Numbers have meaning only in context. A temperature of 98.6 degrees F is normal body temperature, but only in context of the mean. This is not normal for every person. The S&P 500 crossing 1600 is meaningless unless it is in context of what the market is doing. Is it going up or down? How far has it gone from previous levels? Only then does the number have meaning.
A milestone was reached recently, Thursday, May 9th, at the Mauna Loa Observatory in Hawaii. Levels of carbon dioxide reached 400 parts per million (ppm) for the first time in human existence. Daily measurements are made at the observatory of the gases that lead to atmospheric change. One of the main gases monitored is carbon dioxide (CO2). Levels of 400.03 and 400.08 ppm were measured independently by the National Oceanic & Atmospheric Administration (NOAA) and Scripps Oceanographic Institute respectively.
|Mauna Loa Observatory in Hawaii. Click on the image for a larger version. Image Credit: NOAA/ESRL.|
This was a daily mean that was measured for the first time. Hourly measurements exceeded this number quite a few times since mid-April. The monthly mean of CO2 will likely peak this month, at a level of about 399 ppm, and then fall until October. It is likely to pass the 400 ppm in the spring of next year. The yearly mean will not likely cross this level until 2015 or 2016.