The atmosphere is a protective layer of gases that spreads all around the surface of the Earth. It acts like a greenhouse, trapping infrared radiation emitted from the Earth’s surface. This means that the Earth can have relatively warm and stable temperatures all the time.
A greenhouse gas is a gas that absorbs the Sun’s infrared radiation, therefore trapping it in the Earth’s atmosphere. Greenhouse gases contribute to the greenhouse effect, which raises the Earth’s average temperature. The main greenhouse gases are:
The greenhouse effect is essential for life on Earth, but it also contributes to global warming.
1. The Sun emits heat (infrared radiation) down towards Earth.
2. Some of the heat is absorbed by the atmosphere, while the rest reaches the Earth’s surface.
3. Some of the heat that reaches the Earth’s surface is absorbed and the rest bounces back from the surface.
4. However, most of this heat does not get back into space, as the atmosphere absorbs it instead.
Mainly due to human activity, there is a build-up of greenhouse gases in the atmosphere. For example:
The more greenhouse gases there are, the greater the greenhouse effect is. This warms up the Earth over time and causes global warming.
Global warming is the increase in the average temperature of the Earth’s surface.
Climate change refers to changes in long-term weather patterns and is a consequence of global warming. As weather conditions change, species that had perfectly adapted to their environment may be forced to migrate.
Some species may migrate and manage to survive in a different environment. However, some may not adapt or migrate fast enough, causing them to become extinct. This will decrease biodiversity.
Two main consequences of global warming for the organisms on Earth are:
Extreme weather events, such as floods, hurricanes and droughts, will become more frequent and severe. This will decrease the number of available habitats. It will also make food and water more scarce.
A global rise in temperature will cause sea levels to rise. This can happen in two ways:
Rising sea levels will lead to seasonal flooding, which will decrease the number of available habitats.