Global warming is causing regional climate changes, particularly affecting summers in middle latitudes and year-round in low latitudes. Even small temperature increases have significant social and economic impacts. If global warming reaches 2 °C, the temperature anomalies will be much larger than seen since the mid-20th century. The countries with the greatest responsibility for CO2 emissions from fossil fuels do not align with the regions suffering the worst consequences of warming. This mismatch has important implications for global energy and climate policies.