Global Warming

Causes

·         Scientists are more than 90% certain that it is primarily caused by increasing concentrations of greenhouse gases produced by human activities such as the burning of fossil fuels and deforestation. Electricity causes pollution in many ways, some worse than others.  In most cases, fossil fuels are burned to create electricity.

Effects

• Ice is melting worldwide, especially at the Earth’s poles. This includes mountain glaciers, ice sheets covering West Antarctica and Greenland, and Arctic sea ice.
• Sea level rise became faster over the last century.
• Precipitation (rain and snowfall) has increased across the globe, on average.
• Decline of certain species as the Adélie penguins on Antarctica.  Some butterflies, foxes, and alpine plants have moved farther north or to higher, cooler areas. Spruce bark beetles have boomed in Alaska thanks to 20 years of warm summers. The insects have chewed up 4 million acres of spruce trees.

Effects could happen later, if warming continues

• Sea levels are expected to rise between 7 and 23.
• Hurricanes and other storms are likely to become stronger.
• Species that depend on one another may become out of sync.
• Floods and droughts will become more common.
• Less fresh water will be available.
• Some diseases will spread, such as malaria carried by mosquitoes.
• Ecosystems will change—some species will move farther north or become more successful; others won’t be able to move and could become extinct.