Greenhouse gas emissions have increased by 80% since 1970 and by 30% since 1990. Between 2000 and 2020, they were the highest in human history. Why do human activities increase the greenhouse effect so much? And which sectors of activity are mainly concerned?
Over the past decades, the Earth has suffered from accelerated global warming mainly caused by human activity. Man is the only plausible cause to explain this sudden and sustained increase in average temperature which has increased the greenhouse effect.
Greenhouse effect: what gases and what causes?
While a small amount of greenhouse gases are produced naturally (eg water vapor), the majority are emitted by human activities.
The massive use of fossil fuels (coal, oil and gas) and deforestation produce alarming amounts of CO2 which accumulate in the atmosphere.
This gas alone is responsible for two thirds of the greenhouse effect. On a planetary scale, 75% of it is released by hydrocarbons. It is used everywhere: production of electricity in thermal power stations, road and air transport, agricultural machinery, manufacture of cement and steel, heating of buildings and even production of hot water.
20% of the CO2 is released by deforestation : Forests are destroyed by burning trees to increase the area of cultivable land.
Methane, nitrous oxide and ozone
Intensive agriculture and animal husbandry also contribute significantly to greenhouse gas emissions, mainly from methane and nitrous oxide.
the methane is emitted by the digestion of cattle and other ruminants in intensive farming while the nitrous oxide (laughing gas) is essentially given off by the soil, which receives more fertilizer than the crops can absorb.
Rest theozone, another greenhouse gas, which is formed under the action of solar radiation on hot days, when it meets the polluted air in cities.
All these activities are thus directly involved in theacceleration of warming of the planet. This excess of greenhouse gases in the atmosphere has irreparably disrupted the Earth’s climate.
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Greenhouse gas emissions: the top 10
- Coal-fired power plants 20% (2/3 for electricity production)
- Agriculture 20% (mostly methane, because of livestock farming and rice paddies, etc.)
- Transportation 14% (car 6%, truck 4%, planes 2%, ships 2%)
- Deforestation 10% (forests burned to expand agricultural areas)
- Steelworks, boilers and industrial blast furnaces 10%
- Gas and oil power stations 7%
- Cement works 7% (limestone heating)
- Heating of buildings 6%
- Digital activities (internet, computers, telephones, servers) 4%
- Others (waste management, water treatment) 7%
