Over the past decade, the current British government has taken a crack at devolution, giving Scotland, Northern Ireland, and Wales a level of operational government unseen for a century or more. The fledgling administrations of these three “devolved nations” have embarked on very different policy trajectories on the environment, among other policy areas. The sustainable development strategy for the U.K. launched three years ago seems to have got its title right at least: One Future, Different Paths.

Northern Ireland’s journey to democracy has, of course, been long and troubled, so perhaps it’s not surprising to find their ruling Democratic Unionist Party somewhat behind the game on the environment. And they’re apparently not that keen to catch up: In June, the DUP appointed Sammy Wilson as environment minister. Wilson was fresh from winning the Green Party’s award for the assembly member most likely to damage the environment. He is pro-nuclear and strongly opposes the creation of an independent Environment Protection Agency. Environmentalists’ concerns that this does not sound like the right track record for an environment minister were borne out earlier this month when he called climate change a “hysterical pseudo-religion,” and claimed global warming is natural rather than human-caused.

At the other end of the green spectrum is Wales, where the Assembly created back in 1998 has consistently pursued sustainable-development policies for a fairly simple reason: A duty to promote sustainable development is written into their constitution. The Assembly has gone a long way to mainstreaming sustainability thinking, and it now publishes an annual set of national sustainability indicators. (The Assembly has also been a partner with Forum for the Future for the last eight years, so perhaps I’m a bit biased.)

Scotland’s longing for independence was perhaps the most heartfelt, and the Parliament established there in 1999 has the greatest degree of devolved power, including an ability to create primary legislation and vary the tax rate. These arrangements have become a thorn in the flesh for the Labor Party that created them; Labor had hoped the creation of the Parliament would fatally undermine the Scottish National Party, but instead the SNP now controls the government and is on a collision course with Westminster on outright independence for Scotland.

After a slow start, the Scots are starting to look ambitious on the environment, with First Minister Alex Salmond last week announcing a major program of environmental legislation for the coming year. Along with a bill to protect the marine environment and another on flood risk management, there will come a climate-change bill with a target to reduce CO2 emissions by 80 percent by 2050. “There is no dispute in this chamber that climate change is the one of the most serious threats we face,” he said. Scotland has also set itself a target of getting half its electricity from renewable sources by 2020, compared to the U.K.’s goal of about one-third.

Though everyone is glad to see this kind of ambition, government and energy utilities alike are somewhat alarmed by the parallel agenda of devolution. Just as it was with North Sea oil, Scotland is home or gatekeeper for a huge proportion of the U.K.’s renewable energy potential. As the SNP independence campaign puts it, “More than 90 percent of the U.K.’s oil revenues come from the Scottish sector of the Continental Shelf. So it really is Scotland’s oil. In addition, Scotland has 25 percent of Europe’s wind and tidal capacity and 10 percent of its wave power.”

Scotland is also home to a disproportionate share of Britain’s Labor members of Parliament and Labor voters. An independent Scotland would mean Conservative rule south of the border for the foreseeable future, but that holds limited appeal even to Conservatives if the cost to England is loss of access to Scottish energy resources. English politicians have been further alarmed by Scottish Energy Minister Jim Mather’s plan to meet his Norwegian counterpart in October to discuss building the world’s longest electricity connector to Norway to access their plentiful hydropower, helping to meet Scotland’s renewable targets and end its dependence on nuclear power. The whole project could cost more than £2 billion [$3.57 billion]. With the SNP ruling out new nuclear plants in an independent Scotland, it would cast further doubt on how England would keep the lights on.

The SNP is committed to a referendum on Scottish independence by 2012. Though technically such a vote would not be binding on the U.K. government, which remains sovereign, it would be extremely difficult for politicians to ignore. British Prime Minister Gordon Brown, himself a Scot with a constituency in Fife, has got some challenging thinking to do.