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SerrNovik
Coal-fired power plants such as this one in Arizona are a major source of carbon emissions
Key gas concentrations in the atmosphere that drive up global temperatures hit a new high in 2017.
In its annual bulletin on greenhouse gases, the World Meteorological Organization (WMO) says that there is no sign of reversing this upward trend.
Carbon dioxide levels reached 405 parts per million (ppm) in 2017, a level never reached for 3 to 5 million years.
The researchers also noted the resurgence of a forbidden gas called CFC-11.
What are the concentrations?
Concentrations differ from emissions in that they represent what remains in the atmosphere after some of the gases have been absorbed by seas, land and trees.
Since 1990, the impact of these long-lived gases on climate has increased by 41%.
How does the latest data compare to previous years?
The year 2017 continues the rise in CO2 concentrations, which are now 146% higher than the levels of the atmosphere before the industrial revolution.
The increase from 2016 to 2017 was lower than from 2015 to 2016, but it is close to the average growth rate observed over the last decade.
WMO scientists believe that the amount of CO2 in the atmosphere has not been seen for a very long time.
"The last time the Earth had a comparable concentration of CO2, it was 3 to 5 million years ago, when the temperature was 2 to 3 degrees Celsius higher and the sea level was 10 to 20 meters higher than today, "said WMO Secretary General, Petteri Taalas.
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Renewable energy will need to increase rapidly to help the world move away from carbon energy
Why did CO2 concentrations not increase as fast in 2017?
This is due to the impact of El Niño, the natural weather phenomenon that culminated in 2015 and 2016. This has triggered droughts in some parts of the world, which has reduced the capacity of the forests and forest. vegetation from these areas to absorb CO2, from where a greater part remained in the atmosphere.
Does this decline mean that progress has been made?
Not really. Scientists worry a lot that when they measure the chemistry of the atmosphere, things always go in the wrong direction.
"I am very concerned that the three greenhouse gases responsible for climate change (CO2, methane and nitrous oxide) are all increasing," said Professor Corinne Le Quéré of the University of Paris. East Anglia.
"The CO2 concentrations are now well above 400 ppm – levels were 321 ppm at birth, which represents a big increase in human life!"
What about this mysterious CFC-11 gas?
A number of reports have been reported on CFC-11, a gas used in the insulation of homes. Unfortunately, production is a real double threat to the environment, damaging the ozone layer while contributing to global warming.
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LIBRARY NASA PHOTOGRAPHY / SCIENCE
The hole in the ozone layer over Antarctica in 2000
Under the Montreal Protocol of 1987, the global agreement to protect the ozone layer, CFC-11 was supposed to gradually disappear from production.
Instead, the researchers found a marked slowdown in reducing the level of this gas, indicating that someone, somewhere, is making new batches.
Earlier this year, the Environmental Investigation Agency tracked the production of CFC-11 at several factories in China.
Scientists in the field are concerned that the detected levels of this mysterious chemical are a harbinger of worse things.
"It is possible that new shows are only the tip of the iceberg," said Dr. Matt Rigby, an atmospheric chemist at the University of Bristol.
"If the signals we have seen are due to the CFC-11 released during the manufacturing of products such as foams, many other elements could be locked into these new materials, which will eventually be released into the atmosphere during coming months, decades. "
What about methane and nitrous oxide?
The news on these two gases is not good either. Methane is the second most important greenhouse gas and about 60% of it in the atmosphere comes from human activities such as livestock farming, rice cultivation and l '. fossil fuel extraction.
Levels in the atmosphere are now about 1,859 parts per billion, an increase of 257% over what they were before the industrial revolution, and the rate of increase is about constant over the past decade.
Nitrous oxide comes from natural and human sources, including the use of fertilizer and the industry. This now represents about 122% of the pre-industrial level.
What are the implications of all these increases?
They basically emphasize the fact that there is no indication in the atmosphere that efforts to reduce greenhouse gases are succeeding.
The report also highlights the fact that these gases can affect our climate for centuries after their release.
"CO2 stays in the atmosphere for hundreds of years and in the oceans even longer," said WMO Deputy Secretary General Elena Manaenkova.
"There is currently no magic wand to remove all excess CO2 from the atmosphere.
"Every fraction of global warming is important, as is every part of a million greenhouse gases."
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Climate change is likely to increase the impact of forest fires
Will this new study have an impact?
The scientists behind that are hoping for it. They believe that their analysis should be compared to the recent IPCC 1.5C report, which warned that the world must be essentially carbon neutral by 2050.
The WMO newsletter comes about a week or so before the start of the climate talks at the COP24 meeting in Katowice, Poland, where countries will discuss the implementation of the Paris Agreement. on climate and their ambitions for reducing greenhouse gases.
"The new IPCC special report on global warming at 1.5 ° C shows that deep and rapid reductions in carbon dioxide and other greenhouse gas emissions will be required in all sectors of the world. society and the economy, "said Hoesung Lee, chairman of the IPCC.
"The WMO Greenhouse Gas Bulletin, which shows a steady upward trend in greenhouse gas concentrations, highlights how urgent these emission reductions are."
