Intergovernmental Panel on Climate Change

“The window of opportunity is closing”

The latest report from the Intergovernmental Panel on Climate Change (IPCC) shows that we need to act faster to bring climate risks to an acceptable level, say Christian Huggel and Veruska Muccione. We spoke in depth with the two UZH scientists, who served as main authors of the IPCC’s report on the consequences of climate change.
Thomas Gull and Stefan Stöcklin
Adaptations alone won’t fully mitigate the risks of climate change. We can expect there to be heat waves, floods and catastrophic storms. Pictured: Veruska Muccione and Christian Huggel. (Image by Stefan Walter)


In the latest report issued by the Intergovernmental Panel on Climate Change (IPCC) you both worked as main authors. It's been eight years since 2014 when this working group last published a report about “Impacts, Adaptation and Vulnerability”. What are the most important new findings?

Veruska Muccione: The new report places more emphasis on solutions and adaptations to climate change than before. It outlines the different risks and consequences of various temperature scenarios. The goal is climate resilience, meaning that society needs to adapt to and cope with the consequences of rising temperatures. This also applies to nature and the ecosystems that are inhabited and used by humans. The report illustrates the connections between the natural world and humans and also focuses on measures taken in cities that are particularly vulnerable to the effects of climate change.

Christian Huggel: Adaptation efforts receive a lot more attention in this report than in earlier editions. Thousands of studies on adaptation strategies were collated and evaluated, and it turns out that there are now a lot of local initiatives, but they are mostly reactive and not proactive in nature.
The report shows that there is still not enough being done to bring climate risks down to a somewhat tolerable level. This means that we need to be doing so much more in order to hit the brakes on global warming. And we also have to do far more to adapt to current and future climatic changes.
We need transformative measures to achieve this goal, which means that adaptations shouldn’t just be cosmetic, but rather systems need to be changed on a fundamental level.

Could you be more specific?

Huggel: Artificial snow for winter sports is an example of an adaptation that isn’t transformative. It doesn’t change anything on a fundamental level, but instead tries to continue offering something which has proven popular with tourists. In contrast, a transformative approach would involve offering something totally new. But it’s clear that replacing winter sports will be difficult and not something that can happen overnight.

Muccione: Snowmaking systems aren’t a solution for low-lying areas in particular, since it’s often too warm to produce any artificial snow in the first place. This development will only continue to intensify. On top of that, you have the very high water and energy consumption. From a transformative perspective, you have to look at other things to offer tourists and put more emphasis on summer tourism.

You both contributed to the chapter on mountains in the report. What are the global challenges facing mountainous areas?

Huggel: We worked on finding out what action is being taken in mountain regions around the globe. Much is already being done when it comes to water, agriculture and disaster prevention, but it’s still insufficient. What’s needed are synergies between mitigation – meaning the reduction of CO2 emissions – adaptation strategies, and sustainable development. This is the big challenge, since there are a lot of undesirable trade-offs.

Can you give an example?

Huggel: The countries around the Himalayas are facing a lot of challenges because they’re experiencing rapid population growth, but they also need to massively reduce their CO2 emissions. This means they need more renewable energy. The Himalayas are very well suited to producing hydroelectric power. However, if they build up their hydropower capacity with large dams, there are two problems: Since rising temperatures are making mountain regions increasingly unstable, there is the possibility of landslides, which can trigger catastrophic flooding, like what recently happened in India.
Local populations are also heavily impacted when a dam is built, for instance by having to relocate or because of changes in the ecosystem since the water is held behind a dam during the summer. Furthermore, there are social conflicts between locals and the big companies who build and operate these hydroelectric plants.

How can these kinds of conflicts be avoided?

Huggel: Many people in these regions feel marginalized, and justifiably so. These dam projects are often built against the will of the local population. It would be better if the people living there felt supported and assisted. This is often difficult to achieve in reality, however.

You mentioned that one goal is to make ecosystems climate resilient.  Can you explain what you mean by that?

Muccione: Global warming is developing within a certain range, and extreme events have a certain likelihood of happening. But we can’t say exactly what will happen, which is why we work with different scenarios. Climate resilience means that we have the possibility to reduce greenhouse gas emissions, to minimize climate-related risks and the loss of biodiversity, and to achieve the goal of sustainable development.

We can improve our resilience both by implementing major measures and by changing our behavior and making small adjustments. For instance, in the future we can spend more time indoors on hot afternoons, which people in southern countries already do. Or we can increase shade cover on houses and reduce their exposure to the sun so that buildings don’t heat up as much. Here we can learn from people who live in warmer regions. If global warming exceeds 1.5 degrees, we will need additional transformative measures.

Are there good solutions that are also low cost?

Muccione: One example is switching to plant-based nutrition. This has mostly ecological benefits. The switch would reduce CO2 emissions and allow for greater amounts of food to be produced, because plant-based nutrition is less resource intensive than producing meat.

“It's obvious that we need to really pick up the pace of our measures against climate change,” says Christian Huggel. (Image by Stefan Walter)


The IPCC report on the physical science basis of climate change, published last August, showed how important it is to quickly reduce our emission levels. Are we also running out of time for making adaptations?

Huggel: We need to reverse the trend for CO2 emissions this decade – otherwise it’ll be too late. The window for making adaptations won’t be open forever, either. We need to start adapting as soon as possible. Here the report strikes a new tone and warns in no uncertain terms that we can’t waste any time.

There are still residual risks, however. Not everything can be countered with adaptations. There will be heat waves and floods that cause immense damage. Large swathes of land are going to disappear due to rising sea levels, and the damage to infrastructure will cost us dearly. What’s clear is that the higher the temperature climbs, the greater the residual risks.

Does that mean the window of opportunity for making adaptations is closing?

Huggel: Yes. Planning and implementing adaptations takes several years to decades. We can’t just sit around and wait – otherwise it’s too late. Take climate neutrality at UZH, for instance. If we want to achieve our goals by 2030, we need to act now and get started with our planning. Carbon-neutral buildings need to be designed, funded and built. And the buildings will require construction materials, some of which still need to be developed. Adaptations in cities such as green spaces, wind corridors and wind-resistant trees also need time.

What are the greatest risks for Switzerland?

Muccione: Extreme hot spells like in 2003 or 2015 are going to become more frequent. And we’re also going to have to deal with more very dry summers like in 2018. This will impact many different areas: heat will cause health problems for some people, and dry spells will lead to water shortages and increase the risk of forest fires. These changes also endanger certain indigenous plant species, such as native trees that can’t handle hot and dry conditions. And we also have to prepare for the opposite, like heavy rainfall that triggers flooding and landslides. This isn’t something that’s going to occur in 30 or 50 years – it’s already happening.

Are we soon going to be facing situations like the big summertime fires in Sicily or the south of Spain?

Huggel: Drier summers with forest fires are definitely one scenario for Switzerland. But look at places like Australia or California, where the threats are more existential. There are already areas today where forest fires have wreaked immense devastation and that could become uninhabitable due to the fire risk. In some places, the houses that burnt down aren’t even going to be rebuilt. This isn’t one of the scenarios for Switzerland at the moment, fortunately.

What about mountainous areas? Are they going to become so unstable that they won’t be habitable?

Huggel: When it comes to stability in the mountains, there have also been several severe mudslides in Switzerland over the past few years, for instance in Bondo and Guttannen. These kinds of events can force people to relocate, which has already happened in individual cases. Another example is Oeschinen Lake near Kandersteg. If there’s a rockslide and the lake overflows, this could be a huge disaster. These kinds of events could become more frequent in the future. It could also happen that we exhaust our technical possibilities for preventing these events, or they simply become too expensive. This would mean that some areas in the mountains become uninhabitable in the future, even in Switzerland.

Is it possible to say which areas will become uninhabitable due to climate change, for instance in some mountain regions? What are the limits of adaptation?

Huggel: Over the course of the next century, there will be various major regions that become uninhabitable due to the heat. The other big development that will reduce the amount of land where people can live is the rising sea levels. For Europe, for example, we expect that flood damage on the coasts will increase at least tenfold by the year 2100. There are already discussions underway about certain settlements that will have to be abandoned.

Developing countries and emerging markets will be greatly impacted. Is this going to widen the gap between rich and poor countries?

Huggel: Everything is pointing towards climate change making the gap between rich and poor nations even wider. This is because poorer countries have more difficulty affording adaptation measures, for example. Also, in Switzerland we’re not as existentially threatened as countries like India and other emerging markets. It would be naïve to believe that what happens in other countries won’t have any consequences for us, however. The impact will be felt in migration as well as in supply chains and food. Geopolitical instability is also a risk that becomes heightened due to global warming.

Already back in 2009 at the Copenhagen Climate Change Conference, there was talk of establishing a fund that would receive 100 billion dollars per year to finance climate protection measures. Is that enough? 

Huggel: These funding goals haven’t yet been reached. And the fund is a point of contention. Industrialized and developing countries were also arguing over it again last year in Glasgow. It’s not only about money, but also about the measures that receive financing – resettlement, for instance.

Let’s switch over to climate policy. Is Switzerland doing enough to combat climate change?

Huggel: It’s obvious that we really need to pick up the pace. Nevertheless, all important political forces now acknowledge the reality of climate change. People want to do less or more depending on their party. The Green Party has the most ambitious climate plan. It would be compatible with the Paris Agreement but very hard to implement.

Coming back to India, if we’re not ready to take serious steps even if they’re more expensive, what should countries like India think when they have historically been less responsible for global warming and when they have a much lower per capita emission rate than us? We work in these countries and sometimes the discussions become embarrassing when I have to explain that wealthy Switzerland rejected a tougher CO2 law because it would have increased the price of petrol by a few cents.

What’s the solution?
Huggel: We have to do a lot more, mainly when it comes to transforming our society. As we’ve seen during the pandemic, it’s crucial to get the people on board and develop a common vision with a plan that is supported by a majority of the population. We would also need to do the same with climate change – with a great deal of enthusiasm.

Does Switzerland lack a coherent and credible strategy?

Huggel: It's difficult for the Federal Council if they don't have the support of the parties and the population. This is why it's important to enter into a dialogue with people and make sure they are well informed. This includes the scientific community making itself heard. A new dialogue between researchers and parliament has been launched, where it's not about lecturing from our side, but rather having a conversation, for instance about what the limits of adaptation are.

“I believe that researchers have a responsibility to help transform society in a climate friendly way,” says Veruska Muccione. (Image by Stefan Walter)


Do you do anything personally to reduce your carbon footprint? Like avoiding flying to academic meetings, for instance?

Muccione: I almost never fly and welcome the university’s initiative for reducing flights. The pandemic has shown us the value of digital communication. With that said, it’s sometimes still important to see your project partners in person. And high-speed internet doesn’t work everywhere. I believe that researchers have a responsibility to avoid flying whenever they can and to help transform our society in a climate friendly way.

Political discussions primarily revolve around giving things up and how much things cost, but less is mentioned about the opportunities for transformation like efficient sustainable energy or more environmentally friendly food. This leads some people to adopt a defensive stance. Might we need a more positive narrative?

Huggel: I understand that some people are scared and would warn about underestimating this risk – otherwise we could face backlash. From this perspective, it’s tricky if politicians paint a rosy picture and downplay the problems. We’ve discussed losses and damage, things that can’t be whitewashed. But it’s also correct to show the positive sides. This is particularly true for Switzerland, where the development of new technologies opens up enormous opportunities. There’s huge potential here, and it would actually be unacceptable not to seize this opportunity. Switzerland should kick things up a notch – otherwise we’ll miss the boat.

Muccione: It’s up to the scientific community to show the evidence for climate change and propose actions that should be taken. The latest IPCC is a document with a strong message, particularly for politicians, and it shows what should be done and where. Taking action requires entering into a dialogue with researchers, politicians and the general population.

What has it been like for you to work on the IPCC report?

Muccione: For me it was the first time being involved in the IPCC report. The work is really intense and I learned a lot, also from other fields.  It’s extremely interesting to be in such close dialogue with researchers from other cultures from all over the world. The time commitment is at times very intense, however, and doesn’t leave much time for your own research.

Is it an honor to be able to contribute to one of the IPCC's reports?

Huggel: Yes, there’s a great deal of prestige that comes with working on the report. You have to apply, and the selection process is very competitive.

Christian Huggel is a professor and research group leader in the Department of Geography. His research chiefly focuses on the consequences of climate change, climate-related risks and adaptations in mountain regions and high alpine zones around the world. Since 2010, Christian Huggel has served as a main author in Working Group II of the UN's Intergovernmental Panel on Climate Change.

Veruska Muccione holds a PhD in astrophysics. Since completing her dissertation, she has worked on climate risk models and carbon reduction strategies. She has been researching climate-related risks and adaptations in the Department of Geography since 2011. From 2013 to 2016, she served as a coordinator for the University Research Priority Program Global Change and Biodiversity. Veruska Muccione has been a main author in Working Group II of the IPCC since 2019.

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