The Earth's climate has changed over the years and these changes have been influenced by various factors.These factors are classified into two groups: "anthropogenic" (which is human-induced) and natural. Climate change has been observed since the beginning of the 20th century by scientists who have stated that this change can no longer be attributed to natural influences alone. One factor of the changing climate that has gotten considerable attention is global warming, and this occurrence has been happening faster than anyone could have ever predicted. The problem with this change is that it has been created by humans. Therefore, it's important that humans determine how they are contributing to this change and what they can do to minimize their negative effects.
The following segments look at some of the main influences of natural and human climate change and the effects that they are having on the Earth.
As everyone knows, the Earth has a greenhouse effect, which is a natural occurrence attributed to certain types of gases (these are known as greenhouse gases) which are found within the Earth's atmosphere.What these gases do is allow the sunlight to penetrate, but they also consume heat radiation. Therefore, by doing this the heat absorbed by the gases keeps the temperature of the Earth's surface at around 14oC. If the Earth did not have the natural greenhouse effect, then the Earth's surface temperature would be -19oC or thereabouts.
The industrial revolution was created by humans and in doing sothe greenhouse gases in the Earth's atmosphere were increased by a considerable amount. These increases in gases lead to the atmosphere retaining more heat, which directly leads to surface temperatures increasing globally. This temperature change became known as global warming. Other effects have also been attributed to this increase in temperature which has caused the climate system to change. Together the natural and human affects are called anthropogenic climate change.
So what are the main greenhouse gases and what should we know about them?
Other factors that have an effect on the Earth's climate are:
The scattering of solar radiation acts to cool the planet, while absorption of solar radiation by aerosols warms the air directly instead of allowing sunlight to be absorbed by the surface of the Earth. This leads to negative effects on the Earth's climate.
Activity by humans contributes to the atmosphere's increase in aerosols in various ways, accelerating the negative effects the aerosols have on the climate.
Cutting down forests in order to create farmland has caused changes to how much sunlight is now being reflected back into space (the albedo surface) from the ground. Greenhouse gases and their emissions have caused changes that have been estimated at about 1/5th which are being forced on climate change globally, and roughly half of land use changes have occurred throughout the industrial era.
The replacement of forests due to grazing lands and agricultural cropping over North America and Eurasia has contributed to climate change, just as deforestation at high latitudes has along with previously forested areas where solar energy reflects off of snow that covers the land. The snow which is found on trees reflects around half of the sunlight that falls on them; however, open ground that is covered in snow will reflect around two-thirds.
The increased solar energy over North America and Eurasian regions of agriculture has had a cooling effect.
Other changes created on the surface of the land from human activities include:
Analyses indicate that the clearing of forests for irrigated farming and forest clearing in semi-arid and arid lands are two important sources of land cover changes that are climatically major.