Explain the causes and effects of increasing levels of carbon dioxide in the atmosphere

Carbon dioxide is a greenhouse gas that is produced through the burning of fossil fuels such as coal, oil and gas. Increased demands for electricity, heating and cars etc. means that more fossil fuels are being burned, leading to an increase in carbon dioxide in the atmosphere. 

Carbon dioxide plays a key role in the "greenhouse effect". Normally, when the Sun's rays enter the atmosphere, heat is reflected back into space. However, carbon dioxide is a greenhouse gas and so absorbs heat, preventing it from being released to space. This leads to global warming as the Earth warms up as a result of the extra trapped heat. This rise in worldwide temperatures has many effects including polar ice caps melting, rising sea levels, more severe weather storms, crop failures and disappearance of coral reefs.