Global warming refers to the increase in average temperatures of the Earth's atmosphere and oceans since the mid-20th century due to rising levels of greenhouse gases from human activity. The average global surface temperature increased 0.74 degrees Celsius over the past 100 years and is projected to continue rising. Effects of global warming already occurring include melting ice worldwide, rising sea levels, and increased extreme weather events. Potential future impacts this century include more severe hurricanes, droughts and floods, species extinction, and health issues. Solutions proposed include increasing use of solar and other renewable energy sources as well as developing technologies to reduce carbon emissions such as more efficient engines.
