The geographical distribution of fossil fuels unused when limiting global warming to 2 °C

Abstract

Policy makers have generally agreed that the average global temperature rise caused by greenhouse gas emissions should not exceed 2 °C above the average global temperature of pre-industrial times. It has been estimated that to have at least a 50 per cent chance of keeping warming below 2 °C throughout the twenty-first century, the cumulative carbon emissions between 2011 and 2050 need to be limited to around 1,100 gigatonnes of carbon dioxide (Gt CO2). However, the greenhouse gas emissions contained in present estimates of global fossil fuel reserves are around three times higher than this, and so the unabated use of all current fossil fuel reserves is incompatible with a warming limit of 2 °C. 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 2 °C. 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 2 °C. 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 G20 must govern the shift to low-carbon energy

“…Burning all these reserves would release three times more carbon dioxide than the Paris accord permits (roughly 900 gigatonnes of CO 2 equivalent). So at least two-thirds of these assets will have to be written off: 80% of current coal reserves, one-third of oil and half of natural gas 4 .…”

Lessons from first campus carbon-pricing scheme

“…For example, more than 80% of current coal reserves might need to remain untouched if countries are to limit warming to 2° C (ref. 7). …”

The simple arithmetic of carbon pricing and stranded assets

“…The energy transition, the carbon budget, and stranded fossil fuel reserves Recent studies quantify the amount of fossil fuel which must be abandoned in the crust of the earth for global warming to stay below 2°C (McGlade and Ekins 2015). 5 Underlying such estimates is the basic economic idea that fossil fuels are used as long as they are cheaper than renewable energy.…”

“…We also offer rules for the optimal fraction of fossil fuel reserves that should be left in the crust of the earth (cf. Carbon Tracker 2013;McGlade and Ekins 2015) and the optimal transition time to the carbon-free era. Our calculations require only a pencil and the back of an envelope, but yield values very close to those obtained from numerically maximising welfare with a detailed IAM of growth, development, energy, and climate change.…”