Cape Grim predecitions confirmed as we pass the 400ppm mark

Baseline measurements from Tasmania's
Cape Grim are headed in just one direction - up!

As we predicted two months ago, the background atmospheric carbon dioxide levels measured at Cape Grim on Tasmania’s northwest coast have officially passed the 400 parts per million (ppm) mark. Our measurements, compiled by our team at CSIRO together with the Bureau of Meteorology, show that the milestone was reached on May 10.

In the past few days, the 400 ppm level has also been breached in Antarctica, where CSIRO’s measurements at Casey Station show the 400 ppm level was exceeded on May 14.

Together, these measurements show that the atmospheric CO₂ concentration of the entire southern hemisphere is now at or above 400 ppm. It is unlikely to dip back below this level for many decades to come.

Read what an Honorary Fellow with the CSIRO, Paul Fraser and 

Research Group Leader, also with the CSIRO, Paul Krummel, had to say on The Conversation - ”Southern hemisphere joins north in breaching carbon dioxide milestone.”

(Just yesterday on the ABC television news, two Australian climate scientists, including Professor David Karoly from the University of Melbourne, were quoted as saying there was nothing of any particular note about the 400ppm mark, and they suggested the 399 or 401ppm measurements were equally significant.

The trend, however, is what is important for as it continues to rise inexorably and as the numbers relating to parts per million get larger, the world’s weather continues to worsen and so become increasingly less predictable – Robert McLean).