NDC 3.0
From planning to implementation
NDC 3.0 is moving from planning into implementation, so the priority now is monitoring progress and securing follow-up where brain health remains absent.
Climate change is reshaping brain health through heat, air, weather, water, nutrition, and disease vectors. A new report from the Neuro Climate Working Group presents the state of the science and the blind spot it leaves in climate policy.
Climate change is a defining health challenge of the 21st century. Its effects on the heart, the lungs, and the immune system are fairly well recognized. Its effects on the brain are not.
Brain health spans neurological function, cognition, mental health, and neurodevelopment: ultimately, the foundations of human relationships, creativity, productivity, and wellbeing. Despite this central importance to human flourishing, climate policy and risk assessment have largely overlooked the brain.
This page introduces findings from a new report by the Neuro Climate Working Group, a collaborative network of 500+ neuroscientists, clinicians, and public health and policy experts. The report synthesizes the state of the science, identifies knowledge gaps, and offers a research and action agenda to protect brain health in a changing climate.
Excessive heat impairs cognition, neurological function, mental wellbeing, and sleep, raises the risk of neurological diseases and self-harm, and is associated with an increase in emergency department visits for numerous psychiatric disorders.
Extreme weather events bring injury, trauma, displacement, disrupted care, and chronic stress, with neurological and psychological consequences outlasting disasters years after they arrive.
Air pollution increases the risk of stroke, neurodevelopmental disorders, neurodegeneration, and cognitive decline, and is estimated to contribute to roughly one in four dementia deaths worldwide.
Food insecurity impairs brain development, cognition, and mental well-being, with the most severe impacts occurring in the critical first 1,000 days of life, perhaps the most important neurodevelopmental period.
Soil and water contamination raise exposure to arsenic, pesticides, plastics, and heavy metals like lead and mercury: all neurotoxicants that act on neurological development and function across the lifespan.
Vector-borne diseases trigger both acute and chronic neurological complications, from encephalitis to lasting cognitive decline, as climatic shifts extend the habitable range of the insects that carry them.
Lifelong and intergenerational effects can stem from exposures before birth and in early childhood. Repeated exposures accumulate, and harm can pass to the next generation via epigenetic mechanisms.
Unequal burdens fall on children, pregnant women, older adults, people with neurological or mental health conditions, Indigenous Peoples, and displaced populations. These groups often face the greatest exposures yet possess the fewest resources to adapt.
The Neuro Climate Framework introduced here links climate change to brain health through three interconnected pathways: biological, psychological, and social-structural. The pathways compound, and interventions targeting only one often fall short.
A blind spot in climate policy leaves brain health unaddressed by today’s climate-health systems. Only 3% of nationally determined contributions mention mental health, and 0 of 160 national adaptation policies address children’s mental health.
A research agenda offered below names priorities for the next chapter of work: mechanisms, exposure interactions, pre-birth cohorts, data where the brain-health burden is greatest, and protective factors.
An action roadmap illustrates brain-health-protective policies at every scale of governance. There’s a role for everyone here, not least because many mitigatory and adaptive climate-policy measures also protect the brain.
A window for action is opening: between NDC 3.0 implementation, the IPCC’s Seventh Assessment health chapter, and the Belém Health Action Plan, several near-term opportunities exist to write brain health into climate policy, planning, and implementation.
The temperature-dependence of a thinking organ.
Climate change is raising average global temperatures and lengthening the heat waves that punctuate them. The brain, an organ assembled from temperature-dependent biology, is among the first systems to feel it.
Failure of thermoregulation at core temperatures above 40°C brings heat stroke, circulatory collapse, and seizures. Across animals, heat induces neural-circuit “crashes” akin to seizures and stroke, a direct consequence of the intrinsic temperature dependence of biological processes.,
Heat exacerbates existing neurological disorders (stroke, migraine, Alzheimer’s disease, epilepsy, multiple sclerosis) and raises hospital admissions for each., Modeling studies predict a rising burden of Alzheimer’s, other dementias, and Parkinson’s as warming continues.
The mind moves in step with the mercury. Every 1°C-increase is associated with a 2.2-percent rise in mental-health-related mortality; emergency-department visits climb for mood, anxiety, substance-use, and psychotic disorders, as well as for self-harm., Some psychiatric medications impair thermoregulation.
Prolonged heat erodes attention, executive function, and mental acuity., Judges issue harsher verdicts; workplaces shed productivity; impulsivity, aggression, and crime tick upward.,
Neuroscientists believe these effects arise because heat weakens the blood-brain barrier, the tightly packed layer of cells that controls molecular flow between the bloodstream and the brain. Heat also triggers neuroinflammation, oxidative stress (the build-up of unstable molecules that can damage cells), and mitochondrial dysfunction. Each of these harms is ultimately linked to the progressive loss of nerve cells known as neurodegeneration. Neuroimaging ties heat exposure in infancy to reduced myelination and white-matter maturation and disrupted functional connectivity in the adult brain.
“As a researcher and consultant, I see the built environment as our first line of defense against the health impacts of climate change. As someone living with epilepsy, that line of defense is currently failing. When urban heat islands spike, so does the physiological stress on the brain, lowering seizure thresholds and compromising neurological safety.”
Trauma that outlives the storm.
Droughts, floods, hurricanes, and severe storms are growing in frequency and intensity across much of the world. Their reach extends past property and into the nervous system.
Extreme fluctuations stress the brain’s resilience processes, raising the risk of stroke, epilepsy, Parkinson’s disease, and multiple sclerosis., Flooding ushers in water-borne disease (leptospirosis, shigellosis, hepatitis A), which can have severe neurological complications. The disruption of care accelerates decline for those with neurodegenerative conditions and ultimately hits hardest where resources are thinnest.,
Furthermore, the psychological toll compounds through trauma, displacement, financial ruin, and the loss of community and continuity. Floods and typhoons are linked to long-term mental disorders in survivors; disasters can spur anxiety, depression, and post-traumatic stress disorder (PTSD). After California’s deadliest wildfire, researchers documented chronic mental-health harm; more than 7 million Californians saw statistically significant increases in psychotropic prescriptions.
Cognition diminishes, as well, with deficits observed in working memory, processing, flexibility, and sustained attention. Recent studies have documented how wildfires' marks on interference processing and fronto-parietal activity are still visible 6 to 12 months after the fire.
The reach extends to the unborn. In-utero storm exposure is associated with altered amygdala, caudate, and hippocampus structure, as well as with shifts in placental gene expression tied to infant temperament. PTSD from climate disasters also appears to have a neurobiological signature distinct from other trauma.
“Our research has quantitatively shown that wildfires drive community-wide climate trauma: nearly a third of the impacted community can experience symptoms of PTSD, anxiety and depression, alongside cognitive impacts on attention and decision-making.”
The particles that cross into the brain.
Air pollution and climate change form a reinforcing cycle: Many pollutants warm the planet, and heat and wildfire smoke degrade the air in return. The brain pays across the life course.
Ultrafine particles, PM2.5, nitrogen oxides, and polycyclic aromatic hydrocarbons harm the central nervous system. In utero, exposure is linked to neural-tube defects and altered brain structure., In older adults, PM2.5 accelerates brain aging and dementia risk, is worst where socioeconomic inequality is highest, and raises hospitalizations for stroke, Parkinson’s, and Alzheimer’s.,
Prenatal PM2.5 is tied to later psychotic and depressive symptoms in youth; early exposure to particulates, ozone, and heavy metals is tied to neurodevelopmental disorders.,, Repeated exposure raises the risk of schizophrenia, depression, anxiety, and suicide.,
Cognition suffers most in children and older adults., In high-PM2.5 neighborhoods, children’s working-memory development is delayed.
The route runs through inflammation. Fine particulate matter drives systemic inflammation that disrupts the blood-brain barrier, activating immune responses in astrocytes, microglia, and neurons;, ultrafine particles can translocate directly via the olfactory nerve, bypassing the barrier and ferrying neurotoxins with them., Epigenetic changes in exposed neurons hint at effects passed to future generations.,
“As a neurologist, what concerns me most is the risk of ischemic heart disease, stroke, and dementia caused by air pollution from the burning of fossil fuels. Many physicians and patients are unaware of this association.”
The first thousand days and the fish that feed the brain.
Climate change reshapes food systems through flood and drought, ocean acidification, soil degradation, and atmospheric CO₂ that thins the nutrition in staple crops. The developing brain is the most sensitive to the shortfall.
In 2024, 2.33 billion people faced food insecurity and more than 3.1 billion could not afford a healthy diet. Iron deficiency delays cognitive development and drives behavioral problems; iodine deficiency causes brain damage and irreversible impairment. Shortfalls in the first 1,000 days leave lasting motor, behavioral, and cognitive harm,, deepening the socioeconomic disparities already written into brain development.
The microbiome-gut-brain axis helps shape neurological function, psychopathology, and cognition., In severe malnutrition, an infant’s gut microbiota (and the biochemicals it trades with the brain) diverge from the healthy pattern. Heat and pollutants disturb the microbiome, as well.
Docosahexaenoic acid (DHA, an omega-3 essential to the vertebrate brain) may grow scarce as fish populations fall. By 2100, an estimated 96% of the global population may lack adequate access, with the sharpest losses in inland Africa.
“As climate change disrupts food systems and saps the nutritional value of our crops, food insecurity deepens and diets lose the nutrients that are the building blocks of a child’s cognitive future. This damage often begins before birth, when maternal food insecurity during pregnancy can already set a child on a harder developmental path, and it deepens during the first 1,000 days of life, the very window when a child’s brain is being built.”
Neurotoxicants on the move.
Droughts and floods can both spur contamination: Pesticides, pathogens, microplastics, and other toxicants flow into water when soils are degraded and destabilized. And what winds up in water and soil eventually ends up in people.
Climatic shifts drive farmers toward heavier pesticide use; more frequent and intense storms push those chemicals into water, soil, and the food chain., Wildfires and floods can also scatter asbestos, lead, and electronic waste into the environment. Even low-level lead and pesticide exposure can be irreversibly harmful in early life, with documented effects related to anxiety, depression, and mood disorders.,.
Of these neurotoxicants, heavy metals are the most well studied. Lead is known to cause neurodevelopmental delays and cognitive impairment in children; mercury drives severe behavioral and neurological disorders; a warming climate can increase the bioavailability of arsenic as it leaches into groundwater and accumulates in crops. Naturally occurring arsentic and fluoride levels also rise with declining water tables. Accordingly, we can likely consider water treatment and rainwater harvesting as brain-health interventions.,
Rising seas can also push saltwater into aquifers, and warmer, runoff-contaminated water can breed harmful algal blooms (HABs), which can produce neurotoxins like BMAA and domoic acid., Domoic acid alone is associated with memory impairment and neurological symptoms. Rising temperatures can also increase the spread and/or solubility of toxicants, and microplastics can act as carriers for organic pollutants and heavy metals. Microplastics are now accumulating in the brain itself.
Nearly all plastic is made from fossil fuels, and its production alone amounts to more than 5 percent of global greenhouse-gas emissions. Among the 16,000 chemicals associated with plastics are compounds linked to reduced IQ and neurodevelopmental disorders., Furthermore, most plastic ends up as waste, and when it’s burned, it releases the same heavy metals and other neurotoxicants discussed above that can settle in sediments and soils.
Prenatal exposure to pesticides is also linked to neurodevelopmental harm, which means the effects can reach the next generation.,
“Children on the front lines of climate change often live in communities hit hardest by pollution, so-called sacrifice zones. To protect brain development of the next generation from climate change and pollution, bold action is needed at a much larger scale on air quality, food safety, water and sanitation, sustainable production, and waste management.”
New maps for old pathogens.
Zoonotic and vector-borne diseases spread as temperature, humidity, and rainfall patterns shift the life cycles of pathogens and their carriers., A great many of them end up in the brain.
Aedes mosquitoes have pushed into Europe and North America, and changing human behavior (settlement, outdoor exposure, work) increases contact with vectors. Some diseases target the brain directly, as in Japanese encephalitis and neuroborreliosis; others reach it through complication, often by demyelinating and inflaming neural tissue.,
The catalogue is long. Dengue brings encephalitis or encephalopathy in up to 20% of cases; chikungunya brings encephalitis, neuropathy, Guillain-Barré syndrome, and lasting cognitive impairment; Zika spurs microcephaly, cortical thinning, and meningoencephalitis. West Nile: encephalitis in infants and elders. Cerebral malaria: epilepsy and cognitive deficits., Tick-borne encephalitis and Lyme: neurological and mental-health harm, sometimes long-term.,,
Across the lifespan and into the next generation, six climate exposures converge on the same organ, each linked to its own signature of harm.
Harm can begin before birth and compound with age; through nutrition, development, and trauma, some of it passes to the next generation.
Over 60% of the world’s dementia burden falls in low- and middle-income countries, where climate risks are highest and adaptive capacity most constrained.
Weather-related disasters drove 62.1 million internal displacements of children between 2016 and 2023.
These exposures do not act evenly. Dense urban environments create heat islands, and low-income groups breathe higher levels of air pollution while having less access to tree cover, green space, and quality housing.
Vulnerability is defined by the age and health of a body, by where it lives, and by whether it can afford to cool a room or leave a floodplain. Children, older adults, and populations in low- and middle-income countries bear the heaviest share.
Brain health spans neurology, psychiatry, psychology, neuroscience, neurodevelopment, and public mental health: domains governed by separate institutions with siloed budgets. The Working Group’s integrative model maps three interconnected pathways through which climate change reaches the brain. Each cuts across multiple institutional portfolios, and a central design challenge is coordination among them.
Interventions that target only one pathway (say, cutting pollution without addressing the social determinants of exposure; or scaling mental-health services without limiting the factors that generate demand) are often structurally insufficient. Policymakers must act at the convergence.
Policy architecture for climate and health exists for many outcomes and at many levels of governance. Yet it is siloed, and no current system directly addresses brain health. The gap is visible even for mental health, the subdomain with the most traction.
The Lancet Countdown tracks 57 indicators of health and climate change, yet still lacks a dedicated brain-health outcome measure, relying on a mental-health-adjacent sentiment proxy drawn from social media. Major economic assessments, including the World Bank’s most recent assessment for low- and middle-income countries, explicitly exclude mental health.
While the science is progressing quickly, gaps remain.
Mechanisms and interventions. Most of the current evidence base is epidemiological: that is, it shows associations. Underlying biological pathways (related to blood-brain barrier disruption, neuroinflammation, and oxidative stress, for example) are only partially characterized. And few studies assess which environmental interventions protect the brain.
Interacting exposures. Climate, environmental, and social factors interact, and their combined effects can’t be predicted by single-exposure studies. We need to look across the exposome.
The life course before birth. Studies of prenatal and preconception exposures are rare, yet children’s brains are the most vulnerable. Longitudinal studies from pregnancy into older age are needed to better understand sensitive windows and follow transmission across generations.
Data where the burden falls. Many research cohorts (and monitoring infrastructure) are based in high-income countries, and given drastically different exposure profiles, brain-health outcomes shouldn’t be compared across borders.
Frontline leadership. Research agendas and solutions must emerge from climate-vulnerable communities, with the most impacted as partners in research: from setting investigative priorities to interpreting results.
Prevention and resilience. Most studies look for evidence of harm. We understand far less about the potential benefits of the interventions that may strengthen brains under climate stress, including green space, social connection, nutrition, education, and urban planning and cultural practices.
Brain-health-protective policy can be built at every level of governance. Each action below is placed with the pathway it primarily engages, following the Working Group’s integrative model; most engage more than one, and the scales overlap.
Clean air zones and low-emission districts
Cooling centers and equitable cooling access
Heat-mitigating green infrastructure and tree canopy
Air quality standards and emissions reduction
Brain health metrics in national climate vulnerability assessments
Brain-health screening and adapted clinical pathways
Mitigation commitments that reduce cumulative exposure
Health chapter of the IPCC Seventh Assessment Report
Mental health integration in heat-health action plans
Psychological first aid and early-warning systems
Community cohesion and resilience programs
National climate-health strategies with mental health provisions
Crisis mental health intervention for climate disasters
Measurable mental health targets in nationally determined contributions
Operationalization of COP28 commitments on mental health
Operationalization of the Global Goal on Adaptation mental health indicator
Implementation of the Belém Health Action Plan
Environmental justice frameworks in urban planning
Prioritization of climate-vulnerable neighborhoods
Frontline representation in planning decisions
Targeted investment in underserved communities
Research capacity investment in low- and middle-income countries
Disaggregation of cognitive harms in Loss and Damage discussions and fund
cross-cutting
Brain health indicators in environmental health surveillance
Psychosocial risk metrics in heat-health and adaptation plans
A Lancet Countdown brain-health outcome indicator
Cohort and exposure registry linkage
Protecting brain health in a changing climate requires coordinated action across governments, healthcare systems, researchers, educators, communities, individuals, and international organizations. While important knowledge gaps remain, many opportunities already exist to reduce climate-related risks, strengthen resilience, and promote healthier brains across the lifespan.
Several near-term processes open a concrete window for action.
From planning to implementation
NDC 3.0 is moving from planning into implementation, so the priority now is monitoring progress and securing follow-up where brain health remains absent.
Brain health in global scientific coordination
The IPCC AR7 cycle offers the opportunity to incorporate brain health evidence systematically into global scientific assessment.
An international adaptation instrument
The Belém Health Action Plan has put mental health and psychosocial support into an international adaptation instrument; its value depends on implementation monitoring.
Instruments are in place.
The evidence is compelling.
The case for action is complete.
Climate policy cannot be considered comprehensive if it overlooks the organ through which people learn, work, adapt, make decisions, and build resilient societies. Integrating brain health into climate policy is an imperative correction to an approach operating with an incomplete picture of how climate change affects human health.