PricewaterhouseCooper’s (PwC) fifth Low Carbon Economy Index (LCEI) report, which examines the rate of decarbonisation in the G20, shows that over the last five years the world has only managed to average 0.7% decarbonisation annually.

The report warns that even doubling the current 0.7% rate of decarbonisation puts the planet on a path consistent with the most extreme scenario presented by the IPCC, and potential warming of around 4oC by 2100.

It claims that the planet will use up this century’s carbon budget by 2034.

“Put simply, we are busting the carbon budget,” it says.

PwC’s sustainability and climate change specialist Jonathan Grant said: “Given expected economic growth we now need to reduce the emissions per unit of GDP by 6% every year, something never achieved globally, not even once.

“This is equivalent to halving our carbon intensity within the next 10 years, by then all countries would need to have a carbon intensity similar to that of France today and by the end of the century our global energy system would need to be virtually zero carbon,” he added.

Although the report shows the severity of the issue, it does highlight the US and China as examples of rapid decarbonisation, stressing that this is “possible”.

The report suggests that to achieve the same speed of decarbonisation globally there needs to be much greater investment in energy efficiency, renewables, nuclear power and carbon capture and storage.

“We’ll have to tackle emissions from deforestation, there needs to be a meaningful price on carbon to support these efforts,” says Grant.

It also mentions consumers, who will need to demand low carbon products, while voters will need to support the low carbon transition.

But the “central piece in the puzzle” is a global climate change deal in which all countries commit to ambitious targets.

Grant says that without this there’s the risk that decarbonisation efforts in one country just shifts emissions around the world.

“This is why the negotiations leading up to 2015 are so vital,” he adds.

The reportalso highlights that 92% of the small reduction in carbon intensity achieved last year is primarily down to energy efficiency.

PwC partner for sustainability and climate change Leo Johnson said: “While this is positive, there is the possibility that incremental efficiency improvements will tail off once the low hanging fruit has been picked”.

But there are also grounds for optimism says Johnson.

At the national level, countries such as Brazil, France and Argentina present examples of economies with significantly lower carbon emissions per unit of GDP.

Johnson says that China provides the example of using carbon pricing to underwrite risk and stimulate innovation in clean tech sectors.

He adds that at a city level, a number of cities and councils globally have delivered high levels of decarbonisation while enhancing liveability.

Leigh Stringer

Action inspires action. Stay ahead of the curve with sustainability and energy newsletters from edie