Scientists at the US Department of Energy’s Lawrence Berkeley National Laboratory demonstrated the first direct observation of increased radiative forcing due to increased carbon dioxide levels in the atmosphere. This study, published in Nature and linked below, is the first to provide direct observational evidence linking rising carbon dioxide concentrations to the greenhouse effect.
The researchers monitored radiative forcing at the earth’s surface for eleven years between 2000 and 2010 at two locations, the Southern Great Plains and the North Slope of Alaska. Spectroscopic instruments, capable of detecting infrared energy attributed to specific phenomena such as carbon dioxide, clouds, and water vapor, recorded near-daily measurements at each site. The nearly 11,600 results showed a statistically significant increasing trend of 0.2 Watts per square meter per decade of infrared energy due to atmospheric carbon dioxide alone. Radiative transfer equations and additional measurements corroborated these results. Researchers linked these results to data from the National Oceanic and Atmospheric Administration which showed an increase of 22 parts per million of atmospheric carbon dioxide in the same time period. Combined, the researchers concluded that the increase in radiative forcing due to carbon dioxide could be linked to fossil fuel emissions and fires.
These results agree with theoretical predictions of the greenhouse effect, giving credence to current climate models assessing the impact of carbon dioxide. The measurements also allow scientists to evaluate the influence of photosynthesis and temporal variations on the greenhouse effect.
Watch a video highlighting the data from the study below!