Global Warming: An Inconvenient History

This is a well-balanced history lesson. 

It has taken 140 years for the average atmospheric temperature to go up 1 degree Celsius. It is going to take 5,000 more years for the polar ice caps to melt, but by the year 2100 we will run out of most fossil fuels, at which point a 2 to 3-degree increase in temperature might be mildly inconvenient for some, but it is not a global disaster. Humans are adaptable, and the proposed solutions are far more damaging. Getting rid of fossil fuels now, as some have proposed, will have a huge negative economic impact, especially on the poor. So-called renewables are inefficient and have huge environmental impacts of their own. By the time we run out of fossil fuels, we probably will have nuclear fusion which will solve most of our energy problems.

Something funny happens with the climate roughly every 100,000 years. Due to the Milankovich cycles which affect Earth's orbit, we get an 8 to 15-degree spike in temperature followed by a 10 to 15-thousand-year warm period, which is then followed by a rapid decline in temperature and at least 85,000 years of mass glaciation. New York gets covered by a mile of ice. The "normal" state is very cold and all of human civilization arose during a brief 12,000-year warm period since the last cold period. During these 12,000 years, the planet Earth has gone from its maximum tilt, which melts glaciers, to halfway toward its minimum tilt, which will produce the next period of glaciation. We should already be in the cool-down cycle, except for those pesky humans who have warmed the planet a little bit. The preindustrial period from 1500 to 1850 was unusually cold and is labeled "the little ice age." 

Atmospheric CO2 has been in a steep decline for about 40 million years. Calcifying marine organisms are sequestering the carbon at the bottom of the sea. It got so low during the last period of glaciation that it was close to the level where all terrestrial plants would die from CO2 starvation. Sometime in the distant future, we are going to have to put CO2 back into the atmosphere to either prevent the next mass glaciation or to support plant life. We can do this with lime.  

"We are not the enemy of Nature, but its Salvation.." - Patrick Moore.