Arctic 'ice-free by 2040'

The North Pole could be free of ice during the summer by 2040 thanks to the dramatic effects of global warming, a new scientific study has warned.

The ice-bound ocean could melt, bringing disaster for many arctic animals including polar bears.

The dire warning was delivered at the American Geophysical Union Autumn Meeting.

Scientists reported that the Arctic sea ice, which has shrunk over the past 30 years, is not recovering fully in the winter months.

In November, ice coverage was about 800,000 square miles below average, the least amount of sea ice ever recorded by satellites.

“That’s an area the size of Alaska,” said leading ice expert Mark Serreze.

“We’re no longer recovering well in autumn anymore. The ice pack may now be starting to get preconditioned, perhaps to show very rapid losses in the near future,” the University of Colorado researcher added.

A computer prediction showed that by 2040, only a small amount of permanent sea ice will remain along the north coasts of Greenland and Canada, while most of the Arctic basin will be ice-free in September.

Meanwhile, in a signal of the wide-ranging impacts of climate change, carbon dioxide emissions linked to global warming are cooling and shrinking the outermost atmosphere where the international space station and other satellites orbit, scientists reported.

The thinning of the thermosphere, which begins about 60 miles above Earth and extends up to 400 miles, reduces the drag on orbiting spacecraft, keeping them airborne longer. The downside is that the lifetime of space junk is also extended, which can pose a threat to satellites.

“It’s a bit of a two-edged sword,” said Stanley Solomon, a senior scientist at the National Centre for Atmospheric Research.

Using a sophisticated computer model that takes into account the solar cycle and carbon dioxide emissions, Solomon and his colleagues estimated that the air density of the outer atmosphere declined about 5% over the past three decades and could decrease 40% by the end of the century.

Knowledge of how the outer atmosphere responds to carbon dioxide levels could help NASA and international space agencies time their spacecraft launches and calculate their fuel needs.

Solomon said a less dense outer atmosphere should not affect launches in the near-term, but it could be problematic in the future with the increase of space litter.

“In the long haul, it means we have to be even more assiduous about not letting miscellaneous pieces of metal float around,” Solomon said.

Researchers have long predicted that carbon dioxide, a greenhouse gas produced when fossil fuels such as oil and natural gas are burned, would cool the outer atmosphere.

Solomon’s conclusions mirror previous research that predicted similar effects including recent observations that measured the drag of satellites over time.