is a term used to refer to the phenomenon of the increase in global average temperature of Earth's atmosphere and oceans, since 1850, coinciding with the end of the so-called Little Ice Age, or whether in relation to periods larger. This increase would have increased in the last decades of the twentieth century and the first century.
Global warming is associated with climatechange that may have anthropogenic cause or not. The main effect that causes global warming is the greenhouse effect, a phenomenon that refers to the absorption-by certain atmospheric gases, mainly CO2-energy part of the floor beams, as a result of being heated by solar radiation. The natural greenhouse effect that stabilizes the Earth's climate is not a matter to be included in the global warmingdebate. Without this natural greenhouse temperatures would drop by about 30 ° C, with such change, the oceans would freeze and life as we know it would be impossible. To this effect occurs are required these greenhouse gases, but in appropriate proportions. What worries climate scientists is that an elevation of that ratio will produce an increase in temperature due to heat trapped in the loweratmosphere.
The UN body responsible for the analysis of the relevant scientific data, the IPCC (Inter-Governmental Panel on Climate Change or Intergovernmental Panel on Climate Change) - argues that "most of the observed increases in average temperature of the globe from half of the twentieth century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations. This isknown as the anthropogenic theory, and predicts that global warming will continue if they do emissions of greenhouse gases. In the latest report with projections made by IPCC climate models indicate that it is likely that global surface temperature, increase between 1.1 and 6.4 ° C (2.0 to 11.5 ° F) during the 21 st century .
Any kind of climate change also involves changes in other variables.Their multiple interactions cause the only way to evaluate these changes is by using computer models, which try to simulate the physics of the atmosphere and ocean.
The Kyoto Protocol, an agreement originated in the United Nations Framework Convention on Climate Change adopted at the United Nations Conference on Environment and Development, promotes a reduction of pollutant emissions, primarilyCO2. The protocol has been criticized as unfair at times, as the increase in emissions is traditionally associated with economic development, so that nations would be most affected by the performance of this protocol could be those in less developed areas. However, in this protocol, developing nations (including China and India) are exempt of curbing greenhouse gas emissions.
Beyond the generalscientific consensus around the acceptance of the dominant source of anthropogenic global warming, there is an intense political debate about the reality of scientific evidence of it. For example, some of these politicians are saying that the alleged climate consensus is a complete fallacy,  and in January 2009, the Senate Republican minority in the United States drew up a list of over 700scientists who dissented from the anthropic temperature changes on Earth. In 2009 it was discovered the alleged scandal called Climategate, which allegedly showed that scientists at the Climate Research Unit at the University of East Anglia have manipulated data in order to coincide with the global warming theories. However, independent scientific observers question this interpretation. Nature says:"What emails do not show, however, is a big conspiracy to make global warming ..." New Scientist notes that "has not shown that the emails have hacked something involving an undermining of any scientific findings. " Continuing to examine some of the suggestions from skeptics of anthropogenic global warming, the article shows several examples of the lack of adjustment to the facts and rigor,...