A new report from the World Meteorological Organisation shows that atmospheric concentrations of carbon dioxide (CO2) grew at a record pace in 2016 to a level not seen in 800,000 years.
Globally averaged concentrations of CO2 reached 403.3 parts per million in 2016, up from 400.00 ppm in 2015 because of a combination of human activities and a strong El Niño event, according to the WMO's latest Greenhouse Gas Bulletin. Concentrations of CO2 are now 145% of pre-industrial (before 1750) levels.
Released just a week before the next UN Climate Change Conference (COP23) in Bonn, the report underscores the need for a strong and urgent global response to meet the goals of the 2015 Paris Agreement.
“Without rapid cuts in CO2 and other greenhouse gas emissions, we will be heading for dangerous temperature increases by the end of this century, well above the target set by the Paris climate change agreement,” said WMO Secretary-General Petteri Taalas.
Under the agreement, countries agreed to limit the rise of global average temperatures to well below 2 degrees Celsius and as close as possible to 1.5 degrees above pre-industrial levels in order to avoid the worst impacts of climate change. One degree of this rise has already happened.
Highlighting unprecedented changes in the atmosphere in the past few decades, the report points out that concentrations of CO2 are now 145% above pre-industrial levels, methane 257% and nitrous oxide 122% above.
The report warns that rapidly increasing atmospheric levels of carbon dioxide and other greenhouse gases could initiate unprecedented changes in climate systems, leading to severe ecological and economic disruptions.
The annual bulletin is based on observations from the WMO Global Atmosphere Watch Programme. These observations help to track the changing levels of greenhouse gases and serve as an early warning system for changes in these key atmospheric drivers of climate change.
Population growth, intensified agricultural practices, increases in land use and deforestation, industrialization and associated energy use from fossil fuel sources have all contributed to increases in concentrations of greenhouse gases in the atmosphere since the industrial era, beginning in 1750.
Since 1990, there has been a 40% increase in total radiative forcing – the warming effect on our climate - by all long-lived greenhouse gases, and a 2.5% increase from 2015 to 2016 alone, according to figures from the US National Oceanic and Atmospheric Administration quoted in the bulletin.
The last time the Earth experienced a comparable concentration of CO2 was 3-5 million years ago, the temperature was 2-3°C warmer and sea level was 10-20 meters higher than now.