Geologists suggest that up to 10 percent of the planet was buried in ice (though not necessarily simultaneously) during the maximum extent of the great ice ages.

In the nineteenth century, Louis Agassiz helped compile the evidence that large parts of the Earth have been periodically covered with advancing and retreating ice sheets. The last ice age ended between 14,000 and 10,000 years ago. The climate of the most recent 10,000 years has been remarkably stable, at least by comparison to the […]

Yes, though scientists aren’t exactly sure how. The energy emitted by the sun is not constant as once thought. How these slight fluctuations in the sun’s output, associated with sunspots, perturb weather patterns is still an object of intense research. Much of the solar variation takes place in the shorter (ultraviolet) wavelengths to which upper […]

Meteorologists have long talked of the “solar constant” as the amount of energy emit ted by the sun, and once considered it to be a rock-steady number. Not so. Solar out put does indeed vary, on the order of 0.1 percent. Satellite observations show that the sun’s energy output varies over the 11-year sunspot cycle, […]

Yes. There would be less nitrogen, oxygen, and methane, but more carbon dioxide and carbon monoxide. The chemical composition of the Earth’s atmosphere has changed dramatically over time as a result of living organisms. Today about 21 percent of the air we breathe is oxygen. But during the Carboniferous period some 300 mil lion years […]

The primary archive for weather data used in climatological and other studies is the National Climatic Data Center (NCDC), 151 Patton Avenue, Asheville, North Carolina, 28801. Their web page address is http://www.cdc.noaa.gov. NCDC archives a large fraction of the weather data taken by federal agencies and cooperative observers, with records going back well into the […]

The climate of the Earth is constantly changing, and it is the job of paleo-climatologists to use whatever shreds of evidence they can find to piece together the turbulent history of our planet’s climatic past.
About 8,500 years ago, water temperatures around the coast of Greenland were about 10°F warmer than they are today. We know […]

 
 
 
 
Trying to separate out the human impact on climate from the natural chaotic signal is a major scientific challenge. The same effect (increasing temperatures) can arise from multiple causes. Therefore, jumping to conclusions in climate research can be a risky business. If one were to use temperature records from the city of London, one might […]

 
The public may think, from reading press accounts, that carbon dioxide emissions are the only thing that influences climate. The real issue is vastly more complex. Aside from the fact that other greenhouse gases are important, there are numerous factors that influence long-term climate trends, and many of them are natural processes that are quite […]

Rising levels of CO in our air might not be all bad. Researchers suggest that CO not only stimulates plant growth, but also reduces plants’ water consumption. One experiment found that as CO was doubled, depending on the species, the amount of water required by the plant will drop between 17 and 27 percent and […]