The Threat Posed by Climate Change

The Myths against Climate Change

It is now widely accepted that human-induced climate change poses a significant threat to the welfare of the international community and the natural environment. Between the mid 19th century and the early 21st century, the global average surface temperature increased from around 13.7ºC (degrees centigrade) to 14.5ºC. The rate of warming has doubled over the past 50 years.

If the international community does not make a concerned effort to reduce greenhouse gas emissions, there is a risk that the global average surface temperature could rise by a further 6ºC by the end of this century.

Why is the world warming?

It is believed that most of the observed warming since the mid-20th century has been driven by the accumulation of greenhouse gases in the atmosphere, such as carbon dioxide (CO2), methane (CH4) and nitrogen oxides (NOx). The contribution of these gases to the greenhouse effect depends on the molecular structure of the gas and is not equal: methane is four times as effective as a greenhouse gas than carbon dioxide; nitrous oxide (NO3) is 262 times as effective. The term ‘carbon dioxide equivalents’ (CO2-e) is used to describe the combined effects of these greenhouse gases, against the benchmark of carbon dioxide.

The accumulation of greenhouse gases has been caused principally by land clearing (particularly the clearing of forest and the draining of wetlands) and the burning of fossil fuels, such as coal and oil.

The Tipping Point