2
fossil fuel reserves is incompatible with a warming limit of 2oC. Here we use a single
integrated assessment model that contains estimates of the quantities, locations and
nature of the world’s oil, gas and coal reserves and resources, and which is shown
to be consistent with a wide variety of modelling approaches with different
assumptions, to explore the implications of this emissions limit for fossil fuel
production in different regions. Our results suggest that, globally, a third of oil
reserves, half of gas reserves and over 80 per cent of current coal reserves should
remain unused from 2010 to 2050 in order to meet the target of 2oC. We show that
development of resources in the Arctic and any increase in unconventional oil
production are incommensurate with efforts to limit average global warming to 2oC.
Our results show that policy makers’ instincts to exploit rapidly and completely their
territorial fossil fuels are, in aggregate, inconsistent with their commitments to this
temperature limit. Implementation of this policy commitment would also render
unnecessary continued substantial expenditure on fossil fuel exploration, because
any new discoveries could not lead to increased aggregate production.
The reported modelling was published in 2015, when the global policy aspiration
was to limit average global warming to 2oC. Since then the Paris Agreement has
strengthened countries’ commitments to go below 2oC, limiting average global
warming to 1.5oC if possible. The Intergovernmental Panel on Climate Change
(IPCC) has recently published a report showing that this is highly desirable if
substantial climate damages, which would occur at 2oC, are to be avoided. A 1.5oC
‘carbon budget’ is considerably below the 1,100 Gt CO2 carbon budget used for the
2oC scenario, results for which are described above. This means that keeping average
global warming to 1.5oC would require considerably more fossil fuels to remain
unburned than has been estimated here.
PAUL EKINS OBE
University College London
October 26th 2018