Link: https://wattsupwiththat.com/2017/06/30/life-on-earth-was-nearly-doomed-bytoo-little-co2/ Please see link above for original article, embedded hotlinks and comments.
Life on Earth was nearly doomed by too little CO2 June 30, 2017 During the last ice age, too little atmospheric carbon dioxide almost eradicated mankind Guest Essay by Dennis T. Avery Aside from protests by Al Gore, Leonardo Di Caprio and friends, the public didn’t seem to raise its CO2 anguish much above the Russians-election frenzy when Trump exited the Paris Climate Accords. Statistician Bjorn Lomborg had already pointed out that the Paris CO2 emission promises would cost $100 trillion dollars that no one has, and make only a 0.05 degree difference in Earth’s 2100 AD temperature. Others say perhaps a 0.2 degree C (0.3 degrees F) difference, and even that would hold only in the highly unlikely event that all parties actually kept their voluntary pledges. What few realize, however, is that during the last Ice Age too little CO2 in the air almost eradicated mankind. That’s when much-colder water in oceans (that were 400 feet shallower than today) sucked most of the carbon dioxide from the air; half of North America, Europe and Asia were buried under mile-high glaciers that obliterated everything in their paths; and bitterly cold temperatures further retarded plant growth. In fact, Earth’s atmosphere had only about 180 parts per million CO2, compared to today’s 400 ppm: 0.018% then versus 0.040% today. 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 prehistoric humans depended on for food and fur. Recent Cambridge University studies conclude that only about 100,000 humans were left alive worldwide when the current interglacial warming mercifully began.
Page 1