To keep global warming below 1.5 C, our energy systems need to be carbon emission free latest by
2050, and many countries have pledged to do so. A high-level model was built for a fictitious economy
called Utopia to assess three pathways towards a zero-carbon economy by 2050: a gradual (linear)
replacement of fossil fuels by clean energy, an accelerated pathway leading to a carbon free system by
2035, and a delayed pathway, in which replacement takes place from 2035 onwards. The model yields
very clear results. The accelerated pathway is not only 21% cheaper than a gradual phasing out of fossil
fuels, with accumulated savings of $4 trillion over a period of 30 years, but also the climate wins, with
emissions reducing from 32.7 GT to 13.1 GT over the same period. On the other end of the spectrum,
the delayed transition is 20% more expensive than the gradual transition, and a whopping $7.7 trillion
more expensive than the accelerated pathway, with 4 times higher emissions of CO2.
It should be noted that the main driver of the cost difference of the three pathways is the price of carbon.
Running the model without a price on carbon yields a level playing field regarding overall cost for the
three pathways. Of course, in the accelerated pathway, CO2 emissions are much lower than the gradual
or delayed pathway, which should be an incentive in its own right.