The causes of global warming are still not established with absolute certainty. However, most scholars are inclined to believe that the main culprit of raising the temperature on Earth - the people. Earlier increase in mean annual temperature by a few tenths of a degree going on for thousands of years, then with the beginning of human activity that's enough for a couple of decades. This process is called global warming and its consequences can be catastrophic. The threat of global warming can not be underestimated.
Raising the temperature of the surface layer of the atmosphere leads to a shift in climate zones, causing the melting of the Arctic and Antarctic ice, and permafrost, leading to an increase in sea level.
Climate change and the impact on the wildlife. Many species become extinct, others change their traditional habitats. Danger slum resettlement process tropics to temperate latitudes is that tropical animals are carriers of diseases such as malaria. In addition, warming could lead to an increase in the incidence of intestinal infections, asthma, allergies and respiratory diseases.
Climate change is detrimental impact on such sectors as agriculture and tourism, worsen the living conditions in many countries. UN projects that by the middle of this century the number of "climate" refugees reach 200 million people.