Tag Archives: greenhouse effect

Ancient shark teeth give clues to future of Arctic climate change

A new study of sharks that lived in warm Arctic waters millions of years ago suggests that some shark species could handle the falling Arctic salinity that may come with rising temperatures.

The Arctic today is best known for its tundra and polar bear population, but roughly 38 to 53 million years ago during the Eocene epoch, the Arctic was like a huge temperate forest with brackish water, home to a variety of animal life, including ancestors of tapirs, hippo-like creatures, crocodiles and giant tortoises. Much of what is known about the region during this period comes from well-documented terrestrial deposits. Marine records have been harder to come by. (more…)

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Study: Greenhouse gas might have warmed early Mars enough to allow liquid water

The mystery of how the surface of Mars, long dead and dry, could have flowed with water billions of years ago may have been solved by research that included a University of Washington astronomer.

There is evidence that Mars had water at its surface 3.8 billion years ago or before, but scientists are divided on how that might have happened, especially since the sun was about 30 percent fainter back then, thus less able to melt water ice on Mars. (more…)

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Volcanic Aerosols, not Pollutants, Tamped down Recent Earth Warming, Says CU Study

A team led by the University of Colorado Boulder looking for clues about why Earth did not warm as much as scientists expected between 2000 and 2010 now thinks the culprits are hiding in plain sight — dozens of volcanoes spewing sulfur dioxide.

The study results essentially exonerate Asia, including India and China, two countries that are estimated to have increased their industrial sulfur dioxide emissions by about 60 percent from 2000 to 2010 through coal burning, said lead study author Ryan Neely, who led the research as part of his CU-Boulder doctoral thesis. Small amounts of sulfur dioxide emissions from Earth’s surface eventually rise 12 to 20 miles into the stratospheric aerosol layer of the atmosphere, where chemical reactions create sulfuric acid and water particles that reflect sunlight back to space, cooling the planet. (more…)

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Life Possible on Extrasolar Moons

In their search for habitable worlds, astronomers have started to consider exomoons, or those likely orbiting planets outside the solar system. In a new study, a pair of researchers has found that exomoons are just as likely to support life as exoplanets.

The research, conducted by Rory Barnes of the University of Washington and the NASA Astrobiology Institute and René Heller of Germany’s Leibniz Institute for Astrophysics Potsdam, will appear in the January issue of Astrobiology. Heller is lead author of the paper. (more…)

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Book Traces Long Trail of Global Warming Scholarship

Geophysical Sciences Professor David Archer polled the 200 students in one of his Global Warming classes about whether they believed that humans have had an impact on climate. Approximately 90 percent of the students responded “yes,” reflecting the lessons of climate simulations that Archer had shared earlier with the students.

Those computer simulations are able to reproduce the trend toward rising temperatures, but only when they include data on rising carbon dioxide concentrations in the atmosphere. Simulations that omit the CO2 data do not accurately reproduce the changes. Archer says the link helps reveal carbon dioxide emissions as “the smoking gun” behind global warming and climate change. (more…)

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NASA Orbiter Reveals Big Changes in Mars’ Atmosphere

PASADENA, Calif. — NASA’s Mars Reconnaissance Orbiter has discovered the total amount of atmosphere on Mars changes dramatically as the tilt of the planet’s axis varies. This process can affect the stability of liquid water, if it exists on the Martian surface, and increase the frequency and severity of Martian dust storms.

Researchers using the orbiter’s ground-penetrating radar identified a large, buried deposit of frozen carbon dioxide, or dry ice, at the Red Planet’s south pole. The scientists suspect that much of this carbon dioxide enters the planet’s atmosphere and swells the atmosphere’s mass when Mars’ tilt increases. The findings are published in this week’s issue of the journal Science. (more…)

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Taking Measure of the Greenhouse Effect

WASHINGTON — Scientists have long known that heat-absorbing components of Earth’s atmosphere, such as clouds and certain gases, prevent our planet from being an ice-covered ball. Now a study, for the first time, comprehensively calculates the relative contributions of the components responsible for that heating, known as the greenhouse effect.

Besides clarifying an important aspect of climate science, the study also demonstrates that rising concentrations of one heat-trapping gas — carbon dioxide — leads to much more greenhouse warming than just the heat the gas absorbs directly itself.

Various studies have looked at the contributions of water vapor, CO2, and other greenhouse gases. But none had systematically estimated the contributions of each of the main players, says climate scientist Gavin Schmidt of NASA Goddard Institute for Space Studies, and lead author of the new research. (more…)

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