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Cutting meat consumption by 30% has the same climate impact as flying 70% less, switching one-sixth of the world’s cars to electric, or decarbonising nearly every cement plant globally. These are examples of ‘climate wedges’ – equally sized units used to compare different ways of cutting greenhouse gas emissions. Researchers from 911½ñÈÕºÚÁÏ have shown that the world needs around 20 wedges to limit global warming to 1.5°C.

Published in Science, the study by Dr Nathan Johnson and Dr Iain Staffell from 911½ñÈÕºÚÁÏ’s Centre for Environmental Policy describes how complex decarbonisation scenarios can be broken into comparable wedges of emissions.  Each wedge represents a reduction of 2 billion tonnes of COâ‚‚ equivalent per year by 2050, roughly 4% of today’s global emissions.

The study highlights an important point often lost in public debates: there is no single pathway to limiting warming. Indeed, the researchers estimate there are more than six trillion possible combinations of strategies that could collectively deliver the 20 wedges required to align with the Paris Agreement.

Alongside the paper, the team has launched an interactive pathway builder at , where members of the public can explore and share their own ideas for successful global decarbonisation pathways.

A common currency for climate action

The original concept of was introduced in 2004 by Steve Pacala and Rob Socolow to illustrate how incremental actions could stabilise emissions. The new study updates this approach using the latest global emissions data and a wider set of mitigation strategies.

“All too often conversations about decarbonisation centre around large technological solutions, like carbon capture and nuclear reactors, which can feel quite detached from people’s everyday lives. We wanted to broaden the debate so that people can compare a much wider range of climate solutions.” - Dr Nathan Johnson, co-author of the research and a research associate in the Centre for Environmental Policy.

By expressing strategies in a common unit of emissions reduction, the framework allows direct comparison between technological, nature-based and behavioural actions.

The researchers assessed 36 strategies across power, transport, buildings, industry, land and food systems. Each is quantified according to the scale of deployment required to deliver one wedge by 2050.

Examples include:

• Generating 6.6% of global electricity from wind or solar power– requiring 30 or 75 gigawatts of new capacity to be built each year.
• Reducing passenger air travel by 70% – similar to the drop seen during the COVID-19 pandemic.
• Producing 150 million tonnes of clean hydrogen – more than 150 times today’s production.
• Reducing tropical forest loss by 40% compared with historical rates.
• Using electric vehicles for 17% of global passenger land transport, equivalent to around one billion electric vehicles.
• Reducing meat consumption by 30% globally.
• Doubling building insulation to significantly reduce heat loss.

Revealing trade-offs between climate solutions

The framework highlights that actions that appear very different can deliver similar climate impacts.

For example, reducing global meat consumption by 30% would have the same emissions impact as cutting passenger air travel by 70%. Similarly, halving global food loss and waste could deliver emissions reductions comparable to deploying over 50,000 of the largest carbon removal technology operating today.

Yet these strategies have very different implications for lifestyles, infrastructure and public policy.

“There are countless ways that people can reduce their environmental impact, and even more ways to change the systems we live in,” said Dr Iain Staffell, co-author of the research and  Associate Professor in Sustainable Energy at the Centre for Environmental Policy..

“But people need to understand the scale of impact different options have in order to decide which approaches they support.”

Most of the strategies identified in the study already exist, but their levels of deployment vary significantly.

For example, the world installed around 600 gigawatts of solar power capacity in 2024, equivalent to around nine wedges of mitigation. By contrast, delivering a wedge from clean hydrogen or carbon capture and storage would require deployment to increase by more than one hundred times current levels.

Linking climate models to public debate

To connect the framework with existing research, the team translated hundreds of mitigation scenarios used by the United Nations Intergovernmental Panel on Climate Change (IPCC) into wedges.

Across these scenarios, renewable electricity emerges as the largest contributor to emissions reductions. Wind and solar together deliver more than six wedges in typical 1.5°C pathways, while carbon capture and storage contributes around two wedges.

However, the authors note that many climate models emphasise technological solutions such as renewable energy and carbon capture because they are designed to minimise system costs. Nature-based and behavioural options, such as reducing deforestation or food waste are often less visible in these models.

The wedges framework aims to provide a clearer way to illustrate the scale of change required and to support more informed discussion about the trade-offs between different strategies.

“The framework doesn’t prescribe which options are best or which countries should act first. “It simply shows the scale of action required and allows people to explore the many possible ways of achieving it.” - Dr Johnson.

Informing durable climate policy

As net zero policies face growing scrutiny over costs, energy security and lifestyle implications, the researchers argue that accessible tools are essential for building public trust.

By converting complex measures such as gigawatts of electricity generation or hectares of forest restoration into a single unit of mitigation effort, the wedges framework provides a simpler way for policymakers, businesses and the public to compare different options.

The study, , is published in Science. The interactive Climate Wedges pathway builder is available at .