1. Globally averaged as the warmest decade in the past 140 years, with 1998 being the warmest year on record.
2. 1977- The "North Pacific" climatic regime shift making the end of a ~30 year cool phase of the PDO (Pacific Decadal Oscillation) and the beginning of ~21 year warm phase of the PDO; extensive drought conditions in the western U.S.
3. 1930s-Dust Bowl drought impacts 100 million acres of Great Plains.
4. carbon dioxide concentrations in the atmosphere have risen from 290 parts per million (ppm) to 369 ppm, with strong evidence pointing to the burning of fossil fuels as a primary cause of these increases.
5. There has also been increased cloud cover, particularly in the Northern Hemisphere during the past century.