Climate change

• Climate has changed naturally. The Quaternary period began about 2.6 million years ago and has had cold glacial periods and warmer interglacial periods. Evidence for long-term change includes ice cores, ocean sediments, rocks and fossils. Recent evidence includes temperature records, shrinking glaciers and rising sea level.
• Natural causes include changes in the Earth's orbit, volcanic eruptions and changes in the sun's output. Human causes include burning fossil fuels, farming (cattle and rice give off methane) and cutting down forests.
• The greenhouse effect: gases such as carbon dioxide and methane absorb heat leaving the Earth's surface and trap it in the lower atmosphere. More gas traps more heat.
• Mitigation reduces the causes. Examples are renewable energy, carbon capture and storage, planting trees and international agreements. Adaptation responds to the effects. Examples are managing water supply, changing farming and protecting against rising sea level.

Greenhouse effect

Gases in the atmosphere trapping heat leaving the Earth's surface.

Quaternary

The period that began about 2.6 million years ago.

Mitigation

Action to reduce the causes of climate change.

Adaptation

Action to cope with the effects of climate change.

Carbon capture and storage

Trapping carbon dioxide from power stations and storing it underground.

Fossil fuels

Coal, oil and gas, which release carbon dioxide when burned.

• Saying greenhouse gases give off heat. They absorb heat leaving the Earth and trap it.
• Thinking carbon capture means reducing all pollution. It traps carbon dioxide and stores it underground. Planting trees captures carbon naturally.
• Treating international agreements as laws every country must obey. Countries set their own targets and can weaken them or withdraw.

6 questions, 11 marks. Answer, then press Check. The marking guide explains how the marks are worked out. Nothing is saved.