What is climate change?
As noted earlier, climate can be defined as a description of weather over a long period. Earth’s climate has been changing due to natural factors for millions of years, with alternating cycles of warming and cooling. It is important to note that these have occurred over very long periods, as in the case of the Ice Ages.
Since the 1990s, the pace of climate change has increased substantially because of human activity, which is causing Earth to get warmer. Higher temperatures because of climate change contribute to more frequent and increased rainfall, changes in wind patterns and higher temperatures. These factors all worsen the frequency, intensity and impacts of extreme weather events.
Image source: Vektorjuice. (n.d.). Earth climate change, temperature increase, global warming. multiple fires, flora and fauna destruction, planet. Freepik.com
Greenhouse gases and global warming
Earth is a unique planet because it has a protective layer of gases that help to maintain the temperatures that allow life to exist and block out harmful rays of sunlight. Nitrogen (N: 78%), oxygen (O: 21%) and tiny amounts of greenhouse gases (GHGs) make up the majority of the atmosphere. The GHGs trap the heat in the atmosphere, keeping the temperature on Earth at the required level.
The composition of the greenhouse gases is changing because of human activities that add carbon dioxide (CO2) to the air. An increase in the quantity of GHGs means that more heat is retained on Earth’s surface. This causes global warming, which is leading to climate change.
Let us learn a little about the greenhouse gases that are contributing to climate change.
Carbon dioxide (CO2) is produced naturally when people and animals breathe. Volcanoes also produce it. Plants and trees need it to live and absorb it from the atmosphere. Human activities such as producing electricity, running vehicles and cutting down forests and grasslands release extra CO2 into the air.
Methane (CH4) is produced by the breakdown or decay of organic material, so it gets into the atmosphere by natural processes such as the decaying of plant materials in wetlands, seepage of gas from underground deposits and release of natural gases by cattle as part of their digestive process. Human activities such as oil production, rice farming and waste management produce extra CH4.
Earth’s increasing temperatures are sounding an alarm bell!
The Intergovernmental Panel on Climate Change (IPCC), a body of the United Nations, publishes assessment reports on the impact of climate change on the global community. Its sixth assessment report, published in 2022, found that Earth had already warmed by nearly 2° Fahrenheit (1.1°C) since 1850-1900, and that this was because of human-caused emissions of heat-trapping greenhouse gases. Countries agreed to take action to limit the global increase in temperature to less than 2°C, preferably 1.5°C, which is the point at which climate impacts will become increasingly harmful.
Adapted from Centre for Environment Education. (2003). Climate action leadership challenge: An interactive teaching-learning booklet. https://gen4climateaction.org/resource (hard copy only)
