Alaskan tundra fires rage - Global Warming fears

Alaskan tundra fires rage. Fueling Global Warming by increasing levels of Carbon Dioxide in the Atmosphere. (Image: MODIS Rapid Response Team / Goddard Space Flight Center / NASA)

The fire that raged north of Alaska's Brooks mountain range in 2007 left a 1000-square-kilometre scorched patch of earth – an area larger than the sum of all known fires on Alaska's North Slope since 1950.

Carbon Dioxide increase

Now scientists studying the ecological impact of the fire report that the blaze dumped 1.3 million tonnes of carbon dioxide into the atmosphere – about the amount that Barbados puts out in a year. What's more, at next week's meeting of the Ecological Society of America in Albuquerque, New Mexico, two teams will warn that as climate change takes hold tundra fires across the Arctic will become more frequent.

Increased Frequency of Fires

Tundra fires only take off once certain thresholds are reached, says Adrian Rocha of the Marine Biological Laboratory, Woods Hole, Massachusetts. "But projected changes in climate over the next century – increased aridity, thunderstorms, and warming in the Arctic – will increase the likelihood that these thresholds will be crossed and thus result in more larger and frequent fires."

Sigmoids - not so Freudian

This dramatic "sigmoid", an "S"-shaped bundle of plasma, appeared on the surface of the sun in 2007 and later erupted. Now a new model has reproduced the event (Image: NASA/STFC/ISAS/JAXA)

The formation and eruption of large "S"-shaped structures on the surface of the sun have been modelled in the best detail yet. Further refinements of the model might help sun-watchers predict severe space storms days in advance.

'Sigmoids' are S-shaped structures that appear intermittently on the sun's surface. Many produce eruptions of hot ionised gas, or plasma, such as coronal mass ejections and flares. If the eruptions are powerful enough, they can zap satellites, endanger astronauts, and knock out power grids (see Space storm alert: 90 seconds from catastrophe).

Until now, models of the structures have not been able to reproduce the full lifetime of a sigmoid from its beginnings within the sun to its eventual eruption sometimes days later. But now researchers say they have come up with a simple model that could do just that.

"For the first time, we have built a three-dimensional model that shows in a very nice and self-consistent way the evolution and final eruption of a sigmoid," says Vasilis Archontis of St Andrews University in Scotland.