Our atmosphere is composed of many different gases. There are some gases in our atmosphere that act like an insulating blanket to hold solar energy to keep our Earth warm just like a greenhouse keeps plants warm. These greenhouse gases are water vapor, carbon dioxide, methane, and nitrous oxide.
As light radiates from the sun, it is absorbed by land, plants, and oceans and transforms into heat. This heat is later released as infrared radiation. Without greenhouse gases, the earth would heat up during the day, and would be very cold at night. However, because of the greenhouse effect, the greenhouse gases absorb the heat and reduce the heat radiated out to space. Because of these gases, the earth enjoys temperatures suitable for our active and complex biosphere.
Perhaps you have heard about the greenhouse effect in negative terms. As humans have increased their need for energy, industrialization and the combustion of fuels has led to increased levels of carbon dioxide in the atmosphere. As carbon dioxide has the ability to hold solar energy, global warming has increased. Although the global climate change has been small, it has been consistent; leaving scientist to wonder how our climate will change in the next several decades.
Scientific projections indicate that global surface temperature will likely rise a further 1.1 to 6.4 °C during the twenty-first century. The uncertainty in this estimate arises from the use of differing models, and the use of differing estimates of future greenhouse gas emissions. Although most studies focus on the period up to 2100, warming is expected to continue, even in the absence of new emissions, because of the large heat capacity of the oceans, and the lifespan of carbon dioxide in the atmosphere.
Increasing global temperature will cause sea levels to rise, change the amount and pattern of precipitation, and likely include an expansion of subtropical desert regions. Other likely effects include Arctic shrinkage, shrinkage of the Amazon rainforest, increases in the intensity of extreme weather events, changes in agricultural yields, glacier retreat, and species extinctions.
However, despite global warming, it is important to understand that without the greenhouse effect, life on earth as we know it would not be possible.