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The International Panel on Climate Change (IPCC) has presented a new special report on the goal of limiting global warming to 1.5 °C compared to the pre-industrial age. The IPCC had already published figures in 2014, according to which that seemed barely possible. The new report now assesses the prospects in a more positive light. So the situation is not as dramatic then?

The situation is definitely dramatic. Compared to 2014, the IPCC has admittedly corrected its forecasts for the remaining global carbon budget. According to that, humankind does still have a bit more time until this budget is exhausted. But that does not in any way mean that we can lean back and take it easy. It is technically and physically possible to limit the overall warming of the earth to 1.5°C – and the report also quite correctly talks of the accompanying benefits for people and the eco-system.

However, it also makes it very clear that quick, extremely far-reaching and unprecedented changes are necessary. Decarbonising the power supply sector alone will not suffice. We also need to concentrate on agriculture, urban planning, industry and the transport and constructions sectors. We do not have much more time because the earth has already warmed by 1°C and we are already seeing the catastrophic consequences of that.

What is the report’s core message?

The most important message is probably that the 1.5°C goal is achievable but that enormous and immediate efforts are needed. The report makes a clear difference whether the world takes into consideration the two degree goal or the 1.5°C goal. The surface of the sea would not rise by ten centimetres more and less thawing permafrost would set free much less climate-damaging methane. Parts of the coral reefs, which are so important for our eco-system, could remain intact. Worldwide fish stocks would not diminish as much and extreme weather events would take place less frequently and be less intense. In general terms, the consequences of climate change could thus at least remain manageable for humankind.

In which areas does the IPCC see the greatest need for action?

If we do not reach the 1.5°C goal, we will approach a dangerous point. Changes in the climate could become irreversible. CO2 emissions absolutely have to fall quickly, to ‘net zero’ by 2050. A ‘business as usual’ approach is totally out of the question. The special report makes specific proposals as to how this goal can be reached. The conversion of the global energy system to being based on renewable energies, a drastic reduction of the use of fossil fuels such as coal and the transformation of industry are important.

The report also talks of negative emissions, which will be significant in the future for combatting climate change. What is meant by that?

Negative emissions are an aspect of the debate around the 1.5°C goal that must urgently be discussed more fully. Basically it’s about a process which removes more CO2 from the atmosphere than is emitted – through technical solutions. At first that sounds positive because it gives the impression that global warming of the earth can be dealt with via technology and innovation alone. But that is not so. With the current technological possibilities, this is a misleading impression.

So far, there have only been negative emissions sporadically and in a few pilot projects – and here mostly at very high cost and without a real analysis of the possible consequences or its actual efficiency. Concretely, that means that these hopes are based on technologies that still do not exist and whose effects on people and nature are totally unclear. It’s dangerous to believe that we do not have to change anything and can simply carry on as before. In my view, we should therefore reject geo-engineering, meaning the technical intervention into our earth’s system to counter climate change.

In December, the next UN climate change conference is taking place in the Polish city of Katowice, where a rulebook for the Paris agreement should be adopted. What role does the IPCC report play in this summit?

The report plays a very big role. It will not only be about the important task of adopting a set of rules for the implementation of the Paris Agreement and the clarification of numerous questions in the area of climate finance. COP24 in Katowice must also demonstrate greater ambitions in terms of global climate protection to be able to count as a success. The countries’ existing Nationally Determined Contributions (NDCs) are not sufficient to achieve the 2°C goal let alone to consider the 1.5°C goal. If we consider all the current proposals, we are rather on a path to between 3 or 4°C, with the correspondingly devastating consequences for millions of people and our environment.

Could the report build up some pressure?

The national contributions must urgently become more ambitious. Considering this, the messages from the IPCC report are very useful because, on the one hand, they point to the fact that the 1.5°C goal is totally feasible. But they also underline that much more has to be done and that we are under considerable time pressure. Postponing the problem is therefore no longer possible. That produces a sense of urgency, which in my assessment may have a big influence on the negotiations in Katowice in December. In addition, the report also strengthens actors from civil society, who have already been demanding the recommended changes for a long time.

The German government’s climate change policy has recently been sharply criticised. Which recommendations can be deduced from the IPCC report for German energy and climate change policy?

Measured by the information set out in the report, the coming years are perhaps the most important in the history of humankind. Unfortunately, there’s currently still a big gap between the knowledge about what’s necessary and feasible, and concrete actions worldwide. The conclusions of the report send a clear signal to governments on this earth: we need a substantial energy, transport and agriculture transformation. That is of course also true for Germany and the European Union. Those medium term climate change goals must in any case become more ambitious.

What does that mean concretely?

With regard to the special report, in the German government’s ‘Commission on Growth, Structural Change and Employment’, there should be discussion about the phasing-out of coal as early as possible and in a least harmful way to society as possible. According to the IPCC, coal requires the steepest path for reduction in a 1.5°C scenario. But it’s not only governments that are addressed by the IPCC report. We citizens in a rich industrial country such as Germany must change something by, for example, adapting our consumer behaviour and our eating habits. More effective climate protection is not only good for us and our environment. Social justice and reduced inequality are central aspects of a climate-fair future. Let’s tackle it.