Pollution Articles and News

UI researcher finds black carbon implicated in global warming

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Increasing the ratio of black carbon to sulfate in the atmosphere increases climate warming, suggests a study conducted by a University of Iowa professor and his colleagues and published in the July 25 issue of the journal Nature Geoscience.

Black carbons — arising from such sources as diesel engine exhaust and cooking fires — are widely considered a factor in global warming and are an important component of air pollution around the world, according to Greg Carmichael, Karl Kammermeyer Professor of Chemical and Biochemical Engineering in the UI College of Engineering and co-director of the UI’s Center for Global and Regional Environmental Research. Sulfates occur in the atmosphere largely as a result of various industrial processes.

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Global Model Confirms: Cool Roofs Can Offset Carbon Dioxide Emissions and Mitigate Global Warming

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Can light-colored rooftops and roads really curb carbon emissions and combat global climate change? The idea has been around for years, but now, a new study by researchers at Lawrence Berkeley National Laboratory that is the first to use a global model to study the question has found that implementing cool roofs and cool pavements in cities around the world can not only help cities stay cooler, they can also cool the world, with the potential of canceling the heating effect of up to two years of worldwide carbon dioxide emissions.

Because white roofs reflect far more of the sun’s heat than black ones, buildings with white roofs will stay cooler. If the building is air conditioned, less air conditioning will be required, thus saving energy. Even if there is no air conditioning, the heat absorbed by a black roof both heats the space below, making the space less comfortable, and is also carried into the city air by wind—raising the ambient temperature in what is known as the urban heat island effect.

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Korean colleagues enhance ability to capture CO2

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Chemists from UCLA and South Korea report the “ultimate porosity of a nano-material,” achieving world records for both porosity and carbon dioxide storage capacity in an important class of materials known as MOFs, or metal–organic frameworks.

MOFs, sometimes described as crystal sponges, have pores — openings on the nanoscale which can store gases that are usually difficult to store and transport. Porosity is crucial for compacting large amounts of gases into small volumes and is an essential property for capturing carbon dioxide.

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Global Warming Slows Coral Growth in Red Sea

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In a pioneering use of computed tomography (CT) scans, scientists at Woods Hole Oceanographic Institution (WHOI) have discovered that carbon dioxide (CO2)-induced global warming is in the process of killing off a major coral species in the Red Sea. As summer sea surface temperatures have remained about 1.5 degrees Celsius above ambient over the last 10 years, growth of the coral, Diploastrea heliopora, has declined by 30% and “could cease growing altogether by 2070” or sooner, they report in the July 16 issue of the journal Science.

“The warming in the Red Sea and the resultant decline in the health of this coral is a clear regional impact of global warming,” said Neal E. Cantin, a WHOI postdoctoral investigator and co-lead researcher on the project. In the 1980s, he said, “the average summer [water] temperatures were below 30 degrees Celsius. In 2008 they were approaching 31 degrees.”

Cantin and WHOI Research Specialist Anne L. Cohen, the other lead investigator, said the findings were unexpected because D. heliopora did not exhibit one of the typical signs of thermal stress: bleaching. “These corals looked healthy,” said Cohen.

But CT scanning of the coral’s skeletal structure in the laboratory revealed “the secrets that the skeletons are hiding,” she said. “The CT scans reveal that these corals have actually been under chronic stress for the last 10 years, and that the rates of growth were the lowest in 2008,” the final year of the study.

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