This document summarizes key insights from the IPCC's AR6 report on mitigating climate change through energy system transitions. It outlines that reducing greenhouse gas emissions requires substantially reducing fossil fuel use, deploying low-emission energy sources, electrifying energy systems using renewable electricity, improving energy efficiency, and integrating energy systems. Transitioning away from fossil fuels could cost $1-4 trillion by 2050 but maintaining emission-intensive systems may be more expensive than transitioning to low-carbon alternatives. The energy transition will also shift investment patterns and create new economic opportunities while supporting other societal objectives like development and public health.

1. Insights from AR6 WGIII on
energy system mitigation, in
AR6 and Towards AR7
Leon Clarke
Director, Decarbonization Pathways, Bezos Earth
Fund
Senior Fellow, Center for Global Sustainability,
University of Maryland
December 5th, 2023

2. Some Basics: the Energy
Transition
• “Reducing GHG emissions across the full
energy sector requires … substantial reduction
in overall fossil fuel use, the deployment of
low-emission energy sources, switching to
alternative energy carriers, and energy
efficiency and conservation.
• The continued installation of unabated fossil
fuel infrastructure will ‘lock-in’ GHG emissions.
• Electricity systems powered predominantly by
renewables are becoming increasingly viable.”

3. Some Basics: Net Zero
Energy Systems
1. “Substantial reduction in overall fossil fuel
use…
2. Electricity systems that emit no net CO2;
3. Widespread electrification of the energy
system;
4. Alternative energy carriers … in applications
less amenable to electrification;
5. Energy conservation and efficiency;
6. Greater … integration across the energy
system.

4. Transitioning
from Fossil Fuels
“The combined global
discounted value of the
unburned fossil fuels and
stranded fossil fuel
infrastructure has been
projected to be around
USD1–4 trillion from 2015
to 2050 to limit global
warming to approximately
2°C,…”

5. Financing the
Transition
“low-carbon energy
transition will shift
investment patterns and
create new economic
opportunities. …..These
increases will be far less
pronounced, however,
than the reallocations of
investment flows…”

6. The Economics
of the Transition
“Maintaining emission-
intensive systems
may, in some regions
and sectors, be more
expensive than
transitioning to low
emission systems.”

7. Energy as
Development
“Energy systems are linked
to a range of societal
objectives, including energy
access, air and water
pollution, health, energy
security, water security, food
security, economic
prosperity, international
competitiveness,
employment.”

8. @IPCC_CH
#IPCReport
For more information:
IPCC Secretariat: ipcc-sec@wmo.int
IPCC Press Office: ipcc-media@wmo.int
Visit ipcc.ch
@IPCC
@IPCC
linkedin.com/
company/ipcc
Thank you.
Coordinating Lead Author Chapter 6 Energy systems
Leon Clarke