“It symbolizes that so far we have failed miserably in tackling this problem.”

The level of the most important heat-trapping gas in the atmosphere, carbon dioxide, has passed a long-feared milestone, scientists reported on Friday, reaching a concentration not seen on the earth for millions of years.

Read: Carbon Dioxide Level Passes Long-Feared Milestone - NYTimes

“Mr. Obama has a firm grasp of the climate issue, and no one doubts that he cares about it. But as is often the case with this president, the question is whether he will exhibit a sense of urgency to match his intellectual understanding.”