The Grave Threat to Public Health
For decades, climate change has been framed primarily as an environmental and economic issue. However, the international community is now recognizing that the climate crisis also represents a severe public health emergency. Tedros Adhanom Ghebreyesus, Director-General of the World Health Organization, stressed at COP28 on Health Day in 2023 that “the threats to health from climate change are immediate and present.” Health Day marked a historic moment, as it was the first of its kind since the Conference of the Parties (COP) meetings began in 1995. This highlighted the growing recognition that climate change will have devastating impacts on global health.
Climate change is already resulting in fatalities and disabilities due to a range of health issues, including air pollution, infectious diseases, extreme weather events, malnutrition, and mental health problems. Every year, the burning of fossil fuels kills 5 million people, particularly in China and India. Fossil fuels also contribute to the spread of infectious diseases and the ingestion of plastics, which have been linked to various health problems, from stillbirth to lung disease.
Extreme Temperatures: A Mounting Threat
Extreme temperatures, both hot and cold, are another major concern. Extreme temperatures kill 5 million people every year, over half of whom live in Asia. The impacts are especially severe on the elderly, young children, and those with underlying health conditions. Extreme heat is linked to heatstroke, disrupted sleep, kidney injury, poorer pregnancy outcomes, and adverse mental health effects. It also reduces people’s ability to work and exercise, further compromising their health and well-being. The resulting loss in productivity costs societies $863 billion annually.
As the planet warms, extreme weather events like wildfires have become more common, severe, and prolonged. Wildfire smoke is particularly toxic, containing hazardous chemicals and particulate matter that can lead to premature death, cognitive impairment, and diseases of the lungs, brain, and heart.
Infectious Diseases and Antimicrobial Resistance
The COVID-19 pandemic was not the first, and it certainly won’t be the last. Warmer temperatures have made it easier for vectors like Aedes mosquitoes to spread diseases such as dengue, which has grown by a factor of 10 since 2000. Asia currently bears 70% of dengue cases, but that may change as half of the world becomes vulnerable to the virus.
Climate change is also turbocharging antimicrobial resistance (AMR), complicating the treatment of even the most common infections. Every year, AMR kills 5 million people. Extreme weather events, like floods, have accelerated the spread of AMR by creating optimal conditions for it to spread, mainly through overcrowding and poor sanitation.
As infectious diseases surge, they are likely to perpetuate malnutrition in a vicious cycle. The burden of malnutrition is expected to rise further as climate change reduces the nutritional value of staple foods and depresses crop yields by up to 30%.
Addressing the Health Risks of Climate Change
Climate change presents an imminent and existential threat to global health. Fortunately, countries have access to a multitude of lifesaving and highly cost-effective options to quickly cut greenhouse gas emissions and safeguard citizens from the catastrophic health impacts of climate change.
These include mitigation measures, such as the introduction of low-carbon medical products, the enforcement of carbon taxes, and strict air quality regulations, as well as a transition to renewable energy sources. Adaptation strategies can encompass the formulation of multisectoral national health adaptation plans, the capacity-building of relevant health professionals, and the enhancement of weather surveillance systems.
However, the success of such ambitious initiatives relies on genuine international collaboration and innovative financing for climate-vulnerable countries to address the climate adaptation funding gap of $366 billion per year. Closing this enormous funding gap remains a key challenge and will surely be a crucial issue in future COP discussions.
Unraveling the Complexity: Gene-Environment Interactions
The variability in ALS presentations across patients suggests that the underlying causes are likely a complex interplay of genetic and environmental factors. While genetics can explain around 20% of ALS cases, the remaining cases are likely due to a combination of multiple genetic and environmental influences.
Environmental factors alone or genetic factors alone may be insufficient to trigger motor neuron degeneration. Instead, the interactions between these environmental and genetic factors may be the key drivers of the disease process. For example, individuals with a genetic predisposition may only develop ALS when exposed to specific environmental triggers, such as toxins, infections, or lifestyle factors.
Exploring these gene-environment interactions is crucial, as it could help explain the sporadic and variable nature of ALS. However, this is a challenging task, as it requires accurately measuring both genetic and environmental factors, and obtaining large sample sizes to detect meaningful effects.
Newer approaches, such as Mendelian randomization and machine learning techniques, offer promise in unraveling these complex interactions. By leveraging large datasets and advanced analytical methods, researchers may be able to identify the specific genetic and environmental factors that, when combined, increase the risk of developing ALS.
Understanding these gene-environment interactions could pave the way towards precision medicine for ALS, where interventions can be tailored to an individual’s unique genetic and environmental profile. This could lead to more effective strategies for disease prevention, early detection, and targeted therapies.
As we continue to grapple with the devastating impacts of climate change on public health, it is crucial to recognize the complex, multifaceted nature of these issues. By exploring the intricate interplay between genes and the environment, we may unlock new insights that can ultimately improve outcomes for those affected by devastating neurological conditions like ALS.
Conclusion
Climate change represents an imminent and existential threat to global health, with far-reaching consequences that extend beyond environmental and economic concerns. From air pollution and infectious diseases to extreme weather events and malnutrition, the health impacts of climate change are already being felt worldwide, with Asia bearing a disproportionate burden.
Fortunately, countries have access to a range of cost-effective solutions to mitigate greenhouse gas emissions and adapt to the changing climate. However, the success of these initiatives hinges on genuine international collaboration and innovative financing, particularly for climate-vulnerable regions.
Beyond these immediate actions, unraveling the complex gene-environment interactions underlying conditions like ALS may hold the key to unlocking new strategies for disease prevention and personalized treatments. By leveraging the latest advances in genomics and data analytics, researchers can explore how genetic predispositions and environmental factors converge to drive the development of devastating neurological disorders.
As we confront the multifaceted challenges posed by climate change, it is essential that we adopt a comprehensive, holistic approach that prioritizes public health and embraces the power of innovative scientific discoveries. Only then can we truly safeguard the well-being of communities around the world and build a more resilient, sustainable future.
