The scientists assessed the dynamics of 10 social drivers and 6 physical processes. Their conclusion: social change is essential to meeting the temperature goals set in Paris. But what has been achieved to date is insufficient. Accordingly, climate adaptation will also have to be approached from a new angle.

Key Findings at a glance:

Meeting the 1.5°C Paris Agreement temperature goal is not plausible. Limiting the global temperature rise to well below 2°C can become plausible if ambition, implementation, and knowledge gaps are closed.

  • None of the ten social drivers support deep decarbonization by 2050. The drivers corporate responses and consumption patterns continue to undermine the pathways to decarbonization, let alone deep decarbonization.
  • The physical processes permafrost thaw, AMOC instability, and Amazon Forest dieback can moderately inhibit the plausibility of attaining the Paris Agreement temperature goals.
  • The social driver assessments demonstrate that human agency has a large potential to shape the way climate futures will evolve.
  • However, human agency is strongly shaped by injustices and social inequalities, which inhibit social dynamics toward deep decarbonization by 2050.
  • Key concepts and guiding principles toward a Sustainable Adaptation Plausibility Framework are established.
Further information:
  • Key findings (pdf)

  • Hamburg Climate Futures Outlook 2023 (75 MB, pdf)

  • Original Publication: Anita Engels; Jochem Marotzke; Eduardo Gonçalves Gresse; Andrés López-Rivera; Anna Pagnone; Jan Wilkens (eds.) (2023): Hamburg Climate Futures Outlook 2023. The plausibility of a 1.5°C limit to global warming – Social drivers and physical processes; Cluster of Excellence Climate, Climatic Change, and Society (CLICCS). Hamburg, Germany; DOI: 10.25592/uhhfdm.11230

  • Further information (results, key findeings, press release) on the website of CLICCS

About the Hamburg Climate Futures Outlook
63 researchers from the Cluster of Excellence CLICCS were contributing authors to the Hamburg Climate Futures Outlook. They hail from various disciplines of the natural and social sciences, economics and law. Over 20 reviewers from Germany and abroad checked their work. In the CLICCS Plausibility Assessment Framework, the Cluster evaluated ten social drivers and expanded its scientific method to include six additional physical processes.
The Hamburg Climate Futures Outlook is released annually. It analyzes physical and social dynamics and assesses which climate futures are not just possible, but plausible.
Universität Hamburg’s Cluster of Excellence Climate, Climatic Change, and Society (CLICCS) is supported by the German Research Foundation (DFG). Based at Universität Hamburg’s Center for Earth System Research and Sustainability (CEN), it works in close collaboration with eleven partner institutes, including the Max Planck Institute for Meteorology in Hamburg, the Helmholtz Centre Hereon and the German Climate Computing Center.