The Greenhouse Effect M 3 Global Issues The

The Greenhouse Effect M 3 Global Issues

The Greenhouse Effect • Certain gases in the atmosphere trap energy from the Earth's surface. • Increased amounts of these gases are causing global warming. • This means the average temperature of the Earth's surface is increasing.

The Greenhouse Effect • The Earth's atmosphere acts like a kind of greenhouse. • It traps energy and keeps the Earth warm. • It makes the Earth's surface 33°C warmer than it would be otherwise. • Without the atmosphere, the Earth would be a frozen planet with no life.

The Greenhouse Effect

The Greenhouse Effect • The Earth in turn radiates this energy out into space again as infra-red rays. • Some of these rays are absorbed as they pass through the gases of the atmosphere, causing it to heat up. • This traps extra energy in the atmosphere, just like what happens in a greenhouse. • Not all the gases in the atmosphere absorb energy Oxygen, nitrogen and the noble gases absorb very little of the infra-red energy.

Greenhouse Gases Slash and burn of rainforests

Greenhouse Gases Volcanic eruptions

Greenhouse Gases

Human Activity • So the problem is that 'human activity' is increasing the amount of carbon dioxide in the atmosphere. This is causing more energy to be trapped which results in changes to the Earth's climate.

Human Activity • By our actions, we are disturbing the natural balance of the planet. • The Earth's environment may be able to cope in the long run, but there will be severe problems caused by the extra energy

Effects of Global Warming • higher temperatures (2° to 5 °C higher) during the next century • melting of ice masses at the North and South poles • a rise in sea level (of between 20 to 30 m) • more flooding of low-lying land • more violent weather • more cloud cover and heavy rain

Effects of Global Warming • changes in sea currents • deserts to move further north • more storms, hurricanes and floods causing human suffering • changing crop patterns • changes in food webs and possible extinction of some species.