Times: The end of last week saw the carbon concentrations in the atmosphere finally pass the 400-part-per-million threshold. That means carbon levels are higher now than they`ve been for at least 800,000 years, and most likely far longer. There`s nothing special per se about 400 parts per million -- other than giving all of us a change to note it in article like this one -- but it`s a reminder that we are headed very fast into a very uncertain future.
Parts per million and global temperature change,...