Rachel Lowe i Kim van Daalen: "In Catalonia, there is growing concern about diseases transmitted by ticks, sandflies, and rats."

BarcelonaOften when we think about the climate crisis, starving polar bones come to mind and melting glaciers. And yet, the global rise in temperatures and associated extreme events are also a serious threat to human health. Continued exposure to excessive heat causes premature death, worsens mental health and aggravates respiratory and cardiovascular diseases. Sustained heatwave episodes, like those this summer, are associated with a higher level of aggression and conflict, and favor the transmission of infectious diseases, like dengue, malaria and chikungunya.

This relationship between the climate crisis and its impacts on human well-being, and possible mitigation and adaptation measures, are what researchers Rachel Lowe (Icrea), from the global health resilience group at the Barcelona Supercomputing Center - National Supercomputing Center (BSC-Cmi) University of Cambridge, in the United Kingdom, are studying. Both scientists co-led the report by The Lancet Countdown 2024 on climate change and health, when van Daalen was a postdoctoral researcherat the BSC. Precisely in recognition of this work they were awarded a of the 2024 Barcelona City Awards.

How can we talk about the climate crisis and its effects without causing eco-anxiety?

— RL: It's a huge challenge. One of the keys is to focus on everything we can do. Actions as simple as avoiding puddles of water in the garden or in the plant trays on the terrace prevent mosquitoes, which transmit infectious diseases such as dengue fever and malaria, from breeding. Or switching from private vehicles to public transportation or active transportation contributes to reducing greenhouse gases, so we all breathe cleaner air and enjoy better respiratory health.

— KD: In fact, all measures to reduce the climate crisis are highly beneficial for human health. For example, commuting by bicycle improves cardiovascular health. And having more green spaces in the city leads to greater well-being. This is what needs to be explained. We must avoid pessimistic discourses or focusing only on the fact that heat waves cause mortality, that rising temperatures fuel a range of infectious diseases. And that heat, drought, and air pollution impact all human health outcomes, taking a greater toll on vulnerable groups.

Because?

— KD: The climate crisis exacerbates existing inequalities, and women and girls around the world are often disproportionately affected, in part because they may be more exposed to extreme events or have fewer resources to adapt to them. For example, during heat waves, pregnant women face risks of complications such as premature birth and stillbirth, especially in places where access to maternity care is limited.

Many of the actions you listed to mitigate the impact of the climate crisis place the responsibility on citizens. Isn't that unfair?

— RL: I agree that we can't just limit this to the individual level; rather, these are measures that must be implemented at all levels, from governments to citizens. It's the responsibility of city planners to make streets safe for bicycles. And to ensure that trains work and there are enough buses. Now, all of this is failing, and people are forced to take cars, and electric vehicles are still not an option because they're expensive and there aren't enough charging stations. However, as individuals, we can pressure politicians to implement the necessary changes to transition to clean energy, to adapt to the climate crisis, and to take measures to protect ourselves.

Is there any city in Europe that is doing its homework to adapt?

— KD: Barcelona is taking decisive action to adapt to climate change. Since experiencing a major heat wave in 2003, it has had an alert system that warns citizens to take protective measures in the event of heat waves. It has also implemented climate shelters and increased the city's green areas.

In the report of The Lancet warned of the risk of new diseases.

— KD: Many infectious diseases are spreading. One of the clearest examples is the tiger mosquito, long established in southern Europe and now spreading to other areas of the continent, with the risk of transmitting dengue, chikungunya, and Zika. Another example is the Vibrate, a bacterium capable of causing serious and sometimes fatal diseases in humans, which is proliferating on European coasts as sea surface temperatures rise.

— RL: We travel We visit places where these infectious diseases are endemic en masse, and when we return home to Europe, we find that the vectors that transmit them are increasingly present everywhere. This causes people to take these diseases with them wherever they go.

Immigration is often blamed.

— RL: Catalans can bring the flu or meningitis to the places they visit. It's inevitable; globalization doesn't go in one direction. When vectors and people move around the planet, a unique window of opportunity opens for the exchange of viruses and diseases. There's a wealth of research showing that all these new threats we face are not related to immigration, but rather that disease introductions occur because wealthy tourists from Barcelona traveling to exotic destinations become infected because they haven't taken protective measures.

How do you study the relationship between the climate crisis and infectious diseases?

— RL: We develop models to understand transmission patterns in areas where these diseases are endemic. We collaborate with centers in Latin America, the Caribbean, Southeast Asia, and parts of Africa, as well as humanitarian agencies, and, using a combination of climate data and socioeconomic indicators, we generate disease risk prediction models. We also analyze how extreme events can interact and change the risk of an outbreak.

And in Europe?

— RL:We are developing various indicators to enable predictions and early warnings about climate change. We want to combine them with epidemiological data, such as vector distribution, animal populations, case reports, and local transmission of various diseases. Our goal is to bring all this information together and make it accessible to decision-makers implementing preparedness and response plans to try to prevent outbreaks in Europe.

Can you give some examples?

— RL: In Europe, we are developing a platform called EpiOutlook, with the advice of the European Centre for Disease Prevention and Control (ECDC) and the European Environment Agency. The idea is for the platform to be able to send alerts between one and twelve months in advance.

Dengue is a concern in Catalonia.

— RL: Yes, but not only that. There is increasing vigilance and concern about tick-borne diseases, such as those of the genus Hyalomma, capable of transmitting Crimean-Congo hemorrhagic fever. Also, leishmaniasis, transmitted by sandflies. In Barcelona, the rat population is also closely monitored, due to their ability to transmit a considerable number of diseases. When a disease becomes established in an area, it can easily spread very quickly. Infections like dengue can be very dangerous for people with other underlying conditions or for children. In these cases, it can be fatal if medical attention is not received.

Extreme weather events are associated with increased violence and aggression.

— KD: Data shows that violence against girls and women is on the rise. This increase is often linked to the damage and consequences of extreme weather events, such as economic instability, food insecurity, mental stress, and infrastructure disruption. In some contexts, displaced women may find themselves in unfamiliar environments, such as overcrowded shelters, where the lack of protection and privacy can increase the risk of gender-based violence.