9 February 2012
Two CSD papers were among the five winners of the 2010 NOAA OAR Outstanding Scientific Paper Awards, announced last fall by OAR's Acting Assistant Administrator, Craig McLean.
A.R. Ravishankara, John Daniel and Robert Portmann of CSD evaluated the role of nitrous oxide (N2O) emissions in thinning the Earth's ozone layer. The ozone layer is a protective layer of our atmosphere that shields us from excessive ultraviolet light from the sun. Human activities emit chemicals, such as chlorofluorocarbons (CFCs) and N2O, which eat away at this shield.
Their study, published in the journal Science, found that N2O is now the largest ozone-depleting emission and will continue to be so for the rest of this century. The 1987 Montreal Protocol regulates many ozone-depleting gas emissions including CFCs, but nitrous oxide, also a greenhouse gas, is not among them. This research is the first to evaluate nitrous oxide's "Ozone Depletion Potential" (ODP), a quantitative measure widely used to describe the potential impact of a substance on the Earth's ozone layer.
Ravishankara, A.R., J.S. Daniel, and R.W. Portmann, Nitrous oxide (N2O): The dominant ozone-depleting substance emitted in the 21st century, Science, doi: 10.1126/science.1176985, 2009.
Susan Solomon led a team investigating the long-term effects of increasing carbon dioxide emissions. Solomon, now retired from her position at NOAA's ESRL CSD, and her European colleagues found that impacts to future climate are already largely irreversible – even if carbon dioxide emissions are stopped completely.
The study, published in the Proceeding of the National Academy of Sciences, modeled the possible outcomes of future peak levels of carbon dioxide. The models resulted in higher global temperatures that would lead to precipitation changes and sea level rise in every scenario tested, and these impacts continued for centuries, even after new emissions were halted, because of the influence of the oceans. These findings illustrate that while the effects of increasing carbon emissions may be slow to appear, any reduction in emissions now or in the future will take centuries to reverse global impacts.
Solomon, S., G.-K. Plattner, R. Knutti, and P. Friedlingstein, Irreversible climate change due to carbon dioxide emissions, Proceedings of the National Academy of Sciences, doi: 10.1073/pnas.0812721106, 2009.