 Urban greenways help lower local carbon emissions Washington (UPI) Jul 5, 2018 - New research confirms the climate benefits offered by urban greenways. Researchers at the University of British Columbia determined urban greenways help curb local carbon emissions. Supporters of urban greenways argue their creation inspires greener transportation choices by local residents, but few studies have examined the accuracy of the claim. UBC researchers set out to measure the impact of Vancouver's Comox-Helmcken Greenway by surveying residents about their transportation habits before and after the greenway's construction. Researchers interviewed 585 residents -- half living within 1,000 feet of the greenway, half within 1,600 feet. The survey results showed locals reduced their reliance of car and bus transportation in the wake of the greenway's completion, opting to walk and bike more often. "Less commuting also meant they generated 21 percent less travel-related emissions, producing 520 grams of emissions a day, from 660 grams the previous year," researcher Victor Douglas Ngo said in a news release. However, the surveys showed only those living closest reduced their local carbon footprint. Those living slightly farther away actually increased their reliance on vehicular transportation. Researchers believe an increase in car-sharing services in the surrounding neighborhoods explains the rise in vehicular travel. "Car sharing was growing across the city, and people who lived farther from the greenway likely found it more convenient to car share compared to those who were closer to and more influenced by the greenway," said lead investigator Lawrence Frank. Another recent study highlighted the importance of curbing carbon emissions at the city level. The latest findings -- published this week in the journal Transportation Research -- show cities can make progress by promoting healthier transportation habits with the construction of greenways. "As more cities invest in infrastructure to promote health and protect the environment, it's more important than ever to understand the impact of those improvements," Frank said. "To the best of our knowledge, this is the first study that shows a direct causal effect of a greenway investment on individual behaviors and the environment."
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New analysis shows the coastal areas of the Baltic Sea have lost unprecedented amounts of oxygen during the 20th century.
The Baltic Sea hosts some of the largest dead zones, vast expanses of saltwater with little or no oxygen, in the world. Animal life cannot survive inside a dead zone.
The Baltic's massive dead zones are the result of decades of fertilizer and pollution runoff, fueling the growth of algal blooms. When the blooms die, microbial communities consume the decomposing algae, pulling large amounts of oxygen from the water during the process.
While human-caused nutrient inputs have decreased in recent years, the problem of hypoxia persists. Decaying algae do more than feed oxygen-eating microbes. The dying algae also releases phosphorous, fueling cyanobacteria blooms, which pulls nitrogen form the atmosphere.
"As a result, the total amount of nutrients -- phosphorus and nitrogen -- in the water remains high even after human inputs have been reduced," Tom Jilbert, an assistant professor at the University of Helsinki, said in a news release.
"It is a self-sustaining vicious circle that can take decades to reverse," said Sami Jokinen, a researcher at the University of Turku.
This negative feedback loop is exacerbated by global warming. Warmer water can't hold as much oxygen as colder water.
To place the region's oxygen losses in broader historical context, scientists drilled sediment cores from the bottom of the Archipelago Sea, a thin strip of the Baltic Sea lying between Finland and Sweden. The sediment cores helped scientists track the impacts of climate change on oxygen levels and nutrient pollution.
Their analysis -- published this week in the journal Biogeosciences -- showed oxygen levels were low between 900 to around 1350 AD, during a warm period known as the Medieval Climate Anomaly. However, modern coastal oxygen losses are much more severe.
"The interesting finding from our study is that, in the coastal areas, oxygen loss in the modern period really stands out, due to the strong signal of recent human nutrient inputs," Jilbert said.
The research also showed modern oxygen losses picking up steam during the early 1900s.
To curb the problem of oxygen losses in the Baltic, scientists say more needs to be done to slow global warming and limit nutrient loading.
"The good news is that many countries in the Baltic catchment have taken significant steps towards nutrient loading reductions," Jilbert said. "In some coastal regions we are already seeing improvements. Better understanding of the balance between nutrient inputs and climate change will therefore help to guide management of the Baltic in the future."
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