Climate change: “Previous risk assessments were too optimistic”

20 May 2022

The global community does not have much time left to act. We interviewed LMU geographer Matthias Garschagen about the consequences of global warming and the risks of adaptation.

© IMAGO / Markus / Tischler

The goal of limiting global warming to 1.5 degrees is at risk. This was the limit agreed upon by the global community at the Paris Agreement. A study by the World Meteorological Organization now reveals: “The probability that this limit will already be exceeded temporarily in individual years within the next five years currently stands at 50 percent.”

Matthias Garschagen is Chair in Human Geography and heads the Teaching and Research Unit for Human Environment Relations at the Department of Geography at LMU. He knows as well as anyone that the world does not have much time left to act. The LMU geographer is one of the lead authors of the second assessment report by the Intergovernmental Panel on Climate Change (IPCC). On publication of the report on February 28, 2022, Matthias Garschagen gave the following interview, which is keenly relevant for the present moment. In the interview, the climate researcher also explains why a major loss of biodiversity threatens.

What is the report about?

Matthias Garschagen: There are three working groups in the IPCC, each focusing on different areas. The second working group, which has just published the report we’re talking about, assesses the consequences of climate change.

Principally, the report deals with the risks and impacts of climate change and with questions of adaptation. It assesses the current state of the scientific debate, which is voluminous to say the least, and synthesizes this information for political decision-makers. Of the huge number of publications in climate change research, many specifically assess risks and vulnerabilities as well as the possibilities for adapting to climate change. The report helps us understand whether we, as a global community, are on a course that allows us to keep a handle on the risks of climate change as set out in the Paris Agreement. It is very important for informing political decision-making processes in relation to climate change – at the global level first and foremost, but also at national and local levels.

What do you think are the main insights from the report?

Garschagen: The scientific evidence is unequivocal: Climate change is a massive threat to human wellbeing and the health of the planet. Immediate and determined action for climate change mitigation as well as adaptation is more important than ever in order to respond to climate impacts and limit future risks. Global warming of 1.1°C has already caused widespread and often irreversible damage in ecosystems and has affected the lives of billions of people. In addition, we face considerable additional risks in the future, and they will be stronger and come earlier than assumed in the last assessment. Our body of knowledge is now even greater and more robust than seven years ago at the time of the last report. The previous risk estimates were too optimistic. We’re increasingly dealing with feedbacks and complexities in the system, by means of which risks mutually exacerbate each other, such as interdependent water-related and food-related risks. Such compounding risks have received increased scientific attention in recent years.

Has there been any progress in climate adaptation?

Garschagen: Climate change adaptation has been making decent progress. We found a whole lot of adaptation activities in all regions of the world and in all sectors. That being said, the report comes to the conclusion that existing adaptation efforts are insufficient to properly limit current impacts and avert serious risks in the future. To date, adaptation has been rather fragmented, small in scale, concerned with the short-term and nested within sectoral siloes. Efforts are frequently directed toward optimizing the status quo, as opposed to reimagining adaptation more fundamentally. Coastal zones and large cities are good examples: How can land-use planning be adapted to accommodate for long-term fundamental changes in climate hazard exposure? Where should retreat be considered in coastal areas, because protection will become too expensive? In cities, where do we have to radically reconsider how we deal with heat when it comes to things like urban design and landscaping? How do social security systems need to be changed fundamentally? Up to now, we see relatively little adaptation along these lines.

Are we mainly talking about technological solutions for adaptation?

Garschagen: That’s what people often think, and technical solutions tend to dominate the debate, but the report shows very clearly that the majority of adaptation activities currently taking place are squarely focused on behavioral change. They’re about things like whether farmers – and specifically small farmers in arid regions – change their cropping patterns or irrigation mechanisms. So it’s not always about grand technical initiatives, but smaller behavioral solutions, often at the level of individual households, farmers, or small businesses.

In fact, when it comes to technical adaptation we’re even seeing cases of maladaptation – that is, misguided or counterproductive technical solutions – which can end up making risks worse. Many coastal cities, for example, are primarily working towards hard coastal protection aimed at sealing themselves off against sea level rise or stronger storm tides. While such measures might be considered adequate and necessary in the short- and mid-term, they can have the potential to merely delay risks or make them even worse. This is the case if in 80 or 100 years these flood prevention barriers turn out to be too expensive or ineffective, whilst exposed assets have been accumulated in the meantime in what had been considered to be safe areas behind sea walls.


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Which areas will be most affected by climate change risks?

Garschagen: We see – and this, too, is a core finding of the report – impacts in all areas. We are witnessing strong impacts in all regions of the world and in all sectors, such as infrastructure, settlements, food security, agriculture, or fishing.

An example of a hotspot for climate change risks, with very problematic interactions between them, is the Arctic. In this region, we’re seeing above-average changes in the climate as well as above-average impacts. This includes thawing of the permafrost, with the huge risks this entails for infrastructure such as roads and housing developments. It also includes particular risks for indigenous groups, for whom the thawing of changes in sea ice jeopardizes a whole way of life that includes for example hunting on the ice.

We’re also seeing strong effects in many developing countries and emerging economies, where a high level of socio-economic vulnerability is combined with low adaptive capacity. Many areas of Sub-Saharan Africa are affected by several climate impacts at once – aridity, drought, temperature changes – and have comparatively little in the way of resources for dealing with them.

What leeway do we have left in terms of adaptation?

Garschagen: The report shows that adaptation can be effective, but that it cannot eliminate all risks. Particularly in the case of warming pathways that lead us to a temperature increase of 3°C or even more by the end of the century, we see clear signs that our current adaptation efforts – at least in its current guise – will be nowhere near enough to offset the increase in risks.

Even if we manage to keep warming below an increase of 2°C, the report shows that the limits of adaptation will be reached in many regions of the world, especially those with low adaptation capacities. Incidentally, it’s a similar story in ecosystems such as in many warm-water corals. In some cases, we’re already reaching the limits and we can see that adaptation will no longer be capable of fully offsetting the risks.

And when the limits of adaptation are reached?

Garschagen: Risk assessments indicate that over the course of the century there will be major species extinction, with species no longer able to adapt to the changes in things like precipitation, temperature, and shifts in vegetation. The report shows that we can remain within these limits of adaptability if we manage to keep temperature increase to 1.5°C or 2°C. In a world that is 3°C or 4°C hotter at the end of the century, however, we will shoot past these limits.

What conclusions should be drawn from the report?

Garschagen: There are two main conclusions, as far as I can see. Firstly, we must press ahead with climate change mitigation in a swift and effective manner. Ideally, the goal should be 1.5°C, but we must make sure that we limit temperature increase to 2°C at the very most. And we should avoid so-called overshoot pathways, as the report demonstrates. The idea behind overshoots is that we can allow ourselves a higher level of warming for some time before bringing it back down again, as we currently do not yet have sufficient mitigation solutions for instance around carbon sinks, but hope to have these in place in the latter half of the century. But: This is a very big gamble on the future – who knows whether we can mobilize sufficient political will and technological solutions in the future. In addition, the report clearly shows that even with limited overshoot there will be massive and in many cases irreversible impacts. The melting of glaciers or sea ice is a point in case and such effects need to be avoided, also because they will trigger feedbacks in the climate system and make a return to lower warming levels more difficult.

Secondly, climate change mitigation is only part of the answer. We need to also increase our investments in climate change adaptation, as some risks are already unavoidable and irreversible. A certain sea level rise is already baked into the system. We need to adapt to this change in advance, while thinking about the problem in a much more systematic and integrated manner than we have done so far. Our climate adaptation efforts to date have been too superficial and reactive. This will lead us into trouble, because adaptation has long lead times, as the report makes abundantly clear. The creation of a new, more effective land use plan for a coastal city and the construction of large regional irrigation infrastructure have lead times of 10 to 20 years in some cases – these are projects we need to tackle early.

Is politics on the right path here?

Garschagen: We’re seeing a lot of plans for adaptation and many countries have drawn up national adaptation strategies. However, the literature shows that implementation often lags far behind the political announcements. We’re therefore seeing adaptation gaps across sectors and regions. Existing plans and strategies need to be implemented more emphatically. In addition, we need to get more explicit about long-term goals for adaptation. Difficult choices have to be made, for instance regarding the cost-sharing within societies. Such issues need to be addressed and should not be delayed further. One finding of the report is that this is not working well enough at the moment.

Interview: Monika Gödde


Prof. Dr. Matthias Garschagen is Chair in Human Geography and heads the Teaching and Research Unit for Human Environment Relations at the Department of Geography at LMU. He is one of the lead authors of Chapter 16 of the latest assessment report by the Intergovernmental Panel on Climate Change (IPCC), which summarizes and assesses key climate change risks and adaptation capacities and limits. Garschagen was also among the researchers who – in the final stage – went through the twenty-page Summary for Policymakers line by line with delegations from 195 countries until it was adopted. Ultimately, this resulted in a publication that is globally recognized as representing the current state of scientific knowledge. The IPCC has also appointed him as a core author for the synthesis report of the sixth assessment cycle, which is scheduled for publication in the fall.

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