400 ppm: A Dangerous Pollution Milestone Has Been Passed

The concentration of carbon dioxide in Earth’s atmosphere has reached the 400 parts per million (ppm) milestone today according to the U.S. National Oceanic and Atmospheric Administration (NOAA).

Over the last million years, CO2 never exceeded 280 ppm (based on actual readings of atmospheric chemistry from Antarctic ice core data.) Concentrations of greenhouse gases (GHG) are a very different measurement than emission rates. Concentrations have a very long lag time and will not be able to be decreased except over centuries, while emission rates can go down overnight. It is critical to start reducing emissions, because existing concentrations mean that we will see warming over the next 100 years from today’s emissions.

Green Party of Canada leader Elizabeth May and Dr. Andrew Weaver, a BC Green Party candidate running in the upcoming provincial election, believe that this unwanted milestone in the climate saga could be a turning point towards clean technology to reverse this trend.

“We are in a danger zone as we hit 400 ppm.  We must move to immediate reductions in GHG, and shift to new clean technologies,” said Green Leader Elizabeth May, Member of Parliament for Saanich-Gulf Islands.

May recently tabled a private member’s bill to cap the carbon dioxide emissions from coal-fired plants.

“It’s clear that emissions from these plants are some of the most dangerous for the planet. Using clean technologies that exist today can help us move into the 21st century,” said May.

There is a consensus in the scientific community that greenhouse gases should be limited to levels that would avoid allowing global average temperatures to rise by 2 degrees Celsius.  Scientists have marked that wide red line in a band from 425-450 ppm.

Climate scientist and Deputy Green Party Leader of British Columbia, Dr. Andrew Weaver, says this moment can bring a new economic reality to BC.

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