Transcript
Junona Veselova, Kristina Zagidullina“Zaliakalnio” gymnasium
Global warming
What's Going to Happen?
Natural and Amplified Warming
Causes
refers to the current rise in the average temperature of Earth's atmosphere and oceans and its projected continuation.
Average temperatures have climbed 1.4 degrees 1.4 degrees FahrenheitFahrenheit (0.8 degree Celsius) around the world since 1880.
Average temperatures in Alaska, western Canada, and eastern Russia have risen at twicehave risen at twice the global average.
Glaciers and mountain snows are rapidlyGlaciers and mountain snows are rapidly meltingmelting—for example, Montana's 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 percent70 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 7 and 23 inches (18 to 59 centimeters) by century's end.
Some hundred million people live within 3 feet (1 meter) of mean sea level, and much of the world's 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 million species face extinction from disappearing habitat, changing ecosystems, and acidifying oceans.
The ocean's 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 (COCarbon dioxide (CO22) ) 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.”“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 is absorbed by the oceans and land.
Heat (infrared energy) radiates outward from the warmed surface of the Earth.
Some of the infrared energy is absorbed by greenhouse gases in the atmosphere, which re-emit the energy in all directions.
Some of the infrared energy is emitted into space.
Some of the infrared energy further warms the Earth.THE GREENHOUSE EFFECT:
AMPLIFIED 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.
Climate Is Changed by Many Processes
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
Think again
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