How science will keep 1.5°C alive for your city

As national and regional governments grapple to “keep 1.5°C alive” with updated Nationally Determined Contributions (NDC), science-based climate targets offer local governments a clear path towards effective climate mitigation.

According to the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (working Group I) published in 2021, human-induced global warming will see temperatures surpass 2 degrees Celsius (°C) within the 21st century, if critical climate measures are not taken immediately.

This stark warning means climate action plans need to shift gear to have a tangible effect. However, climate planning is notoriously complex. Science-based climate targets offer sub-national governments an informed framework to guide the necessary level of ambitious climate action and limit temperature increases to 1.5°C.


What is a science-based climate target (SBT) and why should your city set one?

Science is fundamental to informing and driving policy and decision-making. Science-based climate targets are aligned with the goals of the Paris Agreement and the latest climate science – to limit global warming to 1.5°C above pre-industrial levels. SBTs follow these three principles:

  1. science-driven: led by the latest climate science, they include 1.5°C-aligned long-term (2050), and mid-term (2030) targets.
  2. equitable: they make equity considerations by looking into historical contributions to emissions and capacity to mitigate them. In other words, they are based on a city’s fair share of emissions that need reducing.
  3. complete: they focus on community-wide emissions, rather than just those of single sectors, and multiple GHGs.


For instance, Wellington City Council, New Zealand, has set a target to reduce community-wide emissions to net zero by 2050. To ensure they meet their long-term target, the local government, through the WWF One Planet City Challenge science-based target methodology, has also set a mid-term target based on their 2018 emissions. Adjusted in line with a 2020 baseline and population growth, this results in a 57 percent reduction in Wellington’s 2020 city-wide emissions by 2030.

Buenos Aires in Argentina has used C40 Cities’ Deadline 2020 science-based climate target methodology to set itself on the path to meet its 2050 carbon neutrality goal. This helped the city identify the emission reduction needed – 53 percent by 2030 – to achieve their long-term target.

With 56 percent of the world’s population residing in urban areas and an estimated 75 percent of global energy-related emissions being emitted in them, both the potential and the imperative to reduce city emissions is immense. Local governments can set SBTs for their territories to achieve impactful climate action.

Setting SBTs offers local governments multiple benefits:

  • Ambitious long term vision: SBTs define the level of action needed from each local government. This makes it easier for towns, cities and regions to plan concrete climate actions by defining the required ambition level – all tailored to the local context.
  • Measurable progress: SBTs help local governments quantify their progress in their territory, while aligning their contribution to the ambition required by the Paris Agreement, smoothing the way for multi-stakeholder collaboration.
  • Recognition: setting SBTs qualifies cities to join the UNFCCC’s Race To Zero, a global campaign that rallies leadership for a zero-carbon future. The Cities Race to Zero already includes 1,049 committed cities. This is especially relevant to cities and local governments that are keen to establish themselves as ambitious, climate-conscious actors.


Setting your science-based target: How the SBTN can help

The Science Based Targets Network (SBTN) is a consortium of core city partners (C40 Cities, CDP, the Global Covenant of Mayors, ICLEI, WRI, and WWF) that evaluates whether your proposed target is consistent with 1.5°C ambition and adheres to the SBT criteria, providing you with feedback and support.

The SBTN helps local and regional governments by:

  • Offering local support to develop your target – for example, introducing the core principles of setting an SBT and helping your local government select the most appropriate methodological framework for setting a community-wide SBT.
  • Reviewing targets reported to platforms such as CDP-ICLEI Track against a 1.5°C alignment (e.g. cities that are members of C40, part of ICLEI’s network, or participating in WWF’s One Planet City Challenge will have their targets checked by these partner organizations) and suggest revisions as appropriate.


Get started

Interested in learning more about city SBT setting? Read the city guide to SBTs and contact:

C40 at the C40 contact page

CDP at the CDP Help Centre




This blog was written by Matteo Bizzotto, ICLEI Global Communication Officer and Maryke van Staden, Director of ICLEI’s Bonn Center for Local Climate Action and Reporting (carbonn Climate Center), with contributions from C40, CDP, and WWF.