Britain's carbon emissions grew faster than the economy last year for the first time since 1996, as a cash-strapped population relegated the environment down its league of concerns and spent more money keeping warm, according to a new report.

The rise in Britain's so-called carbon intensity increases the danger that the country will miss legally binding targets on reducing emissions, warns PricewaterhouseCoopers (PwC), the consultancy behind the report.

Furthermore, it found that Britain's rising carbon intensity is part of a worldwide trend which threatens to push global warming above a two-degree Celsius increase on pre-industrial levels.

This is the temperature that the G8 group of leading economies has pledged not to breach in the hope of avoiding the worst consequences of climate change.

Leo Johnson, partner for sustainability and climate change at PwC, said: "Our analysis points unambiguously towards one conclusion, that we are at the limits of what is achievable in terms of carbon reduction.

"The G20 economies have moved from travelling too slowly in the right direction to travelling in the wrong direction. The results call into question the likelihood of global decarbonisation ever happening rapidly enough to limit global warming to 2 degrees Celsius," Mr Johnson added.

Experts calculate that limiting global warming to 2 degrees would require a 4.8 per cent decrease in carbon intensity every year until 2050 – meaning that emissions need to grow by 4.8 per cent less than the economy every year over that period.

However, global emissions jumped by 5.8 per cent in 2010, while gross domestic product (GDP) increased by just 5.1 per cent in 2010 – resulting in a 0.6 per cent rise in carbon intensity.

The UK recorded the third highest increase in carbon intensity among the G20 group of leading economies last year, as hard-up consumers and companies increasingly dropped green considerations in the pursuit of the cheapest, short-term option. Furthermore, the year was sandwiched between two bitterly cold winters, leaving people with no option but to turn up their heating.

Jonathan Grant, director of sustainability and climate change at PwC, said: "When money is tight people's attention goes elsewhere and it becomes harder to implement high-cost, low-carbon technologies.

"Many people have higher priorities than climate change right now, it is probably fair to say. Maybe people are taking their eye off the ball a bit."

Britain's GDP increased by just 1.3 per cent in 2010, while its carbon emissions jumped 3.5 per cent, resulting in a 2.2 per cent rise in so-called carbon intensity.

If Britain wants to hit its legally binding target of reducing emissions by 34 per cent, on 1990 levels, by 2020, it will need to cut its carbon intensity by 5.6 per cent every year, PwC said.

Most of the other countries that recorded the biggest rise in carbon intensity were from the developing world. Fast-growing countries such as China, Brazil and Korea were among those economies contributing to what Mr Grant calls a "dirty" recovery.

Brazil's growth was the dirtiest among the G20 economies last year, with a 3.5 per cent jump in carbon intensity, with Saudi Arabia second from bottom with a 3.2 per cent increase.