Chapter 5: HOW WE GET THERE – TECHNICAL PATHWAYS TO A
The Stone Age did not end for lack of stone, and the Oil Age will end long before
the world runs out of oil.
- Sheikh Zaki Yamani — Former Oil Minister of Saudi Arabia
The International Energy Agency (IEA) produces an annual in‐depth analysis and
perspective on current trends and future projections for the production and use of
primary and secondary energy sources. This information is used by stakeholders
for long‐term planning purposes. In recent years, the IEA reports have included a
“450 Scenario,” whereby an end‐of‐century atmospheric CO2 concentration of 450
ppm becomes a determining factor for short and long‐term energy projections. The
climate model used by the IEA for the 450 Scenario is based on a remaining global
emissions budget of 1,200 Gt of CO2.1 Complete release of this budget would lead
to an end‐of‐century accumulation of about 450 ppm of CO2 in the atmosphere with
a 50% chance of limiting surface warming to 2°C above pre‐industrial temperatures.
The core objective of the Paris Agreement is to limit surface warming to well below
2°C and, ideally, 1.5°C relative to pre‐industrial temperatures. The level of ambition
contained in the Paris Agreement exceeds the assumption of the IEA 450 Scenario. The
precise meaning of “well below 2°C” is not provided; however, the IEA assumes that
a 50% chance of limiting future surface warming to less than 1.84°C would qualify.2
The IEA concludes that, as of 2014, about 950 Gt of CO2 remained in an emissions
budget that is consistent with limiting future surface warming to well below 2°C.3
This conclusion aligns with the IPCC carbon budget with a 66% chance that surface
warming will be held to less than 2°C.
IEA World Energy Outlook 2016 estimates future use of fossil fuels, nuclear, hydro,
bioenergy and renewables to the year 2040.4 The report is heavily influenced by the
Paris Agreement and is focused on a New Policies Scenario that incorporates both
existing policies in place as of 2016, and climate pledges contained in NDCs submitted
prior to the 2015 Paris climate change conference. Comparisons are made between
the main New Policies Scenario and the 450 Scenario. In addition, some discussions
of the more ambitious Well Below 2°C and 1.5°C Scenarios are included in the report.