Scotland has set itself the world’s toughest climate change targets, in legislation passed yesterday. The country is looking to reduce greenhouse gas emissions by 80% by 2050 and by 42% by 2020 (press release, bill pdf).

“Scotland can be proud of this Bill, the most ambitious and comprehensive piece of climate change legislation anywhere in the world,” says climate change minister Stewart Stevenson (press release).

Ministers in the ruling Scottish National Party have admitted this will make little difference to global emissions overall, but they hope it will set an example to other nations (BBC).

And here lies the catch. As passed, the bill gives the country the option to move rapidly backwards from its ‘Tartan Targets’ if the rest of the world doesn’t come up with similarly tough targets at the forthcoming global summit in Copenhagen (Reuters). Targets can also be downgraded if the UK government’s advisors say they are unrealistic (Guardian).

“We will be looking for any weakening of the position being slipped out during a summer or Christmas recess,” warned Duncan McLaren of Friends of the Earth (The Herald). “A key will be the international reaction to this. If it is well-received and there is praise for Scotland’s leadership in adopting the world’s best targets, it will be harder for Ministers to back down.”

McLaren take heart from one thing: Arnold Schwarzenegger is on his side.