Marshall Institute- Home

A non-profit institution dedicated to providing rigorous, unbiased technical analyses of scientific issues which impact public policy, GCMI is directed by senior scientists of international renown.

MembershipPublicationsAbout UsContact Us

Can Effect Come Before Cause in Global Warming?
New Findings on a Basic Relationship

    Records of ancient climates show a close connection between atmospheric carbon dioxide and the Earth's temperature. Carbon dioxide and temperature have been tracking each other for many thousands of years. In his best-selling book, Earth in the Balance, Vice President Gore stressed this as strong evidence for global warming resulting from our burning of coal and oil for energy.

    But according to recent publications in Science (Fischer, H. et al March 12, 1999, p. 1712) and Nature (Petit, J.R. et al June 3, 1999, p. 431), when researchers looked in detail at the changes in temperature and carbon dioxide, they discovered a remarkable fact. The temperature and the carbon dioxide concentration do indeed vary together but the carbon dioxide changes occur AFTER the temperature changes. When the earth's temperature increases, carbon dioxide also increases, but roughly 1000 years later.

    Clearly, atmospheric carbon dioxide cannot be the cause of a warming that occurred before this carbon dioxide existed. If the increases in carbon dioxide come later than the increases in temperature, these increases in carbon dioxide cannot be the cause of the global warming: apparently they are one of its effects. But why should the warming of the earth cause an increase in the carbon dioxide of the atmosphere? The answer has to do with the oceans: the warmer the oceans, the less carbon dioxide they can hold. Consequently, when the oceans warm they release some of their carbon dioxide to the atmosphere. This explains the connection between carbon dioxide and temperature and it also explains why the temperature changes before the carbon dioxide changes.

Learn more Facts on Global Warming.