Hannah Hoag

Ancient Canadian ice survived previous warm periods.

A 740,000-year-old wedge of ice discovered in central Yukon Territory, Canada, is the oldest known ice in North America. It suggests that permafrost has survived climates warmer than today’s, according to a new study.

“Previously, it was thought that the permafrost had completely disappeared from the interior about 120,000 years ago,” says Duane Froese, an earth scientist at the University of Alberta in Edmonton, Canada, who is the author of the study published today in Science¹. “This deep permafrost appears to have been stable for more than 700,000 years, including several periods that were warmer and wetter.”

Keep reading in Nature.

Image credit: Duane Froese, University of Alberta

In September 2007, I spent three days learning about the grizzly bears in Yellowstone National Park. Read about the field course, offered by the Yellowstone Institute, in the August issue of Discover.

On the southern bank of the Lamar River in Yellowstone National Park, a female grizzly bear forages for tubers, snout to the ground. For a day and a half, she eats and dozes in the same spot, ignoring the huge herd of bison that graze nearby. Much like humans, grizzlies are clever scavengers, feasting on rodents, trout, roots, nuts, berries, insects, and dead animals. But they paid a price for their omnivory, at least at Yellowstone.

Research is revealing that male and female brains are built from markedly different genetic blueprints, which create numerous anatomical differences. There are also differences in the circuitry that wires them up and the chemicals that transmit messages between neurons. All this is pointing towards the conclusion that there is not just one kind of human brain, but two.

Read more in the July 19 issue of New Scientist.

What about the other greenhouse gases that aren’t accounted for by the Kyoto Protocol? Might they be altering our climate too?

Read about nitrogen trifluoride in the August issue of Nature Reports Climate Change.

Our insatiable appetite for gadgets — mobile phones, MP3 players and flat-screen TVs — may be adding a hidden greenhouse gas to the Earth’s atmosphere. Countries that ratified the Kyoto Protocol committed to reducing their emissions of carbon dioxide and five other heat-trapping gases: methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride. But these aren’t the only climate-altering chemicals being produced by human activity. In the 13 years since the Protocol was first drawn up, scientists have discovered that other gases, such as nitrogen trifluoride (NF₃), could become an increasing part of the climate problem.

In the last five years, the Arctic sea ice has stepped up its rapid decline. So much so, that last year, it had researchers speculating that the Arctic ocean could be ice free by 2013. It has huge implications for the Arctic marine ecosystem, but new research shows that the effects of rapid sea ice loss will be felt thousands of kilometres inland. The article (below) appears in the June 26 issue of Nature Reports Climate Change.

Given the ice’s sudden change, sea ice experts are changing the way they make their projections. You can read a bit about them in the article, or you can read their May 2008 Sea Ice Outlook (the first one) here.

Also, worth checking out is an animation showing the flushing of multi-year sea ice from the Arctic Basin. There’s been a nearly complete loss of old ice in the Arctic. Most of the perennial ice is young and thin–and susceptible.

The rapid decline of sea ice could accelerate inland warming over the Arctic region, radically transforming the landscape.

One of the Northern Hemisphere’s natural cycles is the expansion and contraction of the floating Arctic ice cap. Typically, sea ice decreases during the Arctic summer, reaching a low in September, before recovering as temperatures drop in winter. From as far back as satellite measurements began in 1978 until 2000, the average sea-ice extent, or the area of ocean covered by at least 15 per cent ice, has routinely hovered around 7 million square kilometres during the summer minimum.

But in 2002, scientists noticed a sharp drop in the region’s minimum ice coverage. By September 2007, the area covered by ice had been whittled down to a startling 4.3 million square kilometres–40 per cent smaller than in the 1980s. Scientists say the retreat witnessed last year was drastic, unexpected and more than 20 per cent below the previous record minimum.

Not only will the loss affect the marine ecosystem and its dependents, from indigenous communities to marine mammals that rely on the ice for hunting and travel: it stands to alter the Arctic landscape much further afield. According to a new study in the 13 June issue of Geophysical Research Letters, the rapid retreat of Arctic sea ice could accelerate warming 1,500 kilometres inland in northern Alaska, Canada and Russia. During rapid ice retreat, the rate of inland warming could be more than three times that previously predicted from global climate models. <more>