A new report from Imperial College London looks at what measures are required to reduce CO2 emissions and limit the extent of man-made climate change.

Human activities like shipping, construction and industry are increasing the concentration of CO2 entering the atmosphere, which research has overwhelmingly shown is heating the planet and changing our climate.

Many studies, including those by the International Energy Agency, suggest that global CO2 emissions are set to pass 50 Giga-tonnes per year by 2050 if there is no further action by governments to reduce them over the coming years.

Now researchers at Imperial have considered what technologies and interventions are required to limit these global CO2 emissions from human activity to 15 Giga-tonnes per year by 2050, a level that many studies show could help to limit global warming to around two degrees Celsius above pre-industrial levels.

Their report concludes that reaching this target will cost $2 trillion per year by 2050, which is about one per cent of the world's GDP in 2050, and considerably less than this if fossil fuel prices increase with time.

It will require a broad range of low-carbon technologies to be implemented across several sectors of the economy – power, industry, buildings and transport.

Report author, Professor Nilay Shah from the Department of Chemical Engineering at Imperial said: "A fundamental step will be making the power sector emit very low levels of carbon by deploying renewables, nuclear and carbon capture and storage technologies."

The report also requires that industrial manufacturing processes, building heating systems and transport must become increasingly powered by low-carbon electricity, and that all sectors redouble efforts to become energy efficient.

"Although the transition set out in the report is likely to prove challenging, it is achievable if governments increase their actions now," added Professor Shah.

The report was launched on 17 September, by scientists at Imperial's Grantham Institute for Climate Change and Energy Futures Lab.

Speaking at Imperial on Tuesday, Dr Halldór Thorgeirsson, Director of Implementation Strategy at the UNFCCC, which leads the international climate negotiations, welcomed the report. 

He stressed the need for governments to agree about reducing global greenhouse gas emissions at the UN climate negotiations meeting (COP 21) in Paris in 2015, saying:

"It is promising that leadership is increasingly coming from developing countries and from non-state organisations such as businesses, however we are worryingly on course to cause 4 degrees or more of global warming and there is clearly a need for a step change in behaviour from all governments."

Both Dr Thorgeirsson and Professor Shah stressed that there is no silver bullet when it comes to addressing climate change.

"It will require concerted action from all countries and investment in a wide range of technologies to reduce emissions and limit the impacts of climate change." said Professor Shah.

The key findings from the study are:

• If historic trends in energy usage continue, global CO2 emissions are likely to increase to around 50 Giga tonnes per year by 2050, and the global use of fossil fuels will increase by 50 per cent compared to current levels.
• It is technically possible to reduce CO2 emissions to the required 15 Giga tonnes per year if all countries make the transition to low-carbon societies.
• It will cost about one per cent of global GDP per year (approximately $2 trillion) by 2050 to make the required reductions, and could cost significantly less depending on the future price of fossil fuels.
• Renewables, nuclear and carbon capture and storage will play a central role in making the electricity sector nearly carbon neutral.
• Emissions from the industry, buildings and transport sectors will be reduced through increased electrification, programmes to improve energy efficiency and replacing fossil fuels with bio-fuels.
• It will be possible to achieve a 30 per cent improvement in energy efficiency by end users by 2050.
• Fossil fuel demand must be reduced by almost 40 per cent in 2050, compared to current consumption.
• Every country makes a significant contribution to the overall achievement of the low-carbon transition.

Watch the report launch

In the balance: can we halve global CO2 by 2050?

CarbonCaptureenergyfuturesclimatechange