"While the accounting-based approach is probably accurate at global scales, the uncertainties rise for smaller-scale regions," said Miller, also a scientist at the National Oceanic and Atmospheric Administration's Earth System Research Laboratory in Boulder. "And as CO2 emissions targets become more widespread, there may be a greater temptation to underreport. But we'll be able to see through that."
A paper on the subject was published in the April 19 issue of the Journal of Geophysical Research: Atmospheres, published by the American Geophysical Union. Co-authors include Stephen Montzka and Ed Dlugokencky of NOAA, Colm Sweeney, Benjamin Miller, Anna Karion, Jocelyn Turnbull and Pieter Tans of NOAA and CIRES, Chad Wolak of CU's INSTAAR and John Southton of the University of California, Irvine.
One surprise in the study was that the researchers detected continued emissions of methyl chloroform and several other gases banned from production in the United States. Such observations emphasize the importance of independent monitoring, since the detection of such emissions could be overlooked by the widely used accounting-based estimation techniques, said Montzka.
The atmospheric air samples were taken every two weeks for six years by aircraft off the coastlines of Cape May, N.J., and Portsmouth, N.H.
Fossil fuel emissions have driven Earth's atmospheric CO2 from concentrations of about 280 parts per million in the early 1800s to about 390 parts per million today, said Miller. The vast majority of climate scientists believe higher concentrations of the greenhouse gas CO2 in Earth's atmosphere are directly leading to rising temperature
|Contact: Scott Lehman|
University of Colorado at Boulder