The Heat Is On

Most people think of the weather in terms of what to wear for the day. Yet with a summer of record high temperatures shutting down airports and sending many to the hospital, two new UC San Diego professors are focused on how weather will affect how we live in the future. With joint appointments at Scripps Institution of Oceanography and the School of Medicine, epidemiologist Tarik Benmarhnia and bioclimatologist Jennifer Vanos are connecting weather and climate to human health—and helping us figure how we’ll respond, adapt and thrive on our planet.

Why does the public need to care about climate and human health?
JV: Right now, heat waves are affecting us. Air pollution is affecting us. These issues have been longstanding concerns, so regardless of whether climate change factors into the equation, people still die of heat and air pollution exposure. Yet we also know that climate change is exacerbating these effects and that they are likely to get worse, so preparation is important.

TB: And as soon as we see climate-related exposures are killing people or sending people to the hospital, it is quite important to inform the public about the aspects that are affecting them and will be exacerbated in the future, and work toward finding solutions to mitigate these conditions.

Who is most at risk from the climate and health?
JV: By far, the poor—those who may be deciding whether they can afford water or air conditioning, as well as those who work outside and those in developing countries.  In jobs with high heat exposure—whether indoors with no AC or outdoors—oftentimes workers will not get paid if they have to stop due to overheating, so they might continue working, which can be a serious health concern. By following established guidelines, employers must provide longer breaks, which results in lost money to the business. Policy and economics are a large factor in these kinds of behavioral heat adaptation discussions.

TB: It depends on the exposure of interest, but in general, the elderly and children are vulnerable for physiological reasons—a lower capacity for thermoregulation, for instance. In addition, low socioeconomic communities affected by other social determinants of health, like unemployment, lack of material resources, for example, can also be more vulnerable with regard to environmental exposures.

What factors are you studying right now?
JV: With regard to children, I ran an outdoor observational field experiment this summer within children’s play spaces in El Cajon using new flexible sensors created in Professor Todd Coleman’s bioengineering lab to determine how microenvironmental conditions affect kids’ physiological response during warm and sunny conditions. For instance, the way we design structures significantly affects fine-scale exposures to extreme heat and radiation—such as the heat radiating from black rubber in the sun—so using an airport reading miles away doesn’t provide us the most accurate information. Because of this, we use very advanced sensors to collect microclimate and physiological data that can provide that evidence for how children respond to certain exposures, and are also able to monitor personal UV-radiation exposures. This is important for getting parents and communities involved in designing healthy spaces and pushing safe policies forward.

TB: Where Jenni works at the individual level, I look more at large-scale effects on populations. Right now I’m involved in a research project in California that looks at how heat and drought could affect population health through different mechanisms. For example, those factors will cause wildfires, so how will wildfire smoke affect the population? And drought in association with extreme precipitation causes water and sanitation problems, so what are the effects then in the coastal zones for swimmers and beachgoers?

What can we expect from the future as far as climate and human health?
JV: The million-dollar question! Climate modeling is a huge challenge in itself, and when you try to model human behaviors as well, it gets even more challenging. But we know some important factors, such as aging, will affect vulnerability and mortality rates. So working toward solutions and adaptation strategies to protect the elderly and other vulnerable populations from heat are important research areas.

TB: We can likely expect heat waves to increase in intensity, frequency and duration. And because there is a limit to what humans can handle, eventually it will simply be impossible to live in some places without concerted mitigation strategies, and efforts to control the contributing factors.

What excites you about your dual role here at UC San Diego?
TB: Typically, as an epidemiologist, I would primarily be working within medicine, but my joint appointment at Scripps allows for close work with climatologists to determine an outlook on heat waves and climate factors for the next 50, 60, 70 years. So we can make plans now for what future generations are going to be dealing with, and not wait until it’s too late.

JV: No idea is too big here. I’ll throw out a wild idea to someone and they’ll say, ‘Great! Let’s do it!’ Like the flexible sensor work with bioengineering, or another project we’re working to develop with the DroneLab using infrared cam-eras and fine-scale hyperspectral imaging in urban areas. So that’s another bridge we’re building, not just connecting weather and health, but harnessing technology to help the process. We hear all the time that those connections are the wave of the future, but at UC San Diego it’s here now, and we’re doing it.