How the climate could yet be saved

At the beginning of April, the third subreport of the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) (AR 6) will be published. This report gives a detailed presentation of what humanity must do to stop climate change. It thus concentrates on reducing our greenhouse gas emissions from, for example, coal-fired power plants, transportation, or heating systems. Like the first and second parts, the report will span several thousand pages and show the current state of research findings. Diplomats from the 195 IPCC member states are currently conducting negotiations on the approximately 30-page “Summary for Decision Makers.” This document, however, must be based on the research findings contained in the actual report. This procedure ensures two things, says the co-director of the Potsdam Institute for Climate Impact Research, Professor Ottmar Edenhofer: All countries have to go through the underlying report in detail, as well as officially acknowledge its content by adopting it.

The as yet unpublished report will feature some new elements in comparison with the report (AR 5) from 2014: It will concentrate more heavily on the role of non-governmental actors, such as companies and financial institutions. This will be the first time that it contains a chapter on the demand for energy and energy-intensive goods, and it will examine the social aspects of our societies’ transformation in much greater detail than before. “Science has drawn up the map indicating all the danger zones and paths, thus allowing policymakers to make decisions on the basis of facts,” says Edenhofer. The initial point is the still increasing emissions, as well as the existing climate protection measures. So far, these have fallen short of reaching the climate goals that the states have set for themselves. Furthermore, according to calculations performed by the Climate Action Tracker, these climate goals are not enough to stop warming at two degrees – not to mention 1.5.

However, the report is also intended to make it clear that it is technically and economically feasible to achieve a faster reduction in emissions and that with suitable accompanying measures, no negative social effects need to be feared. That said, individual, one-off measures will not be sufficient for such. Transforming the economy and society toward a sustainable future reality will require a holistic approach, which also takes into account the institutional and economic framework conditions. In this regard, the financial markets will also play a key role, a sector that has come into the spotlight just in recent years. “The point is about using the world's enormous flows of finances to help secure our future instead of endangering it,” says Professor Kerstin Lopatta from the University of Hamburg. This means that companies would need to submit reports on their emissions in as standardized a manner as possible, as well as on the climate risks to which they are exposed. At present, there are various committees working on standards for these reports.

That said, even with a much more effective climate policy, humanity in the future will have to remove already emitted carbon dioxide (CO₂) from the atmosphere. On the one hand, this has to do with the nature of the “net-zero targets” that still contain residual emissions which are simply compensated for in another way. On the other hand, according to Professor Sabine Fuss from Berlin's Humboldt University, one should expect the warming to temporarily exceed the 1.5 degree limit. There are various options available for extracting CO₂, but they all have a limited capacity. The least controversial of these options include the reforestation of suitable areas and the rewetting of bogs, as well as some actions in the seas – for example, the restoration of kelp forests and seagrass meadows. If done properly, this can also be advantageous for biodiversity.

That said, BECCS is somewhat more complicated. Here, bioenergy (BE) – that is: wood or other biomass – is burned to generate energy and then the CO₂ is captured and sequestered underground (CCS). However, using BECCS on a large scale would require huge biomass plantations. Another option is to filter CO₂ from the air, using Direct Air Capture (DAC) and then dispose of it again via CCS. Although this option does not require much space, it does require enormous amounts of green electricity.

The second part of the IPCC Assessment Report, published in February, has demonstrated the urgency of cutting emissions in half by 2030 and reducing them to net-zero by 2050: The current warming of 1.1 degrees has more severe consequences than previously expected and “the medium and long-term effects are up to many times higher than those currently observed.” For this reason, the hope remains that the decision makers of the world will actually view the third part of the IPCC report as a map and that they will lead humanity out of the climate crisis.