2015•04•21

An interview with Dr. Matthias Garschagen, UNU-EHS senior expert, on why we need to look at complex systems to understand current and emerging climate threats and on his role at the American Association of Geographers (AAG) conference.

You are going to the Annual Meeting of the (AAG), what is happening there?

Dr. Matthias Garschagen: The AAG meeting covers geography topics from across the board but has also become a leading platform in the field of global change that allows researchers from all directions to come together and discuss emerging topics of high importance. It’s therefore a great opportunity to jointly develop future lines of research and debate the topics of tomorrow.

Why is this year’s conference important for you?

MG: For the field we’re working in – global environmental change – 2015 is a big year. World leaders are expected to sign a new climate agreement in December and the UN is defining the sustainable development goals, where climate change plays a central role. Also the recently adapted Sendai Framework for Disaster Risk Reduction has many linkages to global climate change. The risk of disasters is in many respects related to climate change, if you think about cyclones or floods, for example. Hence, the reduction of disaster risk is a prime policy concern that also relates to climate change.

At the AAG meeting, you convene a session on tipping points, can you explain this more?

MG: A tipping point is when a system abruptly shifts to a new trajectory or to a new configuration. We do not need to dive too deep into the theoretical details but a system can in this context be thought of as a set of elements and processes that interact – often in a very complex manner – and by doing so form an integrated whole. In that sense, for example, a city or a region with a particular land-use and farming pattern can be considered a system – and of course any sort of ecosystem for which we use this term regularly. Now, climate change might have such effects that many of these systems are fundamentally altered. If this happens abruptly, it could be considered a tipping point.

So is a tipping point reached when a system is exposed to a stressor and at a certain point can no longer deal with the stress and tips over?

MG: Yes, that could be the case. So try to think of a gradual process but which suddenly accelerates at a certain point in time or experiences an abrupt change – and you try to understand what is happening, what has caused this change, and what could be its knock-on effects. The tricky thing is that in many cases these sudden changes are not foreseeable; we may even have difficulties understanding them afterwards.

What could be a climate change related tipping point?

MG: On the global level we can for example look at global atmospheric and ocean systems, particularly with regards to their circulation. For example, in the Arctic colleagues have analyzed the effects of changes in the salinity levels of sea water, that is, the concentration of salt in the water, due to the increasing amounts of freshwater from snow and ice melt. The system might be able to buffer this change up to a certain point but then could tip over and experience an abrupt disturbance, with far reaching consequences for global ocean circulation and even climate conditions.

What could this result in?

MG: That’s what people are trying to find out. For our work on vulnerability and adaptive capacity, we focus on how these tipping points, these abrupt changes in climate systems, can lead to abrupt changes in impacts for people.

Then we can ask how communities can adapt to these abrupt changes and whether there are maybe also tipping points in adaptation processes and adaptive capacities. This dimension is largely neglected to date. We need to ask whether, at certain levels of impacts, people will no longer be able to adapt or will need drastically increased resources for adaptation, which might exceed the capacities of many communities.

What could be tipping points in adaptation then and why are they important to consider?

MG: Let’s say you have a dyke system that is designed to withstand a 4 meter storm surge. At the same time let’s also assume that this system has some buffer built into its design. Hence, even if the intensity of expected storm surges increases to, say, 4.5m due to climate change, this will not pose a major problem. The given dyke may still be able to accommodate that, if you apply some minor improvements and invest in proper maintenance.

However, if the intensity of potential storm surges increases beyond the threshold of 4.5m – in this example – you might be confronted with the need to retrofit the entire dyke system as a whole. This may mean moving from intermittent maintenance to tearing down the system and building a new one or increasing the entire dyke by 1 or 2 meters. It is quite obvious that this would require an entirely different level of input resources. Hence, a gradual change in the storm intensity might translate into an abrupt tipping point in the adaptation process. Once you start thinking this through, there are quite a few examples for such adaptation tipping points. Yet, interestingly they have not yet received a lot of attention.

What do these tipping points mean for adaptation policies and financing frameworks?

MG: Countries which are already seriously looking at climate change adaptation funding often build their budget plans and policies on the assumption that we have a gradual change to which we can gradually adapt and that hence we can spread out financial inputs gradually.

This is a good starting point and has obvious reasons as it makes financial planning and political decision making more manageable. But if you take tipping points seriously – and I would urge to do so – and if you try to understand what they could mean for the required timing and amount of adaptation resources, this also has distinct funding implications.

So you may have a constant demand for funding over 10 or 15 years and then you, for example, need a major redesign of a piece of major infrastructure, which would require a large amount of funding at a specific point in time. Such non-linear distributions are currently not being budgeted for. And while they might level out on the global scale, they turn into increasingly severe challenges the more you move towards the local level, where potential spikes in required adaptation resources cannot be met.

You conduct a lot of field work in Asia, what could be an adaption tipping point there?

MG: In Asia you have rice varieties that are able to deal with different level of salinity (concentration of salt) in the water. So if an area is affected by increasing salinity levels – be it climate-driven or locally caused due to poor land use practices — farmers might at first be able to switch to more salt-resistant types of rice. But when salinity surpasses certain thresholds you have to eventually rethink whether you have to shift away from rice altogether in those areas, which would imply significant changes not only for the affected farmers but for the economic profile of the entire region. These are questions that colleagues and I have been exploring in the Mekong Delta. At the same time the example shows that adaptation tipping points might not only concern hard factors like the change of land use or the dyke system mentioned earlier. Rather, we also need to keep our eyes and ears open to understand the cognitive and cultural tipping points in adaptation processes. Changing away from rice cultivation in the Mekong Delta, for example, is not only about cost-benefit-analysis but also about the deep values and identities that are attached to rice farming. Hence, the question emerges whether and how we also need to see adaptation decisions in connection to tipping points, for instance, in years with particularly severe crop loss due to salinity.

So in your session on tipping points at the AGG conference, what are your objectives?

MG: My main point for the session at the AGG conference in Chicago, which I convene jointly with William Solecki who is lead author of the Intergovernmental Panel on Climate Change (IPCC), is that tipping points need to receive more attention in climate change adaptation debates. Hence, it is time to take stock of our current knowledge and to collect research needs for the future. Do we really understand adaptation tipping points and how they might shape future adaptation trajectories? I would argue not really – at least not well enough to sufficiently inform sound decision making. This year we will take key decisions and some of those will have very long-term implications. To make good decisions, we need to have a thorough understanding of how the system will change over the next years, and how non-linearities and tipping points will not only shape the impacts from climate change but also the adaptation processes.

In Chicago, we would therefore like to bring together leading experts and ask them, “In your work, do you see the tipping points in adaptation processes and capacities, and how can we better understand this conceptually, empirically and methodologically?”

To learn more about the session at the AAG conference and to read the abstract of Dr. Garschagen, please click here.