Saturday, April 21, 2012

Global warming: Colorado researchers pinpoint atmospheric greenhouse gas ... - Summit County Citizens Voice

Valuable program threatened by NOAA funding cuts

A NASA map shows global temperature anomalies in March 2012.

By Summit Voice

SUMMIT COUNTY â€" An intensive long-term monitoring program has enabled researchers to analyze and compare emissions from man-made fossil fuels and trace gases in the atmosphere, which could help measure the effectiveness of efforts to reduce greenhouse gases â€" but the program is being threatened by budget cuts.

“We think the approach offered by this study can increase the accuracy of emissions detection and verification for fossil fuel combustion and a host of other man-made gases,” said CU-Boulder Senior Research Associate Scott Lehman, who led the study with CU-Boulder Research Associate John Miller.

Lehman, with the Institute of Arctic and Alpine Research, said the approach of using carbon-14 has been supported by the National Academy of Sciences and could be an invaluable tool for monitoring greenhouse gases by federal agencies like NOAA.

Unfortunately, NOAA’s greenhouse gas monitoring program has been cut back by Congress in recent years, Lehman said. “Even if we lack the will to regulate emissions, the public has a right to know what is happening to our atmosphere. Sticking our heads in the sand is not a sound strategy,” he said.

Developing the data involved looking at atmospheric gas measurements taken every two weeks from aircraft during a six-year period over the northeast United States to collect samples of CO2 and other environmentally important gases.

The researchers were able to separate carbon dioxide originating from fossil fuels and natural sources by comparing levels of carbon-14. CO2 from released during combustin of coal, oil and gas has almost no carbon-14 that isotope has a half-life of about 5,700 years, while the fuels are millions of years old.

By contrast, CO2 from biological sources like plant respiration is rich in carbon-14.

The team also measured concentrations of 22 other atmospheric gases tied to human activities as part of the study, said Miller, of the CU-headquartered Cooperative Institute for Research in Environmental Sciences. The diverse set of gases impact climate change, air quality and the recovery of the ozone layer, but their emissions are poorly understood.  The authors used the ratio between the concentration level of each gas in the atmosphere and that of fossil fuel-derived CO2 to estimate the emission rates of the individual gases, said Miller.

In the long run, measuring carbon-14 in the atmosphere offers the possibility to directly measure country and state emissions of fossil fuel CO2, said Miller. The technique would be an improvement over traditional, “accounting-based” methods of estimating emission rates of CO2 and other gases, which generally rely on reports from particular countries or regions regarding the use of coal, oil and natural gas, he said.

“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 under-report. 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 temperatures on the planet.

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