A Global Warning
Scientists have figured out what the earth’s climate, particularly temperature, has been doing for the last 650 million years. It started out with very low levels of CO₂. The entire earth was covered over 1.61 km (1 mile) deep in ice. It was -40°C (-40°F) at the equator. Almost all life was wiped out. Ten million years later, it swung to the opposite extreme and again it wiped out almost all life.
250 million years ago, CO₂ levels rose and wiped out 95% of life on earth.
55 million years ago CH₄, methane a greenhouse gas 25 times as potent as CO₂ was the culprit. Crocodiles were living at the North Pole, then eventually the warming fried the entire earth and wiped out almost all life.
The famous chemist, Svante Arrhenius (Nobel prize winner who discovered ions), published his calculations in 1896 about the relationship between CO₂ and global temperatures. His work has been confirmed from over a century of observation and from our new ability to study the deep past.
The point is scientists are certain of the effects of CO₂. They also know we have already pumped it higher than it has been for 3 million years and if we do not charge our ways, will more than double that. We know that is already sufficiently high to trigger an extinction event. Climate-change extinction events are not like asteroid ones. The effects build gradually, usually over thousands or millions of years. The one we are creating now is happening very fast, over only a few centuries.How the Earth Was Made, Life After People, a Global Warning - The History Channel Our Planet Box Set ~ Roedy (1948-02-04 age:69)