Global warming is caused by the tendency for some gases, like carbon dioxide, to trap heat in the earth's atmosphere. This seems to be causing a gradual increase in the average world temperatures, melting of the ice caps, rising ocean levels, and changes in weather patterns.

Pollutants such as nitrous oxides help to create smog and haze, and make it difficult for elderly people and people with lung problems to breathe.

The fission nuclear power plants that are already in use have produced thousands of tons of radioactive waste that are sitting in drums waiting for disposal. This waste will be toxic for thousands of years and where to put it has become a gigantic technical and political problem. No one wants this waste anywhere near their own communities, and the technology of safely storing it is unproved and still under development.

While radiation leaks are rare, there have been some small leaks and even a few larger ones. Small leaks allow radioactive gases to get into the atmosphere, which if breathed, could help cause cancer. One very large leak in the Soviet Union allowed radioactive material to contaminate a considerable area, which is still unusable today.

If you drive by a nuclear power plant, you might see the huge cooling towers that are required to cool the hot reactor. The water from these cooling towers contains excess heat energy and is released into the local rivers or lakes. The warmer temperatures that are created allow organisms that would not normally thrive to grow and kill off some of the previous inhabitants.