We provide reference forecasts for worldwide CO2 emissions from fuel fossil combustion and cement production based on an ARFIMA approach. Our projections suggest a time path for emissions that is inconsistent with the general IPCC decarbonization goals. Indeed, we project emissions to increase, over the next three decades, to levels about 11-12% above the 2010 level. For the IPCC goals to be achieved it is necessary to reduce emissions by 57.4% and 97.4% of 2010 emissions by 2030 and 2050, respectively. Furthermore, the bulk of these efforts have to take place by 2030. This implies that the policy efforts necessary to achieve such goals are not only daunting but also frontloaded. Finally, the presence in the data of long memory with mean reversion suggests that policies must be persistent to ensure that these reductions in emissions are also permanent. These results add to the sense of urgency in dealing with the issue of decarbonization. The policy efforts necessary to achieve IPCC decarbonization goals are urgent, daunting and frontloaded.