Overview and Impacts on Arid Land Water Resources

Abstract

The amount of research and the resulting publications on global climate changes has been truly explosive since the 1990s. The evidence is now indisputable that global climate has been warming since about 1900 and that the increase in greenhouse gases, including carbon dioxide, methane, and nitrous oxide have been a major cause of the increase. Variations in climatic conditions control the hydrologic cycle on the Earth at many scales, both spatial and temporal. Natural factors have produced cycles of global climate change ranging from extremely warm conditions, during which no polar ice existed on the planet (referred to as “Greenhouse Earth”), to the “Snowball Earth” (also called “Icehouse Earth”) when a large part of the entire planet was frozen. Natural climate changes were created by variations in the solar radiation reaching the Earth.