The photo was taken on Feb. 26, 2000. The difference in the brightness of solar radiation reflected by the land surface and the heavy dust cloud showed that nearly all the sunlight in the visible and near infrared part of the solar spectrum hitting the dust cloud was reflected back into space. Very little heat and light were absorbed by the iron-rich dust particles. The U.S. Environmental Protection Agency joins many scientists in saying on its global warming Web site that determining the extent of global warming is difficult and there are many complicating factors. For example, as the ocean warms, evaporation will increase, leading to more cloud formation.
Clouds play a dual role in the atmosphere.
They cool the Earth by reflecting incoming radiation, and they warm the Earth by trapping outgoing radiation underneath. The amount of cooling and warming depends on the type, amount and distribution of clouds. Currently, they appear to cool more than they warm. If more evaporation occurs, clouds may offset the warming. Warming of the oceans will release vast amounts of hydrocarbon gases from melting gas hydrates, which will increase global warming.