Causes of Climate Change
- Published: Thursday, 20 June 2019 13:14
Michiel Haas – the Netherlands
- Earth has a changing climate
Our Earth has always had a changing climate. Warming and cooling have taken place in varying wave movements and are controlled by, among other things, the angle of the earth's axis to the sun. These periodic long-term climate changes have been described by the Serbian mathematician Milutin Milankovitch (1879-1958). The last ice age, also known as the Weichselien, ended some 11,700 years ago. This was preceded by a long period in which it was considerably colder than it is now. No trees grew in the Netherlands, a cold polar wind blew, and the oceans were about 6 degrees colder than today. According to Milutin Milankovitch, the next ice age will take place in approximately 55,000 years. Other scientists are less certain about that. But after warming irrevocably comes cooling.
- Earth atmosphere or climate
The Earth has an atmosphere around it, which is bound to the Earth by gravity. This atmosphere is of great importance for life on Earth. The atmosphere tempers the sunlight, maintains the Earth's energy balance and protects against harmful radiation, such as ultraviolet radiation. This atmosphere is like a blanket around the Earth and that is why we also speak of a kind of greenhouse. That is why the temperature on Earth is pleasant. Without the atmosphere, the temperature would be -18 degrees Celsius, with this atmosphere the average temperature is +15 degrees Celsius.
The atmosphere consists of a mixture of different gases. The volume ratios of these gases in the lower layers of the atmosphere, up to about 90 km altitude, are almost constant, except for the share of water vapor.
The atmosphere is bound to the Earth by gravity and is part of the rotation of the Earth. Without an atmosphere, life on Earth would not be possible. Because of our unbridled burning of fossil fuels we are changing the atmosphere around the Earth with all the consequences that entails. (Photo: nasa-43566 on Unsplash)
- Greenhouse gases
The most important greenhouse gases are:
- Carbon dioxide CO2 - colourless and odourless gas, non-toxic, is absorbed by plants; is released by burning fossil fuels, by composting and decaying and by melting permafrost;
- Methane CH4 - colourless and odourless gas, flammable, occurs naturally in swamps and peat and is released by melting permafrost, by forest fires and decaying material: human influence strongly through livestock farming, agriculture, landfills and burning fossil fuels;
- Nitrous oxide N2O - laughing gas, colourless and slightly sweet-smelling gas, is used in anaesthetics, to give engines more power, emissions via agriculture, manure and fertilizer, chemical industry, waste incineration, burning fossil fuels;
- Water vapor H2O - strongest greenhouse effect due to the large quantity in the atmosphere; increasing water vapor in the atmosphere increases the greenhouse effect, but due to cloud formation less sunlight will be absorbed, causing cooling again;
- Chlorofluorocarbon compounds CFC's -in aerosols and in coolants of e.g. refrigerators and air conditioners, is now prohibited because of ozone layer depletion;
- Sulfur hexafluoride SF6 - is a colourless and odourless gas, the gas is five times denser than air, it is used in electrical engineering and medical engineering;
- Ozone O3 - a colourless to light blue gas with an unpleasant pungent odor, ozone is naturally formed in the atmosphere under the influence of electrical discharges (such as during thunderstorms) and ultraviolet radiation; the warming effect is still unknown.