The amount of CO2 in the Earth’s atmosphere has reached its annual peak. According to scientists from the Scripps Institution of Oceanography (California) and the National Oceanic and Atmospheric Administration (Maryland), carbon dioxide has reached 419.13 parts per million (ppm). Since when 63 years ago CO2 has begun to be measured with reliable instruments such a high level has never been recorded (measurements are made at the Mauna Loa observatory in Hawaii). But it also represents the peak from well before the beginning of human history. You have to go to thePliocene period, between 4.1 and 4.5 million years ago, to find a time when there was such a high level of carbon dioxide in the earth’s atmosphere. Before the industrial revolution, CO2 levels were equal to 278 ppm.
The world has crossed the threshold of 400 ppm in 2013, but it took only eight years old to touch that of 420. It’s an indication of how countries have so far failed to lower the emissions curve and slow global warming. The CO2 concentration data gives a clear idea of how real the risk is to achieve tipping points in the climate system, with consequences such as the melting of the West Antarctic Ice Sheet. Numerous studies show that the lower the CO2 concentrations, the greater the chances that climate change will be more manageable for society and the planet’s natural systems.
The pandemic “positive” effects canceled
Between 2020 and 2021, the amount of carbon dioxide in the atmosphere increased by 1.8 ppm: at the end of May 2020 the value had stood at 417,9 ppm (the peak concentration normally occurs just at May, when the vegetation of the northern hemisphere begins to bloom and absorb a large amount of CO2 from the air). It is a slightly lower increase to those of previous years, even if in the range of natural variability. According to Pieter Tans, scientist with the National Oceanic and Atmospheric Administration, the temporary decrease in global carbon dioxide emissions due to the pandemic has been reversed by natural variations affecting the speed with which CO2 accumulates in the air. In fact, although in 2020 the concentration of CO2 in the atmosphere decreased by 7% (equal to about 2.6 gigatons of carbon dioxide), the net emissions they did not drop significantly and long enough to be noticeable.
The “psychological threshold” of 420 ppm
The amount of CO2 in the atmosphere will most likely exceed next year 420 ppm. Ralph Keeling, who oversees Mauna Loa’s observations from her post in Scripps, called her one “Psychological threshold”. And he added: «We are moving deeper and deeper into a territory in which we almost certainly never wanted to arrive“. While Tans pointed out that CO2, a greenhouse gas emitted through human activities such as the burning of fossil fuels, deforestation and agriculture, has a vita Rather long: each molecule remains in the air for up to a thousand years. “In terms of human civilization, these emissions will last forever“. The British National Meteorological Service, the Met Office, observed in January: ‘It took about 200 years for CO2 concentrations to increase by 25% from the beginning of the industrial era. But now, alone 30 years after that, we are approaching an increase in 50%».