Global warming, as the name suggests, is the long-term rise of the Earth’s average temperature. Certain gases in the atmosphere act like glass in a greenhouse, allowing sunlight through to heat the earth’s surface but trapping the heat as it radiates back into space. These greenhouse gases are what builds up in the Earth’s atmosphere, thus making the Earth hotter. This process is leading to a rapid change in climate, also known as climate change.
Many people think of climate change being the same as global warming, however, climate change is used to describe the shift that is now affecting the Earth’s weather and climate system. Climate change encompasses not only rising average temperatures but also extreme weather events, shifting wildlife populations and habitats, rising seas, and a range of other impacts. As humans continue to produce such greenhouse gases that will trap the heat in the atmosphere, these changes will continue to emerge and impact life on Earth.
So what exactly causes global warming?
Global warming occurs when air pollutants and greenhouse gases collect in the atmosphere and absorb sunlight and solar radiation that have bounced off the Earth’s surface. Normally, this radiation would escape into space—but these pollutants, which can last for years to centuries in the atmosphere, trap the heat and cause the planet to get hotter. That’s what’s known as the greenhouse effect. There are several greenhouse gases responsible for warming, and humans emit them in a variety of ways. Most come from the combustion of fossil fuels in cars, buildings, factories, and power plants.
Causes of greenhouse effect include:
1. Carbon dioxide (CO2)
Greenhouse effect is primarily a problem of too much carbon dioxide (CO2) in the atmosphere. This carbon overload is caused mainly when we burn fossil fuels like coal, oil and gas or cut down and burn forests. Other times, carbon dioxide is released through natural processes such as respiration and volcano eruptions. Humans have increased atmospheric CO2 concentration by more than a third since the Industrial Revolution (the transition to new manufacturing processes) began. This is the most important long-lived “forcing” of climate change.
Methane is a greenhouse gas as is carbon dioxide. Human activity has increased the amount of methane in the atmosphere, contributing to the causes of climate change. Some examples of human activities that contributes to methane being produced include the decomposition of wastes in landfills, agriculture, and especially rice cultivation, as well as ruminant digestion and manure management associated with domestic livestock. On a molecule-for-molecule basis, methane is a far more active greenhouse gas than carbon dioxide, but also one which is much less abundant in the atmosphere. While methane is a more potent greenhouse gas than CO2, there is over 200 times more CO2 in the atmosphere.
3. Nitrous oxide
Nitrous oxide is powerful greenhouse gas that has an atmospheric lifetime of 110 years. It is produced by soil cultivation practices, especially the use of commercial and organic fertilizers, fossil fuel combustion, nitric acid production, and biomass burning. Although relatively small amounts are released, it has a high “global warming potential” (310 times that of carbon dioxide). Nitrous oxide also contributes to ozone depletion, thus reducing the protection offered from harmful UV sun rays.
4. Chlorofluorocarbons (CFCs)
CFCs are also powerful greenhouse gases. The production of CFCs began for the purpose of refrigeration, air conditioners, aerosol spray cans, and industrial cleaning products. CFCs’ contribution to global warming has been small, but now largely regulated in production and release to the atmosphere because of their ability to contribute to ozone depletion.
Since 1906, the global average surface temperature has increased by more than 1.6 degrees Fahrenheit (0.9 degrees Celsius)—even more in sensitive polar regions. The heat is melting glaciers and sea ice, shifting precipitation patterns, and setting animals on the move. Much of this melting ice contributes to sea-level rise. Global sea levels are rising 0.13 inches (3.2 millimeters) a year, and the rise is occurring at a faster rate in recent years.
Other global warming effects could take place later this century, if warming continues. These include:
Sea levels are expected to rise between 26 and 82 centimetres or higher by the end of the century.
Hurricanes and other storms are likely to become stronger. Floods and droughts will become more common.
Less freshwater will be available, since glaciers store about three-quarters of the world’s freshwater.
Ecosystems will continue to change: Some species will move farther north or become more successful; others, such as polar bears, won’t be able to adapt and could become extinct.
Rising temperatures will likely lead to increased air pollution, a longer and more intense allergy season, the spread of insect-borne diseases, more frequent and dangerous heat waves, and heavier rainstorms and flooding. All of these changes pose serious, and costly, risks to public health. We can all do our part in slowing down the process of global warming with something as simple as recycling or switching to solar energy.