The annual ZERO IN reports by the CONSTRAIN project provide information on scientific topics that are crucial to the Paris Agreement, including background and context on new developments at the science-policy interface. This includes new insights into the complex processes represented in climate models and what they mean for temperature change and other climate impacts over the coming decades.
These advances in climate modelling are particularly relevant when it comes to the heart of the Paris Agreement: the Long-Term Temperature Goal (LTTG), put in place to avoid the most catastrophic impacts of climate change. The LTTG calls for “holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels”.
The latest generation of climate models (CMIP6) is improving our understanding of the climate system and where global temperatures are heading, including when we might pass the 1.5 or 2˚C thresholds, as well as the mitigating actions that can help us to avoid doing so. However, the new model results require careful interpretation.
We also need to understand how temperature change is measured in the context of the LTTG, to both assess how global temperatures have changed to date, and to use the models effectively in making decisions that affect our climate future. This is particularly important given the economic and societal choices the world faces in the light of the COVID-19 pandemic.
This year’s ZERO IN report therefore focuses on the new CMIP6 climate models and the science behind the LTTG, highlighting how improved understanding in both areas can help us to better plan for what lies ahead. In particular, we find that whilst the effect of COVID-19 on climate has so far been negligible, a green recovery could profoundly alter the trajectory of climate change over the next two decades. Our findings also reaffirm the importance of stringent near-term emission reductions and reaching net-zero CO2 emissions by 2050 to get the world on a 1.5°C pathway.
In addition, we provide our annual update on the remaining global carbon budget. This includes an estimate for the budget remaining from the start of 2021 alongside further context on the use of carbon budgets in national and regional policy.
Unabated: the Carbon Capture and Storage 86 billion tonne carbon bomb aimed at derailing a fossil phase out
The climate talks at COP28 have centred around the need for a fossil fuel phase out. Our analysis quantifies the risk posed by restricting a phase out commitment to only ‘unabated’ fossil fuels.
No change to warming as fossil fuel endgame brings focus onto false solutions
The CAT's annual warming estimate has risen by 0.1˚C to 2.5˚C. The estimate is largely influenced by weak existing targets rather than shifts triggered by updated Nationally Determined Contributions.
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.
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.
Railway development: lessons for the EU
This paper analyses how EU railway policy for a low-carbon future can be enhanced, drawing insights from Japan and Switzerland.