More greenhouse gases are warming the earth

Although carbon dioxide, or CO₂is the most well-known greenhouse gas, several others, including methane and nitrous oxide, are also driving global warming and changing the Earth’s climate.

Methane

CO₂ it is responsible for about two-thirds of the warming attributed to greenhouse gases, said Piers Forster, an expert at the University of Leeds and author of reports for the IPCC, the UN’s climate watchdog.

Methane, or CH4, is the second most important greenhouse gas associated with human activity after CO₂.

About 40 percent of methane comes from natural sources, mainly wetlands, but the majority (about 60 percent) is associated with human activities such as agriculture (breeding crops and growing rice), fossil fuels and waste.

Its warming potential is 80 times greater over 20 years than that of CO₂but its life is short, making it an important lever in efforts to reduce global warming in the short term.

Reducing methane emissions “can be cool in the short term, because the atmosphere of methane drops very quickly,” said Mathijs Harmsen, a researcher at the Netherlands Environmental Assessment Agency PBL.

Policies should “focus on picking the low-hanging fruit, so low-cost measures such as reducing gas emissions,” he said.

Despite the global commitment to reduce global warming signed by many countries, including the European Union and the United States, the trend is not good.

“Methane is rising faster than any other major greenhouse gas and is now 2.6 times higher than pre-industrial levels,” said a group of international researchers under the Global Carbon Project, in a study published in academics. journal Environmental Research Letters.

Nitrous oxide

Nitrous oxide, or nitrous protoxide (N₂O), is the third largest greenhouse gas and about 300 times more powerful than CO₂.

It is mainly produced by making nitrogen fertilizers and manures used in agriculture.

Some emissions come from human activities (chemical industry, wastewater, fossil fuels) or natural resources (land and oceans).

“Globally human-caused emissions, which are controlled by adding nitrogen to crop fields, have increased by 30 percent over the past 40 years,” concluded a major study in the journal. Nature in 2020.

The main problem is the proper use of fertilizers.

“Two-thirds of climate change mitigation is an opportunity for N₂O can be seen by reducing fertilization on only 20% of the world’s crops, especially in humid agricultural areas, “wrote the French researcher Philippe Ciais in 2021.

Fluorinated gases

Fluorinated greenhouse gases (PFCs, HFCs and SF6) are found in refrigerators and freezers, heat pumps, air conditioners and electrical appliances.

Even at a minimum, they stand out because of their extreme warmth.

For example, SF6, found in electricity, has a greenhouse effect 24,000 times greater than CO.₂ over 100 years.

The Montreal Convention signed in 1987, ratified by 195 countries, has already significantly reduced the atmospheric presence of CFCs, an ozone-depleting fluorinated gas.

In 2016 the Kigali agreement also provided for the phase-out of HFCs.

And last year the EU confirmed an agreement to gradually ban the sale of equipment containing fluorinated gases, especially HFCs, with the aim of phasing them out completely by 2050.

© 2024 AFP