How likely is it that we can limit global warming to 1.5 degrees by 2100? To answer this question, a new analysis focused on social influencing factors. The result: As things currently stand, it is not plausible that the climate target can still be achieved. Above all, consumer behavior and the reactions of companies are slowing down urgently needed climate protection measures. By contrast, physical tipping points, including the melting of the ice sheets, will only play a minor role in global temperature up to 2050.
At the UN climate conference in Paris in 2015, most countries in the world agreed on the goal of limiting global warming to a maximum of two degrees, better still 1.5 degrees Celsius, by 2100 compared to the pre-industrial level. Although many measures have already been planned and implemented since then, the efforts made so far fall far short of what is necessary. An important goal along the way is to massively limit carbon emissions and reduce them to zero as soon as possible, i.e. to achieve full decarbonization. The extent to which this succeeds depends above all on social developments at the political, economic and individual levels.
Plausibility instead of feasibility
A research team from the Cluster of Excellence "Climate, Climatic Change and Society" (CLICCS) at Universität Hamburg has now analyzed how social factors influence the plausibility of the 1.5 degree target. In their second Hamburg Climate Futures Outlook, they come to the conclusion that social change is essential in order to achieve the Paris climate goals. However, current developments make it unlikely that corresponding changes will be implemented in good time, according to the researchers. As early as 2021, the team found in the first Hamburg Climate Futures Outlook that the plausibility of complete decarbonization by 2050 is low.
"When it comes to future climate scenarios, most studies focus on theoretical feasibility," explains the research team. This applies, for example, to the climate reports of the Intergovernmental Panel on Climate Change (IPCC). “However, these reports neglect social dynamics that have a crucial impact on whether necessary measures are put in place. In our analysis, on the other hand, we analyzed a wide range of societal and physical factors that influence the plausibility of climate scenarios.”
Societal drivers in both directions
Out of ten societal drivers that the team included in the analysis, seven support the reduction of carbon emissions - although not enough for full decarbonization by 2050. Among these positive influencers are the climate policies of the United Nations, including in particular climate agreements, transnational initiatives such as the European emissions trading, national climate laws, climate protests and other social movements. In addition, climate lawsuits, for example against mineral oil companies, reduced investments in fossil fuels and the dissemination of knowledge about climate change. However, according to the analysis, these factors are going in the right direction, but not strongly enough: "The required complete decarbonization is simply progressing too slowly," says CLICCS spokeswoman Anita Engels from the University of Hamburg.
Two important societal drivers continue to stand in the way of reducing CO2 emissions: consumer spending habits and corporate reactions. The research team sees the tenth influencing factor, the media, in an ambivalent role. By contributing to knowledge transfer, they can support decarbonization and help consumers make their consumer behavior more climate-friendly and companies feel that they have a social obligation to do business more sustainably. On the other hand, the media can also promote narratives that run counter to climate goals.
Physical tipping points have a minor influence
In addition to the societal factors, the team also analyzed how physical processes, which represent possible tipping points, affect the achievement of the climate goals. The result: The thawing permafrost, a weakening Gulf Stream and the loss of the Amazon rainforest have a moderate impact. On the other hand, other serious changes such as the loss of Arctic sea ice, the melting of the ice sheets and regional climate changes will have little impact on global temperatures by 2050. "The fact is: These feared tipping points could drastically change the conditions for life on Earth - but they are largely irrelevant for achieving the temperature targets of the Paris Agreement," explains CLICCS co-speaker Jochem Marotzke from the Max Planck Institute for Meteorology in Hamburg.
The authors also included current developments such as the Covid-19 pandemic and the war in Ukraine. "Reconstruction programs and measures to mitigate the socio-economic impact of the Covid-19 pandemic have entrenched dependence on fossil fuels, making the transition to full decarbonization less plausible than previously thought," the team said. With regard to the Ukraine war, an empirically based assessment is not yet possible. Depending on the political decisions to become less dependent on Russian gas, this could accelerate or undermine the phase-out of fossil fuels.
Human creative freedom
"Our assessments of the social drivers show that human action has great potential to shape the way the climate future will evolve," the authors write. “We conclude that full global decarbonization by 2050 is currently implausible. Nevertheless, limiting global temperature rise to well below two degrees Celsius may become plausible if gaps in ambition, implementation and knowledge are closed.”
Source: CLICCS (University of Hamburg), doi: 10.25592/uhhfdm.11230