Farewell to 400 parts per million

World ‘beyond return’ of historic carbon dioxide milestone

Record surge in CO2 through 2015 and 2016 saw atmospheric concentrations rise faster than 2 parts per million average to well above 400 ppm

By Ed King
Published on 13/06/2016, 5:00pm, Climate Home

Farewell then, 400 parts per million.

The past 12 months have seen a record surge in carbon dioxide emissions say scientists, driven by the burning of fossil fuels and boosted by a rampant El Nino phenomenon.

Tropical forests and plants that once would have been expected to reduce global CO2 levels by September have suffered badly under this El Nino, reducing their ability to soak up carbon.

That means the iconic milestone of 400 parts of carbon dioxide in every million molecules of air has likely been passed for good, says a study published in the journal Nature Climate Change.

The inexorable rise of CO2 emissions

1966 – 322.39 parts per million
1976 – 333.46 ppm
1986 – 348.05 ppm
1996 – 364.17 ppm
2006 – 382.66 ppm
2016 – 404.83 ppm 

(Source: NOAA)

Despite a new UN climate pact agreed by 195 countries, the findings raise serious questions about the pace of efforts to slow global warming in what is set to be the hottest year on record.

(Continued here.)

Vox Verax note: CO2 rose by 22 ppm in the decade 2006-2016. Assuming a simple arithmetic rise in emissions of a constant 22 ppm per decade, the atmosphere will reach 450 ppm by 2037 and 500 ppm by 2059. If the rise continues according the current rate of 5.5% per decade, this is what the next few decades will look like:

2026 - 427.10 ppm
2036 - 450.59 ppm
2046 - 475.37 ppm
2056 - 501.51 ppm

 Vox Verax will leave what this means to the many scientists more versed in this subject than we are.