|Carbon dioxide||Burning fossil fuels|
The concentration of carbon dioxide in the atmosphere has increased in the last 200 years.
The extra carbon dioxide is causing an enhanced greenhouse effect, greater than would happen naturally. There is a correlation between the increase in atmospheric carbon dioxide concentration, and temperature change.
As the concentration of carbon dioxide has increased, the global average temperature has generally increased too.
There is a correlation between the consumption of fossil fuels and the amount of carbon dioxide in the atmosphere (and also between the consumption of fossil fuels and the average temperature of the atmosphere). While a correlation between two factors does not necessarily mean that one causes the other, the majority of climate scientists believe that the increase in atmospheric carbon dioxide caused by burning more fossil fuels is causing the increase in atmospheric temperature and changes in the Earth's climate. A report from the Intergovernmental Panel on Climate Change (UN, 2014) stated that there is a 95% probability that human activity has caused an increase in the Earth's temperature. It cites human-produced greenhouse gases such as carbon dioxide as major contributors to the observed increase in our planet's temperature over the past 50 years.
Some scientists disagree. They might claim that climate change is a result of a natural cycle.
Suggest two reasons why climate change leads to rising sea levels.
Water from melting glaciers and polar ice enters the oceans. As the Earth's temperature increases, seawater warms up and expands.
There are international treaties aimed at reducing the emissions of carbon dioxide and other greenhouse gases. However, even if these emissions could fall significantly, it would take a long time for the Earth's temperature to stabilise then decrease. In the meantime, there are ways to mitigate the effects of climate change. These include:
These steps are expensive, need to be on a large scale, and may themselves harm the environment.