By the mid-1980s, Thatcher had lost faith in coal and oil as secure energy sources for Great Britain, due to her confrontations with British mine workers and the oil crisis of the 1970s. Thatcher favoured nuclear power and upon learning that nukes, unlike coal and oil, didn't emit carbon dioxide, used it to forward her agenda.
Thatcher also showed the perceptiveness that Gore et al lack to this day:
"Whatever international action we agree upon to deal with environmental problems," she warned, "we must enable all our economies to grow and develop, because without growth you cannot generate the wealth required to pay for the protection of the environment." She added it was industrial innovation, not radical ideology, that would lead to solutions.
Common sense--something in short supply, sadly, when it comes to environmental issues.