Global warming is the increase in the average temperature of Earth’s near-surface air and oceans since the mid-20th century and its projected continuation. According to the 2007 Fourth Assessment Report by the Intergovernmental Panel on Climate Change (IPCC), global surface temperature increased during the 20th century. Most of the observed temperature increase since the middle of the 20th century was caused by increasing concentrations of greenhouse gases, which results from human activity such as fossil fuel burning and deforestation.
Greenhouse gases are gases in our atmosphere that absorb and emit radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect leading to the warming of the planet. The main greenhouse gases in the Earth’s atmosphere are water vapour, carbon dioxide, methane, nitrous oxide, and ozone. The contribution to the greenhouse effect by a gas is affected by both the characteristics of the gas and its abundance. For example, methane is about eighty times stronger greenhouse gas than carbon dioxide, but it is present in much smaller concentrations so that its total contribution is smaller. When these gases are ranked by their contribution to the greenhouse effect, the most important is Carbon dioxide.
CARBON DIOXIDE INFO
Carbon dioxide (CO2) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth’s atmosphere in this state. CO2 is a trace gas comprising 0.039% of the atmosphere.
Carbon dioxide is a colourless odourless gas (at low concentrations) and was one of the first gases to be described as a substance distinct from air. In the seventeenth century, the Flemish chemist Jan Baptist van Helmont observed that when he burned charcoal in a closed vessel, the mass of the resulting ash was much less than that of the original charcoal. His interpretation was that the rest of the charcoal had been transmuted into an invisible substance he termed a “gas” or “wild spirit” – Carbon dioxide was born. The properties of carbon dioxide were studied more thoroughly in the 1750s by the Scottish physician Joseph Black who is generally attributed to the scientist who discovered Carbon dioxide in 1973.
CARBON DIOXIDE AND THE ENVIRONMENT
The link between Carbon dioxide and the environment was first suggested in 1827 by Jean-Baptiste Fourier who theorized that an atmospheric effect kept the earth warmer than it would otherwise be – he used the analogy of a greenhouse. Finally, in 1896, Svante Arrhenius proposed that carbon dioxide emissions from the burning of coal would enhance the earth’s greenhouse effect and lead to global warming. In 1967, a computer simulation calculated that global temperatures might increase by more than 4 degrees Fahrenheit, depending on carbon dioxide levels. 20 years later, an ice core from Antarctica revealed a link between carbon dioxide levels and temperature going back more than 100,000 years. Warnings like these encouraged international actions on climate change.
In 1979, the world held its first climate conference. The conference called on governments “to foresee and prevent potential man-made changes in climate” and the modern-day climate debate commenced.