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Halving global CO2 emissions will cost less than 1% of GDP – report

Cutting emissions to safe levels is both technologically and economically feasible, say scientists

Pic: Flickr / Terry Hassan

By Sophie Yeo

Global emissions could be cut to 50% of current levels using available technology says a new report, which estimates this would cost less than 1% of the total GDP in 2050.

By keeping emissions at 15 gigatonnes per year, instead of the 31.6 Gt that the International Energy Agency predicted was emitted in 2011, the world would be broadly on track to stay beneath 2C, the level beyond which the planet can expect catastrophic change.

These are the findings from scientists at Imperial College London, who, looking only at technologies that are currently or soon to be available at a commercial level, calculated exactly what would need to be done to provide for future energy demand without tipping the world into climate disaster.

“The way we did it at Imperial was to take a very bottom-up perspective, which was to look in detail from a very technological perspective at what would be required to get there, but to superimpose on that a geographical context, because different solutions are likely to be relevant in different parts of the world,” said lead author Professor Nilay Shah.

“We looked at three sectors, so those sectors were what goes on in buildings, industry, and the transport systems, and by using projections of population and GDP in those regions, we were about to predict what would be the demand for the energy services associated with those sectors.”

The study comes nine days ahead of the UN’s Intergovernmental Panel on Climate Change releases the first part of its fifth assessment on climate science, where it is expected to warn that carbon dioxide emissions are set to contribute to rising sea levels, melting polar ice caps and extreme weather events.


Their calculations mean that the necessary cuts could be achieved without any significant reductions in the services that current energy production makes possible.

The best way of achieving the 15 Gt/yr target is decarbonising the electricity sector through use of near-zero-carbon generation technologies, such as carbon capture and storage, nuclear and renewables.

But, the report adds, there will need to be a shift towards electrifying current industrial manufacturing processes, building heating systems, and vehicles.

Investment in the technology that will allow this to develop will need to begin soon, if it is going to be able to penetrate the market in time to allow the world to reach its 2050 targets.


Despite the dramatic upheaval of industry that such a large scale introduction of low carbon technology would involve, the proportion of the GDP that it would demand remains surprisingly low – $2tn per annum of a projected 2050 GDP of $235tn – because of the side effects of the technology.

“A large part of the transformation comes from deploying new technologies which save energy, avoid increasingly expensive fossil fuels, and in many cases are projected to fall in cost over time,” write the authors in the report, published on Tuesday by the Grantham Institute for Climate Change.

And, they add, these costs could fall further to around $400bn per year under a scenario in which fossil fuels prices become much more expensive.

In such a scenario, the transition to a low carbon economy could pay for itself in the long run, they say, citing the relatively high prices of oil since the onset of the global financial crisis in 2008 as a strong economic impetus for reducing reliance on fossil fuels.

Without a range of mechanisms to increase energy efficiency and limit the use of fossil fuels, the researchers predict that, by 2050, the world will be emitting 50 Gt/yr of CO2.

“The nature of the challenge is that if we don’t take concerted action, we might be in that region, which is probably consistent with a 4-6C temperature rise,” said Shah.

They add that the 15 Gt/yr target will only limit global warming to the level needed if certain pathways are taken to achieve this target, and if emissions remain low thereafter.

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