BY CONSTANZA BINEY
What if the greatest threat to your brain wasn’t genetics or aging, but rather the changing climate? Climate change has long been recognized for its impacts on physical health, heightening respiratory conditions and the spread of infectious disease. However, its effects on the brain remain an underrecognized crisis. Emerging research reveals that climate-driven factors, specifically air pollution and extreme temperatures, have been increasing the prevalence and severity of neurological disorders such as Alzheimer’s and stroke. As the most common form of dementia, Alzheimer’s affects over 50 million worldwide, while stroke remains one of the leading causes of disability and death.1 By accelerating neurodegeneration and vascular damage through these conditions, climate change poses a growing threat to global brain health—one that demands immediate attention.
Understanding the Brain’s Greatest Threats: Alzheimer’s and Stroke
Before exploring how climate change worsens these conditions, it’s important to understand what these conditions are and why they matter.
Alzheimer’s Disease is a brain disorder that slowly deteriorates memory and thinking abilities. It occurs when harmful proteins known as amyloid and tau build up in the brain, blocking communication between brain cells and causing them to die.2 As more and more neurons perish, people with Alzheimer’s begin struggling with remembering things, making decisions, and even performing everyday tasks.2 Ultimately leading to an unfortunate and untimely death.
Stroke happens when blood flow to the brain is suddenly cut off, either by a blockage (ischemic stroke) or a ruptured blood vessel (hemorrhagic stroke).3 Without oxygen-rich blood, neurons begin to die, leading to serious damage.3 Strokes can cause paralysis, speech problems, memory loss, and, in severe cases, death.
Air Pollution and Alzheimer’s: The Hidden Brain Threat
Air Pollution Accelerates Cognitive Decline
Growing evidence suggests that air pollution plays a significant role in the rising prevalence of Alzheimer’s Disease (AD). Tiny, invisible pollutants like fine particulate matter (PM2.5), nitrogen dioxide, and heavy metals don’t just linger in the air—they invade the brain through the nose, bypassing its natural defenses.4,5 Once inside, they trigger chronic inflammation, disrupting neural communication and speeding up the buildup of two toxic proteins, amyloid beta plaques and tau tangles, both of which are also key markers of Alzheimer’s Disease.5 The damage does not stop there. Air pollution also fuels oxidative stress, a biochemical chain reaction that weakens and kills brain cells over time.5 This silent assault increases the risk of cognitive decline, memory loss, and ultimately dementia.
Who is Most at Risk?
The effects of air pollution are far from evenly dispersed. Older adults in densely populated cities face the highest exposure, breathing in pollution daily for decades. And perhaps even more concerning, low-income communities, often located near highways, factories, and industrial sites, are faced with a disproportionate burden. These areas have higher concentrations of environmental toxins, making their residents more vulnerable to Alzheimer’s disease.
Heat Waves and Stroke Risk: A Deadly Connection
Extreme Heat Increases Stroke Risk
As global temperatures rise, the risk of stroke rises as well. Heat waves are no longer a seasonal inconvenience—they are life-threatening, posing a serious threat to brain health. Studies show that hospitalizations for stroke spike during extreme heat, with higher nighttime temperatures worsening recovery outcomes.6,7 The link between heat and stroke lies in how extreme temperatures strain the body’s vascular system. Dehydration thickens the blood, making clot formation more likely, while heat stress elevates blood pressure, increasing arterial strain.6,7 Additionally, heat-induced inflammation damages blood vessels, further raising the risk of ischemic stroke.7
Who is Most at Risk
Populations that face greater risk include elderly individuals with hypertension or heart disease. They struggle to regulate body temperature, making them more prone to dehydration and blood pressure spikes. Outdoor workers and people from low-income communities without access to cooling infrastructure may also experience prolonged heat exposure, increasing their vulnerability to heat strokes. As climate change fuels more intense and more frequent heat waves, the connection between extreme heat and stroke remains an urgent yet under-recognized public health crisis.
Fighting Back: Solutions to Protect Brain Health
Reducing Air Pollution to Prevent Alzheimer’s
Improving air quality is one of the most effective ways to protect brain health. Stricter air quality regulations and a transition to clean energy sources can significantly reduce the levels of fine particulate matter (PM2.5- microscopic particles that are 2.5 micrometers or smaller in diameter and can enter the bloodstream through the lungs), nitrogen dioxide, and heavy metals in the air. Cities can also implement urban planning strategies that minimize traffic-related pollution to protect public health. Incentives can include expanding green spaces and improving public transportation to reduce car emissions. On an individual level, people can take protective measures by using air purifiers indoors and wearing masks on high-pollution days, particularly in areas with poor air quality.
Protecting Against Heat-Related Strokes
Preventing strokes during extreme heat events requires a proactive public health approach. Establishing public cooling centers and issuing heat alerts for at-risk populations can help protect those that are most vulnerable, including the elderly and outdoor workers. Community-based programs that check on elderly residents during heat waves can prevent heat-related complications before they become life-threatening. Additionally, increasing public education on the importance of hydration and stroke prevention, especially in high-risk regions, can empower individuals to recognize early warning signs and take preventive action.
An Urgent Need for Preventative Measures
The connection between climate change and neurological health is no longer speculative—it is an urgent and growing crisis. Alzheimer’s disease and stroke are already among the most devastating health conditions worldwide, and climate-driven factors such as air pollution and extreme heat are accelerating their severity. As temperatures rise and pollution levels remain high, millions more are at risk of cognitive decline, disability, and premature death.
Addressing this crisis requires immediate action. More research is needed to fully understand the long-term neurological effects of environmental factors, while stronger policies must be implemented to reduce air pollution and mitigate extreme heat risks.8 Additionally, healthcare systems must adopt proactive measures to protect vulnerable populations. The link between climate change and brain health is not just a warning — it’s a wakeup call. In protecting the earth, we safeguard the essence of who we are: our memories, dreams, and ability to create. Without action, these foundations of humanity risk being lost in many individuals.
Constanza Biney is a first-year in Pierson College.
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References
- ADI – Dementia statistics [Internet]. ADI – Dementia Statistics. Available from: https://www.alzint.org/about/dementia-facts-figures/dementia-statistics/
- What is Alzheimer’s? [Internet]. Alzheimer’s Association. Available from: https://www.alz.org/alzheimers-dementia/what-is-alzheimers
- About stroke [Internet]. Stroke. 2024. Available from: https://www.cdc.gov/stroke/about/index.html
- Air pollution linked to dementia cases [Internet]. National Institutes of Health (NIH). 2023. Available from: https://www.nih.gov/news-events/nih-research-matters/air-pollution-linked-dementia-cases
- Southam KA, Vincent AJ, Small DH. Do Microglia default on network maintenance in Alzheimer’s disease? Journal of Alzheimer S Disease [Internet]. 2016 Mar 30;51(3):657–69. Available from: https://doi.org/10.3233/jad-151075
- Corliss J. Hot weather tied to increased odds of stroke [Internet]. Harvard Health. 2024. Available from: https://www.health.harvard.edu/staying-healthy/hot-weather-tied-to-increased-odds-of-stroke
- Koda A. Study links higher temperatures to increased stroke risk [Internet]. Yale School of Medicine. 2024. Available from: https://medicine.yale.edu/news-article/study-links-higher-temperatures-to-increased-stroke-risk/
- Zuelsdorff M, Limaye VS. A framework for assessing the effects of climate change on dementia risk and burden. The Gerontologist [Internet]. 2023 Jul 1;64(3). Available from: https://doi.org/10.1093/geront/gnad082
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