Feasibility of GHG emissions phase-out by mid-century
A review of existing low emissions scenarios carried out by Ecofys for the Global Call for Climate Action concludes that it is technically and economically feasible to phase out net greenhouse gas (GHG) emissions almost entirely by 2050. These scenarios can be categorised broadly as one of two types: scenarios with nearly 100% of energy from renewable energy sources (RES) and scenarios with less than 100% renewable energy but carbon capture and storage. The speed of transition in all scenarios would be unprecedented and a step change would be needed now in almost all countries. However, the scenarios suggest this can be done mostly with technologies currently available and at a cost of less than 5% of annual GDP until 2050.
There are challenges associated with a global phase-out of emissions by 2050. Increasing shares of renewable energy mean that investment in the energy sector needs to be diverted to different solutions, for example, investment into smart grids and storage to manage supply and demand. Saving energy is a key strategy for high RES share scenarios because high efficiency can facilitate an energy supply based almost entirely on renewable sources. In other scenarios, we need considerable use of solutions that can produce net negative emissions such as carbon, capture and storage for bioenergy and forestry. To achieve a complete phase-out, options are needed to remove the approximately 10% of current GHG emissions that cannot be removed with current technologies.