The most important thing that trees do is absorb carbon dioxide and turn it into oxygen, which we inhale to keep alive. One very significant reason why we need trees is because of global warming. Global warming is the rise of temperature in the earth's atmosphere. This occurs when there is an abundance of carbon dioxide in the atmosphere and trees aren't able to absorb enough carbon dioxide. The warming of the earth will cause more water to evaporate from the ocean, which will increase precipitation, hurricanes, and other storms.

Also, as a result of global warming, scientists fear the polar ice caps will melt and the sea level will rise and flood coastal lands. Global warming could also cause mangrove forest and estuaries to flood, and coral reefs may not be able to grow fast enough to keep with rising sea levels. Not only do trees positively help global warming, but they also help out the ozone layer. The dictionary definition of the ozone layer is: "A region of the upper atmosphere, between about 15 and 30 kilometers (10 and 20 miles) in altitude, containing a relatively high concentration of ozone that absorbs solar ultraviolet radiation in a wavelength range not screened by other atmospheric components." All the fossil fuels that humans burn have an overwhelming effect on the ozone layer. Aerosol and gasoline are a couple of fossil fuels that have been released into the air, and when they are released they rise up and break down the ozone layer, bit by bit. Swamps and methane from rice patties are not good for the atmosphere, as well. Another big contributor is Chlorofluorocarbons, which is used in sprays and air conditioners. The ozone layer protects life forms on Earth from harmful ultraviolet radiation, which can cause cancer and mutation. Radiation can also harm plankton in Antarctica, triggering a chain of reactions, leading to death, because so many animals rely on plankton. Every year the holes in the ozone layer increase in size, and it is time we try to help.