life of the swampy world died, were buried, and locked up a lot of the excess CO2. It became coal, oil, and gas.
250 years ago we all started digging up all this sequestered carbon and burned it for various purposes. We've dug up a good share of the coal, sucked up even more of the oil, and have tapped a lot of the natural gas. All of the carbon we dug up and burned became the CO2 that is causing the planet to rapidly warm up. That's what CO2 does.
A lousy 2ºC is no crisis you say. It is, because the amount of CO2 that it takes to warm up the earth that much will be
very hard to remove. As we continue to add CO2, even at an decreased rate, the climate will continue to warm. At 2ºC increase, serious climate and weather problems start to ensue.
Why? Physics and chemistry again. Put a lot more energy into the atmosphere and the result will be more extreme weather, more erratic weather, and worse.
So, Question, we can be much more sure of negative climate developments than we can of beneficial economic developments.