Impact on global climate

Question 1

Greenhouse gases

Answer 1

A gaseous compound in the atmosphere that is capable of absorbing infrared radiation, thereby trapping and holding heat in the atmosphere. Examples include CO2 and CH4. Without these the Earth would be frozen.

Question 2

Enhanced greenhouse effect

Answer 2

Increased emissions resulting from anthropogenic activities such as burning fossil fuels and deforestation have increased the concentration of greenhouse gases, making them more effective in trapping radiation given off by the Earth.

This explains why average global temperatures have increased by 0.8°c since 1880.

Question 3

Global warming

Answer 3

This refers to the long-term warming of the planet.

Global temperatures show a rise since the early 20th century and most notably since the late 1970s. Worldwide, since 1880 the average surface temperature has increased by 0.8 °C.

Question 4

radiative forcing

Answer 4

The difference between the incoming solar energy absorbed by the Earth and energy radiated back to space. It is the amount that the Earth’s budget is out of balance and is a measure of recent human activities. It is measured in watts/m² of the Earth’s surface.

Question 5

greenhouse effect

Answer 5

This is the natural process by which the atmosphere traps some of the sun’s energy, warming the Earth enough to support life.

Question 6

Albedo

Answer 6

It is the reflectivity of a surface.

It is the ratio between the amount of incoming insolation and the amount of energy reflected back into the atmosphere. Light coloured surfaces reflect more than dark surfaces, meaning light coloured surfaces have a higher value.

Question 7

climate change

Answer 7

refers to the broader range of changes that are happening to our planet. These include rising sea levels, shrinking mountain glaciers, accelerating ice melt in Greenland, Antarctica and the Arctic