Climate change is here and accelerating 2024 broke all records, exceeding the 1.5 °C limit pledged by nearly 200 countries in the 2015 climate agreement, and further records have been broken in 2025.¹ Many serious adverse weather events have been recorded recently, the occurrence or severity of many of which was unlikely to have been observed had there not been anthropogenic climate change.² The levels of culprit greenhouse gases continue to increase,³ though there are some signs that emissions from some countries may have peaked. However, even if greenhouse gas emissions were to stop tomorrow, the embedded impact of those already in the atmosphere would continue global warming unless they are removed.

For human health, climate change is among the most serious challenges, converging with other global threats such as biodiversity loss and environmental degradation. Climate change threatens to reverse the gains in human health over the past decades and render meaningless sophisticated advances in disease treatment and prevention measures. The Lancet Countdown’s authoritative global annual stock take of the situation for human health warns of the need to act with increasing urgency.⁴ For the large proportion of the human population depending on outdoor work for their livelihood, climate change and its impacts represent serious challenges. Exercising outdoors, with all its benefits, will become increasingly difficult for everyone.⁵

For epilepsy, the impacts of climate change are already being felt and are likely to increase.⁶ The magnitude of increases in global average surface temperatures may appear modest, but the increased energy in the environment that this represents causes changes across seasons. It generates more frequent and severe adverse weather events, such as droughts, food shortages, wildfires, heatwaves, and floods. Changes in local environments can also alter the ranges of vectors that can carry neurological infections. Increased pressures on the environment can lead to conflict and forced migration, challenging healthcare provision and increasing health risks. Together, these changes, occurring at a rapid pace, pose multilayered epilepsy risks.⁷

Epilepsy incidence is likely to rise or change in its geographical patterns. Conflict is associated with head injury, a proportion of which leads subsequently to epilepsy. Temperature extremes and other climatic factors contribute to an increased incidence of stroke.⁸ The numbers of post‐stroke epilepsy will probably increase. As vector ranges expand, neurological infections will lead to meningitis, encephalitis, and novel forms of encephalopathy of unknown origins in extended at‐risk or naïve populations. Examples include the spread of tick‐borne encephalitis, West Nile encephalitis, dengue fever, and changing patterns of meningitis and Zika‐related encephalopathy.⁷

For people with epilepsy, climate‐change‐related impacts are likely to be detrimental.^{6, 7} Sleep is vital for everyone; for many with epilepsy, sleep disturbance carries the risk of aggravating or precipitating seizures. As temperatures rise, heatwaves become more frequent and intense, generating elevated nocturnal temperatures that can disrupt sleep,⁹ and in turn aggravate pre‐existing epilepsy and increase SUDEP risk.¹⁰ Heatwaves can increase the frequency of inter‐ictal discharges and seizures as recorded by prolonged intracranial EEG.¹¹ In non‐air‐conditioned hospital facilities, heat waves may create internal environments that are not conducive to the management of acute admissions for epilepsy. At the molecular level, the behaviour of many proteins, such as ion channels, fundamental to brain function, is exquisitely temperature‐sensitive; mutant proteins may also exhibit this sensitivity.⁹ Cerebral thermoregulation shows diurnal rhythmicity, loss of which can occur, for example, in severe head injury, and compromises recovery.¹² Altered thermoregulation may occur post‐ictally.¹³ It may be a feature of some rare epilepsies,¹⁴ rendering people affected by these epilepsies even more vulnerable to heatwaves or other unseasonal temperature extremes. Some antiseizure medications, and other drugs, such as anti‐psychotic agents and anti‐muscarinic drugs, can impair thermoregulation to dangerous extents in different ways, further increasing risks.⁹ Floods and wildfires compromise supply chains, risking interruption to the supply of antiseizure and other medications.¹⁵ Multilayered risk scenarios can easily be imagined, posing significant risks to people with epilepsy.^9,16

Ultimately, mitigating climate change requires intergovernmental action, drastic reductions in greenhouse gas emissions, and systemic adaptations that must be implemented now. In epilepsy, there remains much to be learnt about the mechanisms by which climate‐change‐related events and environmental changes pose risks. Those most at risk need to be identified, and adaptation plans need to be put in place.¹⁷ There are actions we can take now, even whilst we seek to understand mechanisms better and to devise specific counteractions. There is no option: for healthcare professionals, it is not a matter of either providing care for people with epilepsy or dealing with climate change. We have to do both together, as we did in the pandemic. The challenge is clear, as is the need for action.