Health challenges are intimately linked to climate change. How will we prepare?
Introduction
In 2018, a report from the Lancet Countdown firmly established that rising temperatures and extreme weather events are accelerating health risks all over the world; the 2021 report from the same group described the situation as “code red.” Fortunately, accelerating innovation in technology is delivering the opportunity to radically transform the future of health—while addressing environmental sustainability, inequities, and more. As emphasized by the Lancet Countdown, “the form and pace of the world’s response to climate change will shape the health of nations for centuries to come.”
Digitizing the health impacts of climate change
Health-impacting events arising from climate change will take a variety of forms, will affect species beyond humans, and will change in frequency, severity, and location over time. It is therefore critical to support technological innovation focused on digitization and decentralization, so that individuals and local communities—no matter how well or poorly resourced—are empowered to monitor, test, treat, contain, and prevent a dynamic spectrum of health threats.
To identify meaningful digital biomarkers of climate-driven health impacts, strong digital infrastructure should rest on a mindset shift toward “connectedness” that seeks to harness the variety of information embedded in the environment, humans, and animals. Health “connectedness” is an acknowledgment of the dense and interconnected networks by which materials and signals are exchanged between the human body and the world around it.
One well-established connectedness perspective is the One Health framework, a collaborative, interdisciplinary, and intersectional set of approaches that have been in development for 200+ years. One Health spans the fields of basic research, human public health, veterinary work, agricultural health, and environmental monitoring and mitigation. Infectious diseases (including zoonoses, which are diseases that have made the evolutionary jump from an animal species to humans), antimicrobial resistance, and food security—all of which are influenced by climate change—are also encompassed by the One Health umbrella. Crucially, One Health integrates multistakeholder knowledge for local, national, and global levels of policy.
For example, a connectedness perspective would have predicted that intensive use of antibiotics in food animals would lead to the rise of antimicrobial resistance genes in the bacteria living in those animals. Those bacteria and genes would enter wastewater and be flushed into soil and other bodies of water, spreading the antimicrobial resistance to other microbes, other plant and animal hosts, and eventually to humans through our food and environment.
Each point in this network contains signals about the presence and dynamics of the spread of antimicrobial resistance. These signals can be digitized through clinical data in electronic health records as well as through biotechnologies such as DNA sequencing and other -omics technologies. If monitoring approaches focus on antimicrobial resistance in human patients alone, then potentially informative signals in places like barns, food processing plants, and sewers are overlooked. An even broader perspective would capture indirect signals with health relevance, such as changes in rainfall and temperature that would indicate a forthcoming geographical redistribution of agricultural sites and therefore new routes of transmission of antimicrobial resistance.
Machine learning and artificial intelligence are delivering deeper insights for epidemiology and public health from complex data sources. These computing approaches will also be increasingly useful for forecasting changes in public health due to climate change and modeling the impacts of potential interventions in silico before their deployment. Publicly available and interoperable data—across a broad range of human and environmental signals—will be key to both public and private efforts to harness artificial intelligence and machine learning for this nascent innovation space. To achieve these goals, it will also be important to bridge the data divides between sectors and societies.
Overall, in the coming years, innovators, policymakers, and funders should be pursuing digitized and decentralized approaches to combat the health effects of extreme heat/cold, storms, drought/flooding, pollution, fire, malnutrition, infectious diseases, and more. This strategy crucially empowers citizens and organizations to act as on-the-ground “sensors”, delivering key insights into the “jobs to be done” as well as potential solutions suitable for the local context.
Dangers affiliated with shifting climate zones
Adequate digitization of environmental, human, and non-human signals (as has been proposed for COVID-19)—plus subsequent monitoring, data integration, and evaluation—could underlie critical early warning systems for global and local health. Shifting climate zones will have large impacts on food and water security, the livability of our cities, infectious diseases, pollution, and other crucial elements of life. Fortunately, many of these elements are being targeted by climate adaptation strategies. Nonetheless, much more work is needed and many opportunities are still being missed due to a lack of resources, focus, and political and popular will.
Infectious disease is an important example of the impact of shifting climate zones. The global rise of temperatures is leading to expanding tropical zones, habitats in which disease-carrying mosquitos thrive. Such mosquitoes often spread diseases like malaria, zika, dengue, and Chikungunya, all of which are dangerous and in some cases fatal to humans. Other disease vectors are also expanding their ranges. Regions that have never faced the threats associated with tropical climates will begin to; other regions may eventually become too hot for these vectors and pathogens.
Climate change will also increase the danger of zoonotic events by shifting wildlife-livestock-human interfaces, where people come into close contact with wild and domesticated animals. These interfaces occur where cities encroach on former wild spaces, in areas where rural agriculture is dominant, and where humans are interacting with and/or eating non-domesticated species. The importance of these interfaces to global human and economic health has been illustrated all too effectively by the COVID-19 pandemic. Development also causes these interfaces to shift over time; climate change is likely to become a major accelerant of human migration and construction. Therefore, the local and geopolitical decisions that we make today will critically impact the future health of citizens around the world.
Even seemingly mild temperature increases can combine with other environmental stressors such as agricultural pollution to drive events like harmful algal blooms (HABs), which can directly endanger the health of humans, pets, livestock, and other animals and plants. Although the number of recorded HABs has increased in recent decades, it is difficult to disentangle the effects of climate change from the effects of increased ecological monitoring. Nonetheless, the danger of paralytic or even fatal poisoning by toxins in shellfish harvested from a HAB persists for wild fishing as well as aquaculture, with potential negative socioeconomic effects and mass plant and/or animal mortality.
Encouragingly, diverse signals have been evaluated and, increasingly, integrated to monitor HABs and their impact on health. In the United States, the CDC has established a One Health framework for voluntary reporting of HABs and associated cases of human and animal illness. An open-access database of global marine biodiversity (including DNA and ecological data) and a UNESCO database of harmful algal events provide further signals. Additional alarms were sounded after the catastrophic death of 1,100 Florida manatees in 2021 (out of an estimated population of 6,000), many of which appear to have starved due to the devastation of Florida’s seagrass, their primary food source, by HABs, as revealed by aerial imagery. Nonetheless, legislation intended to act on subsequent recommendations of Florida’s Blue-Green Algae Task Force died in appropriations.
This case study of HABs illustrates the integration of a diversity of data types and sources to surface links between changing climate and changing health threats. It reminds us that data are necessary but not sufficient to prompt action. This case study also highlights the urgency of expanding the amount and types of publicly available and interoperable data that can prepare health systems for emerging threats and inform policymakers about effective interventions.
Overall, local and central governments should be preparing today for shifting disease burdens over short-, medium-, and long-term horizons. Regulation, monitoring (particularly through digital markers), testing, treatment, containment, and vaccination are all weapons in our arsenal, but they require financing, R&D, manufacturing, and distribution. Perhaps most importantly, they require political commitment—from policymakers and citizens—to gathering a diversity of data types, making them available, and acting on insights from those data.
Looking Forward
Evolution is a relentless and merciless experimenter—and infectious disease is certainly not the only threat to human health arising from climate change. If we draw a laser focus on coronaviruses today, we are almost certainly ignoring the next, potentially preventable human-health disaster to come. In contrast, by committing to investment in people-centered, forward-looking technologies, systems, and mindsets, we have the chance to safeguard our health and our planet against tomorrow’s challenges, be they natural or man-made. Critically, on a global level, the IPCC predicts that water security and food security will be stressed—perhaps even compromised—as well, further exacerbating human health challenges.
The “connected” mindset of the One Health framework—the ability to recognize the value of signals that are not obviously immediately connected to human health—is a crucial element of this investment. How can citizens be empowered to act as detectors, innovators, and agents of change on the front lines of climate change and health? Through reliable digital infrastructure, rigorous data analysis and transparency, public storytelling, and education. Curricula from primary school through higher and professional education (for example in medical and veterinary schools) could serve as common touchpoints for this mindset shift across society.
Platform approaches to innovative solutions are especially powerful because they can be repurposed to a variety of challenges; note that work began on the basic research underlying mRNA vaccines decades before COVID-19. Similarly, developing and resourcing approaches to supply chain resilience, decentralized and nimble production, and physical and digital monitoring will empower citizens and governments to build better for the future of health in the face of climate change—for infectious disease and beyond.
Opinions expressed by Non Resident (Senior) Fellows do not necessarily reflect the opinion of the Atlantic Council GeoTech Center.
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