PUBLIC SIGMA XI LECTURE
Our Changing Greenhouse: The Importance of CO2
Date: Tuesday, April 17, 2007 Time: 3 p.m.
UT Dallas Conference Center Auditorium, CN 1.112
During the almost four billion years that life has been present on Earth, the composition of our atmosphere has evolved from one that contained a much higher concentration of greenhouse gases such as carbon dioxide and very little free oxygen to the present one with a relatively small amount of carbon dioxide and an abundance of oxygen.
Despite these changes in our greenhouse, the surface temperature of the planet has remained within an optimum range for life to exist and evolve. Feedback processes that regulate the concentration of carbon dioxide have stabilized Earth’s climate over the eons.
At several times in the planet’s history, however, the concentration of this gas has dropped low enough to result in the build-up of extensive ice sheets. Eventually, the feedback processes replenish carbon dioxide and return the climate to an ice-free condition.
This oscillation of Earth’s climate between icehouse and hothouse conditions, largely controlled by the amount of carbon dioxide in the atmosphere, illustrates the sensitivity of our climate to this greenhouse gas.
- Updated: April 10, 2007