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13 January 2016
Ocean circulation changes may have killed cold-water corals
Successive and abrupt changes in North Atlantic ocean circulation over the past 4,500 years seem to have caused major reductions in some cold-water coral ecosystems, finds a study published in Geophysical Research Letters, a journal of the American Geophysical Union.
The new study shows changes in sea surface circulation over the last few thousand years were more sudden than previously thought and in some cases led to abrupt collapses of cold-water coral ecosystems. The researchers found the first evidence that perturbations in the Atlantic Meridional Overturning Circulation (AMOC) led to cold-water coral ecosystems decline from 100 to 1,200 years ago.
18 December 2015
A natural experiment: City in pristine Amazon shows pollution alters ecosystem
Human-made pollutants are changing cloud patterns over the Amazon, altering ecosystems in the process.
Sometimes, the best experiments come ready-made from nature. The Brazilian city of Manaus has a population of almost 2 million people and sits in the heart of an otherwise pristine stretch of Amazonian rainforest, near the place where the Negro and Solimões tributaries fuse to form the Amazon River. New research using the area as a testing ground shows that Manaus city pollutants meddle with the Amazon’s cloud cover, rain and ecosystem, according to scientists who presented the finding at the 2015 American Geophysical Union Fall Meeting.
Policy changes in Mongolian capital could improve health, decreasing lives lost to air pollution
Exposure to dangerous contaminants in Ulaanbaatar, Mongolia could increase by 10 percent or more by 2024, exacerbating health problems in one of the most polluted cities in the world, a new study finds.
Residents of Ulaanbaatar, the most populous city in Mongolia, rely heavily on coal to survive frigid winters in a valley where air pollution is easily trapped. Air pollution in Ulaanbaatar caused an estimated 1,250 premature deaths in 2014, according to Drew Hill, a graduate student in environmental health at the University of California, Berkeley. Hill was part of a research team that presented an air pollution and health report to the Mongolian Ministry of the Environment and Green Development in the summer of 2014.
Rainforests not so rainy: Cutting trees cuts rainfall
Deforestation threatens to upset the delicate water balance within the Amazon rainforest by altering not just ground cover but patterns of rainfall overhead, according to a new study.
Previous research has shown that during the dry season, areas of the Amazon cleared for cattle grazing get more rainfall than the surrounding forest. But most of this research was conducted in the 1980s, when the Amazon was deforested in small patches only a few kilometers wide, said Jaya Khanna, a researcher at Princeton University and lead author of the new study. Khanna’s is the first long-term study of the effects of deforestation on precipitation in the Amazon. Her results, presented at the 2015 American Geophysical Union Fall Meeting, show that rainfall patterns in cleared areas today are vastly different from those in the 1980s.
14 September 2015
Breaking down India’s monsoon
Studying El Niño and La Niña’s effects in regions, sub-seasons, may improve rainfall forecasts.
21 July 2015
Study: Most rain comes from ice clouds
Benjamin Franklin was the first to surmise that, even on a hot summer’s day, the raindrops falling on our heads might begin life as ice particles at high altitudes. In the centuries since 1780 it became possible to probe the atmosphere directly by balloon and by aircraft, and remotely from the ground and from satellites. These observations confirmed Franklin’s suspicion. However, two questions remain: how large are the fractions of rain produced by liquid clouds and by ice clouds? And how variable are they over the globe and over time?
29 June 2015
Beijing quadrupled in size in a decade, new study finds
A new study shows that Beijing quadrupled in physical extent between 2000 and 2009. The new buildings alone — not including the impacts of additional city dwellers and their cars — increased heat and changed wind and pollution patterns in a ring around Beijing.
29 April 2015
Lucky break kept major hurricanes offshore since 2005
For the last nine years the United States has dodged the hurricane bullet: No major tropical cyclones have made U.S. landfall. Such a remarkable “hurricane drought” has never been seen before – since records began in 1851. It beats the previous record of eight years from 1861-1868, say researchers who have looked into the probabilities of the unusual streak, what it means for the chances of hurricanes this year and whether or not insurance premiums reflect the risks. Their conclusion: the hurricane drought is mostly a matter of dumb luck.
10 April 2015
The surprising strength of ‘rainpower’
Torrential rains inside hurricanes might be acting as a control knob on these giant storms, reducing their intensity by as much as 30 percent, according to a new study.
19 March 2015
Harvesting “big data” to help farmers
Scientists are using massive amounts of information about the climate, weather and land to develop new tools farmers can use to grow more food without harming the environment.
GeoSpace is a blog on Earth and space science, managed by AGU’s Public Information staff. The blog features posts by AGU writers and guest contributors on all sorts of relevant science topics, but with a focus on new research and geo and space sciences-related stories that are currently in the news.