We still hear it a lot from detractors of scientific reality: the climate is continually changing, and humans have nothing to do with it. This is false.
The Earth has experienced several climatic cycles during its evolution. Coolings and warmings that had nothing to do with humanity, created by changes linked in particular to volcanic activity and solar radiation.
Then arrived Homo sapiens – modern humans –, a primate native to Africa which spread across the planet over a period of 300,000 years.
If the species has left its mark there for several thousand years already – particularly since its populations became sedentary – it is only in the last 200 years that its activities have modified the climate.
When humans began burning fossil fuels like coal, oil and gas to create powerful machines, this combustion generated greenhouse gas emissions which over time formed a veritable “atmospheric lid » around the Earth which traps heat from the Sun and causes temperatures to rise.
The proof is made
Scientists have raised the possibility of a link between human activities and climate change since the late 1800s, when Swedish chemist Svante Arrhenius theorized that the buildup of carbon dioxide (CO2) could to create a greenhouse effect leading to global warming. The idea did not strike people’s minds at the time, even if it slowly gained ground.
However, it was only following the reports of the Intergovernmental Panel on Climate Change (IPCC) – published from the 1990s – that the evidence became clear and definitive, and above all, widely accepted. everyone: scientists and governments.
Today, it is clearly established that human activity is the main cause of climate change. The latest IPCC summary report published in March 2023 – written by hundreds of scientists and endorsed by the governments of every country in the world – further confirmed this.
This influence is manifested by a rapid and large-scale change in different components of the climate system (atmosphere, oceans, cryosphere and biosphere), which notably increases extreme climate phenomena.
And for those who doubt the scientific consensus established by the IPCC, the conclusions of a survey published in 2021 could not be clearer: no less than 99.9% of the 88,125 climate-related studies peer-reviewed and published between 2012 and 2020 show that climate change is mainly caused by humans.
