The
natural greenhouse effect is caused by molecules of gases (water, methane, and carbon dioxide) suspended in the upper atmosphere. These molecules reflect infrared light and heat and prevent heat from escaping the Earth's atmosphere. This greenhouse effect is supported by the earth's carbon and water cycles and has kept the earth comfortably warm enough for life for millions of years.
The
enhanced greenhouse effect (which is what has happened because of the human activity of
deforestation (destroying forests) and
burning fossil fuels (coal, oil and natural gas)), is
global warming. The additional greenhouse gases that these activities have caused means the earth is warming, and especially quickly since 1980, and this warming is causing
climate change.
Global warming causes climate change, and that could change rainfall and weather patterns. The temperature increase may have a dramatic affect on many different animals, especially those that thrive and require very cold, or very hot climates. Ice will melt (including the ice on mountains), sea levels will rise. Winters may become shorter, but harsher. Summers may become increasingly hotter. Hurricanes and tornadoes may become gradually stronger and more common, and their range may become larger.