Achieving global climate goals by 2050, pathways to a 1.5° C future

The world remains far from meeting the primary goal outlined under the 2015 Paris Agreement on climate change: reducing greenhouse gas (GHG) emissions to keep global average temperature rise to well below 2° C by 2100 and making every effort to stay under 1.5° C. Current emissions are rebounding from a brief decline during the economic downturn related to the Covid-19 pandemic. To get on track to meet the goal of the Paris Agreement, research suggests that GHG emissions should be roughly halved by 2030 on a trajectory to reach net zero by around midcentury.
Although these are global targets, every sector and country can and must contribute, especially higher-income countries that have a greater capacity to act. And while there are movements in this direction as demonstrated by a series of updated pledges or nationally determined contributions (NDCs) as part of the ratcheting mechanism to the Paris Agreement these efforts alone do not achieve a 1.5°C compatible pathway. Even in the most optimistic case, they have only a roughly 50% probability of limiting warming to 1.8°C, leaving a large gap throughout the century, especially in the shorter term, where a lack of ambition makes a temperature overshoot pathway highly likely.
The body of scientific understanding of what lies ahead continues to grow including with the release of the most recent set of assessment reports from the Intergovernmental Panel on Climate Change (IPCC). In particular, the Synthesis Report of the IPCC Sixth Assessment (Longer Report), published in March 2023, paints a grim picture of increased climate hazards and risks to ecosystems and humans if global warming reaches or exceeds 1.5° C. Each additional fraction of a degree increases the associated climate risks. In short, the Sixth Assessment Report argues that “any further delay in concerted anticipatory global action on adaptation and mitigation will miss a brief and rapidly closing window of opportunity to secure a livable and sustainable future for all.”
In this report, we identify the potential for various sectors distributed across 10 global geographies to pursue emissions reduction opportunities that would meet the Paris Agreement goals, with a focus on 2050. Using the integrated assessment model called the Global Change Analysis Model (GCAM), we developed a range of climate scenarios that build on the Representative Concentration Pathways Shared
Socioeconomic Pathways (RCP-SSP) scenario framework. Our scenarios are extensions to the RCP-SSP process; they include additional constraints to 1) better reflect the multiple benefits of sustainable development, technological progress, and the potential of behavioral change as reflected by ClimateWorks programmatic aims (see a detailed discussion of parameters in the Technical Summary), and 2) reflect the growing consensus regarding the level of ambition needed to reach net-zero carbon
dioxide emissions by 2050.
We selected parameters for testing through a co-production process with ClimateWorks’ sectoral experts to arrive at a Central, or anchoring, scenario. In addition to this Central scenario, we offer a new set of Ensemble scenarios that further test a selection of key parameters, allowing a better understanding of the options around which a pathway might be designed. This enables an informed discussion on a wider range of possible outcomes and reveals additional nuance, linkages, and trade-offs to climate change mitigation strategies.

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