Outline

1. Global Warming

Global Warming

• Global warming refers to the increase in the average temperature of the Earth's near-surface air and oceans in recent decades and its projected continuation.
• The global average air temperature near the Earth's surface rose 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the last 100 years.
• The Intergovernmental Panel on Climate Change (IPCC) concludes that most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in manmade greenhouse gas concentrations via the greenhouse effect.
• Climate models referenced by the IPCC project that global surface temperatures are likely to increase by 1.1 to 6.4 °C (2.0 to 11.5 °F) between 1990 and 2100.
• An increase in global temperatures is expected to cause other changes, including sea level rise, increased intensity of extreme weather events, and changes in the amount and pattern of precipitation.
• Other effects of global warming include changes in agricultural yields, glacier retreat, species extinctions and increases in the ranges of disease vectors.
• Although most studies focus on the period up to 2100, warming and sea level rise are expected to continue for more than a millennium even if greenhouse gas levels are stabilized.
• These basic conclusions have been endorsed by at least 30 scientific societies and academies of science, including all of the national academies of science of the major industrialized countries.