Global warming Whats Going to Happen? Natural and Amplified Warming Causes
refers to the current rise inthe average temperature of Earthsatmosphere and oceans and itsprojected continuation.
Average temperatures have climbed 1.4 degrees Fahrenheit (0.8 degree Celsius) around the world since 1880. Average temperatures in Alaska, western Canada, and eastern Russia have risen at twice the global average.
Glaciers and mountain snows are rapidly melting —for example, Montanas Glacier National Park now has only 27 glaciers, versus 150 in 1910.
South Cascade Glacier, Washington1928 1979 2003
Coral reefs, which are highly sensitive to small changes in water temperature, suffered the worst bleaching—or die-off in response to stress—ever recorded in 1998, with some areas seeing bleach rates of 70 percent. percent
An rise in the amount of extreme weather events, such as wildfires, heat waves, and strong tropical storms, is also attributed in part to climate change by some experts.
Sea level could rise between 7 and 23 inches (18 to 59 centimeters) by centurys end. Some hundred million people live within 3 feet (1 meter) of mean sea level, and much of the worlds population is concentrated in vulnerable coastal cities.
Glaciers around the world could melt, causing sea levels to rise while creating water shortages in regions dependent on runoff for fresh water. Strong hurricanes, droughts, heat waves, wildfires, and other natural disasters may become commonplace in many parts of the world.
More than a million species face extinction from disappearing habitat, changing ecosystems, and acidifying oceans. The oceans circulation system, known as the ocean conveyor belt, could be permanently altered, causing a mini-ice age in Western Europe and other rapid changes.
The greenhouse effect is a natural warming process. Carbon dioxide (CO2) and certain other gases are always present in the atmosphere. These gases create a warming effect that has some similarity to the warming inside a greenhouse, hence the name “greenhouse effect.”
Increasing the amount of greenhouse gases intensifies the greenhouse effect. Higher concentrations of CO2 and other greenhouse gases trap more infrared energy in the atmosphere than occurs naturally. The additional heat further warms the atmosphere and Earth’s surface.
Sunlight brings energy into the climate system; most of it isabsorbed by the oceans and land.
Some of the infrared energy furtherTHE GREENHOUSE EFFECT : warms the Earth.Heat (infrared energy) radiates AMPLIFIED GREENHOUSEoutward from the warmed surface of EFFECT:the Earth. Higher concentrations of CO2 andSome of the infrared energy is other "greenhouse" gases trap moreabsorbed by greenhouse gases in infrared energy in the atmospherethe atmosphere, which re-emit the than occurs naturally. The additionalenergy in all directions. heat further warms the atmosphere and Earth’s surface.Some of the infrared energy isemitted into space.
CO2 and Other Greenhouse Gas Variations Human Activity and Greenhouse Gas Reducing Other Greenhouse Gases Ocean Circulation Volcanic Eruptions Solar Variations Orbital Variations Land Use Changes
Factors that can amplify or reduce the effect of the causes of change are known as "feedbacks." Some of the key feedbacks are described in the following sections. These feedbacks consist of interconnected processes in which a change in one leads to a change in another, which ultimately leads to further changes in the first.
Aerosols Clouds Water Vapor Ice-Reflectivity