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23 December 2015
Large asteroid hit would make the world burn, go dark
Sixty-six million years ago, an asteroid crashed into Earth. Its impact, scientists believe, caused global catastrophic fires, transformed the climate, and caused the extinction of the dinosaurs. A new study shows that if a similar asteroid were to strike Earth today, the soot from fires alone would severely alter the climate and imperil life.
22 December 2015
Ancient solar storms may explain how Mars morphed into a cold, barren desert
In March of this year, the sun hurled a giant magnetic solar storm into Mars. The solar wind, full of charged particles, slammed into the red planet’s atmosphere, bouncing or “sputtering” the oxygen into deep space.
Researchers now think the same process could have evaporated Mar’s water several billion years ago, according to a new study presented at the 2015 American Geophysical Union Fall Meeting and recently published in AGU’s publication Geophysical Research Letters.
21 December 2015
Climate change and bark beetles spell doom for Rocky Mountain spruce forests
The combination of climate change and spruce bark beetles could drastically alter Rocky Mountain spruce and pine tree populations over the next three centuries, according to a new study. Using an improved model of forest growth, death, and regeneration, a group of scientists predicts that spruce populations will decline and lodgepole pines will take their place.
According to new research presented at the 2015 American Geophysical Union Fall Meeting, the demographics of a forested region can be dramatically affected by insect outbreaks and fires over time. In addition, different kinds of trees have different tolerance to drought, strong winds and temperature changes. “These act to create competition between individual species and even between trees,” said Adrianna Foster, an environmental scientist at the University of Virginia and lead author of the new study.
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.
17 December 2015
Music of the Earth
Stanford University’s Miles Traer, once again, is cartooning from the AGU Fall Meeting in San Francisco.
Beware the Icebergs of Pluto
Stanford University’s Miles Traer, once again, is cartooning from the AGU Fall Meeting in San Francisco.
Tiny fuel spills at gas stations can contaminate soil
The oil or gas leaks that grab headlines tend to be big events such as the Deepwater Horizon spill in 2010, but smaller-scale spills can be a problem, too, new research finds. Even a few drops dribbled from the nozzle of a gas station fuel pump can penetrate concrete and contaminate soil and groundwater below, according to researchers at Johns Hopkins University in Baltimore, Maryland.
In the past, regulators and researchers assumed that most spilled fuel would evaporate into the atmosphere, said Markus Hilpert, a hydrologist at Johns Hopkins University. The possibility that small fuel droplets might seep through the concrete pad under a gas station to the soil and water below was largely ignored, he said.
Harbor seals hang out on glacier ice
Harbor seals are the most widespread pinniped species in the world. They range as far south as Baja California in Mexico, and as far north as Artic Canada and Greenland. In the colder areas of that vast distribution, they sometimes make themselves at home on floating chunks of ice below tidewater glaciers.
Glaciers are constantly on the move, flowing slowly downhill under the force of their own weight. When that path leads them into the ocean, they’re called tidewater glaciers. During the summer, harbor seals, up to several thousand at a time, congregate in Alaska’s tidewater glacier fjords.
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.