Global Warming

Global warming have become the global issue because of the rising level of CO₂ during last deglaciation. Many scientists have long suspected that the rising levels of CO₂ and global warming that ended the last Ice Age were somehow linked, but establishing a clear cause and effect relationship between CO₂ and global warming from the geologic record has remained difficult.

The key to understanding the role of CO₂ is to reconstruct globally averaged temperature changes during the end of the last ice Age, which contrasts with previous effort that only compared local temperatures in Antartica to carbon dioxide levels. Even the CO₂ levels still unclear become the main factor of global warming but people still concern that this factor as one effect factor to this nature symptoms, because the rising temperature reflected in Antarctic ice cores came before the rising levels of CO₂ happened.

Some scientists explain that small changes in Earth's orbit around the sun affected the amount of sunlight striking the northern hemisphere, melting ice sheets that covered Canada and Europe. The fresh water flowed off of the continent into the Atlantic Ocean, where it formed a lid over the sinking end of the Atlantic Meridional Overturning Circulation, a part of a global network of currents that brings warm water up from the tropics and todays keeps Europe temperate despite its high latitudes. The ocean circulation warms the northern hemisphere at the expense of the south, the researchers say, but when the fresh water draining off the continent at the end of the last Ice Age entered the North Atlantic. It essentially put the brakes on the current and disrupted the delivery of heat to the northern latitudes.