Like the glass in a greenhouse, certain gases that occur naturally in the
atmosphere tend to trap the sun's heat. This natural "greenhouse
effect" helps keep the Earth's average temperature at a comfortable 59°
Fahrenheit. Without these greenhouse gases, the Earth would be about 0° F, like
a deep- frozen snowball. But human activities are causing some greenhouse gases,
such as carbon dioxide, to build up in the atmosphere. Whenever we burn fossil
fuels (gasoline, oil, coal or natural gas), more carbon dioxide is emitted to
the atmosphere. Forest destruction and agriculture also release greenhouse
gases. If we do not act to reduce our emissions of these heat-trapping gases, it
is predicted that global temperature could rise 2° to 6° F in the next 100
years. Just a few degrees' difference in the global average temperature can mean
a major climate change. Why Act Now? Global warming is not like turning on a
heater; we can't just turn it off afterwards if the Earth warms too fast for
comfort. Once we emit greenhouse gases into the atmosphere, most of them remain
there for decades, continuing to trap heat. If we wait until all the
consequences became obvious, it could be too late to do much about them. These
children are cooling off in a fountain in Manhattan, where about 15 days each
year are over 90° F. By the middle of the next century, 48 days a year could be
that hot. But we can act now to insure against the risk of disruptive future
warming, by reducing our greenhouse gas emissions today. The exhibition
describes many practical options that could not only cut these emissions but
also save money and reduce air pollution.