Hopes and Fears of a Climate Scientist. Impacts and Adaptation

It is a good time to reflect on our hopes and fears about climate change. As our leaders come together to negotiate climate action, the outcomes will set a path for how the climate system will evolve and how much change our economies will have to navigate over coming decades. I am going to do this from a 35-year-long perspective. Some of you might just be starting to think about your careers or about how climate change could affect your lives and future dreams. I am looking at it from a point of view of someone who is approaching the end of his career, reflecting on how much things have changed during that time, and all the climate impacts I have seen first-hand. And I also want to share with you some of my hopes and fears for the future. I am going to do it the other way around, I am going to start with some of my major concerns first, and then end with my hopes, so we all arrive at a more optimistic place, despite what is, undoubtedly, a very challenging future ahead. 

Let me begin by recalling one of the low-income settlements, in Accra, in Ghana where I have been working. When we think about such communities, we cannot fail to imagine the consequences of climate change. You can almost feel the heat radiating from the metal roofs here. This is very apparent, yet beneath the surface there are also concerns about clean water supplies, sanitation, and flooding in these communities. As I will be explaining later, these kinds of places are really on the front line of climate change. The communities here are already experiencing extraordinary temperatures; yet projections from climate models suggest that these conditions will get even more extreme in years to come without significant action on climate change. 

Now, I mentioned I have been working in this research area for a few decades and over that time, I have seen many extreme events first-hand. I have seen flooding on a number of continents on a huge scale. I have seen too little water, the consequences of catastrophic droughts for people’s livelihoods and ecosystems. I have seen how rising temperatures have begun to affect ecosystems, in rivers and fresh waters. I have begun to see and experience, first-hand, what it is like to move and work amongst people in these extraordinarily hot urban environments. So, that gives me a real sense of the urgency of climate change. I guess you have had similar experiences too where you had direct contact with some form of climate extreme. But I have also looked at these issues with my researcher hat on, but my lifetime is just a small speck in the continuum of how climate has evolved over decades and centuries before, and so a lot of my work has been to deal with how we can understand the present risks of floods and droughts in the context of long-term climate variability and change. 

For example, my index of flooding across the UK shows that there have been decades with lots of floods, decades with few floods, and we are actually in a very flood-rich period at the moment. I have also been concerned about how we can estimate the impact of climate change in places where there are very little data and institutions are fragile, like Yemen; their people are already suffering from a whole host of issues, both climatic and non-climatic. So, what kinds of information can we bring together from satellites, from ground-based measurements, from models, to estimate how climate change could impact such vulnerable people and ecosystems? I have also been developing tools, like the Statistical Down-Scaling Model (SDSM), to enable other researchers, in other places, to evaluate these impacts for themselves by looking into the future, to think about how the climate might change locally, how different adaptation measures may perform, with or without climate change, to really help us pick the best solutions, given the uncertainty in the future. As I have mentioned before, I am doing more research now in the urban environment: a key front line in terms of global temperature change, plus impacts on urban infrastructure and people’s livelihoods. Later, I am going to concentrate more on some case studies to illustrate some of these points. Let me just share with you three of my working principles, which I also hope will chime with your own thinking.

Graphic 1. Representation of the statistical downscaling methodology

Elaborada por Ángel Llera a partir de un modelo del autor.

Some Ideas that Guide Our Work 
First of all, I would like to say that the data and our ability to monitor the environments is one of our key assets for managing future climate risks. Without the ability to monitor we are unable to manage. We have got to know where we have come from, where we are now, and where we are going in the future. So, protecting, observing networks or things that are measuring rainfall, river flow, the condition of glaciers, the state of soils, and of ecosystems, wetlands, sea levels—these are critical data sets that we are going to need even more in the future. With these data sets we can track emergent risks, as in the case of temperature changes in rivers and how that could be managed by, for example, planting more trees along the river side, creating more shaded habitats to protect fragile ecosystems from rising water temperatures. So data are a crucial asset for the future and essential for monitoring to manage. 

Second, I think that the ability to look into the future—even if it is just the next season is an essential part of the toolkit. A lot of my research has focused on how we can take information, for example, about temperatures in the Pacific Ocean and how that affects weather patterns over coming months, seasons and even years, and how we can translate that knowledge into things like changing river flows, coming into key pieces of infrastructure, as we can see with the largest hydro-powered dam in Tajikistan. In this case, for example, we can look at the central Pacific Ocean and we can see cooler temperatures during “La Niña”. That tells us that there is a higher than average likelihood of low flows or drier conditions in seasons ahead, which enables hydro-power managers to operate the dam in ways to preserve stocks or to manage the potential for hazards in conditions where there are expected higher flows. So, that ability to look into the future is a powerful tool now and it is going to be an essential tool in the future. Forecasting is here to stay as part of our solution set for climate change, helping us to adapt to the uncertainty of future climate change.

And then thirdly, there is already lots of really fantastic research on climate change impacts and adaptation measures out there, but the gap is in translating that knowledge into practice, such as guidance that engineers and managers can apply in their local circumstances. So I have devoted a significant part of my career to the task of taking the science of hydrology and climate change, and seasonal forecasting, and turning that into guidance, even recipes, or even an Excel tool where people can simply adjust some numbers in a spreadsheet to help manage a particular risk or design something to withstand future climate-driven floods or droughts. There is going to be a huge demand for this sort of approach over coming decades. 

For those of you who are thinking about where your careers might take you, I think this is a really exciting opportunity where we can bring together the best available science with workable solutions on the ground. So that is a little bit about me and what makes me tick. Before I go into my hopes and fears, I would just like to share with you this quote which I think really captures my attitude. On the one hand, it might be tempting for us to despair about the future, but I think that a healthier way to go about this is to adopt an attitude like that of Maya Angelou who said: we hope for the best, we prepare for the worst, and we are not really surprised about anything that could happen in between. I believe these sentiments give us a good balance of hopes and fears, as well as being prepared. I am going to show that way of thinking with some examples. 

Fears 
Let’s begin with some of my key fears, and I am just going to give you three for illustrative purposes. Number one on my list is preparing for the loss of snow and ice. This is a given. This is already happening all over the planet. The vast majority of the Earth’s ice stores, and ice sheets, are in retreat. Going back to my first-hand experience, when I was a student, I went to the Swiss Alps and took some photographs in 1986. And then, decades later, I found myself in a lecture theatre telling students—who were the same age as me at that time, but 25 years later—about the same glacier. In the time between my visit and teaching the students, during that 25-year period, this glacier has retreated 400 meters. So, in half a working career, 400 meters of ice has gone from this little glacier. Now if we scale that up across the whole of the Alps, across the whole of the planet, that is a significant amount of ice and melted water that is going into the ocean and contributing to sea level rise. But it is also really significant in terms of the ability of communities in mountain areas downstream; their ability to generate power, their ability to access clean water, and their ability to produce food that depends on water for irrigation. There is a growing concern amongst hydrologists of the fate of these so-called water towers—these big stores of snow and ice in the Himalayas and elsewhere—that, ultimately, sustain the livelihoods and the well-being of nearly two billion people on the planet. It is a huge number of people who depend on those snow and ice stores, for their livelihoods, their energy, and their water needs. So, what happens with those great water towers really matters for a huge proportion of the human population. 

As I mentioned before, my second concern is a need to prepare for sea level rise. This is happening because of that melted water from the upstream snow and ice stores as well as due to the thermal expansion of the oceans. Sea level rise is going to continue not just to the end of this century but for centuries to come, so I have deliberately made some projections for the year 2200. You can see that, depending upon the ability of our leaders to negotiate emission cuts, we can have a lower bound and an upper bound projection for the amount of thermal expansion or the changes in ocean currents, melted water from glaciers and great ice sheets like the Arctic and Greenland, and also from local factors such as storm surges. So, there is huge uncertainty, which is partly scientific but partly down to whatever our leaders can negotiate in coming years about cutting emissions. The year 2200 might seem like a long way ahead, and it is, but there are certain types of infrastructure such as new nuclear power plants where you have to think that far into the future because of the long operating time scale of the facility and maybe the need to store spent fuel on that same site. So, it has got to be secure maybe even to 2200. Preparing for sea level rise is a really key concern that faces many countries and megacities, especially those with significant populations at or beneath sea level. 

Thirdly, we need to prepare for the almost unavoidable rise in deadly heat in cities. As the global mean temperature rises, as cities expand, they have their own temperature warming effect. If those conditions get so high, combined with humidity, we can have conditions that are lethal to millions of people located in some of the largest cities—in the tropics, especially. There are maps showing those cities that are already experiencing heat stress that is lethal. Then, you can see the extra cities that become potentially dangerous with a given amount of global warming. With one and a half degrees, some cities in West Africa begin to experience deadly conditions. In the most extreme scenario of four degrees of global warming there are even more cities at risk. What is clear from studies like this is the large number of cities, especially in southern and southeast Asia, which are really on the front line of this concern. 

If we just think about where on the planet cities are growing most rapidly, such places are adding to the concern. Preparing for deadly heat is a really significant task that lies ahead. And also, we must not be surprised by unusual extreme events, so we have to begin to imagine events that are either super rare or have yet to be seen. For example, in another study, we looked at the possibility of a hurricane being followed by a heat wave. Why would we do that? Well, a hurricane has the potential to knock out power grids, and with it, air conditioning. If you take out air conditioning for many key cities in the world, they would be without their primary defense against extreme temperatures. A hurricane with extreme heat could lead to very difficult, even lethal circumstances, in those parts of the world touched by storm tracks. For the present condition at one and a half degrees of global warming to two and a fourth degrees of global warming, and, in the worst case scenario, with four degrees of global warming, we could expect to see these kinds of events more than once every year in the future. That is something rather somber to think about for cities in vulnerable regions. 

We must not forget that there is a whole host of other non-climatic risks, as the present pandemic has taught us. We cannot just focus all of our efforts on climate change. We have to look at climate change alongside other key risks that humankind faces over coming years, and many of the risks identified are actually amplified by climate change. Livelihood crises could be exacerbated by extreme weather and climate change. Loss of biodiversity or resource exploitation could be exacerbated by climate change. So, we need to look at climate change alongside this host of other risks that our leaders have to think about and make contingencies for. Those are the things that I am most concerned about as someone who has worked in this field for quite a few years. Now, let us put a more positive spin on things. Let us think about the hopes for the future. 

Hopes 
One of the hopes at the top of my list is that negotiations and emission cuts will be sufficient to avoid tipping points whereby major changes in the climate system could occur. For example, if global warming continues to the point where permafrost and tundra thaws, that could release significant amounts of methane into the atmosphere and exacerbate global warming. Likewise, if climate change leads to the large-scale die-back of the Amazon rainforest, those carbon stocks could be released into the atmosphere and exacerbate global warming. So my big hope is that we do not get to one of these tipping points. We avoid what could be some very nasty, rapid changes in climate if some of these tipping points are crossed. My hope is that we do not get to that. 

My second hope is that, as we think about climate action to drive down emissions, we also think about continuing to achieve and deliver on development goals. The 17 Sustainable Development Goals (SDG) overlap with plans for climate action. In some cases, the sustainable development goal is aligned with climate action, and you get a win-win situation. Sometimes, they might be playing in opposition to one another. For example, if we look at SDG 6, which is around clean water and sanitation, and 6.6 is about protecting and restoring water-related ecosystems. By containing the amount of climate change, we are protecting key ecosystem functions. It is a good thing that the actions are working together, but some climate actions —such as replacement of land with biofuel crops for renewable energy—could have an effect on water, so they might be in opposition. We have got to be smart about how we achieve climate action and, at the same time, deliver development advances to many people who still lack the basic necessities of life: secure livelihoods, food and water, and so forth. 

Thirdly, my hope is that we can see all of these things as a whole, bringing them together, so we do not look at water in isolation of health or of ecosystems. This means that we have to strive for future human and natural systems that are resilient to climate change but also improving people’s public health, providing them with quality housing, high quality infrastructure, sustainable livelihoods, and social protection. 


Some examples 
How do we bring all of those things together whilst achieving these adaptation goals? That is a key question. Now in the remainder of this piece, I would like to just share with you some insights we have gained from a case study which is about managing some of those threats: threats from rising temperature in one of those front-line communities I talked about earlier. We know the historic pattern of extreme humid heat measured at weather stations all around the world. There are places where conditions are already approaching or exceeding lethal temperatures. You can see the concentration of those in southern and southeast Asia, and, increasingly, in West Africa. Those are the places where we have really got to keep a close watch in terms of this emergent threat. But I am emphasizing here that the meteorological data on which we have relied for so long is about outdoor temperature conditions. 

This does not translate into the actual temperatures people experience indoors, where they spend their time sleeping and sometimes working. We need to think in different ways about how those rises in temperature might translate into changes in conditions inside people’s homes and workplaces. I am going to refer to two cities in Ghana: Tamale in the north and Accra in the south. There is a standard weather station in Tamale in Ghana. The compound for the weather station is nothing like the conditions that we see in a typical urban environment; yet the data derived from stations like this are being used to track climate change and to monitor rising threats from high temperatures. In fact, we are measuring conditions inside a Stevenson screen using thermometers and tiny tags, to keep track of temperatures almost on a second by second basis. What we were interested in, in this particular project, was how indoor temperatures have changed, what are the key factors affecting indoor temperatures, and what are the things that households and business owners can do to manage high indoor temperatures as a primary adaptation step. To do that, we put 130 or so of these tiny tags in and around people’s homes, in and around workplaces and other public spaces. We also recorded lots of information about the building type, the roof materials, the wall materials, the dimensions of the building, the number of occupants, and the use of the spaces. We recorded all of that information to empirically understand the factors that are controlling indoor temperatures. 

Some of the results from those field observations reveal extraordinary temperatures. In one living room, a peak temperature of more than 45° C was registered. Even in some of the cooler buildings, the really large buildings, temperatures inside routinely exceed 30° C. In smaller buildings in typical single-story compounds, temperatures well above 40° C have been registered. It is not just in people’s homes! One temperature trace shows what we measured in a maternity ward and in a children’s ward inside a hospital, compared with the official record recorded at the weather station at the airport. The peak temperatures in this case are roughly the same, but unlike at the airport, the conditions during the night within the hospital are much more extreme than is suggested by official records. We are seeing that temperatures do not actually fall below 30° C at night in both wards. Through gathering all of these data, we wanted to look at how the building type, the building materials, the presence of ceiling insulation, presence or absence of shade from trees and other vegetation or other buildings, all affect indoor temperatures. We also recorded the types of measures that occupants might take to manage these really extreme temperatures. Some of the data show the effect of roof material. Traditional roofing material with thatch is used for several structures, and in several rooms. The thatch keeps temperatures lower during the peak of the day, but it also elevates temperatures at night. There is a trade-off here. Do you want to have cooler temperatures during the day? Or do you want cooler temperatures at night, which will affect your ability to sleep? If you have a metal roof, you can experience much higher indoor temperatures during the day, but the temperatures drop much more during the night. So, again, it is a trade-off. You might be more comfortable at night, but during the day some of these conditions are truly extraordinary. 

The conditions inside the room are hotter than the official conditions at the recording station, the weather station. The difference between a room that has an insulated roof and one that does not is important. During the day, the uninsulated roof is much hotter than the insulated roof. But, during the night, the opposite happens. The uninsulated room is cooler, and the insulated room is hotter. So, again, there is a trade-off. What is the appropriate action on a home-by-home basis in terms of protecting the occupants from the extreme indoor temperatures? We put all of those factors into a statistical model to see the effects of the location of the city (whether it was near the coast), whether it was in the north or the south—the size of the building, the wall type, the roof type, whether or not ceilings were insulated, whether the house was shaded, whether the occupants had fans or air conditioning. We put all of those factors into a statistical model and it showed that the key thing, the most influential factor, is actually the roof material, and whether or not the ceiling is insulated. 

In the second phase of this project, we are setting up test cells to examine what is the best material, the best design of the roof—in terms of overhang, its reflectivity, and other factors—to manage indoor temperatures as best as we can and to do that in an affordable way. Keeping in mind that these communities have limited resources, we are looking for low-cost, affordable solutions that deliver the maximum benefit on a home-by-home basis. Hopefully, over the next year or so, we will be able to report on those findings. We are really excited about this project because it has adopted a low-tech approach in terms of the data gathering, and yet it is providing—hopefully—some really useful insights that can be returned to the communities and the planners in terms of how to build, design retrofit buildings to improve the temperature conditions inside at low cost. That is what we are trying to achieve here. 

Just some closing remarks. It is fair to say, and we all recognize, that there are significant climate-related risks ahead. And, from my point of view, the key ones surround water, food, and energy security. Often, we have looked at those three in isolation, whereas in reality we need to look at how they play off against one another. We need to have an integrated strategy for managing those risks. I have given you just a sample of some of the risks that lie ahead and, in the frontline communities, the ones who are most at risk, are perhaps most exposed to climate change, those who are in mountain regions, dependent upon water towers for their livelihoods, food and water security. Other vulnerable communities are in large and growing cities that are experiencing extraordinary temperatures, and sometimes flash flooding, which is another story. Also, communities in coastal zones and their infrastructure, which are going to have to contend with unavoidable sea level rise. 

But to end on a positive note, I think there is a significant opportunity here for climate science, the climate impacts-and-adaptation community, to offer up sensible and pragmatic solutions that are affordable and can deliver benefits now such as forecasting systems, low-cost retrofitting of homes, that will continue to deliver benefits into the future and contribute to sustainable development of some of the most vulnerable communities. 

---