By Caroline Wyatt
BBC News correspondent in Paris
As the Kyoto Protocol comes into force, some scientists are suggesting that nuclear power could make an unexpected comeback as a "cleaner" alternative to conventional energy sources.
They point to France, which derives some 78% of its energy from its 58 nuclear reactors, which operate with little or no public opposition.
France is struggling to control emissions from transport
The French President, Jacques Chirac, is a big fan of nuclear energy.
He recently told a nuclear safety conference in Moscow that nuclear energy in France was not only the most economic choice, but also the most environmentally friendly.
While nuclear power does have its environmental opponents in France, they are far outweighed by friends of the nuclear energy lobby, which numbers some surprising allies.
They include French environmentalist Bruno Comby, who has written several books including one titled Environmentalists For Nuclear Energy.
He also founded Environmentalists For Nuclear Energy (EFN), an international association aimed at promoting nuclear energy.
EFN believes that environmental opposition to nuclear energy is based on a misunderstanding.
"If well-managed," Bruno Comby says, "nuclear energy is very clean, does not create polluting gases in the atmosphere, produces very little waste and does not contribute to the greenhouse effect."
His beliefs are echoed by the independent scientist James Lovelock, an environmentalist and so-called green.
As a lifelong supporter of nuclear energy, he recently argued that civilisation was in imminent danger from global warming and must use nuclear power - "the one safe, available energy source" - to avoid catastrophe.
French energy providers point out that alternative sources of energy remain uneconomical compared with nuclear energy.
A recent British report by the Royal Academy of Engineering showed that the nuclear option was the second cheapest means of generating electricity, at $0.043 (2.3p) per kilowatt hour, after gas at $0.04 (2.2p), while wind power cost more than $0.09 (5p) per kWh.
Growth in emissions
However, despite its championing of nuclear energy, France is among the European countries unlikely to hit its Kyoto target for reducing greenhouse emissions.
Each EU country pledged to reduce its 1990 greenhouse gas emissions by 8% by 2010.
Nuclear power has some surprising allies in France
By the end of 2003, France was off-target by almost 10%, with only Sweden and the UK expected to meet their commitments.
For France, the target represents 552 million tonnes of greenhouse gases a year.
Despite using mainly nuclear power, France is still looking for ways to reduce its other emissions.
While carbon dioxide emissions have been brought down 15.5% from 1990 to 2001, and French industry has reduced emissions by 25% and energy generation companies by 22%, emissions through transport and house heating increased over the same period.
Carbon dioxide emissions from transport have also risen more than 26% since 1990, and emissions from house heating more than 12%.
These last two sectors produced 47% of greenhouse gases emitted in France in 2001.
So while nuclear energy may be part of the solution for France, on its own it is not enough to live up to its Kyoto promises.