Methodology

The decarbonisation pathways for all G20 countries, and the global scenario, were developed with the One Earth Climate Model (OECM), noting that the overall remaining carbon budget cannot exceed 450 GtCO2 between 2020 and 2050 if we are to limit the mean global temperature rise to +1.5°C with a likelihood of well over 50%. The OECM is an integrated energy assessment model that covers the entire energy system of a country or region, broken down into 16 industry-specific sectors. The methodology was developed by the Institute for Sustainable Futures at the University of Technology Sydney, with the support of the Institute of Networked Energy Systems and Energy Systems Analysis of the German Aerospace Center and in close co-operation with the finance sector of the Net-Zero Asset Owners Alliance and the United Nations Principles for Responsible Investment.

The methodology of the OECM provides high technical resolution and has been extensively documented in the scientific literature: 

One Earth Climate Model – Integrated Energy Assessment Model to Develop Industry-Specific 1.5°C Pathways with High Technical Resolution for the Finance Sector.

The term ‘technical resolution’ refers to the level of detail with which the model captures specific technical processes, such as steel, aluminium, and cement production, transport modes, and vehicle types, and the energy-generation technologies used for power, (process) heat, and fuel supply. The calculation methods of the OECM are described in detail. 

1.5 °C pathways for the Global Industry Classification (GICS) sectors chemicals, aluminium, and steel. 

The sectorial breakdown is based on the Global Industry Classification Standard (GICS) and defines the system boundaries for the sector-specific decarbonisation scenarios. 

Global sector-specific Scope 1, 2, and 3 analyses for setting net-zero targets: agriculture, forestry, and processing harvested products.

Reporting corporate GHG emissions is important, and the focus is no longer on direct energy-related CO2 emissions but includes other GHGs emitted by industries. The Greenhouse Gas Protocol, a global corporate GHG accounting and reporting standard, distinguishes between three ‘scopes’:

Scope 1—emissions are direct emissions from owned or controlled sources.
Scope 2—emissions are indirect emissions from the generation of purchased energy.
Scope 3—emissions are all the indirect emissions (not included in Scope 2) that occur in the value chain of the reporting company, including both upstream and downstream emissions.

The OECM altered the Scope 3 emission accounting as it was developed for company assessment, not for industry or country-wide assessments.

Achieving the Paris Climate Agreement Goals: Global and Regional 100% Renewable Energy Scenarios with Non-energy GHG Pathways for +1.5°C and +2°C

Achieving the Paris Climate Agreement Goals: Part 2: Science-based Target Setting for the Finance industry — Net-Zero Sectoral 1.5˚C Pathways for Real Economy Sectors

Renewable Resource Assessment [R]E-SPACE based on a Geographic Information Systems (GIS) approach and provides maps of the solar and wind potentials in space-constrained environments. GIS attempts to emulate processes in the real world, at a single point in time or over an extended period. The primary purpose of GIS mapping is to ascertain whether renewable energy resources (primarily solar and wind) are sufficiently available in each region. It also provides an overview of the existing electricity infrastructures for fossil fuel and renewable sources.