This study compares emission pathways aimed at limiting temperature increase to 2°C under varying constraints. In a first set of pathways, the timing of emission reductions is such that over the 2010–2100 period, assuming full participation from 2013 onwards, mitigation costs are minimized. In a second set of pathways, we set emissions in 2020 at a level based on the pledges of the Copenhagen Accord.
In the ‘Copenhagen Potential’ scenario, climate talks result in satisfying conditions linked by countries to their ‘most ambitious’ proposals. Contrasting, in the ‘Copenhagen Current’ scenario, climate talks fall short of satisfying the conditions to move beyond current unilateral pledges. We include scenarios with and without the availability of bio-energy in combination with carbon capture and storage.
We find that for a ‘Copenhagen Potential’ scenario, emissions by 2020 are higher (47 GtCO2eq/yr) than for a least-cost pathway for 2°C (43 GtCO2eq/yr with a 40–46 GtCO2eq/yr literature range). In the ‘Copenhagen Potential’ scenario the 2°C target can still be met with a likely chance, although discounted mitigation costs over 2010–2100 could be 10 to 15 % higher, and up to 60 % in the 2040–2050s, than for least-cost pathways. For the ‘Current Copenhagen’ scenario, maintaining an equally low probability of exceeding 2°C becomes infeasible in our model, implying higher costs due to higher climate risks. We conclude that there is some flexibility in terms of 2020 emissions compared to the optimal pathways but this is limited.
The 2020 emission level represents a trade-off between short-term emission reductions and long-term dependence on rapid reductions through specific technologies (like negative emission reductions). Higher 2020 emissions lead to higher overall costs and reduced long-term flexibility, both leading to a higher risk of failing to hold warming below 2°C.
When will global greenhouse gas emissions peak?
The IPCC says peaking before 2025 is a critical step to keep the 1.5°C limit within reach. With emissions set to rise in 2023, this leaves limited time to act. To assess if we can meet this milestone, we look at when global emissions might peak, as well as what we can do to get there in time.
Wind and solar benchmarks for a 1.5°C world
This report presents a detailed methodology for determining the amount of wind and solar capacity that is required for a country to align with the Paris Agreement’s 1.5°C temperature goal. While the focus of the report is the method, it includes illustrative benchmarks for Brazil, China, India, Indonesia, Germany, South Africa.
A 1.5°C future is possible: getting fossil fuels out of the Philippine power sector
The Philippines is also one of the fastest-growing developing countries: poverty is in decline, access to energy is rising and, with that, demand for energy services. However, fossil fuels still dominate the energy system, accounting for 78% of power generation in 2022. This report sets out what the Philippines government needs to do to get the country’s power sector onto a 1.5˚C compatible emissions pathway, replacing fossil fuels with renewable energy.
State of Climate Action 2023
This report finds that global efforts to limit warming to 1.5°C are failing across the board, with recent progress made on every indicator – except electric vehicle sales – lagging behind the pace and scale needed to address the climate crisis.
Production Gap Report 2023
Governments, in aggregate, still plan to produce more than double the amount of fossil fuels in 2030 than would be consistent with limiting warming to 1.5°C. The persistence of the global production gap puts a well-managed and equitable energy transition at risk.
Emissions impossible: Unpacking CSIRO GISERA Beetaloo Middle Arm fossil gas emissions estimates
This report provides an independent evaluation of the CSIRO and GISERA assessments of the potential greenhouse gas emissions that would result from the exploitation of the Beetaloo fossil shale gas reserves.
Adjusting 1.5°C climate change mitigation pathways in light of adverse new information
This study uses an integrated assessment model to explore how 1.5°C pathways could adjust in light of new adverse information, such as a reduced 1.5°C carbon budget, or slower-than-expected low-carbon technology deployment.
The effects of political knowledge use by developing country negotiators in Loss and Damage negotiations
This article traces how developing country negotiators used knowledge to further their interests in loss and damage negotiations from 2003 to 2013.
Ramping up energy storage: lessons for the EU
This paper explores how the EU can enhance its policy for a low-carbon future by learning from successful energy storage approaches in California, South Korea, and Australia.
2030 targets aligned to 1.5°C: evidence from the latest global pathways
Our new method applies sustainability limits and minimises the need for carbon dioxide removal to set key 2030 global targets for renewables, fossil fuels and emissions.