From NASA’s monthly news roundup published electronically this week.
UPDATES of some text and graphs.
NASA:
“Carbon dioxide (CO2) is an important heat-trapping (greenhouse) gas, which is released through human activities such as deforestation and burning fossil fuels, as well as natural processes such as respiration and volcanic eruptions. The first graph shows atmospheric CO2 levels measured at Mauna Loa Observatory, Hawaii, in recent years, with average seasonal cycle removed. The second graph shows CO2 levels during the last three glacial cycles, as reconstructed from ice cores.
”Over the past 171 years, human activities have raised atmospheric concentrations of CO2 by 48% above pre-industrial levels found in 1850. This is more than what had happened naturally over a 20,000 year period (from the Last Glacial Maximum to 1850, from 185 ppm to 280 ppm).”
