What are the current estimates for 21st century climate change?
• The latest Intergovernmental Panel on Climate Change projections for 21st century average global temperature increase is 2.5-10.4oF, based upon multiple climate models and multiple assumptions regarding future greenhouse gas emissions. • Regional warming may be greater or less than the global average. For example, temperature increases in the United States are projected to be approximately 30% higher than the global average. The Arctic is likely to experience the greatest warming. • Associated with this warming will be an increase in global average sea level of 4-35 inches, depending on the magnitude of warming. • Global precipitation patterns will also be altered by temperature increases. Generally, the hydrological cycle is expected to accelerate leading to increases in precipitation at the global level. However, these global increases may not necessarily balance the increased evaporation under warmer conditions, and some regions may experience a decrease in precipitation.
