The rising global incidence of skin cancer underscores the need to better understand the environmental and behavioral factors contributing to this public health crisis.¹¹ Climate-related changes such as increasing temperatures and depletion of the natural stratospheric ozone layer may increase UV radiation exposure, which is well established as a major driver of both melanoma and non-melanoma skin cancer.^1,12,13 Severe UV exposure promotes photocarcinogenesis through oxidative stress, DNA instability, and double-strand breaks. UV exposure also impairs DNA repair mechanisms, including p-53-mediated cell cycle checkpoints.¹² The stratospheric ozone layer serves as an essential UV filter protecting the Earth from a substantial amount of damaging UV rays.¹² Historic ozone depletion contributed to increased UV burden and remains relevant to understanding skin cancer risk.¹² However, this relationship requires nuance. Owing in large part to policy interventions such as the Montreal Protocol on Substances that Deplete the Ozone Layer, the ozone layer is now gradually recovering.^8,14 The Montreal Protocol is estimated by the United Nations Environment Programme to prevent skin cancer in two million people yearly by 2030.¹⁴ Even so, the dermatologic effects of prior ozone depletion, long latency periods for skin cancer development, and regional variability in UV burden remain important considerations. Skin cancer incidence continues to rise, and rates of both melanoma and non-melanoma skin cancers (NMSC) are predicted to rise annually. Since 1990, the number of NMSC cases increased 281% globally with over 6 million cases in 2021 alone.^11,15–17 This rate is projected to increase by approximately 50% over the next two decades, with an even steeper rise in those currently aged 55 and older.¹¹ Beyond malignancy, chronic UV exposure significantly contributes to DNA damage, oxidative stress, hyperpigmentation, and photoaging.¹⁸ This risk may be further exacerbated by societal behavioral factors, including increased time spent outdoors and decreased use of sun-protective measures.¹²

Although skin pigmentation offers some inherent sun protection, skin cancer can affect any individual, including those with more richly pigmented skin. Patients with more richly pigmented skin often experience worse outcomes as opposed to those with less pigmented skin. This is in part due to delayed diagnoses subsequent to misconceptions about risk, delayed detection, lack of awareness, and limited representation in dermatological education.¹⁹ Patients with skin of color are also more likely to experience hyperpigmentation disorders such as melasma, for which sun exposure, including both UV and high-energy visible light, is a major driver.^20,21 These patterns suggest that changes in UV exposure may worsen existing inequities in dermatologic outcomes in multiple types of skin disease including skin cancer. Sun protection will thus become increasingly paramount for all individuals, regardless of skin pigmentation and geographic location. Multimodal methods are recommended, incorporating broad-spectrum sunscreen with frequent reapplication, UPF clothing, wide-brim hats, wide sunglasses, seeking shade, and sun avoidance during peak UV intensity times.

Other photosensitive conditions, including polymorphous light eruption, cutaneous lupus erythematosus, rosacea, dermatomyositis, and porphyrias, may also be influenced by changing patterns of UV exposure. Together, these findings suggest that climate change is not only relevant to skin cancer prevention, but also to a broader management of photosensitive disease in dermatologic practice.

Climate change is reshaping the fundamental epidemiology and geographic distribution of many infectious diseases, including those with dermatologic relevance (Table 1). Changes in temperature, precipitation, humidity, and ecological disruption may influence the survival, reproduction, vectors, and animal reservoirs of infectious microorganisms.^1,22,23 Warmer temperatures globally are associated with expansion of the geographic range of pathogenic microbes and vectors into new regions. In parallel, more frequent extreme weather events may create ideal conditions for existing infections to flourish and new ones to emerge. Further exacerbating this spread, climate instability can drive human migration and increase human exposure to infectious agents by disrupting healthcare infrastructure and microbial habitats, consequently leading to limited resources, poor sanitation, and overcrowding. Many of these shifting infectious diseases manifest with cutaneous signs for which patients seek medical care.

341258 Table 1.

Consistently warmer temperatures at higher latitudes have contributed to the increased spread of the mosquito-borne illnesses Chikungunya, Dengue, and Zika viruses into novel regions, including the southern United States.^22,24,25 These infections can present with characteristic cutaneous findings in addition to systemic symptoms such as fever and arthritis/arthralgia.^22,24,26 Dengue, the fastest-growing vector-borne disease, has cutaneous manifestations in up to 82% of patients, including a morbilliform or petechial rash that often has characteristic islands of sparing, diffuse pruritus, transient facial flushing, and occasional mucosal involvement.^22,24,27 Zika and Chikungunya infections can present similarly with a morbilliform exanthem, and patients with Zika virus may have acral maculopapular involvement as well as conjunctivitis and palmar desquamation.^13,22 Climate-induced shifting patterns in exposure are clinically important as diseases that were once considered geographically limited may become increasingly relevant in routine differential diagnosis and testing.

Similar to mosquitoes, the increasing geographic range and longer active season of ticks that transmit tick-borne illnesses are at least in part due to climate change.²⁸ Tick-borne illnesses, including Lyme disease, Rocky Mountain Spotted Fever, Southern Tick-Associated Rash Illness (STARI), anaplasmosis, and babesiosis, as well as other vector-borne parasitic diseases such as Leishmaniasis, Chagas disease, and New World Screwworm myiasis, are widening their geographic risk regions across the United States secondary to climate change.^4,22,29–32 Such vector spread is predicted to continue, increasing the likelihood that dermatologists will encounter vector-borne infections in regions where they were previously uncommon.^33 ^

Increasingly frequent and extreme weather events, such as droughts and floods, may alter infectious disease risk by creating conditions favorable to both established and emerging infections. Flooding has been linked to a rise in Mycobacterium marinum, Vibrio vulnificus, leptospirosis, and dermatophyte infections.^22,33,34 At the other extreme, droughts have been associated with increased cases of coccidioidomycosis due to excessive changes in soil conditions.^{4,19,22,31,35} With climate change models, coccidioidomycosis is predicted to become endemic in a larger range, including Idaho, Montana, Nebraska, North Dakota, South Dakota, and Wyoming by 2100, in addition to its current endemic areas of Arizona, California, New Mexico, West Texas, and Utah.³⁶ As a disease that is commonly underdiagnosed even in endemic regions, these projected shifts reinforce the need for improved awareness and earlier recognition.^35,37

Climate change also carries the potential threat of previously unidentified or resistant infectious diseases. For example, infectious vectors, including Bacillus anthracis and Francisella tularensis, are emerging from thawing permafrost in Arctic regions of the Northern Hemisphere and mountainous areas of the Southern Hemisphere.²² The virulence and health implications of such pathogens remain uncertain, but they potentially carry a significant risk for human disease. Additionally, some microbes may develop increased thermotolerance, which may contribute to the re-emergence of previously controlled diseases and reduce the effectiveness of existing infection-control strategies, such as sanitation, antibiotics, and vaccines. For example, viruses such as Chikungunya, Dengue, Leishmaniasis, and West Nile have evolved to replicate at higher temperatures.²² Severe or resistant strains of known infections are increasing globally, such as drug-resistant dermatophytes, and are catalyzed by climate change and antimicrobial resistance.^38–40 Collectively, these patterns suggest that climate change may alter not only where infectious dermatoses occur, but also how frequently and unpredictably they are encountered in practice.

Mirroring broader patterns of health inequity, vulnerable populations disproportionately bear the dermatologic manifestations of climate change.^1,41 These consequences include greater exposure to infectious diseases, burns from UV radiation and external heat-retaining surfaces, and exacerbation of chronic dermatoses by air pollution and low-resource living conditions.^1,29,41,42 Structural barriers such as inadequate healthcare access, unstable living conditions, greater environmental exposure, and limited access to protective and preventive resources like sunscreen or clean water compound these risks and contribute to a disproportionate disease burden.⁴³ Vulnerable groups at an elevated risk include people at the extremes of age, people experiencing homelessness, those with substance use disorders or otherwise altered sensorium, people experiencing poverty or with limited resources, immunosuppressed patients, patients with genetic immunodeficiencies or skin cancer predispositions, and those enduring displacement.^{1,11,12,34,41,44}

Climate instability drives human displacement (climate refugees) through extreme weather, resource insecurity, and uninhabitable living conditions.⁴⁵ Certain regions such as coastal communities are especially at risk.⁴⁶ Affected populations may be forced to reside in unsanitary and overcrowded environments with limited medical infrastructure and availability of clean water and food.³⁴ These conditions increase the risk of infectious dermatoses while also worsening management of chronic skin disease and reducing access to preventative resources.²² Immunosuppressed patients, including organ transplant recipients, patients receiving immunosuppressive medications, and those with HIV or inborn immunodeficiencies, may face greater risk from infectious diseases at baseline, which would be exacerbated by shifts due to climate change. Populations of increased susceptibility to carcinogenesis from increased UV exposure include organ transplant recipients - as they currently have an elevated risk for more numerous and aggressive skin cancers, and those with genetic susceptibilities or predisposition to skin cancer, such as patients affected by albinism, xeroderma pigmentosum, and basal cell nevus/Gorlin syndrome.^11,12 Overall, climate change acts not only as an environmental stressor, but also as a force that amplifies existing social and medical inequities relevant to dermatologic health.

Dermatologic practice contributes to environmental burden through procedures, single-use disposables, and plastic and polystyrene packaging for products and medications.^{30,32,47–49} While many types of clinical waste are unavoidable, such as sharps, bloody gauze, gloves, and biohazard chemicals, dermatologists can play an important role in reducing waste whenever possible. Practical resources are available to help providers and practice managers identify actionable opportunities to reduce emissions at the clinic level. The British Society for Dermatological Surgery has a freely available sustainability guidance toolkit.⁵⁰ The AAD Climate Change and Environmental Issues Expert Resource Group newsletter also offers sustainable advice.⁵¹

Procedures are a key target for waste-reduction interventions. These examples are particularly valuable because they move the discussion from abstract sustainability goals to concrete, clinic-level interventions. Limiting gauze, alcohol swabs, and instruments on biopsy and excision trays can reduce waste.^30,47 For example, a recent interventional study of 98 biopsy trays at 4 outpatient dermatologic clinical sites found that at baseline, 100% of biopsy trays had over 2 wasted supplies, with a mean of 10.1 wasted items per tray.⁵² After an educational intervention focused on climate change and standardized tray setup, only 16% of trays had more than 2 wasted supplies, and the mean number of wasted supplies decreased to 1.6. In surgical settings, actionable steps include switching from single-use to reusable instruments and drapes, reducing packaging material (the largest source of dermatologic surgical waste at 65% by weight), and reducing unnecessary surgical garb and drapes.³² Unplugging and turning off equipment such as lasers, computers, and hyfrecators overnight and over weekends can reduce energy consumption.^30,47 Prioritizing reusable products and advocating for reducing packaging in biologics and other medications is another avenue to minimize climate impact.⁴⁷

The environmental implications of AI represent a related but distinct issue. AI is increasingly being incorporated into dermatology for uses such as malignant lesion detection, image analysis, diagnostic support, and patient-facing tools.^{18,19,53–56} These tools have shown promising and innovative early applications in dermatology, although the specialty-specific environmental implications of their development and deployment remain incompletely characterized.⁵⁷ Although concerns about consent, privacy, and accountability in dermatologic AI use have received growing attention, the environmental costs of these systems remain largely uninvestigated. AI systems, especially large language models, require substantial resources, including computational infrastructure, data storage, and the transfer of massive datasets, as well as the training and retraining of algorithms.^57–59 This all requires significant electricity consumption and cooling power; in 2023, these data centers accounted for 4.4% of US electricity, and as AI usage increases exponentially, it is predicted that in the next decade these data centers could comprise 20% of global electricity use.^59,60 However, strategies exist to shift towards more sustainable models, which will be critical to avoid spurring further environmental damage.⁶⁰ Given the adverse healthcare outcomes associated with climate change, the use of AI in healthcare—including dermatology—should consider environmental sustainability alongside clinical performance, ethics, and implementation.