. Earth Science News .
Current warming sharpest climate change in 5,000 years: study

The massive Arctic fresh-water melt in the past 10 years has helped one species of microscopic algae move from the Pacific ocean to the North Atlantic. The last time that algae appeared in the North Atlantic was 800,000 years ago, the Cornell research found.
by Staff Writers
Washington (AFP) Nov 6, 2008
Research on Arctic and North Atlantic ecosystems shows the recent warming trend counts as the most dramatic climate change since the onset of human civilization 5,000 years ago, according to studies published Thursday.

Researchers from Cornell University studied the increased introduction of fresh water from glacial melt, oceanic circulation, and the change in geographic range migration of oceanic plant and animal species.

The team, led by oceanographer Charles Greene, described "major ecosystem reorganization" -- or "regime shift" -- in the North Atlantic, a consequence of global warming on the largest scale in five millennia.

"The rate of warming we are seeing (now) is unprecedented in human history," said Greene, whose research appears in the November 2008 issue of the journal Ecology.

In order to forecast the path of climate change, Greene and colleagues have been reconstructing major episodes of warming and cooling in the Arctic over the past 65 million years.

They have found in the paleoclimate record periods of rapid cooling, with average temperatures plunging by 10 degrees Celsius (18 degrees F) within just decades or even years.

But the rise in temperatures over the past five decades is unmatched since the onset of human civilization, Greene said.

The paleoclimate data gives the scientists more insight into the impact of melting Arctic ice sheets and glaciers on the North Atlantic oceanic system.

They have found "extensive" shifts in the geographic range of numerous plant and animal species.

For instance, the massive Arctic fresh-water melt in the past 10 years has helped one species of microscopic algae move from the Pacific ocean to the North Atlantic.

The last time that algae appeared in the North Atlantic was 800,000 years ago, the Cornell research found.

The increase of fresh water can have a huge impact on the ecosystems of the Atlantic continental shelf, for instance extending the growing seasons of phytoplankton and microscopic drifting animals fundamental to the food chain.

"Such climate-driven changes can alter the structure of shelf ecosystems from the bottom of the food chain upwards," according to Greene.

In another example, the collapse in the last century of cod populations in the north Atlantic is partially due to overfishing, but also partly due to Arctic glacial melt adding more fresh and colder water to the ocean, which stifles cod reproduction.

At the same time, the research noted, less cod and colder water benefited shrimp and snow crab populations.

"As climate changes, there are going to be winners and losers, both in terms of biological species and different groups of people," said Greene.

The Cornell studies also focused on the way the introduction of more freshwater in the north Atlantic can disrupt circulation patterns further south.

"When Arctic climate changes, waters in the Arctic can go from storing large quantities of fresh water to exporting that fresh water to the North Atlantic in large pulses, referred to as great salinity anomalies," Greene explains.

By modeling the current changes, the Cornell researchers posited that the highly saline water of the deep North Atlantic will likely not be heavily affected by the "pulses" of fresh water during the 21st century.

"Continued exposure to such freshwater forcing, however, could disrupt global ocean circulation during the next century and lead to very abrupt changes in climate, similar to those that occurred at the onset of the last ice age," the studies said.

"If the Earth's deep ocean circulation were to be shut down, many of the atmospheric, glacial and oceanic processes that have been stable in recent times would change, and the change would likely be abrupt," said Greene.

Share This Article With Planet Earth
del.icio.usdel.icio.us DiggDigg RedditReddit
YahooMyWebYahooMyWeb GoogleGoogle FacebookFacebook



Related Links
Climate Science News - Modeling, Mitigation Adaptation



Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News


Canada to offer Obama continental climate change pact
Ottawa (AFP) Nov 6, 2008
Canada's prime minister said Thursday he hoped to work with US president-elect Barack Obama on a North American deal to curbing greenhouse gas emissions linked to global warming.







  • Flood-hit Vietnam capital moves to contain disease outbreaks
  • China rebuilds six months after quake, amid frustrations
  • Simulated Seismic Signals Could Help Save Lives
  • Death toll in southwest China rain rises to 43: state media

  • Financial crisis puts heat on Australian govt over climate plan
  • Africa left behind in Kyoto carbon offset trade: experts
  • Current warming sharpest climate change in 5,000 years: study
  • Canada to offer Obama continental climate change pact

  • New NASA Technique Measuring Glacier Driven Sea Level Changes
  • Paloma Still Intensifying And Turning Northward
  • CHRIS Satellite Imager Celebrates 7 Years Scientific Success
  • ISRO's New Satellite Could See Through Even Cloudy Sky

  • Southwall's Heat Mirror Insulating Glass
  • Fuels Of The Future May Come From Ice That Burns, Water And Sunshine
  • Six navy personnel killed in Nigeria gun battle
  • World oil prices up on OPEC chief's remarks, China stimulus plans

  • AIDS vaccines: New hope for problem-plagued path
  • Death By Hyperdisease
  • Experimental HIV vaccine may have increased infection risk: study
  • Seeing Life In Viruses

  • Coral Reefs Found Growing In Cold, Deep Ocean
  • Jogger runs mile with rabid fox locked to arm
  • Climate change pushing lemmings over the edge: study
  • India leads world in snake-bite deaths

  • White House defends last-minute deregulation push
  • Smelly effluent mars affluent Dubai's beaches
  • Study: Biosolids pose little worker risk
  • China struggling to meet environment goals: official

  • China's media workers not in good physical shape: report
  • Scientists compare human, chimp genetics
  • World's tallest man riding high after becoming a dad
  • Ancient Bone Tool Sheds Light On Prehistoric Midwest

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2007 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement