April carbon-dioxide levels highest in human history

Carbon dioxide levels in April reached the highest level in human history and highest in hundreds of thousands of years, David Perlman reports for the San Francisco Chronicle. Measurements by instruments on a mountain in Hawaii "showed that for the entire month of April, levels of the gas exceeded 400 parts per million for the first time, said Pieter Tans, a climate scientist at the National Oceanic and Atmospheric Agency who monitors the instrument record." (Chronicle graphic)

"The precise average for the entire month was 401.25 parts per million as of Tuesday, he said, and that level had only reached the crucial 400 threshold for the first time during a single day a year ago before dipping slightly," Perlman writes. "Records from ice cores drilled in Antarctica reveal air bubbles trapped in the ice as long ago as 800,000 years ago and not one of those gas bubbles has revealed carbon dioxide levels higher than 300 parts per million, Tans said."

Mark Z . Jacobson, a Stanford Univeristy atmospheric scientist and environmental engineer, told Perlman, "The rise of carbon dioxide levels above 400 parts per million is an indicator that the problem of global warming is getting worse, not better. This means we need to focus more heavily on solutions to this problem, namely converting to wind, water and solar power for all purposes." (Read more)