Scientists consider the Arctic to be a bellwether for climate change, but until recently, they've had to rely on samples collected thousands of kilometres away from the Pole.

In fall 2004, scientists explored the Arctic Ocean with two icebreakers and drilling rigs on the Lomonosov ridge on the Arctic seabed, about 250 kilometres from the North Pole.

The icebreaker allowed scientists to drill into a climatic time capsule - the multi-year ice is harder and thicker than ice accumulating in one Arctic winter.

"At times, the drill site was covered with ice two to three metres thick," recalled geologist Jan Blackman, a professor at Stockholm University and chief co-scientist on the expedition.

"It was like driving into a brick wall."

In three studies appearing in Thursday's issue of the journal Nature, researchers document how the region went from greenhouse to icehouse conditions.

First, the Arctic Ocean went through a warm period with temperatures of 23 C, like a tepid bath.

Then, about 49 million years ago, freshwater was released into the Arctic, cooling it to about 10 C.

At the time, the salinity was dilute enough for freshwater ferns to cover much of the surface in the summer, the team said.

Cooldown

The fast-growing greenery likely absorbed carbon dioxide, helping to cool the Arctic, theorized Henk Brinkhuis of Utrecht University, a co-author of one of the papers.

Pebbles carried to the middle of the Arctic basin, dropped by icebergs, suggest ice started to form about 45 million years ago, the start of the region's current "icehouse" conditions.

The findings suggest the Northern Hemisphere cooled earlier than previously thought, coinciding with when the climate was also changing in the Antarctic.

The temperature swings show the rate of change in carbon dioxide levels and warming are similar to those forecast in coming centuries, a journal commentary notes.

"In one respect future warming will be different," wrote Heather Stoll, a geoscientist at Williams College in Williamstown, Mass. "It will be amplified at high latitudes by the reduction in snow and sea ice cover."

The blanket of reflective snow and sea ice over the poles reduces the amount of sunlight absorbed by the Earth, helping to cool the planet.

"We have been providing tools to kill the monkeys, but still there are many continuing to destroy farm produce," he told AFP.

Zanzibar Agriculture Minister Burhan Saadat Hajji last week gave 300 bullets to help Tumbatu's 10,000 inhabitants get rid of the aggressive monkeys, but residents said the donation was woefully inadequate.

At least 900 monkeys were killed in an extermination drive last week, they said, stressing that thousands more were still ravaging their banana, cassava and sweet potato fields and threatening their homes.

"We have intensified hunting, but our problem is a lack of tools," Tumbatu farmer Khamis Hassan told AFP. "One bullet costs about one cent but can kill only one monkey and we can't afford to buy thousands of bullets."

"We are afraid of monkey attacks, especially on children, and sometimes they reach our homes and grab our cooked food," he said. "It's just getting worse and worse."

The findings raise concerns about plans to rebuild levees, said the study's lead author, Tim Dixon, a geophysicist at the University of Miami.

"My concern is the very low-lying areas," Dixon told the Associated Press. "I think those areas are death traps. I don't think those areas should be rebuilt."

The worst shrinking of the ground - which scientists call subsidence - occurred in sections of the Mississippi flood plain where levees were breached by the hurricane's surging water, the study's authors report in Thursday's issue of the journal Nature.

Some parts of the city sank faster than others, the team said:

* The districts of Lakeview on the south shore of Lake Pontchartrain.
* Kenner, near Louis Armstrong New Orleans International Airport in the eastern part of the city.
* Regions bordering St. Bernard Parish, west of Lake Borgne.

Water levels after Katrina exceeded expected levels by between 90 centimetres and 1.7 metres, the scientists found.

Subsidence may have also led the base of the levees to fail, allowing the walls to be damaged by the surge, the team said.

The study's authors were divided on the cause of the subsidence.

Dixon blamed overdevelopment and drainage of wetlands, which could cause the highly organic soil to dry out and become compacted.

Study co-author Roy Dokka, director of the Louisiana Spatial Center at Louisiana State University, attributed the shrinking to natural seismic shifts in eastern New Orleans, not human interventions.

Firefighters said its likely she was hit by a bolt of lightning that apparently struck outside and traveled into the house yesterday afternoon. She was found lying on the floor by her 14-year-old granddaughter.

Fire officials think the lightning likely struck across the street from the couple's home and traveled into the house through a water line. The lightning continued into the couple's backyard and ripped open a small trench.

A family member said he will no longer assume it is safe to be indoors during a lightning strike.

Dime-sized hail and wind gusts of up to 45 miles-per-hour moved across coastal Baldwin County. As much as three inches of rain fell in some areas in three hours.