ABSTRACT
Earth has experienced a series of warm and cold periods throughout its history, with climate and temperature changes showing temporal and spatial distribution. Over the past 100 years, Earth’s average surface temperature increased by about 0.8°C (1.4°F) and the rate of temperature increase accelerated toward the end of that time frame. Climate model projections by the Intergovernmental Panel on Climate Change 152(IPCC) indicate that during the twenty-first century, global surface temperature is likely to rise a further 1.1°C-2.9°C (2°F-5.2°F) for their lowest emissions scenario, and 2.4°C-6.4°C (4.3°F-11.5°F) for their highest. The range of these estimates arises from the use of models with to concentrations.
