The atmosphere and surface of the system is like a huge "glass house" so that the surface has always maintained a certain temperature, produced for human and other organisms living environment. In this system, both to solar radiation through the atmosphere and reach the ground, while ground radiation to prevent loss, we have the atmosphere of this effect on the ground called the atmospheric greenhouse effect. Greenhouse gases called "greenhouse gases", which allows free passage of solar radiation, while absorbing surface long-wave radiation issue. These gases are carbon dioxide, methane, chlorofluorocarbons, ozone, nitrogen oxides and steam, etc., most notably carbon dioxide. The past century the global climate is gradually warming, with the same time, atmospheric levels of greenhouse gases are rapidly increasing. Many scientists agree that emissions of greenhouse gases caused by a large number of aggravating the greenhouse effect may be the underlying causes of global warming.
Greenhouse gas emissions of human activities include: fossil fuel burning activities, all carbon dioxide emissions. In the fossil fuels, the highest carbon content of coal, oil second, and natural gas lower; fossil fuel gas during the mining of coal, natural gas leakage emissions of carbon dioxide and methane; cement, lime, chemical emissions from industrial processes such as carbon dioxide; paddy fields cattle and sheep and other ruminant methane emissions from the digestive process; land-use change to reduce the absorption of carbon dioxide; waste methane and nitrous oxide emissions.
Human burning of coal, oil, natural gas and trees, a large amount of carbon dioxide and methane into the atmosphere, warming the earth after, so the carbon cycle imbalances, changes in the Earth's biosphere energy conversion form. Since the industrial revolution, atmospheric carbon dioxide increased by 25%, far more than scientists can survey the past 16 years out of all the historical record, and no signs of slowing down now.
The main causes of global warming is nearly a century of human heavy use of fossil fuels (such as coal, oil, etc.), large amounts of carbon dioxide emissions and other greenhouse gases. These greenhouse gases on the short-wave radiation from the sun with a high degree of permeability, while the long-wave radiation reflected from the Earth are highly absorbent, it is often said that the "greenhouse effect", leading to global warming.
The world is divided into boreal forest (northern) forests, temperate forests and tropical forest categories. According to experts, today's forest ecosystems, is the natural evolution after 8000 years has been gradually formed.
Today, all of the forests have become a large-scale exploitation of the logging industry goals. In the tropics, many of the forest is now gone in the past 50 years have been cut empty. Only from 1960 to 1990, there more than 450 million hectares of tropical forest were engulfed, the world's tropical forests account for 20% of the total area; have millions of hectares of tropical forest in the deforestation, farmland degradation and mineral exploitation.
Moreover, the global illegal logging and illegal timber products trade continues to increase, especially in countries with tropical forests and lax government enforcement of Russia and other countries. The international market for cheap wood products demand, has further exacerbated the situation.
Intergovernmental Panel on Climate Change, climate models, according to projections to the year 2100, estimated that global temperatures will rise by about 1.4-5.8 degrees Celsius (2.5-10.4 degrees Fahrenheit). According to this forecast, global temperature will occur over the past 10,000 years, has never been great changes, and thus the potential to bring significant global environmental impact.