Watch a video where scientists discover bubbles of ancient atmosphere in ice cores with trapped greenhouse gases that are over 200,000 years old. Study graphs and look for patterns in the data to see how temperature and greenhouse gases have changed over time.
The greenhouse effect is a natural phenomenon, keeping the Earth warm enough for life to exist. Greenhouse gases in the atmosphere, including carbon dioxide, methane, nitrous oxide and water vapour, trap heat from the sun. Most scientists believe the Earth is getting warmer because of human activities, in particular the use of fossil fuels. This began with the Industrial Revolution (1760 to 1840). Manufacturing shifted to factories and steam power was used in the textile, electric and automobile industries. Steam power and steam engines primarily burned coal as their energy source, releasing greenhouse gases. Since then, the population has grown from 700 million to 7.5 billion people. More people and more things use more energy and produce more greenhouse gases.
Ice cores provide evidence about environmental conditions from the past. Ice cores are like tree rings, where a new snow layer is created each year. The layers provide historical information about how much snow fell each year and contain materials like debris from forest fires or volcanoes, dust carried by the wind, bubbles of gases from the atmosphere and samples of insects or pollen. The information helps us understand how greenhouse gases in the atmosphere have fluctuated from the past to the present.