An international team of scientists, who did a chemical analysis of the ice core, found the average annual snowfall had been constant for more than 100 years but that it started to increase in 1850, which they believe is a sign of global warming.

"We argue that this increase in snow accumulation is associated with a warming of the atmosphere over Western Canada," Professor Kent Moore, of the University of Toronto, said in a statement.

It may seem paradoxical but Moore and his team explained that warmer air holds more moisture and during the winter it can be released as snow.

The scientists, whose research is reported in the science journal Nature, said their study provides evidence of higher surface temperatures and atmospheric warming, which point to climate change due to greenhouse gases.

"We're seeing evidence that both of these climate modes have been intensifying," Moore added.

Their findings are consistent with earlier research which showed that levels of carbon dioxide, a leading greenhouse gas linked to climate change, also began to rise in Western Canada around 1850 and were due in part to the Industrial Revolution.

Moore said studies of global warming trends point the finger of blame at human activity and he emphasised the need for action to reduce global warming.

"We need to be serious about this. Kyoto is a start - I don't know if it's all we have to do. But for our children and our children's children's sake, we need to deal with this because we caused this," Moore added.

Climate experts have warned that global warming will increase the risk of droughts, floods and other natural disasters around the globe.

The 1997 Kyoto Protocol on climate change aims to cut greenhouse gas emissions in the developed world by 2012 to 5.2 percent below 1990 levels.

But the United States, the world's biggest air polluter, has refused to ratify the treaty because it does not bind developing countries.

In order for the pact to take effect, it must be approved by states accounting for at least 55 percent of the industrialised world's 1990 gas emissions.