What is the greenhouse effect?
Natural Greenhouse Effect
The term greenhouse is derived from the glass houses people build to trap heat inside to create a warm environment in which to grow food. The Earth’s atmosphere, much like a greenhouse, traps heat, but in a different way. Gases high in the atmosphere, such as carbon dioxide (CO2) behave like a giant piece of curved glass wrapped around the planet. The Sun’s rays pass straight through the carbon dioxide, a greenhouse gas, and warm up the Earth. The warming planet gives off heat energy which radiates out toward space. Some of this outgoing radiation does not pass through the atmosphere, but is reflected back down to Earth, effectively trapping heat and keeping the planet warm enough for life to exist. This is called the natural greenhouse effect, and it’s a good thing.
Enhanced Greenhouse EffectThe greenhouse effect would be nothing to worry about were it not for one important thing. Since the industrial revolution started in the 1800s, humans have been burning large quantities of coal, oil, and other fossil fuels primarily to generate energy and later fuel transportation. When burned, fossil fuels release carbon dioxide (CO2) into the atmosphere. As humans burn large quantities of fossil fuels we are increasingly heating up the atmosphere via a phenomena called “the greenhouse effect”. The carbon dioxide (CO2) drifts up into the atmosphere and makes Earth’s greenhouse gas just a little thicker. This is called the enhanced greenhouse effect. As a result, more of the Sun’s heat gets trapped inside the atmosphere and the planet warms up more than it should.
Because of all the fossil fuels humans are burning, there is now more carbon dioxide (CO2) in the atmosphere (as of April 2017 we reached 410 parts per million). Carbon dioxide hasn’t reached this height in millions of years. It’s a new atmosphere that humanity will have to contend with, one that’s trapping more heat and causing the climate to change at a quickening rate.
This burning of fossil fuels and subsequent releasing of CO2 into the atmosphere is fueling climate change.
Currently, 80% of the world’s energy comes from fossil fuels. There are other man-made sources of greenhouse gases – CO2 from burning fossil fuels is simply the largest source. The amount of energy people use is increasing too. Unless humans change things, the amount of carbon dioxide (CO2) in the atmosphere will continue to increase—and the Earth will continue to heat up and global warming will get worse.
More information on the greenhouse effect from the Intergovernmental Panel on Climate Change.