Our climate is changing. Scientific evidence shows that the global average temperature is rising, and rainfall patterns are shifting. It also shows that glaciers, Arctic sea ice and the Greenland ice sheet are melting. The Intergovernmental Panel on Climate Change′s Fifth Assessment Report shows that the warming since the mid-20th century is predominantly due to an increase in greenhouse-gas concentrations as a result of emissions from human activities. Combustion of fossil fuels and changes in land use are largely responsible for this increase.