Britain today became the first country to unveil its greenhouse gas emission limits for the years after 2020.

Between 2023 and 2027 the total amount of greenhouse gases emitted by the UK will be cut to 50% below 1990 levels. However, the government will also push for Europe to move to a 30% target for 2020 and if the UK looks like it is getting out of step with the rest of the continent, the country’s ‘carbon budget’ could be upped.

“Today’s announcement makes the UK the first country in the world to have declared a legally binding target on greenhouse gas emissions beyond 2020. This is significant,” said Tom Delay, the chief executive of the Carbon Trust, which advises UK businesses on carbon emissions. “Now we have set the long-term course we must fine tune the plan to reach it.”

Under the 2008 Climate Change Act the UK government has to set ‘carbon budgets’ for five year periods up to 2050, by when an 80% cut from 1990 levels should have been achieved. The first three budgets were set in 2009.

Today’s pledge sets the UK to limit itself to 1,950 million tonnes of carbon dioxide over the period of the fourth budget, energy minister Chris Huhne told Parliament today.

But emissions from industrial and energy sectors are determined by the European Union’s Emissions Trading System, he noted. So, if the EU sets easier targets than the UK, sectors outside industry and energy could have to pull more than their share of the weight.

“To overcome this and to provide clearer signals for businesses and investors, government will review progress towards the EU emissions goal in early 2014. If at that point our domestic commitments place us on a different emissions trajectory than the Emissions Trading System trajectory agreed by the EU, we will, as appropriate, revise up our budget to align it with the actual EU trajectory,” says Huhne.