Researchers from the URV answer key questions about the consequences and challenges of the increased frequency and intensity of heatwaves for ecosystems, infrastructure, health, public activities, tourism and agriculture

Enric Aguilar, researcher at the Department of Geography

Director of the URV’s University Institute for Research in Sustainability, Climate Change and Energy Transition, Enric Aguilar is an expert in climate data.

How do rising temperatures affect sea level?

The rise in temperatures across the planet will affect sea level through two mechanisms. The first mechanism is through the melting of continental ice sheets, which will flow into the ocean and raise sea level. And the second and main mechanism is the thermal expansion of water which, like any liquid, increases in volume when its temperature rises. Projections for the Mediterranean region by 2050 suggest a rise of 23 or 24 centimetres if we do what we are supposed to mitigate it. But in the worst-case scenario, it could be 30 centimetres.

What are the consequences?

It has an obvious impact on the loss of ecosystems and on infrastructure. And this is relevant to the Tarragona region, where we have a really sensitive natural and socio-economic ecosystem in the form of the Ebro Delta. There is a real danger of a loss of part of the Delta’s territory because, in addition to sea-level rise, it is also affected by a lack of sediment inputs upstream and a consequent loss of the deltaic mass.

Between 23 and 30 centimetres is a lot for infrastructure located near the sea, such as the T-340 road in the Delta, the B-10 and the coastal ring road in Barcelona. It is also significant for rail infrastructure, such as the Tarragona–Barcelona line and the Masnou line. On top of the additional maintenance requirements, they will also find themselves compromised by rising sea-levels. The overtopping of harbour breakwaters and the loss of beach land must also be taken into account.

Has there been a change in the behaviour of storms?

We need to think not only about the rise in the average sea level but also about what happens during extreme events, such as Storm Gloria. Such storms tend to push waters inland and will cause even more damage if the starting sea level is higher.

---

Ferran Grau, researcher at the Pre-Departamental Unit of Architecture

A member of the URV’s Urban Research Centre, Ferran Grau specialises in architectural and urban adaptation in response to the effects of climate change.

How can architectural design and urban planning intervene to mitigate the effects of high temperatures?

The consequences of what we are experiencing today have their origins mainly in the 1960s and 1970s, when construction often took place very close to the sea, on the banks of rivers and streams and in wetlands. Therefore, the first thing to do when intervening in what has already been built is to analyse where it has been constructed. Afterwards, it will probably be necessary to deconstruct or de-pave and, at an architectural level, adapt these buildings to reduce energy demand, mainly by insulating them well or integrating passive climate-control systems.

And when it comes to building from scratch?

When we have to work in brand-new locations, the first thing we must do is study them thoroughly, to understand, at a territorial level, their relationship with infrastructure and how we access them. So, if we have to engage in newbuild, we must do so by taking into account passive climate control systems that reduce energy demand, and avoid paving the ground or, if we do, make it as permeable as possible. And above all, in our climate, water management is very important, both in existing built areas and in newbuild areas, due to climate change.

---

Indira Paz, researcher at the Department of Biochemistry and Biotechnology

A member of the Food, Nutrition, Development and Mental Health research group, Indira Paz specialises in the impact of diet and lifestyle on cardiometabolic health and mental health.

How does the rise in temperatures affect people’s health?

With the increased frequency of heatwaves, our bodies have to adapt to maintain a stable body temperature. And this increases the risk of dehydration, heatstroke, physical exhaustion and also mood changes (becoming more apathetic or more irritable).

Which groups are at the greatest risk?

People with chronic illnesses, such as diabetes or hypertension, are at greater risk of these heat-related consequences. This also includes children, who forget to drink water when they are playing, and older adults, because as we age we lose our sense of thirst, so that by the time we feel thirsty, we are already dehydrated.

How should we stay hydrated?

It is important to have ways to stay hydrated throughout the day, as it is better to drink small amounts of water constantly. We can also use water-rich foods: fruits like watermelon and melon, or vegetables like cucumber, which provide us with water and help us stay hydrated. It is preferable to eat foods such as cold soups, like gazpacho, rather than large, high-fat meals because they are harder to digest and therefore produce more heat.

And what about physical activity?

For those who want to do some physical activity, it is important to remember that it is preferable to do it early in the morning or late in the afternoon, when temperatures have dropped a little, to stay hydrated and to wear light clothing to avoid overheating.

---

Òscar Saladié, a researcher in the Department of Geography

Dean of the Faculty of Tourism and Geography and member of the Group for Territorial Analysis and Tourism Studies at URV, Òscar Saladié leads a new line of research on adapting human tower building events to climate change.

What adaptations need to be made by outdoor public activities such as human tower building events?

All outdoor activities are subject to the weather and, therefore, to the rise in summer temperatures and to a greater frequency and intensity of heatwaves, largely due to climate change. Therefore, in the face of an increased likelihood of adverse weather conditions and their coinciding with the celebration of events such as human tower building events, organisers must adapt their activities to the new climate reality. How? For example, by changing the schedule: if the activity takes place during the hottest part of the day, when temperatures are at their highest, it should be moved to the early morning or late afternoon.

If this is not possible for sociocultural reasons, another option is to create more shade and, obviously, there must be a constant supply of water, both for the human tower builders and for the attending public. It is a matter of using common sense: not exposing yourself excessively to the sun, staying hydrated, covering your head, etc. to reduce the risks of negative health consequences.

---

Anna Boqué, a researcher in the Department of Geography

A member of the URV’s Centre for Climate Change, Anna Boqué is an expert in climate services and adaptation to climate change in different sectors.

Are tourist destination preferences changing?

Global temperature changes affect tourism because tourists try to seek out the best possible conditions for their holidays, as they are a time for enjoyment. Consequently, it is no surprise that tourist destinations that were once optimal for comfort in July and August are no longer so.

This change in temperature may cause tourists, on the one hand, to seek cooler destinations such as countries in northern Europe, the northern parts of Spain or mountain areas. On the other hand, they may to try to avoid July and August, which would have the knock-on effect of extending the tourist season into spring and autumn.

---

Míriam Lampreave, researcher at the Department of Biochemistry and Biotechnology

A member of the Viticulture Research Group at URV, she is an agronomic engineer specialising in viticulture.

How do heatwaves affect crops?

We’re no longer talking about peaks, but rather heatwaves during which temperatures climb to 35 to 40 degrees Celsius for several days. On top of that, three years of severe drought have resulted in water deficits. Heatwaves affect both the fruit and the plant. The farmer is concerned with both the qualitative and quantitative impact: how their yield will decrease and what its quality will be. But in the long run, if this thermal stress persists and repeats, it can lead to the death of the plants.

In addition to all this, changes towards a climate with higher temperatures and lower humidity have exacerbated the impact of pests and diseases and have e favoured the emergence of new ones in areas where the optimal conditions for their development did not previously exist. This is the case with greenfly and downy mildew affecting vines, which have increased in severity, as have olive fly and various fungal diseases in horticultural crops.

What about grapevines, specifically?

The grapevine is a drought-resistant plant and has strategies it already uses to combat these situations. However, when the situation becomes very extreme, there comes a point when it can no longer fight or adapt and a process of deterioration begins at all levels. We have now been in this situation for several years.

Some of the varieties are already beginning to be severely damaged because the plant halts its activity and diverts all its resources into trying to survive when temperatures are very high. This means it doesn’t grow, the grapes don’t ripen or increase in weight and, consequently, we end up with unripe grapes, low yields and unacceptable quality.

What tools do winegrowers have to tackle this situation?

One option is to move vineyards to colder areas. In fact, vineyards used to be found all over Catalonia, including in mountainous areas. Vines are being replanted and abandoned areas are being recovered, so we have to head in this direction. And some of the areas that are suffering will have to uproot or abandon their vines; these include some of the low-lying areas of Priorat, Montsant and Penedès. However, not all the vineyards we have in Catalonia can be moved to the Pyrenees because high-mountain cultivation is much more complicated and there wouldn’t be room for all the hectares of vineyards we currently have on the plains.

Another option is to change varieties; the most adapted are the native ones, such as Garnacha or Xarel·lo, whereas foreign varieties such as Chardonnay, Pinot or Gewürztraminer are not able to survive here in these thermal conditions. Therefore, the strategy is to replace the varieties that have begun to suffer.

Another possibility might even be to replace current crops with species native to tropical areas, such as mango, avocado, loquat, papaya or cherimoya. However, many of these crops have higher water requirements than Mediterranean dry-land crops. Since the tropical climate is wetter than the semi-arid Mediterranean one, their viability without irrigation may be limited.

A fourth option is to irrigate, because water acts as a coolant: if the plant has water, even when temperatures are very high, it can transpire and maintain its temperature below the limit conditions and trigger the entire ripening process. In Terra Alta, for example, which is a thermally challenging area, they have water, and in Penedès and Priorat they have started to install irrigation. The problem is that in Catalonia there isn’t enough water to irrigate the entire vineyard area, so this isn’t the definitive solution either.

Another strategy is soil management: trying to minimise the loss of irrigation and rainfall water so that the plant can make use of it. This is because, with high temperatures, soil water evaporates very easily. However, plant cover, mulching and different types of ploughing can prevent water from evaporating, so that the plant makes the most of the little there is.

These are measures that can be applied to arid, Mediterranean crops. In any case, there needs to be a national strategy to find the best solution according to each area and the varieties cultivated there, because there is no single solution that will fit all.