22 February 2005

Experts warn of changing weather patterns

One day after the Kyoto Protocol went into effect climate experts issued a report on Thursday saying the Earth is getting warmer with polar ice melting resulting in dramatic climate changes, especially in the north.

"The debate over whether or not there is a global warming signal is now over, at least for rational people," said Tim Barnett of the Scripps Institution of Oceanography.

Using new computer models that look at ocean temperatures instead of the atmosphere, the United States marine physicist evaluated nine million temperature readings made by the US National Oceanic and Atmospheric Administration (NOAA) to calculate a steady ocean warming of a half degree Celsius from 1969 to 1999.

The observed temperature changes in the oceans is conclusive proof that global warming is being caused by human activities, according to the researchers speaking at at an annual meeting of the American Association for the Advancement of Science.

At the same time sea levels are being changed by the melting of Greenland's ice cap, which contains enough ice to raise sea levels globally by seven metres, according to Ruth Curry of the Woods Hole Oceanographic Institution.

Curry found that between 1965 and 1995, melting ice from the Arctic region poured into the normally salty northern Atlantic, changing the water cycle, which in turn affects ocean currents and, ultimately, climate.

"As the Earth warms, its water cycle is changing, being pushed out of kilter," she said. "Ice is in decline everywhere on the planet."

If the trend continues, it threatens the sensitive circulation system called the Ocean Conveyer Belt. Curry warned it is in danger of shutting down, and the last time that happened, 8 000 years ago, northern Europe suffered extremely cold winters.

Though Curry is concerned the ice cap is in danger of collapsing, she added that the ocean currents are now intact but said "the system is moving in that direction".

Melting Artic ice is also depleting important food supplies for animals and shrinking ice shelves meant big animals such as walruses, polar bears and seals were losing their homes, according to Sharon Smith of the University of Miami.

Smith found birds were also suffering. "In 1997 there was a mass die-off of a bird called the short-tailed shearwater in the Bering Sea."

Warmer waters caused a plankton called a coccolithophore to bloom in huge numbers, turning the water an opaque turquoise colour, preventing the shearwater from seeing its prey.


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