The greenhouse effect is a process that occurs when gases in Earth’s atmosphere trap the Sun’s heat. This process makes Earth much warmer than it would be without an atmosphere. It’s one of the things that makes Earth a comfortable place to live.
Human activities are changing Earth’s natural greenhouse effect. Burning fossil fuels like coal and oil puts more carbon dioxide into our atmosphere. And some other activities put other greenhouse gases into it.
Too much of these greenhouse gases can cause Earth’s atmosphere to trap more and more heat. This causes Earth to warm up.
Last week, in prime time, and in front of 4 million viewers, Eric Zemmour, a writer and TV celebrity known for his far-right nationalism and who currently dominates political talk in France claimed that “there are debates between scientists on global warming” …
It’s stupid. And it’s wrong (there is no debate). But I guess he doesn’t care : quoted recently on Twitter by a person close to the polemicist, Tocqueville said in 1851, that “a dwarf on the top of a great wave can reach the top of a cliff that a giant placed on dry land at the bottom could not climb “. He relies on the wave. That’s it !
What is true is that the question of “climate data” remains a complicated issue.
To the concept of concentration in the atmosphere, I prefer to speak in terms of gigatons of emissions. Because this can be used as a public policy tool.
According to The Economist last week, there are four organizations that publish reliable emissions data:
- One is BP, an oil company. Its global emissions figures include only the carbon dioxide released from burning fossil fuels. In 2019 it estimated that number was about 34 gigatonnes.
- The International Energy Agency, a global forecaster, gives a similar number.
- The Global Carbon Project, the provider I usually use to prepare my courses, gives a slightly higher figure of 36 gigatonnes, including emissions from cement, which account for about 7% of total emissions.
- The UN Environment Programme, on the other hand, counts all greenhouse gasesand looks at all sources, such as methane released by landfill sites or belching cows. Their researchers estimate that greenhouse gas emissions from human activity were the equivalent of 59 gigatonnes of carbon dioxide in 2019.
I hope that relying on The Economist or on the UN Environment Programme will not be seen as the proof I am a dangerous leftist…
Yet, those seeking to understand how all these different data points fit together should look at the Sankey diagram published by the World Resources Institute (WRI), an environmental think-tank
The good news : over the next few years, more and more emissions data will be produced, coming from environmental metrics of firms. Researchers at universities and non-profit groups will also spend ever-more time compiling new datasets. Improving technology, such as satellite imagery and artificial intelligence, will help too.
And hopefully, in a couple of years, it will become more complicated for politicians to say that ““there are debates between scientists on global warming” …
Iconography : Greenland ocean sunset, 6 August 2016 © William Bossen