Hamburg Climate Futures Outlook

The purpose of the Hamburg Climate Futures Outlook 2023 is to systematically analyze and assess the plausibility of certain well-defined climate futures based on present knowledge of social drivers and physical processes. In particular, we assess the plausibility of those climate futures that are envisioned by the 2015 Paris Agreement, namely holding global warming to well below 2°C and, if possible, to 1.5°C, relative to pre-industrial levels (UNFCCC 2015, Article 2 paragraph 1a). The world will have to reach a state of deep decarbonization by 2050 to be compliant with the 1.5°C goal. We therefore work with a climate future scenario that combines emissions and temperature goals.

Download the study as accessible PDF and as ePub
Fact sheets: key information at a glance
Key Findings: the most important findings at a glance
Figures: key graphics at a glance and for download (as jpeg files)
Authors and reviewers of the Hamburg Climate Futures Outlook 2023
Contact

yellow hands balance several colored globe on long object

Photo: CLICCS/Universität Hamburg

1.5-degree goal not plausible: social change more important than physical tipping points

Limiting global warming to 1.5 degrees Celsius is currently not plausible, as is shown in a new, central study released by Universität Hamburg’s Cluster of Excellence “Climate, Climatic Change, and Society” (CLICCS). Climate policy, protests, and the Ukraine crisis: the participating researchers systematically assess to what extent social changes are already underway – while also analyzing certain physical processes frequently discussed as tipping points. 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. To press release

Key Findings in a nutshell

→ 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.