Freshwater Runoff From Greenland Ice Sheet Will More Than Double By End Of Century

The Greenland Ice Sheet is melting faster than previously calculated according to a scientific paper by University of Alaska Fairbanks researcher Sebastian H. Mernild published recently in the journal Hydrological Processes.

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The study is based on the results of state-of-the-art modeling using data from the Intergovernmental Panel on Climate Change as well as satellite images and observations from on the ground in Greenland.

Mernild and his team found that the total amount of Greenland Ice Sheet freshwater input into the North Atlantic Ocean expected from 2071 to 2100 will be more than double what is currently observed. The current East Greenland Ice Sheet freshwater flux is 257 km³ per year from both runoff and iceberg calving. This freshwater flux is estimated to reach 456 km³ by 2100.

Mernild’s results further show a change in total East Greenland freshwater flux from today’s values of 438 km³ per year to 650 km³ per year by 2100. This indicates an increase in global sea level rise estimates from 1.1 millimeters per year to 1.6 millimeters per year.

“The Greenland Ice Sheet mass balance is changing as a response to the altered climatic state,” said Mernild. “This is faster than expected. This affects freshwater runoff input to the North Atlantic Ocean, and plays an important role in determining the global sea level rise and global ocean thermohaline circulation.”

Mernild is conducting the research as part of the University of Alaska’s International Polar Year efforts. He was appointed a University of Alaska IPY postdoctoral fellow by UA president Mark Hamilton in 2007.

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Southern tip of Greenland on November 2, 2001. New data shows that the Greenland Ice Sheet is melting faster than previously calculated.

Life's Raw Materials May Have Come From The Stars, Scientists Confirm

Scientists have confirmed for the first time that an important component of early genetic material which has been found in meteorite fragments is extraterrestrial in origin, in a paper published on 15 June 2008.

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The finding suggests that parts of the raw materials to make the first molecules of DNA and RNA may have come from the stars.

The scientists, from Europe and the USA, say that their research provides evidence that life’s raw materials came from sources beyond the Earth.

The materials they have found include the molecules uracil and xanthine, which are precursors to the molecules that make up DNA and RNA, and are known as nucleobases.

The team discovered the molecules in rock fragments of the Murchison meteorite, which crashed in Australia in 1969.

They tested the meteorite material to determine whether the molecules came from the solar system or were a result of contamination when the meteorite landed on Earth.

The analysis shows that the nucleobases contain a heavy form of carbon which could only have been formed in space. Materials formed on Earth consist of a lighter variety of carbon.

Lead author Dr Zita Martins, of the Department of Earth Science and Engineering at Imperial College London, says that the research may provide another piece of evidence explaining the evolution of early life. She says:

“We believe early life may have adopted nucleobases from meteoritic fragments for use in genetic coding which enabled them to pass on their successful features to subsequent generations.”

Between 3.8 to 4.5 billion years ago large numbers of rocks similar to the Murchison meteorite rained down on Earth at the time when primitive life was forming. The heavy bombardment would have dropped large amounts of meteorite material to the surface on planets like Earth and Mars.

Co-author Professor Mark Sephton, also of Imperial’s Department of Earth Science and Engineering, believes this research is an important step in understanding how early life might have evolved. He added:

“Because meteorites represent left over materials from the formation of the solar system, the key components for life -- including nucleobases -- could be widespread in the cosmos. As more and more of life’s raw materials are discovered in objects from space, the possibility of life springing forth wherever the right chemistry is present becomes more likely.”

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Stardust from Murchison-meteorite. New finding suggests that parts of the raw materials to make the first molecules of DNA and RNA may have come from the stars.