Jonathan Knockstrand via AFP
The Arctic has warmed almost four times faster than the rest of the world over the past 40 years
Climate – Scientists bring us good news about climate. According to a study published in the scientific journal PNAS, the Montreal Protocol, signed in 1987, has significantly delayed the effects of climate change at the North Pole… Above the South Pole, it was thought to reduce the hole in the ozone layer. .
Researchers from the Universities of Santa Cruz, Columbia and Exeter estimate that the agreement made it possible to delay the first ice-free Arctic summer by 15 years. This landmark event of climate change is currently predicted for the middle of the century, which could happen a few years later.
Agreement against the hole in the ozone layer
However, the Montreal Protocol was originally designed not for climate, but for protecting the ozone layer. In 1985, humanity learns that a hole has formed in the atmosphere above its head. Worse yet, the loophole grows alarmingly larger every year. The disaster caused ChlorofluorocarbonsGases used since the 1930s in everyday products such as refrigerators, refrigerants, and aerosols.
This is a common shock because the ozone layer is essential to the survival of mankind. We must act quickly lest the hole widen further and hope to reverse course. In the space of two years, about thirty states agreed to drastically reduce their use of ozone-depleting substances, writing in black and white the Montreal Protocol.
Subsequently, more countries decided to sign it, and thus in 2009, the Montreal Protocol became the first environmental treaty to achieve global recognition with 196 signatories. The hole in the ozone layer is currently shrinking. But the Montreal protocol was particularly useful for the climate.
No ice-free summer at the North Pole before 2050
“Our results clearly demonstrate that the Montreal Protocol is a very powerful climate protection agreement and has done more than just heal the hole in the ozone layer above the South Pole,” say researchers from the University of Santa Cruz, Columbia and Exeter. study
By comparing climate models with how the planet would have been without the treaty and what it would be like today, ODS’s range of ozone-depleting substances, including CFCs, has had a significant impact. Climate.
Without their drastic reduction, scientists estimate that the planet will warm by an additional 0.5 degrees Celsius by 2050. Even worse, the Arctic polar cap will be nearly 1°C warmer than predicted.
As you can see in the image below, the snow effects are impressive. 1,000 tonnes of ODS emissions are about 7 km.2 Snow in the Arctic.
According to the study, 1,000 tons of ODS emissions save about seven square kilometers of sea ice in the Arctic.
Because apart from destroying the ozone layer, ODS has a very powerful greenhouse effect. For example, CFCs (chlorofluorocarbons) have 5,000 to 14,000 times the thermal energy of an equal mass of carbon dioxide (CO).2), the main greenhouse gas responsible for climate change. Once in the atmosphere, ODS has a particularly long lifetime.
Controlling them has slowed climate change, but certainly not reversed it. Due to human activities, the planet has already warmed by an average of 1.1°C since pre-industrial times, with this figure rising to 2.2°C on the European continent. By the end of the century, the scenario favored by scientists and the government is that the thermometer in France has risen 4°.
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