Science Briefs


figure of satellite orbits

The Earth has warmed 1°F in the past century and mountain glaciers are retreating. Is this a human-made climate change, a presage of larger future change, or just natural variation?

Some climate "forcings", which cause climate change, are being measured now. Examples are fluctuations of the energy coming from the sun (a natural forcing) and increasing atmospheric carbon dioxide (a "greenhouse" gas which warms the Earth and is increasing due to humankind's burning of coal, oil and gas). But other climate forcings are not being measured accurately, the prime example being atmospheric aerosols. These fine particles in the air, which are also produced by fossil fuel burning, scatter sunlight to space, cooling the planet, and thus countering greenhouse warming to some unknown degree.

GISS scientists have defined observations that can be made from a small satellite to determine precisely many of these climate parameters. Climate forcings operate by altering the solar energy absorbed by the Earth or the heat energy emitted by Earth, and thus can be measured via changes to these spectra.

Data from the proposed small satellite, Climsat, can help teach Earth sciences. The Climsat data can illustrate month-to-month and year-to-year climate variability, and it can be used to involve students in the research process. The Climsat data will yield global maps of important climate parameters that can be distributed over the internet. The solar and thermal spectra are themselves fundamental and can be related to many science topics. Curriculum modules based on Climsat can be designed to give all students understanding of global change and to challenge precocious students to get involved in global change research.

Plots of solar radiation reaching Earth and of Earth's own radiation


Hansen, J., W. Rossow, B. Carlson, A. Lacis, L. Travis, A. Del Genio, I. Fung, B. Cairns, M. Mishchenko and M. Sato. 1995. Low-cost long-term monitoring of global climate forcings and feedbacks. Climatic Change 31, 247-271.