Greenpeace and the WWF, as well as some socially-responsible investment funds including the Co-operative Asset Management warn that investments in oil sands are high risk
Fund managers and campaign groups such as WWF and Greenpeace warn that investors in Royal Dutch Shell and BP are facing growing risks as a result of the companies' involvements in Canada's oil sands.
James Marriott of Platform, another campaign group, said: "Our argument to investors is that there is an investment reason not to go further into something that is full of risk." They predict the likelihood of a price will be put on carbon dioxide emissions threatening the viability of oil sands projects.
Canada's vast oil sands reserves have attracted interest from all the big western oil companies, which have found themselves shut out or facing growing difficulties in other resource-rich countries.
Many companies have plans for a steep increase in their production from the oil sands of Alberta in western Canada.
However, production from the oil sands is difficult and costly. The oil must be separated from the sand, either by being mined out by diggers and then mixed with hot water, or by being heated with steam piped underground so it flows and can be pumped out.
The high energy use in these processes means it has much higher emissions than conventional oil production, according to a report by Greenpeace and Platform. The findings will be presented to today's private meeting, to be attended by about 60 people representing leading investment institutions, organised by the UK Social Investment Forum.
The report cites estimates that conventional oil production generates an average of 28.6kg of carbon dioxide per barrel, whereas oil sands production generates 80kg-135kg per barrel; almost five times as much.
Both John McCain and Barack Obama, the US presidential candidates, are talking about setting a price on carbon dioxide emissions.
Shell said that although the extraction of oil in Alberta did create higher emissions, the total emissions from the oil, including its use by the customer, were only 15 per cent higher on average. It added that fuel produced from many conventional oil fields could have similar total emissions as fuel from oil sands.