Some 1,500 scientists from more than 50 countries around the world on Monday urged Canadian governments to protect the country's 566.6 million-hectare boreal forest.

The forest — described by the researchers in an open letter as one of the world's last remaining and largest intact forest and wetland ecosystems — is a major source of fresh water in North America, home to billions of animals and important to the livelihood of First Nations communities, they noted.

According to the researchers, the boreal forest is threatened by logging, mining, oil and gas operations and other activities, and will continue to be at risk unless federal, provincial and territorial governments increase the area that enjoys protected status from the current 10 per cent to at least 50 per cent.

"The world scientific community is recognizing that the Canadian boreal forest is more important than they knew," Jeff Wells, a scientist with the International Boreal Conservation Campaign and the Boreal Songbird Initiative, told CBC.ca.

"About 50 per cent of migratory bird species, or aboutthree to five billion birds, migrate through the region, it has the world's largest reservoirs of fresh water in its 1.5 million lakes and ponds … and [it]is a critical shield against global warming," said Wells, who holds a PhD in avian ecology.

The region constitutes about one-quarter of the world's forest and is one of five remaining regions that serve a global environmental balancing role, he said.

Scientists say the forest is the world's largest storage mass for carbon — a crucial link to help curb global climate change. It is capable of storing 186 billion tonnes of carbon, or the equivalent of 27 years of carbon dioxide emissions from planetary consumption of fossil fuels, according to the researchers.

Wells said that in other parts of the world —including the United States — upwards of 90 per cent of forest and grasslands that serve as obstacles to global climate change have been destroyed, changing ecosystems and resulting in the extinction of species.

"The carrier pigeon went from [a population] of three to five billion to zero in about 100 years. It was one of the most common species but the last one died in a zoo in 1914.We don't want to repeat that."

Ecological models suggest that a four-degree increase in temperature will put 40 per cent of all species at risk of extinction, he said, citing recent research.

'People once thought clean water was unlimited'

Scientists have only recently started to realize the global importance of the Canadian boreal forest, Wells said.

"People once thought clean water was unlimited, they thought clean air was unlimited, they thought animals were unlimited. Now we know they're not," he said.

The elimination of ecosystems and species that have occurred to date are a direct result of that, Wells said.

"It's a function of lack of vision, lack of knowledge, and poor planning," Wells said.

The International Boreal Conservation Campaign, the Canadian Boreal Initiative and the Boreal Songbird Initiative, backed by U.S.-based Pew Charitable Trusts, publicly released the letter Monday.