Climate change does not only mean getting hotter in summer. Among its innumerable consequences are also those that affect our health in many different ways. Stopping the rise in temperatures is a matter of public health, as pointed out by Rachel Lowe, research professor at ICREA (Institució Catalana de Recerca i Estudis Avançats), head of the global health resilience team at the Barcelona Supercomputing Center (BSC) and director of Lancet Countdown in Europe, an organization that in its 2022 report explained how global warming is causing loss of life, money, and threatens the health of billions of people.
How does the MareNostrum supercomputer help to understand the effect of climate change on our health?
The supercomputer allows us to analyze a whole series of data sets, mainly climate, and make very precise observations, predictions and projections about how the climate has changed in recent years and how we expect it to change in the short term, from months to years, and also until the end of the century. And this can help us create different scenarios for how health will be affected by climate, depending on the kind of decisions that governments make about adaptation and mitigation strategies.
What can you see now?
Right now, for example, you can see that people in one part of Barcelona are probably more likely to contract some diseases caused by the weather. Climate impacts are uneven, and certain people in society are more vulnerable to the impacts of climate change. And furthermore, we see this type of variation across the planet.
Who is more vulnerable?
People in the South suffer the worst consequences of climate change, even though they are the least responsible for contributing to anthropogenic climate change. In Europe we can see that the South is more vulnerable to increased climatic suitability for infectious diseases, reduced labor productivity due to extreme heat, and unsafe hours for outdoor exercise. Within cities it depends on socioeconomic conditions. When it comes to infectious diseases, proximity to mosquito breeding sites and the ability to protect yourself.
You have data to teach policy makers.
We can use the climate information that supercomputers generate and then translate this information into meaningful health indicators that can really show how much climate change is affecting our health. For example, we can track changes in temperature-related mortality, by sex and age, and see which groups are especially vulnerable and where they are most affected. We may also see the length of the transmission season for diseases such as dengue and malaria increase.
These diseases were not in Europe until recently.
This has a huge risk in Europe, especially since there are parts that are very well connected to other parts of the world that experience endemic transmission of these diseases. So through travel and trade, combined with climate change, there is a real risk of these diseases becoming established in Europe.
What are the current conditions in Spain?
In the latest Lancet Countdown report for 2022, we have shown that Spain is at much higher risk related to temperature than the European average. Furthermore, there is also a greater tendency for the mosquito transmission season to be extended. And you also suffer from lower labor productivity due to the heat. So Spain is definitely a hot spot, the Mediterranean region is warming much faster than the world average. It is definitely a place where you have to act immediately.
Is there an area free of these risks?
It is definitely a global problem. It affects the health of everyone everywhere. There are certain areas where they are more vulnerable, for example, cities, coastal areas, mountainous areas, areas that are more exposed to sea level rise or melting glaciers, which are exposed to flooding . And then certain groups in society that are more vulnerable, such as children, women, the elderly, people with socioeconomic difficulties, people with disabilities. Even though everyone's health has been threatened, we have to act collectively to really make sure that we are protecting the most vulnerable sections of society.
How do you work with a supercomputer to get all this evidence?
To feed information into our health impact models, we use a number of different Earth observation and climate data. These can be grid products, representing weather conditions for the entire planet, at a spatial scale of about nine kilometers. These are a kind of maps that represent the conditions on the entire planet, over many decades, with an hourly temporal resolution. We also use data from weather stations from drone images. And we can use these types of images to correct larger-scale satellite images. We combine all of this information to try to make the best possible representation of what is happening on the ground. We can then integrate this data into our health impact models to help us predict how likely a dengue outbreak is to occur in this particular area. Or where malaria is most likely to reemerge, for example.
Can you predict which people are already threatened?
We published a projection in which we estimated that we were seeing the change in the length of the transmission season and the population at risk for both dengue and malaria around the world. We estimate that if warming continues as it has, by the end of the century, we could see 4.7 billion more people at risk of these diseases. Whereas if we made a concerted effort and kept the global temperature below one degree Celsius, that figure would be cut in half.
How can it be avoided?
This demonstrates the importance of making sure that we do not exceed those dangerous limits for human survival and that we keep the global temperature below 1.5 degrees, because that will have a huge impact on the population at risk of diseases such as dengue and malaria. That was the study we did. But also these very dangerous temperatures will have many impacts, as we can see happening now with temperature related mortality, wildfires, it's just huge impacts from these extreme temperatures.
What would be your message to decision makers?
I think I would tell you that climate action is not only good for the climate, but also for our health. Taking steps to reduce emissions has enormous health benefits. For example, changing the way we travel. Increasing active transport, not only leads to cleaner air, but also improves people's physical activity, changing diets to stop eating meat, which causes a huge amount of emissions that can also help and also lead to people to live a longer, healthier lifestyle. Anything we can do to improve energy access in the city and the way we get around, it's all good for the planet and good for our health.
What is the situation in Barcelona regarding climate and health?
In Barcelona and the surrounding regions, we have the tiger mosquito, capable of transmitting diseases such as dengue, chikungunya and zika. There is a surveillance program to keep track of imported cases and control mosquitoes around those cases to try to stop transmission. But that kind of system can only work for so long. So we have to make sure that all the surveillance systems are very integrated, that we understand exactly what kinds of major diseases are coming in, what the distribution of mosquitoes is, who is most at risk, and make sure that we can break any cycle of transmission.
Anything else?
We have to reduce traffic and pollution in the city. Barcelona has one of the worst air pollution rates in Europe. Drastic measures must be taken to improve the air pollution situation here.
