'We've watched these ponds go from cradle to grave.'

In July 1983, 40 lush ponds, rich with tiny microscopic life, dotted Ellesmere Island's Cape Herschel, providing a welcome refuge for eider ducks and other High Arctic birds.

But in July 2006, two researchers, John Smol from Queen's University and Marianne Douglas from the University of Alberta, were astounded to see many of these same ponds empty and etched with cracked soil. The surrounding mossy wetlands had become tinder-dry.

"We used to have to put on hip waders to walk through them. Now you could do it in running shoes and light some of these mosses on fire," Smol said. "We've watched these ponds go from cradle to grave. We've seen them go to dry land in front of our eyes."

On earlier visits to Cape Herschel during the 1990s, the two researchers became alarmed when they saw dropping water levels in the ponds and changes in water chemistry, which they attributed to warming trends since 1850. When they arrived in Cape Hershel last July, during the warmest year on record for that portion of the Arctic, they were shocked to see parched land.

"It's worse than we thought," Smol said. "The system is changing and changing very fast."

"At no time in human history have we ever seen changes occur so fast," Douglas said.

The impact of the ponds' disappearance is "likely to be severe"- there will be less food for birds and less drinking water for animals. As well, the lower water levels in ponds that haven't dried up completely will lead to a more concentrated level of pollutants.

Because of the extreme dryness of the terrain, fire is also a risk, which could contribute even more global warming.

In their recent paper, published in the Proceedings of the National Academy of Sciences, the two say a key "tipping point" in climatic change has been passed with the disappearance of these 6,000-year-old ponds.

By measuring changes in water quality over 24 years, they found the water in these ponds is evaporating due to warming. That's because the concentration of salts in the pond water has been steadily increasing – similar to what happens when a pot of soup is left to simmer on a stove.

"If you take the lid off, it is similar to what we are observing in these ponds. The soup will slowly decrease in volume and it will get saltier and saltier as the water evaporates, leaving the salts behind," Smol said.

The same process is occurring in the Cape Herschel ponds where water levels have dropped and the remaining water is more concentrated by evaporation due to warming.

The disappearance of these ponds is troubling because similar ponds are the most common source of surface water in many Arctic regions.

"If it's happening here, I'm sure it's happening in other areas," Smol said.

Earlier this week, Smol and Douglas headed back to Cape Herschel. There, they expected to see more drying, thanks to on-site equipment, which records temperatures every six hours year-round.

Based its data, they were able to see the ponds melted a full five weeks earlier in 2005 and 2006 than in 1986.

On July 14 – the same date as on previous years since 1983 – they'll take photos, water temperature readings and samples and gather collections of algae and plankton from the remaining ponds.

Their repeated visits show the value of long-term observations, the two researchers emphasize, because if they hadn't returned to the same place year after year they might not have noticed the abrupt changes to the ponds.

Poppies and saxifrage may now take root where the ponds flourished.

The ponds may still fill up occasionally in the future as warmer winters forecast for the High Arctic bring more snow. However, Smol and Douglas aren't sure this will offset the water evaporation due to the longer and warmer ice-free seasons.