The full paper can be found here
“Given projected world population dynamics, this objective requires reducing per capita emissions in the second half of this century from about 2 tonnes carbon equivalent (tC) to about 0.3 tC per year. In other words, the world will have to cut emissions to the per capita average of India today – quite a significant reduction for most industrialised countries (US average per capita emissions are about 5tC) and for countries that aim at similar lifestyle standards. For example, 0.3 tC is the amount of greenhouse gases emitted by an individual flying – one way – from the EU to the US East coast!”(Vox EU)
An essential component of a 550ppm goal would be a drastic change in power generation.
… the necessary investments are very large. To achieve the 550 ppm target, between 30 and 40 1 gigawatt (GW) coal-with-CCS [carbon capture and sequestration] power plants need to be built each year from 2015 onwards, a value in line with the historical capacity building of traditional coal plants (that make up for roughly 50% of electricity generated in the world)
However, 20 1GW nuclear plants or more would need to be built each year in the next half century, bringing the nuclear industry back to the construction rates of the 1980s. External costs, such as those related to nuclear waste disposal or proliferation risks, could make this scenario undesirable
Despite a small absolute potential of renewables, an almost three-fold capacity expansion with respect to a baseline scenario—more than for any other generation technology—and an overall 17-fold expansion of present installed capacity should be achieved by 2050. This is equivalent to about 60,000 new large open-sea wind turbines. What a different world!
TA findings in the paper concerns the output of a cost model. The Italian researchers put the costs at between 2.1 and 3.7 % of world GDP over the course of the 21st century