5 November, 2018

How do we limit warming to 1.5°C: informing the Talanoa Dialogue question, “How do we get there?”

Authors

Bill Hare, Michiel Schaeffer, Carl-Friedrich Schleussner and Robert Brecha

Informing the Talanoa Dialogue question, “How do we get to 1.5°C?”

Integrated Assessment Models of climate change mitigation, assessed in IPCC Special Report on Global Warming of 1.5°C (IPCC SR1.5), show a large spectrum of 1.5°C- compatible pathways that limit warming to this level during the century, or exceed it by only a limited amount of less than 0.1°C (“low overshoot”). This Climate Analytics submission to the Talanoa Dialogue, which unpacks in some detail the implications of these pathways.

This submission unpacks in some detail the implications of 1.5°C compatible mitigation pathways assessed in the IPCC Special Report on Global Warming of 1.5°C (IPCC SR1.5). Integrated Assessment Models of climate change mitigation, assessed in IPCC SR1.5, show a large spectrum of 1.5°Ccompatible pathways that limit warming to this level during the century, or exceed it by only a limited amount of less than 0.1°C (“low overshoot”).

Where we are:

The IPCC SR1.5 assesses the state of scientific knowledge on impacts of climate change, both currently experienced and likely to be felt in a future of 1.5°C warming or more, and related global greenhouse gas emission pathways. The report shows that we will be able to limit warming to 1.5°C, if the world takes further action substantially beyond what is implied by current Nationally Determined Contributions under the Paris Agreement (PA) in aggregate. However, any
delay in near-term emissions reductions will lead to an increasing risk of greater temperature overshoot (with associated larger climate-change impacts and higher damages), a stronger reliance on uncertain mitigation options such as Carbon Dioxide Removal, and higher overall mitigation costs.

Where we want to go:

The IPCC SR1.5 has assessed global greenhouse gas emission pathwaysthat examine the technical and economic feasibility of limiting warming to 1.5°C. Simultaneously, the IPCC SR1.5 considers many dimensions of sustainable development that go beyond potential and actual impacts of climate change. The IPCC SR1.5 Summary for Policy Makers focuses on 1.5°C compatible mitigation pathways that limit global warming to 1.5°C, or below throughout the 21st century with no or limited (0.1°C) overshoot. These 1.5°C compatible pathways generally bring warming back to around 1.3°C warming by 2100 after a peak warming of 1.5°C or slightly above (less than 1.6°C) around the 2060s, and to achieve this have total greenhouse gas emissions peak around 2020 and decrease rapidly to global zero around the 2060s. Although the IPCC SR1.5 also assesses other pathways, these lead to higher warming levels. These include pathways that return warming to 1.5°C by 2100, but achieve this after an overshoot to as much as 1.9°C, which is clearly not holding warming “well below 2°C” as specified in Paris Agreement Article 2.1 and would be associated with climate risks, impacts and damages close to 2°C.

The principle part of this submission to the Talanoa Dialogue is on the question, “How do we get there?”. To this end we examine the many PA-compatible pathways toward the 1.5°C limit and highlight those that appear most likely to maximize synergies with sustainability and feasibility
criteria.

Some key conclusions from our analysis are that:

Rapid reductions in energy demand across all sectors are fundamental for 1.5°C compatible pathways that also limit negative emissions through carbon capture technologies.
A rapid and almost complete phase-out of coal by 2050 in the power sector is a universal message, with the highest agreement across scientific publications. Crucially, most of this transformation needs to happen right now, because the use of coal in the power sector needs to be reduced from currently over 35% of global electricity supply to only 3-10% by 2030.
At the same time, total coal use in energy and industry needs to be reduced to 60-80% below 2010 levels by 2030 and to up to 95% below 2010 levels by 2050.
Natural gas, even if combined with Carbon Capture and Storage (CCS) is reduced sharply as well, to 8% (3–11%) of global electricity in 2050.
With a high rate of electrification of transportation, substantial reductions in oil use are projected, with oil use by 2030 as much as 35% lower than in 2010, and 30-80% lower by 2050.
Renewable energy technologies (excluding biomass) reach a particularly high share in electricity supply of 45-65% in 2030 and 70-85% in 2050.
In addition, total primary energy needs to be supplied by renewable energy (excluding biomass) at a share of 50-65% by 2050, displacing fossil fuels from traditional markets for power generation, mobility and heating.
1.5°C compatible transformation will require significant additional investment worldwide in low-emission infrastructure as well as redirection of financial resources away from carbon-intensive investments. Global annual investments in low-carbon energy technologies overtake fossil investments already by around 2025 in 1.5°C pathways.

Publications

Spatially resolved emulated annual temperature projections for overshoot pathways

This study presents a new dataset of annual temperature projections for different overshoot pathways (when the 1.5 °C of global warming limit is exceeded). The data offers a unique opportunity to study local and regional climate change impacts of a range of overshoot scenarios, including when temperature thresholds might be exceeded, and by how much.

Geological Net Zero and the need for disaggregated accounting for carbon sinks

This study in Nature show that definitions of net zero now in widespread use will not actually stop global warming. The paper demonstrates that relying on natural carbon sinks, such as in forests or oceans, to 'offset' ongoing fossil fuel emissions will lead to continued warming.

The role of northern forests in limiting warming to 1.5°C

Northern forests are critical in the race to net zero CO₂ by mid-century. Protecting and restoring these forests, alongside steep and rapid reductions in fossil fuel emissions, is essential both to mitigating emissions and to supporting forest ecosystem services and biodiversity.

LNG shipbuilding industry heading to huge oversupply

The LNG shipbuilding industry appears to be doubling down on building new carriers, ignoring the global shift to a low carbon economy and putting itself into an even worse oversupply situation than a year ago, we find in our updated report.

Fracking the Kimberley: the Canning Basin development plans

We've calculated the climate implications of fracking the Canning basin, part of the remote and pristine Kimberley region in Western Australia. Four companies have their eyes on this region, home to the endangered bilby.

Australia's global fossil fuel carbon footprint

This report unpacks the global carbon footprint from Australia's exported fossil fuels, especially coal and gas; exports that are set to continue at the same level through to 2035, threatening the 1.5˚C warming limit.
Australia has a global carbon footprint that far exceeds its economic size and population - and is responsible for around 4.5% of global fossil carbon dioxide emissions, with 80% of those emissions coming from its fossil fuel exports.

Evaluating the near and long-term role of carbon dioxide removal in meeting global climate objectives

For 1.5°C pathways with limited overshoot, most of the mitigation between now and 2030 should come from emissions reductions (70%), with reductions from cutting non-CO2 emissions (20%) and land-based carbon dioxide removals such as afforestation and preventing deforestation (10%) making up the remainder.

Article 6.4 progress update: work of the Supervisory Body on the Paris Agreement Crediting Mechanism

The Article 6.4 mechanism, now known as the Paris Agreement Crediting Mechanism, allows countries to trade reductions in carbon emissions in a manner that goes beyond zero-sum offsetting, to achieve their commitments under the Paris Agreement. This briefing aims to update Small Island Developing States and Least Developed Countries on the standards and procedures that have been adopted by the supervising body (Article 6.4) to inform the design of projects.

What does a just transition look like for Caribbean Small Island Developing States?

This briefing aims to provide some preliminary information on what just transition encompasses in the context of Caribbean Small Island Developing States.

What good looks like: G7 climate policy 2024 update

This brief outlines seven key policy recommendations for this June’s G7 summit that, if adopted, would demonstrate the ambition and leadership needed to keep the Paris Agreement’s 1.5°C limit in sight.

The 1.5°C limit and risks of overshoot

This briefing looks at what the 1.5°C limit means in terms of adaptation and loss and damage for the most vulnerable countries and regions. It finds that slowing down warming is critical to buy us time to adapt and also to avoid irreversible loss and damage. Even if warming rises above 1.5°C (overshoot) we can bring it down again with ambitious emissions reductions.

Le seuil de +1,5°C et le risque de dépassement de ce seuil

Ce rapport examine ce que la limite de 1,5 °C signifie en termes d'adaptation et de pertes et dommages pour les pays et régions les plus vulnérables. Il constate qu'il est essentiel de ralentir le réchauffement pour nous donner le temps de nous adapter et pour éviter des pertes et des dommages irréversibles. Même si le réchauffement dépasse 1,5 °C, nous pouvons le faire baisser à nouveau en réduisant les émissions de manière ambitieuse.

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