Tiempo Climate Newswatch

The Arctic Ocean may become seasonally ice-free within the next 100 years, according to a recent assessment. The finding results from a week-long meeting of a team of interdisciplinary experts, organized by the National Science Foundation Arctic System Science Committee. "What really makes the Arctic different from the rest of the non-polar world is the permanent ice in the ground, in the ocean and on land," said lead author Jonathan Overpeck from the University of Arizona. "We see all of that ice melting already, and we envision that it will melt back much more dramatically in the future as we move towards this more permanent ice-free state."

The team saw little hope that natural processes will counteract the effects of global warming. "I think probably the biggest surprise of the meeting was that no one could envision any interaction between the components that would act naturally to stop the trajectory to the new system," reported Overpeck. The sensitivity of the Arctic is the result of feedback systems that accelerate changes in the system. As shiny snow and ice melts, for example, more and more solar radiation is taken up by the darker land and ocean that is revealed.

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Background

• ENS
• Discovery

• Arctic impacts report, ACIA

A lead author has resigned from a Climate Change Science Program panel reporting to the Bush administration after the chapter he was responsible for was re-drafted by other members of the panel. Roger Pielke Sr, of Colorado State University, claims that panel members involved in recent research on temperature trends in the tropical atmosphere have attempted to exert undue influence on the deliberations of the panel. "When you appoint people to a committee who are experts in an area but evaluating their own work," he told the New York Times, "it's very difficult for them to think outside the box of their research."

Pielke is concerned that "by seeking to limit the scope of my chapter and the report, more generally, important scientific issues were overlooked or downplayed - for example, describing and explaining recent regional trends in surface and tropospheric temperatures." While he respects the sincerity of the panel's scientists, "the broader perspective captured by the actual charge to the committee would better serve both science and policy."

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Comment

• New York Times
• New York Times

• Weblog, Roger Pielke and Andy Revkin
• National Center for Policy Analysis

The World Meteorological Organization (WMO) has reported that the winter-time ozone hole over Antarctica has grown from last year, but has not reached the peak extent seen in 2003. The hole expanded to 29 million sq km in September 2003, extending to the southern tip of South America.

According to Geir Braathen, from the Norwegian Institute for Air Research, concentrations of ozone-depleting substances have "leveled off" and are set to decline, but "we still expect the ozone hole to appear annually and it actually might be a little bit worse in the next five to 10 years, then the situation will start to improve." He expects that the ozone hole is not likely to close till the mid-21st century.

More information

Background

• Reuters
• Voice of America

• The Ozone Hole Tour, Cambridge University