Bags of garden fertilizer are labeled with three numbers, such as 15-4-5. These numbers indicate the percent of nitrogen, phosphorus, and potassium in the product. The remainder of the bag is filler that helps the fertilizer disperse.
Two years ago, we talked about a report out of the observatory on Mauna Loa in Hawaii of the first modern measurements of carbon dioxide levels greater than 400 parts per million. But it was only in that location and only for a brief period of time.