(Press-News.org) SALT LAKE CITY, May 14, 2012 – If the world's nations ever sign a treaty to limit emissions of climate-warming carbon dioxide gas, there may be a way to help verify compliance: a new method developed by scientists from the University of Utah and Harvard.
Using measurements from only three carbon-dioxide (CO2) monitoring stations in the Salt Lake Valley, the method could reliably detect changes in CO2 emissions of 15 percent or more, the researchers report in the online edition of the Proceedings of the National Academy of Sciences for the week of May 14, 2012.
The method is a proof-of-concept first step even though it is less precise than the 5 percent accuracy recommended by a National Academy of Sciences panel in 2010. The study's authors say satellite monitoring of carbon dioxide levels ultimately may be more accurate than the ground-based method developed in the new study.
"The primary motivation for the study was to take high-quality data of atmospheric CO2 in an urban region and ask if you could predict the emissions patterns based on CO2 concentrations in the air," says study coauthor Jim Ehleringer, a distinguished professor of biology at the University of Utah.
"The ultimate use is to verify CO2 emissions in the event that the world's nations agree to a treaty to limit such emissions," he says. "The idea is can you combine concentration information – CO2 in the air near the ground – and weather patterns, which is wind blowing, and mathematically determine emissions based on that information."
Ehleringer did the study with four Massachusetts atmospheric scientists: Kathryn McKain and Steven Wofsy of Harvard University, and Thomas Nehrkorn and Janusz Eluszkiewicz of Atmospheric and Environmental Research, Inc.
While the method can detect changes of 15 percent or more in CO2 levels, determining absolute levels is tricky and depends on certain assumptions, but it can be done, Ehleringer says.
"The model [new method] predicts more CO2 emissions than we see," based on a federal government survey that previously estimated carbon dioxide emissions based on interviews with gas- and coal-burning utilities and sellers of fuel and natural gas, he says. "That shouldn't surprise you. People are underreporting."
Estimating CO2 Emissions
Ehleringer began monitoring carbon dioxide levels in the Salt Lake Valley in 2002 as part of a National Science Foundation-funded study of the urban airshed. The monitoring network measures CO2 from six sites across the Salt Lake Valley and a seventh well above the valley at Snowbird.
"It is the most extensive publicly available and online data set of CO2 concentrations in an urban area in the world," he says (co2.utah.edu).
The new study created a computer simulation of CO2 emissions in the Salt Lake Valley using three sources of information:
CO2 measurements from three sites – the University of Utah, downtown Salt Lake City and Murray, Utah, about halfway south down the valley's length.
Data from weather stations in the valley, crunched through weather forecasting software used to predict wind and air circulation.
Satellite data showing what parts of the valley are covered by homes, other buildings, trees, agriculture and so on.
The emissions estimates from the simulation were compared with the results of the government survey that estimates CO2 emissions.
"You come up with estimates for emissions that are within 15 percent or better of the actual emissions for the region," Ehleringer says.
Even though that is not as precise as desired by the National Academy of Sciences, "it is a very powerful first step," he adds. "However we would like to be within 5 percent for treaty verification purposes."
Because urban regions are major sources of CO2, "a large fraction of a country's emissions likely emanate from such regions, and results from several representative cities over time could provide strong tests of claimed emission reductions at national or regional scales," the researchers write.
The simulation showed how ground-level CO2 concentrations increased overnight when air was calm, and then decreased in the morning as sunlight mixed the air and plants consumed CO2 due to photosynthesis. Sometimes the simulation failed to catch the exact time this mixing occurred.
That is part of the reason the researchers argue satellite measurements through a mile-thick vertical column of air may better estimate CO2 concentrations and thus emissions by being less sensitive to ground-level variations close and far from emissions sources like smokestacks or intersections with idling vehicles.
Several satellites around the world now make limited CO2 measurements. But the researchers write that "no presently planned satellite has the necessary orbit or targeting capability" for the desired urban CO2 measurements.
Several previous studies looked at CO2 levels in various cities, but none at the full urban scale or with accuracy near what is required for treaty verification, the researchers say. The only study that accurately measured an urban area's CO2 emissions over time – in Heidelberg, Germany – did so with a method too expensive for routine use.
Ehleringer's part of the research was funded by the U.S. Department of Energy. The study says his coauthors were funded by NASA, the National Science Foundation and – without specifics – "by the U.S. intelligence community," which would be involved in treaty verification.
University of Utah Public Relations
201 Presidents Circle, Room 308
Salt Lake City, Utah 84112-9017
(801) 581-6773 fax: (801) 585-3350
Measuring CO2 to fight global warming
University of Utah and Harvard scientists develop way to enforce future greenhouse gas treaty
ELSE PRESS RELEASES FROM THIS DATE:
Despite an unprecedented rate of economic growth, Chinese people are less happy overall than they were two decades ago, reveals timely new research from economist Richard Easterlin, one of the founders of the field of "happiness economics" and namesake of the Easterlin Paradox. In 1990, at the beginning of China's economic transformation, a large majority of Chinese people across age, education, income levels, and regions reported high levels of life satisfaction. Sixty-eight percent of those in the wealthiest income bracket and 65 percent of those in the poorest income ...
Anthropologists working in southern France have determined that a 1.5 metric ton block of engraved limestone constitutes the earliest evidence of wall art. Their research, reported in the most recent edition of the Proceedings of the National Academy of Sciences, shows the piece to be approximately 37,000 years old and offers rich evidence of the role art played in the daily lives of Early Aurignacian humans. The research team, comprised of more than a dozen scientists from American and European universities and research institutions, has been excavating at the site ...
PROVIDENCE, R.I. [Brown University] — A new study led by Brown University researchers reports that percutaneous endoscopic gastric (PEG) feeding tubes, long assumed to help bedridden dementia patients stave off or overcome pressure ulcers, may instead make the horrible sores more likely to develop or not improve. The analysis of thousands of nursing home patients with advanced dementia appears in the May 14 edition of the Archives of Internal Medicine. "This study provides new information about the risks of feeding tube insertion in people with advanced cognitive impairment," ...
What is the connection, if any, between sudden cardiac death and people with HIV/AIDS? And can that knowledge help prolong their lives? In a comprehensive, 10-year UCSF study, researchers found patients with HIV/AIDS suffered sudden cardiac death at a rate four times higher than the general population. "As part of my ongoing research in 2010, we were looking at every instance of sudden death in San Francisco," said first author Zian H. Tseng, MD, an electrophysiologist and an associate professor of medicine in the UCSF Division of Cardiology. "I noticed that many of ...
A new study describes a compound that selectively kills cancer cells by restoring the structure and function of one of the most commonly mutated proteins in human cancer, the "tumor suppressor" p53. The research, published by Cell Press in the May 15th issue of the journal Cancer Cell, uses a novel, computer based strategy to identify potential anti-cancer drugs, including one that targets the third most common p53 mutation in human cancer, p53-R175H. The number of new cancer patients harboring this mutation in the United States who would potentially benefit from this ...
Asymptomatic patients who undergo treadmill exercise echocardiography (ExE) after coronary revascularization may be identified as being at high risk but those patients do not appear to have more favorable outcomes with repeated revascularization, according to a report published Online First by Archives of Internal Medicine, a JAMA Network publication. The article is part of the journal's Less is More series. Cardiac events and recurrent ischemia (a temporary shortage of oxygen caused by impaired blood flow; identified in the study as new or worsening cardiac wall motion ...
According to a small clinical trial reported by investigators from Japan, acupuncture appears to be associated with improvement of dyspnea (labored breathing) on exertion, in patients with chronic obstructive pulmonary disease (COPD), according to a study published Online First by Archives of Internal Medicine, a JAMA Network publication. The management of dyspnea is an important target in the treatment of COPD, a common respiratory disease characterized by irreversible airflow limitation. COPD is predicted to be the third leading cause of death worldwide by 2020, according ...
Among African Americans with type 1 diabetes mellitus, narrower central retinal arteriolar equivalent (average diameter of the small arteries in the retina) is associated with an increased risk of six-year incidence of any cardiovascular disease and lower extremity arterial disease, according to a report in the May issue of Archives of Ophthalmology, a JAMA Network publication. "Retinal arteriolar narrowing has long been described as one of the characteristic changes associated with hypertension and cardiovascular disease (CVD)," the authors write as background information ...
PITTSBURGH, May 14 - A small, external bioreactor holding human cells pumped out an anti-inflammatory protein to prevent organ damage and other complications in a rat with acute inflammation caused by bacterial products in a model of sepsis, according to a report from researchers at the University of Pittsburgh School of Medicine and the McGowan Institute for Regenerative Medicine. The findings were published today in the inaugural issue of Disruptive Science and Technology. Inflammation is a necessary biological response that brings cells and proteins to the site of ...
Major depressive episodes can be prevented, and to help ensure that they are, the health care system should provide routine access to depression-prevention interventions, just as patients receive standard vaccines, according to a new article co-authored by UCSF researcher Ricardo F. Muñoz, PhD. The article builds on a 2009 Institute of Medicine report on prevention of mental, emotional and behavioral disorders, which provided presented evidence that mental disorders can be prevented. The article, "Major Depression Can Be Prevented," will appear in a special section ...