Starting in 2025, the world must halve emissions by 2030 to limit global warming close to around 1.5°C. This proposed trajectory means emissions need to drop around 12 percent per year, according to a new analysis by Swedish NGO, Klimatkollen, in collaboration with the Exponential Roadmap Initiative.

We’ve done the math on what upholding the Paris Agreement means in practice starting now in 2025. Instead of halving every decade – the Carbon Law rule of thumb – we need to cut emissions around 12 percent per year. This provides citizens with a yardstick to hold decision makers in business and politics to account, says Frida Berry Eklund, Co-founder of Swedish climate data NGO, Klimatkollen.

Based on the level of carbon emissions in 2024, and the remaining carbon budget to stabilise global temperature at around 1.5°C, as outlined in the Global Carbon Budget 2024, the world must now halve emissions every five years, starting 2025, equating roughly to 12% emission cuts annually. The calculation assumes a 50:50 chance of limiting global warming to around 1.5°C and a global carbon budget of 305 billion tonnes of CO₂ from 2025, as leaving 5.5 billion tonnes of CO₂ residual emissions by 2050. The updated Carbon Law calculations show what is needed from countries, companies, cities and other organisations.

The remaining carbon budget for a 50:50 chance of 1.5°C is being used up at about 1 percent every month. To avoid crucial tipping points in the earth systems, emissions must fall as fast as possible, while avoiding economic collapse. Hitting 1.5°C last year should be a clear signal to step up action to safeguard our earth system, says Owen Gaffney, Co-founder of Exponential Roadmap Initiative.

The Carbon Law, is a science-based framework first proposed by Johan Rockström, Owen Gaffney and Johan Falk in 2017, inspired by Moore’s Law in computing, providing a rule of thumb – halving emissions every decade from 2020 onwards. However, we are now five years behind schedule as emissions are still rising which has prompted the new calculations.

We need to scale up climate solutions at an unprecedented, exponential pace to phase out the fossil fuel economy. The first halving of emissions by 2030 is absolutely achievable with today’s technologies – many companies are already proving it – and solutions for the next halving are within reach. The science is unequivocal about what must be done; now we all have to do everything possible to unlock the unprecedented speed needed to keep 1.5°C within reach, says Johan Falk, Co-founder of Exponential Roadmap Initiative.

More info

• Full analysis, Applying Carbon Law From 2025, here
• Q&A about An Updated Carbon Law Trajectory here
• Original Carbon Law presented here

Contact

• Frida Berry Eklund, Klimatkollen, frida@klimatkollen.se, +46 (0)73 620 08 13
• Johanna Bergmark, Exponential Roadmap Initiative, johanna.bergmark@exponentialroadmap.org, +46 (0)703 81 68 69
• Owen Gaffney, Exponential Roadmap Initiative, owen.gaffney@exponentialroadmap.org
• Johan Falk, Exponential Roadmap Initiative, johan.falk@exponentialroadmap.org