By Richard Black
Environment Correspondent, BBC News website
US conservation groups have begun a new legal case aimed at forcing government action on climate change.
They have filed a petition with the UN arguing that Waterton-Glacier Peace Park, a protected area, is being damaged by rising temperatures.
Similar actions have been lodged over sites in the Himalayas and Andes.
The case, filed on the first anniversary of the Kyoto Protocol's entry into force, could compel the US to reduce greenhouse gas emissions.
Petitioners argue that the US, as a signatory to the UN World Heritage Convention, has a legal duty to protect areas with World Heritage status, including Waterton-Glacier.
"The effects of climate change are well-documented and clearly visible in Glacier National Park," said the petition's lead author Erica Thorson from the International Environmental Law Project.
"Yet the US has not taken action to protect the world heritage of the park by reducing its greenhouse gas emissions pursuant to its obligations under the World Heritage Convention."
Globally, glaciers have lost an average 6m in height in 20 years
Straddling the US-Canada border where the province of Alberta meets the state of Montana, Waterton-Glacier was the first region in the world to be declared an International Peace Park.
Conservation groups argue that climate change threatens to have four major impacts on the park:
- average summer temperatures have increased 1.66C between 1910 and 1980, and precipitation levels have decreased by as much as 20%
- the loss of more than 80% of the park's glaciers is the result of climate change
- since 1850, the area covered by glaciers in the park has decreased by 73% and continues to decrease
- loss of the glaciers will reduce stream flow
- climate change threatens mountain and prairie species which live in the region, through a reduction in water and other mechanisms
In 2004 conservation groups co-ordinated by the legal environmental organisation Climate Justice filed similar petitions on behalf of the Sagarmatha National Park in the Himalayas, the Belize Barrier Reef, and Huascaran National Park in Peru.
The Sagarmatha petition is supported by Everest pioneer Sir Edmund Hillary, who said: "The warming of the Himalayas has increased noticeably over the last 50 years... this has caused several and severe floods from glacial lakes, and much disruption to the environment and local people."
In July, Unesco, the UN cultural and scientific agency which manages the World Heritage Convention, announced the establishment of a commission to examine the cases.
It is due to report later this year.
Since then, other legal actions have been initiated against the US over the impact of climate change on Inuit peoples living in the Arctic, and on two species of coral.