Emissions trajectory

The study, which appears in the US magazine Science, doesn't beat around the bush.

"If current greenhouse gas (GHG) concentrations remain constant, the world would be committed to several centuries of increasing global mean temperatures and sea level rise," the opening lines read.

Indeed, keeping temperatures stable would require the "near elimination of anthropogenic CO2 emissions." Yet that, as the authors concede, is not going to happen.

Current energy infrastructure - such as existing coal-fired power plants - is expected to contribute substantially to further emissions.

"Cumulatively, we estimate that 496 gigatonnes of CO2 will be emitted from the combustion of fossil fuels by existing infrastructure between 2010 and 2060," the report says.

Factoring in emissions from non-energy sources, we could expect CO2 levels to stabilize at around 430 parts per million, leading to a temperature increase of around 1.3 degrees Celsius above pre-industrial levels.

However, the paper says the important thing to note is that this warming is still below the two-degrees-threshold widely regarded as the dangerous point that we need to avoid.

So on the bright side, our most critical investment decisions are still in front of us.

"The primary threats posed by climate change are a consequence of emissions from devices that do not yet exist," the report says.

The big picture

Researcher Steven Davis says his team approached the study aware that it was "unrealistic and implausible" to expect the world to stop producing new carbon-emitting devices as of tomorrow, but that it was a vital step to calculate the impact of our existing infrastructure.

And he is not entirely unhappy with the results.

"It's not bad news, but I'm not ready to say it's good," Davis told Deutsche Welle. "My hope is that there is a kernel of optimism, and that maybe we still have a chance to turn the ship around."

Given that existing infrastructure is not going to push the climate over the two-degree-mark, Davis says it might make sense to let existing coal-burning power plants run their course rather than force their early closure.

"It may be better not to spend political capital on trying to decommission them early but to focus on building the right energy technologies now."

The power of association

Refraining from building new carbon-intensive devices will be difficult enough as it is, Davis says, because our current infrastructure carries its own "inertia."

"Take a filling station," he said, "by existing they make it easier to build another car. Whereas if we had a tonne of battery charging stations, that would be an incentive for building electrical cars."

Indeed switching to electric vehicles - powered by renewable energy sources – may prove crucial based on current demand for automobiles.

Although car sales in the US and Europe have been steady since 2000, China's ownership growth-rate has risen to a staggering 20 percent per annum - with a profound effect on the global picture.

"Between 1990 and 2007, the number of motor vehicles in operation worldwide increased by 56 percent," the report states, adding that the trend is likely to continue.

Which is a big problem, Davis says, but one that is still within our power to solve.

"It is all slow in coming because the transition to carbon-free energy sources is a very difficult process," said Davis. "What our paper clearly shows is that we should be focused and concentrated on building everything we can in a carbon-free way right now."

Author: Tamsin Walker
Editor: Nathan Witkop