CAUSES OF CLIMATE CHANGE

 Global warming

The decade 2011-2020 was the warmest on record, with global average temperatures rising 1.1 degrees Celsius over pre-industrial levels in 2019. Global warming caused by humans is currently increasing at a rate of 0.2°C every decade. A 2°C rise in temperature compared to pre-industrial times has serious effects for the natural ecosystem as well as human health and well-being, including a significantly increased risk of damaging and potentially catastrophic changes in the global environment. As a result, the international community has recognized the importance of keeping global warming below 2°C and pursuing efforts to keep it below 1.5°C.

Greenhouse effect

The greenhouse effect is the primary cause of climate change. Some gases in the Earth's atmosphere behave as greenhouse glass, trapping heat from the sun and preventing it from escaping into space, causing global warming. Many of these greenhouse gases occur naturally, but human activity is increasing the concentrations of some of them in the atmosphere, in particular:

• carbon dioxide (CO₂)
• methane
• nitrous oxide
• fluorinated gases

Human-caused CO2 is the most significant contributor to global warming. Its concentration in the atmosphere had risen to 48% above pre-industrial levels by 2020. (Before 1750). Human activity also emits lower amounts of other greenhouse gases. Methane is a stronger greenhouse gas than CO2, although it has a shorter lifespan in the atmosphere. Like CO2, nitrous oxide is a long-lasting greenhouse gas that builds up in the atmosphere over decades to centuries.  Between 1890 and 2010, natural processes such as variations in solar radiation or volcanic activity are estimated to have contributed less than 0.1°C to total warming.

Causes of rising emissions

The first cause of rising emissions is carbon dioxide and nitrous oxide are produced when coal, oil, and gas are burned. Next, destruction of forests (deforestation). By absorbing CO2 from the atmosphere, trees assist to control the climate. When trees are cut down, the beneficial effect is gone, and the carbon contained in the trees is released into the atmosphere, so contributing to the greenhouse effect. Moreover, increased livestock production. When cows and sheep digest their meal, they produce a lot of methane. Nitrous oxide emissions are produced by nitrogen fertilisers. Furthermore, fluorinated gases are emitted by fluorinated gas-using equipment and goods. These emissions have a warming effect that is up to 23 000 times stronger than CO2.