Carbon dioxide (CO2) concentrations in the Earth’s atmosphere have increased at a record pace in 2016 to their highest levels in the last 800,000 years, says the World Meteorological Organization (WMO) Bulletin on greenhouse gas.
Specifically, average global CO2 concentrations reached 403.3 parts per million (ppm) in 2016, up from 400.00 ppm in 2015.
The reason? Human activity combined with a particularly strong El Niño episode. The concentrations of this greenhouse gas in the atmosphere currently represent 145% of those observed before industrialization (before 1750).
WMO scientists believe that the abrupt changes in atmospheric CO2 observed over the last 70 years are unprecedented. These variations, along with other greenhouse gases, risk triggering an irreversible change in global climate systems and causing “serious ecological and economic upheaval,” warns the signatories of the annual WMO Bulletin.
Concentrations of greenhouse gases (which also include methane, ozone, water vapor and nitrous oxide) are the main drivers of climate change in the atmosphere.
Since industrialization, the atmospheric content of greenhouse gases has been increasing due to several factors, including:
- Population growth
- The exploitation of fossil fuels for energy purposes
- More and more intensive farming
Since the 1990s, the positive radioactive forcing of the planet (which induces a warming of our climate system) has increased by 40%. Only from 2015 to 2016, the increase recorded is 2.5%.
If greenhouse gas emissions, particularly CO2, are not reduced quickly, we will be facing a dangerous rise in temperature by the end of the century, well beyond the target. in the Paris Agreement on Climate.
Petteri Taalas, Secretary General of WMO
“Future generations will inherit a much less hospitable planet,” he adds.
The last time the Earth had CO2 content comparable to todays, it was 3 to 5 million years ago. At that time, the temperature was 2 to 3 ° C higher and the sea level was 10 to 20 meters higher than the current level.
The WMO Bulletin on Greenhouse Gases reports annually on concentrations of these gases in the atmosphere. By emissions, scientists hear how much gas is released into the atmosphere. By concentrations, they describe those remaining in favor of the complex interactions that occur between the atmosphere, the biosphere, the cryosphere and the oceans.
The ocean now absorbs about a quarter of total CO2 emissions and the biosphere accounts for another quarter, limiting the increase in atmospheric CO2.