Climate change
Climate versus weather
Average weather conditions over longer periods and over large areas. is different from The day-to-day condition of the atmosphere. because climate refers to the average temperature and cycles of weather over long periods of time – decades at least. People might talk about the weather being windy last week, or hotter last year than the year before. But unless the data is compared for many years a judgment cannot be made about whether the climate is changing.
Are humans causing global warming?
Human activities are increasing the amount of some greenhouse gases in the atmosphere. For example:
- burning Natural, finite fuel formed from the remains of living organisms, eg oil, coal and natural gas. in industry, vehicles and A building that generates electricity. releases carbon dioxide
- The cutting down of trees and forests to allow a different land use. releases carbon dioxide when trees are burnt and reduces the absorption of carbon dioxide through A chemical process used by plants to make glucose and oxygen from carbon dioxide and water, using light energy. Oxygen is produced as a by-product of photosynthesis. Algae subsumed within plants and some bacteria are also photosynthetic.
- farming cattle and growing rice in Fields where rice is grown. releases A colourless gas that can do harm to life forms.
The amount of carbon dioxide in the atmosphere has increased over the past 150 years as a result of human activities.
Over the same time, the average temperature of the surface of the Earth has also increased.
One of the commonly used pieces of evidence that humans are causing global warming is that there is a strong A relationship between two sets of data, such that when one set changes you would expect the other set to change as well. between the increase in global carbon dioxide levels caused by human activities and the increase in global temperatures over the same timescale.
The vast majority of scientists believe that humans are responsible for the increase in greenhouse gases and therefore global warming. This is because the majority of evidence in A process by which a scientific report is reviewed and checked for accuracy by other science experts before being published in a journal or on an official science website.A science magazine which normally specialises in a specific area of science and publishes research which has been done by scientists and checked (peer reviewed) by other scientists. supports the theory that human activities are causing an increase in greenhouse gases and this is causing global warming.
Climate science is complicated and it is difficult to predict what will happen to greenhouse gas emissions in the future. Data is analysed using computer models based on the physics that describes the movements of mass and energy in the atmosphere and oceans. The climate is affected by many factors, and detailed data is not available from all locations on Earth, leading to uncertainties in the predictions.
Learn more about climate change with Dr Alex Lathbridge.
Listen to the full series on BBC Sounds.
In this podcast, learn the key facts about climate change. Listen to the full series on BBC Sounds.
