Britain's greenhouse gas emissions fell by 8.6 percent in 2009, but this was largely because of the recession and levels will likely rise as economic growth returns, a study said Wednesday.

The Committee on Climate Change, an independent body which monitors Britain's progress on tackling global warming, called for a "step change" in mitigation efforts if tough targets on cutting emissions are to be met.

"The recession has created the illusion that progress is being made to reduce emissions," said committee chairman Adair Turner as it published an update to parliament.

"Although emissions have declined substantially, our analysis shows that this is almost wholly due to a reduction in economic activity and not from new measures being introduced to tackle climate change.

"So we are repeating our call for new policy approaches to drive the required step change, in order that the UK can ensure a low-carbon recovery."

The 2008 Climate Change Act set a legally-binding target for Britain of cutting greenhouse gas emissions by 80 percent by 2050 and at least 34 percent by 2020, based on 1990 levels.