By
Bryan Dyne
13 May 2013
Daily concentrations of carbon dioxide measured by the National Oceanic and Atmospheric Administration at Mauna Loa, Hawaii exceeded 400 parts per million (ppm) on May 9 for the first time since measurements began there in 1958. Furthermore, geochemical studies indicate that this is the highest level of CO2 for at least 800,000 years and possibly the highest level in the past 3 million years.
Mauna Loa is the oldest site that has continuous measurements of carbon dioxide and thus acts as the benchmark for all other monitoring stations worldwide. Every hour it measures the number of molecules of carbon dioxide per every 1 million molecules of dry air (mostly oxygen and nitrogen). Over the past several weeks, hourly readings have spiked above 400 ppm, but last Thursday was the first time that the carbon dioxide concentration averaged over the day exceeded 400 ppm, a result that has been expected for some time.
Carbon dioxide concentrations are used as a measurement for global warming because they are closely linked with global temperature changes. Other greenhouse gases, such as water vapor and methane, are relatively stable in Earth’s atmosphere. Carbon dioxide levels, however, change over time. More energy from the Sun is trapped in Earth’s atmosphere when CO2 concentrations are higher. Thus
This article originally appeared on : World Socialist Web Site