14 August 2017
If the world woke up tomorrow and decided to hold emissions at today’s level through the end of the century, it might be possible to reduce atmospheric levels of carbon dioxide down to the level targeted in the Paris Agreement. However, the technology needed to achieve this goal would not come cheap, nor would it be guaranteed to work. This is one of the topics set to be discussed by leading experts at the upcoming World Green Economy Summit – Dubai on 24 and 25 October 2017.

The cost of the technology needed for enough negative emissions projects to reduce atmospheric concentrations of carbon dioxide is estimated between $89 trillion and $535 trillion through 2100, according to new research led by noted climate scientist James Hansen.   Although eye-poppingly high in comparison with today’s global economy, which was $78 trillion in 2014, their magnitude is less when factoring in future growth in the economy. If the cost were spread across the time period from now until the end of the century and economic growth continued at the average rate since 2006, the midpoint of the negative emissions projects in total would be 0.7 percent of total gross world product.

This may seem like an acceptable trade-off until you realise that the spending contemplated for negative emissions projects would have almost no direct positive impact on society except for avoiding future catastrophe. These trillions and trillions of dollars would all be spent to steer the asteroid of climate change away from earth to maintain a habitable environment for our grandchildren.

By comparison, a United Nations goal for official development assistance by developed countries, who represented about half of the world’s GDP at the time, was also 0.7 percent of GDP. This would have been enough to fully achieve the Millennium Development Goals, but the target was viewed as being too lofty.

The world faces a very concrete decision to make about our priorities as we lay out the plans for the future green economy. If we maintain today’s emissions levels by reducing carbon intensity of the economy by just enough to keep emissions from rising above today’s level, we will build up a debt to future generations that increases by 0.7 percent of GDP every year. In order to repay the debt, future generations will have to sacrifice the equivalent social welfare improvement of twice of what would have achieved the MDGs and continue to spend this much for 5-1/2 times longer.

The debt that we would leave to future generations by opting for flat emissions growth and future negative emissions technology (hardly the worst imaginable outcome with the U.S. exit from the Paris Agreement) would be more than 11 times costlier than the spending that would have been required to achieve the MDGs. Fortunately, there is an alternative that is far less costly.

With actions in support of the Paris Agreement, we can and should finance the transition to a green economy by putting a market price on the true social costs of carbon emissions. Even if governments took a catch and release approach by rebating the carbon fees back to their populations, it would still be effective. For it would bring market pressures fully to bear on the ultimate coordination problem for humanity and ensure a green, climate debt free future for generations yet to be born.

Any opinions expressed here are the author’s own.