"We must not find ourselves in a situation where Russia does not sign the Kyoto protocol. This is a priority in the EU's foreign policy," Danish environment minister Hans Christian Schmidt said.

Despite the fact that more than 100 mostly developing nations have already ratified the treaty, the withdrawal by the United States and Australia means that Russia must ratify it if Kyoto is to enter into force.

The treaty sets individual targets for industrialised countries to trim their emissions of carbon gases, the byproduct of burning fossil fuels, on average by 5.2 percent below their 1990 levels over the next 10 years.

The treaty has a number of mechanisms aimed at harnessing the market to reduce carbon pollution, one of which is emission trading in carbon dioxide among industrialised signatory countries from 2008.

This will set up a "carbon market", potentially worth billions of dollars a year, where these countries can buy and sell emissions "credits" in order to meet their treaty obligations.

With the closure of its most polluting industrial plants since the collapse of the Soviet Union, Russia has built up considerable credit on its quota.

Moscow should therefore be able to sell several million tons of carbon dioxide on the future carbon market.

However, Russia is uneasy about the EU's willingness to buy its credit.

"We must send a clear signal to Russia that we will buy its quotas and that we will invest there," Schmidt added.

EU Environment commissioner Margot Wallstrom said it was in Russia's interest to ratify the protocol in order to benefit from the resulting transfer in technology.

The Kyoto treaty provides for a mechanism whereby industrialised signatory countries can claim credits for investing in emission-cutting projects in countries like Russia.

Wallstrom said she hoped Russia will ratify the protocol before the international conference on climate change scheduled to be held in Moscow at the end of September.

SPACE.WIRE