When Too Little CO2 Nearly Doomed Humanity
Dennis Avery
Posted: Jun 04, 2017 12:01 AM

Aside from the expected protests of Al Gore and Leonard Di Caprio, the public didn’t seem to raise its CO2 anguish much above the Russians-election frenzy the media already had going. Statistician Bjorn Lomborg has already pointed out that the Paris CO2 emissions cuts would make only a 0.05 degree C difference in earth’s 2100 AD temperature. And that’s in the unlikely event that all parties actually kept their pledges.

During the last Ice Age, however, too little CO2 in the air almost eradicated mankind. That’s when the much-colder water in the oceans sucked most of the CO2 from the air. There were only about 180 parts per million in the atmosphere, compared to today’s 400 ppm.

The Ice Age’s combined horrors—intense cold, permanent drought, and CO2 starvation—killed most of the plants on earth. Only a few trees survived, in the mildest climates.Much of the planet’s grass turned to tundra, which is much less nourishing to the herbivores we depended on for food and fur. Cambridge University’s recent studies say that, worldwide, only about 100,00 humans were left alive when the current Interglacial warming mercifully began.

The few surviving prey animals had to keep migrating to get enough food. That forced our ancestors to migrate with them, in temperatures that routinely fell to 40 degrees below zero (both Fahrenheit and Celsius). The Neanderthals had been living in warm caves protected from predators by fires at the cave mouths. They had hunted their prey by sneaking through the trees—which no longer existed. They apparently couldn’t adapt, and starved. Cambridge finds no signs of genocidal warfare.

The most successful human survivors—who provided most of the DNA for modern Europeans—were nomads from the Black Sea region. The Gravettians had never had trees, so they invented mammoth-skin tents, held up by salvaged mammoth ribs. They also developed spear-throwers, to kill the huge mammoths from a safe distance. Most important, they tamed wolves into dogs, to protect their tents from marauders, to locate the game animals on the broad tundra, and to harry the prey into a defensive cluster. The scarcity of food in that Glacial Maximum intensified the wolves’ appreciation for the bones and bone marrow at the human camps.

Carbon dioxide truly is “the gas of life.” The plants that feed us can’t live without inhaling the CO2, and then they breath out the oxygen that lets humans keep breathing too.

Our crop plants evolved about 400 million years ago, when CO2 in the atmosphere was about 5000 parts per million! Our evergreen trees and shrubs evolved about 360 million years ago, with CO2 levels at about 4000 ppm. When our deciduous trees evolved about 160 million years ago, the C02 level was about 2200 ppm—still five times the current level

There’s little danger to humans of too much CO2 in the air they breathe. The EPA says 1000 ppm is the safe limit for lifetime human exposure. The CO2 alarm in nuclear submarines is set at 8,000 ppm, and space shuttles often get to 5,000 ppm.

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https://townhall.com/columnists/dennisav...manity-n2335975