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WHAT IS CLIMATE CHANGE?
Climate change is different from changes in the weather. Weather can change from day to day and hour to hour, while climate is the average pattern of weather over a long time. Climate change is an alteration of the earth’s general weather conditions. The most prominent part of climate change is the rising temperature at the earth’s surface.
Apart from increasing average temperature, climate change also includes changes in rainfall patterns and an increase in extreme weather events that lead to phenomena such as floods and droughts.
- There is an increase in the average global temperature of about 1°C.
- A 0.19 m rise in the average global sea level has been observed.
- There is reduced snow cover in the northern hemisphere, melting ice sheets in Greenland and Antarctica and there's a 4% decrease in Arctic ice.
- Average precipitation over mid-latitude areas in the Northern hemisphere has significantly increased. There are more heavy rainfall events over most land areas. This leads to a higher risk of flooding in certain areas.
- Since the 1970s, droughts are longer and more intense. Drying in the Sahel, the Mediterranean, southern Africa and parts of southern Asia.
- Though some places have become colder, the general trend is a decrease in cold days and nights, with an increase in heat waves, as well as warmer days and nights.
- Over 30% of the increase in carbon dioxide has been absorbed by the oceans. The oceans are now 26% more acidic and in combination with warmer seawater, this is impacting marine life.
THE AIR IS ARROUND US
When we breathe, we take up oxygen through our lungs and exhale carbon dioxide. Plants take up carbon dioxide and release oxygen into the atmosphere. Nitrogen is needed by living organisms. As a gas, it is absorbed into the soil, where bacteria convert it into a solid form that plants can use. The water and gases in the atmosphere allow the sun’s rays to reach the earth’s surface while trapping the radiation released by the earth. The trapping of radiation, known as the natural greenhouse effect, makes the layer of the atmosphere close to the earth’s surface warm enough to support the life on Earth.
WHAT IS AIR POLLUTION?
Air pollution is contamination of the air by any chemical or compound that changes the natural characteristics of the atmosphere. This includes harmful substances in the air that may negatively affect human, animal and plant life. The substances that cause air pollution are called pollutants. Pollutants that are released directly from sources are called primary air pollutants. Examples include carbon monoxide (CO) from vehicle exhausts and sulphur dioxide (SO2) from burning coal.
- Combustion (burning of substances that contain hydrogen and carbon) emits carbon dioxide. Industrial processes that involve burning coal, oil or other fuels can thus cause serious air pollution.
- Industrial plants such as brickworks, steelworks, plants converting coal into oil, chemical plants, sawmills, paper mills and cement manufacturers are among those that can produce harmful pollutants.
- Power stations that produce energy by the burning of fossil fuels such as coal, gas and oil also contribute to air pollution. Most of South Africa’s electricity comes from the combustion of coal. The emissions produced include sulphur dioxide, carbon monoxide, various nitrogen oxides (NOx), mercury (Hg) and tiny particles, such as ash.