Intended for healthcare professionals


A pathway to net zero emissions for healthcare

BMJ 2020; 371 doi: (Published 01 October 2020) Cite this as: BMJ 2020;371:m3785

Linked Editorial

Towards a carbon neutral NHS

  1. Renee N Salas, affiliated faculty123,
  2. Edward Maibach, distinguished university professor4,
  3. David Pencheon, associate and honorary professor5,
  4. Nick Watts, executive director6,
  5. Howard Frumkin, professor emeritus7
  1. 1Harvard Global Health Institute, Cambridge, MA, USA
  2. 2Center for Climate, Health, and the Global Environment, Harvard TH Chan School of Public Health, Boston, MA, USA
  3. 3Department of Emergency Medicine, Harvard Medical School, Boston, MA, USA
  4. 4Center for Climate Change Communication, George Mason University, Fairfax, VA, USA
  5. 5Medical and Health School, University of Exeter, Exeter, UK
  6. 6Lancet Countdown: Tracking Progress on Health and Climate Change, London, UK
  7. 7University of Washington School of Public Health, Seattle, WA, USA
  1. Correspondence to: R N Salas rnsalas{at}

The healthcare sector has a profound responsibility and opportunity to reduce greenhouse gas emissions to limit the widespread health harms of climate change. Renee N Salas and colleagues chart a path to net zero emissions for healthcare

Key messages

  • Greenhouse gas emissions from healthcare are substantial, and the health sector has generally lagged most other industries in reducing its carbon footprint

  • Healthcare leaders and organisations have both a responsibility and an opportunity to chart a path to net zero emissions

  • Doing so can improve health, protect healthcare delivery by minimising disruptions, yield economic benefits, and establish the healthcare sector as a leader in climate action

  • Rising to the challenge of net zero in healthcare will require broad transformative steps, such as reducing demand through preventive care, powering the entire enterprise with clean energy, choosing medical supplies and equipment with lower carbon footprints, and reducing travel through telemedicine

The Intergovernmental Panel on Climate Change has made clear that limiting global heating to 1.5°C above pre-industrial levels will greatly reduce the probability of sustained public health catastrophes. To achieve this, human caused carbon dioxide (CO2) emissions must fall to roughly half of 2010 levels by 2030 and to net zero by 2050. Emissions of other greenhouse gases (GHGs) must reach net zero soon thereafter (between 2063 and 2068).1

To achieve net zero GHGs, emissions from all sources—electricity generation, industry, transportation, buildings, and so on—must be reduced to as close to zero as possible, and any remaining emissions must be balanced by removing CO2 from the atmosphere, through such means as reforestation and direct physical-chemical removal. Modelled estimates vary on the specifics, but the needed direction of travel is clear—we must urgently and radically reduce GHG emissions.

Net zero is technically feasible across much of the world’s economy, although some sectors, such as steel and cement manufacturing and long distance air travel, will prove more difficult. Nations, cities, investors, and businesses are increasingly committing to net zero targets. To date, one national healthcare system—the NHS in England—has committed to delivering a net zero health service across its full scope and proposes that its approach—a clear plan, a suite of interventions, and a process to drive increased ambition over time—be built on by other systems.

Healthcare delivery is substantially more energy intensive than most other commercial and service activities,2 and the health sector has lagged in efforts to reduce emissions. By striving for net zero, the healthcare industry can help limit climate change and its downstream consequences, promote public health through reduced air and water pollution, create cost savings by eliminating waste and inefficiency, and become leaders in the global effort to limit global heating to 1.5°C.

This paper charts a course to net zero emissions in healthcare. We describe efforts to date, recount the benefits of net zero operations, review available strategies, and identify knowledge gaps.

Healthcare’s carbon emissions

Decarbonising healthcare begins with identifying and quantifying the sources of CO2 emissions, known as the “carbon footprint,” and of other GHG emissions. This is complex. It requires defining system boundaries, which encompass the production and transport of medical supplies, patient and staff transportation, energy use in medical facilities, the investment portfolios of health care organisations, and more (fig 1). Complete accounting requires consideration of the entire life cycle of healthcare products and processes and allocating all associated carbon footprint contributions (box 1). If a blanket, defibrillator, or medication used in a hospital is manufactured at a distant factory in a process that emits large amounts of CO2, then that item is said to carry “embedded carbon,” which is attributed to the hospital, not the manufacturer.

Fig 1
Fig 1

Measured and unmeasured healthcare sector activities that contribute to greenhouse gas emissions by scope3

Box 1

Key concepts and definitions

Two core concepts for GHG emission quantification

  • Life cycle analysis—“cradle to grave” assessment that captures all emissions associated with a product or activity, from manufacturing to use and disposal.

  • Multi-region input-output modelling—an analytical approach that tracks flows of goods and services from different sectors of the economy into the health sector, monetises these flows, links monetary accounts to GHG emissions in each sector, and allocates “embedded” carbon emissions to the health sector34567

Three emission scopes

  • Scope 1 emissions fall under the direct control of the healthcare facility (eg, on-site fuel combustion, fleet vehicles, anaesthetic gas leaks)

  • Scope 2 emissions derive from electricity purchased by the facility

  • Scope 3 comprises all other indirect emissions (eg, embedded carbon in purchased supplies and equipment, employee commuting, waste disposal).8

Scope 1 emissions are under healthcare facilities’ most direct control. But over 70% of healthcare emissions arise from the diverse categories in scope 3, which very few health systems calculate or report—a failure of accountability.3 The NHS is a notable exception.


Globally, the carbon footprint of healthcare in 2016 represented an estimated 4-6% of all emissions (fig 2).4 The United States has the second highest per capita emissions, with healthcare estimated to contribute upwards of 10% of carbon emissions,9 second only to Iceland, where import emissions are substantial.10 Emissions rose in many countries between 2007 and 2016, including China (180%), South Korea (75%), Japan (37%), and the US (19%).4 The dramatic rise in China came during a decade of major poverty reduction and investment in healthcare services.

Fig 2
Fig 2

Estimated carbon footprint in 2016 across national health systems. Data from Watts et al4 were used to allow country comparisons across one methodology. Additional international comparison data, with differences in values given varying methodologies, are available from Karliner et al,2 Lenzen et al,5 and Pichler et al.6

Carbon footprints vary across medical specialties (table 1) and treatments (table 2). The carbon footprint of renal dialysis, for example, varies fourfold depending on technique,24 and the that of pharmaceutical manufacturing varies fivefold across companies,16 indicating considerable room for improvement among high emitters. Comparison is stymied by heterogeneity in assessment methods. The carbon footprints of entire specialties and treatments have not yet been quantified, nor the experiences of countries other than the US, United Kingdom, and Australia.

Table 1

Estimated carbon footprint across specialties and health industry sectors

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Table 2

Estimated carbon footprint across procedures and treatments

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Benefits of reducing emissions

Approaching and achieving net zero offers a wide range of benefits for healthcare. Perhaps most importantly, it advances the core mission of health institutions—improving health—because measures that mitigate the climate crisis yield numerous health benefits (often called “co-benefits”). In the long term, healthcare emissions reductions will contribute to reducing the many adverse health effects of the climate crisis.25 More immediate benefits26 include the increased physical activity, improved air quality, reduced noise, and avoided car crashes associated with shifting from automobile travel to walking, cycling, and transit27; the improved air quality associated with a shift from fossil fuel combustion to renewable power sources2829; the reduced risk of cardiovascular disease and some cancers associated with a shift from meat heavy to plant forward diets30; and the improved health, wellbeing, and productivity associated with green, energy efficient hospitals and clinics.31

Global assessment of healthcare environmental footprints shows that they are wide ranging, often avoidable, and predominantly indirect (scope 3, see box 1).5 Healthcare systems need to use their considerable influence to decarbonise not just their internal operations, but their total supply chains and models of care and prevention. We need to increase the quality and precision of healthcare, not simply the amount. Getting to net zero will enable healthcare providers to deliver high quality care today and in the future. Quality of care and environmental performance should be increasingly connected given their interdependence.[5]

Health institutions can realise substantial financial benefits through spending less on energy, maintenance, supplies, and other factors and through reducing waste, even when up-front investments are taken into account.323334 This is especially important given the economic challenges facing healthcare systems in the covid-19 pandemic. The shift to carbon neutral energy use, together with reduced energy use through conservation, for example, is projected to save Boston Medical Center $153m (£120m; €130m) between 2010 and 2030.35 Getting to net zero also offers health institutions an opportunity for broader community leadership.36 Lastly, environmental initiatives can motivate the healthcare workforce and build employee morale.37

Solutions within and outside of healthcare systems

Recovery from the covid-19 pandemic and its associated economic downturn provides the opportunity to reimagine and transform healthcare systems so they are resilient to future social, economic, and environmental challenges, particularly towards net zero performance. A range of transformative solutions must be considered both within and outside of healthcare (table 3). Some solutions are system-wide, such as creating a culture of sustainability and implementing consistent and valid carbon metrics, an explicit reduction trajectory, and associated accountability processes. Other solutions pertain to specific operational aspects of healthcare delivery, from clean, renewable energy to transportation, from food services to supply chain management, and still others relate to individual specialties or treatments. Innovative care models might be more acceptable in the wake of covid-19. Many of the adaptive practices that were implemented at scale and pace during the pandemic—more telehealth consultations, more care closer to home, more empowered self-care, less travel—could benefit patient, purse, populations, and planet. When inevitable trade-offs arise, such as balancing energy intensive infection control measures with reduced energy use, they will need to be managed with careful adaptive management based on rigorous data collection and analysis.

Table 3

Example solutions for the healthcare sector with potential internal and external actions

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Creating a culture of sustainability in healthcare can draw from models in other industries and from successful healthcare quality improvement and change management efforts, such as in patient safety.474849 An inclusive culture can be created by connecting the climate crisis to clinical practice and the institutional mission,50 as well as to fundamental healthcare values such as “do no harm,” and by defining institutional success according to the triple bottom line (social and health improvements, economic performance, and environmental impact).5 This can engage people at all institutional levels, from non-clinical staff to health professionals. The creation of a chief sustainability officer position could help ensure that sustainability is prioritised across institutional decision making,51 but senior leaders need to support and hold to account a pan-organisational approach to avoid isolating the actions to one department. People skilled at conflict analysis and resolution could help manage inevitable conflicts from impeding the rapid transformation required.

Accurate carbon footprints for healthcare are essential for decision making and evaluating cost effectiveness.52 Assessments that extend beyond carbon emissions can look at other environmental impacts that harm health, such as air pollutants and water depletion.5 But current measurement practices need to be better standardised, and because a large portion of healthcare emissions relate to the supply chain, scope 3 emissions need to be routinely included. New metrics could be developed to reflect the carbon intensity of care per unit of health improvement delivered, applying the methods of value based healthcare to environmental performance.5354 Transparent reporting should extend to healthcare supply companies and lead to open commercial advantage, assisting in selection by hospitals and incentivising low carbon production. Data, analytical techniques, and trained personnel must be available in countries where they are currently absent, especially low and middle income countries. Multinational firms that supply product lines globally can help by disclosing the carbon footprints of their products to all purchasers.

Achieving net zero requires efforts that extend beyond conventional clinical care. Primordial and primary prevention—including poverty and inequality reduction, strong social networks, tobacco and substance abuse control, healthy diets, and physical activity—are intrinsic to this transformation because they reduce the need for healthcare and therefore for energy and resource intensive treatments. Investment policy is also a part of this transformation. Healthcare institutions, by divesting their financial holdings in fossil fuels, can both advance their mission and help normalise the withdrawal of social license from this industry.55

Financial incentives can be tied to environmental performance, including GHG emissions. An example comes from the implementation of Medicare, the US national healthcare insurance programme for elderly and disabled people, in the 1960s. The government secured the rapid racial integration of hospitals by withholding reimbursement from segregated hospitals.56 Similarly, reimbursements could be withheld from healthcare systems or facilities not moving toward decarbonisation. Such incentives are easier to implement when health and financial incentives are aligned: where the system monetises health rather than illness.

The covid-19 pandemic has catalysed the rapid expansion of low carbon practices such as telehealth and virtual meetings; the concurrent carbon benefits will help institutions move toward net zero.43 Other innovative models that reduce in-person healthcare encounters will also deliver environmental and economic benefits, after their efficacy and safety are documented. Similarly, the rapid expansion of virtual meetings and conferences46 will probably lead to reduced professional travel after covid-19, saving time and money while reducing carbon footprints.

Specific initiatives within healthcare systems around the globe are shown in box 2.

Box 2

Case study examples of efforts to reduce GHG emissions

A national health system getting to net zero

The NHS, having worked for a decade to reduce its emissions, has now set out clear targets and a process to reach net zero for the emissions it controls directly (its carbon footprint) by 2040, and the entirety of its emissions by 2045.5758 This plan is now the most ambitious decarbonisation effort under way in the world, but the NHS has already shown its capability to reduce emissions, decreasing total GHG by 26% from 1990 to 2020. This work and future targets have been informed by a Net Zero Expert Panel,59 a nationwide call for evidence,60 and national and international technical expertise. The full suite of interventions needed to reach net zero covers a broad range, from technical and engineering based interventions to improving buildings and transport systems and rethinking new models of care that will enable a more sustainable, less carbon intensive approach to health and care.

Individual health systems

Gundersen Health System, an integrated healthcare organisation based in La Crosse, Wisconsin, USA, and serving communities in the states of Wisconsin, Minnesota, and Iowa, represents one of the biggest US efforts to achieve net zero for its portfolio of buildings. By focusing on two main initiatives—reducing resources consumption through energy efficiency and conservation and investment in clean, renewable energy—Gundersen has made substantial progress toward reduced energy use and has identified an additional goal of offsetting all utility energy consumption with equivalent, renewable, local energy generation. Gundersen relies heavily on wind energy; two wind farms in Lewiston, Minnesota, and Cashton, Wisconsin, each generate about 5 megawatts of energy, enough to collectively power 2600 homes each year. Gundersen fully converted from fossil fuels to locally produced energy by 2014; together with other efforts, such as waste reduction, it calculates annual operational savings of $3.7m.6162

Bhagat Chandra Hospital, a multispecialty, 85 bed facility in Dwarka, New Delhi, India has achieved considerable financial and environmental benefits by transitioning to solar energy, conserving approximately 93 000 kg CO2 emissions since 2016. Through a coordinated, hospital-wide initiative, Bhagat Chandra has installed 50 kW solar panels that connect to the electrical system and reduce 20-30% of its energy consumption. In addition to this major change in energy reliance, the hospital has made other major changes to transition to clean energy including: installation of 4 star electrical appliances, swapping of conventional light bulbs for LEDs, and installation of auto lock on doors to maintain temperature and minimise unnecessary energy use. When taking into account the market cost of solar panels, the economic investment in the panels will be returned in six years and will save 65 000 kg CO2 and $14 800 in energy costs per year.63


Butaro District Hospital, a 150 bed facility located in the Northern Province of Rwanda, was constructed as a low carbon building in collaboration with Partners in Health, the Rwandan Ministry of Health, and MASS Design. Butaro Hospital minimises energy consumption through the use of non-permeable continuous flooring, natural daylight, natural ventilation, and optimised fans and UV lights to ventilate while minimising transmission of airborne infections. Many of the materials for the construction of the facility were sourced locally (including volcanic rock from the Virunga mountain chain), and targeted labour practices were implemented so that 4000 jobs were created for local residents and 85% of the costs of building construction were channelled into the local economy, resulting in substantial economic savings compared with other Rwandan hospitals.646566

Specialty specific interventions

In 2012 Albert Einstein Hospital, located in Sao Paulo, Brazil, found that nitrous oxide (N2O) made up over half of its total hospital emissions. The hospital convened a team focused on limiting reliance on N2O and was able to reduce its use for anaesthetic procedures by 23%. It need only be used when it lowers the morbidity and mortality compared with other anaesthetic drugs. Albert Einstein Hospital has continued to make progress on reducing GHG emissions through less reliance on N2O and was recently presented with the 2020 Challenge Climate Champions award for its 7% reduction in total GHG emissions solely through reduced N2O.6667


Every day, the Melbourne Health Production Kitchen prepares nearly 3000 meals for patients at the Melbourne Hospital City Campus in Australia. Previously, all surplus food was sent to landfills. Beginning in February 2018, the extra food was diverted to the community, preventing 25 kg of food from waste, providing 4200 meals a month, and reducing emissions due to food waste by 17 tonnes of CO2 equivalent (CO2e) per year.68

Through a different approach, the Buddhist Tzu-Chi Dialysis Center in Malaysia has reduced its carbon footprint by promoting vegetarianism and using reusable food containers. Implementing an “only vegetarian” policy since the centre opened in 1997, the centre saves 4.9 kg of CO2 emissions for every kg of tofu served in place of chicken. They have also seen major falls in carbon footprint by reducing the use of plastic bags.69


Taiwan’s Taichung Tzu Chi Hospital has reduced its carbon emissions by a dramatic 3 tonnes per year through the implementation of a hospital carpooling application that has encouraged the carpooling of 6500 employees and patients since 2016. These efforts have saved 3112 tonnes of CO2e from 2011 to 2015.70

Landspitali, the National University Hospital of Iceland, has substantially reduced its carbon footprint by increasing eco-friendly travel to and from work from 21% to 40% of employees. Through the design of a green travel agreement, Landspitali has created economic and health gains for its employees while minimising CO2e.71

Supply chain interventions and responsible purchasing

The Philippine Heart Center has adopted a strategy of green procurement and incorporating environmental considerations into their decisions about products and services. Moving forward, it plans to acquire knowledge on carbon emission accounting to be able to more accurately estimate the effects of green procurement on carbon output.72

Kaiser Permanente, an integrated managed care consortium based in Oakland, California, USA, has made concerted efforts to purchase environmentally responsible computers. It has been able to reduce the use of toxic materials and energy, resulting in energy cost savings of $4m a year.73


Overcoming barriers to transformation

System change at scale is challenging. Complex systems have considerable inertia, vested interests have outsize influence, and even well intentioned people are often too busy to engage in the process of change.

Leadership commitment is critical. Industries and companies whose leaders champion sustainability goals are the most successful in meeting those goals. Boards of healthcare institutions should require this commitment in the leaders they select, and professional associations—in clinical professions and in healthcare administration—should promote environmental sustainability as a core value among their members and use sustainability or environmental performance as one of their measures of quality.74 At the same time, “rank and file” commitment among healthcare personnel is critical. Training programmes in medicine, nursing, and other health professions should incorporate climate change mitigation and adaptation in their curriculums.7576 Environmental performance should be integrated into position descriptions, on-the-job training, performance evaluations, and promotional activities in the workplace.

Evidence based principles of individual and organisational behaviour change can be systematically applied to accentuate and accelerate the process of culture change,49777879 although policy changes are the most powerful way to affect behaviour and culture change in healthcare and other organisations.8081 Applying a “communities of practice” approach has shown great promise in accelerating individual and organisational behaviour change in healthcare8283 and in other professional settings relevant to sustainability.

Incentives for change are also critical. In addition to healthcare reimbursement schemes, other financial incentives include discounting the purchase of renewable energy and tax incentives for reduced carbon emissions. Standards and regulations have a place—either voluntary standards adopted by industry groups or governments or compulsory standards promulgated by governments, or both. These might apply to medical equipment and supplies, to medical procedures, and even to entire clinics and hospitals.

Transparency is effective in motivating change. We need validated, standardised, and widely accepted indicators of GHG emissions across the health sector. Institutions should use these indicators to track their emissions and disclose their results regularly. “Eco-labelling” of products and supplies with their carbon footprints might also be useful, both in influencing consumer choices and in driving industry practices, although further research is needed on its effectiveness.8485

Finally, gaps in knowledge are frequently a barrier to change that must be filled.

Critical knowledge gaps

Knowledge gaps fall into several categories. First, we need a detailed understanding of the sources of emissions across the healthcare delivery life cycle. Of particular importance are major elements of the supply chain such as pharmaceuticals and medical equipment. This requires sophisticated but user friendly methods of quantifying carbon footprints, which require further development.86 Second, research and development efforts need to deliver innovative equipment, supplies, and practices that reduce the carbon footprint. Third, we need these innovations to be tested to establish safety and efficacy. Fourth, we need economic analyses of low carbon innovations to establish their costs and benefits. Fifth, we need sustained collaborations between healthcare providers and senior management, technical experts in sustainability, and behavioural scientists to develop and test methods of accelerating progress towards net zero and to move the field towards evidence based change management procedures. The research needed to achieve these broad knowledge goals requires multidisciplinary collaborations, including engineers, process analysts, and clinicians. Biomedical research funders, both public and private, should support the needed investigations.

Unique considerations in low and middle income countries

Healthcare settings in low and middle income countries generally have small per capita carbon footprints and expenditures, but the overall environmental intensity can be quite large.5 But many of these healthcare systems might not be in a position to reduce energy use, alter procurement practices, or make other disruptive changes. With 59% of healthcare facilities in low and middle income countries reportedly lacking reliable electric power,87 the scarcity of energy and materials in many facilities is the pressing challenge.8889 Insufficient electricity limits access to lighting, ventilation, water, refrigeration, and functioning diagnostic and treatment equipment, with potentially dire consequences for patients. A study of Ugandan emergency obstetric care, for example, found that only 2% of primary health centres, 29% of referral health centres, and 61% of hospitals providing obstetric care had reliable electrical power supplies; this contributed to unacceptably high mortality from uterine rupture, haemorrhage, and other complications of childbirth.90 In a survey of surgeons across 39 African nations, most working in regional or national referral hospitals, 48% reported at least weekly power failures, 40% had experienced compromised surgical field lighting, 32% reported delayed or cancelled surgery as a result, 29% had operated using only mobile phone lights, and 18% had directly experienced poor surgical outcomes as a result.91 These disruptions to care are especially lamentable given the heavy burden of disease and disproportionate threat of climate change in low and middle income countries.92

For healthcare facilities in such circumstances, the path to net zero must include provision of reliable electricity. This requires leapfrog technologies (bypassing fossil fuels and conventional electrical grids in favour of solar and wind generation and on-site battery storage) and local innovation.93 Fortunately, this approach is affordable and practical and is increasingly being implemented. Between 2008 and 2015 the Indian state of Maharashtra, for example, installed 407 hybrid solar photovoltaic systems, mostly in remote health facilities, to promote reproductive and child health.94 Such strategies are championed by the non-governmental organisation Sustainable Energy for All,95 which the United Nations launched in 2011 through its Powering Health Care Initiative.96

Many of the supply chains to healthcare institutions in low and middle income countries are global. As manufacturers and suppliers improve the efficiency and reduce the carbon footprints of their products, they should ensure that those benefits reach healthcare systems in low resource settings. “Environmental dumping” of obsolete equipment and supplies must be avoided in low and middle income countries.97

Experience in low resource settings can offer invaluable guidance for wealthy countries. The carbon footprint of phacoemulsification cataract removal, for example, is reported to be 20 times lower in India than in the UK, with similar clinical outcomes.19


Without decisive and urgent action, the climate crisis will increasingly undermine human health and disrupt healthcare delivery. There are both moral and practical reasons for health professionals to be at the forefront of climate action9899—to embrace the drive to decarbonise the economy and to reach net zero emissions. This is crucial in hospitals, clinics, and pharmacies. Healthcare must lead from the front, which entails urgently getting our own house in order by charting a pathway to net zero.


We thank Katherine Raphael and Kristen Riley for their support on this manuscript.


  • Contributors and sources: The authors on this analysis represent diverse perspectives and expertise with an international scope. This project was led by RNS, through whom the article was commissioned, who is an emergency medicine physician and climate and health expert based in Boston, MA, USA. EM is a climate and health communication expert based in Fairfax, VA, USA, whose work focuses on public understanding of climate change and clean energy. DP is a physician and sustainability expert based in Exeter, UK. NW is a climate and health expert based in London, UK, with additional expertise in sustainability. HF is a climate and health expert based in Seattle, WA, USA with extensive expertise on environmental health policy. The unique knowledge of each author was leveraged in the conceptualisation and construction of this analysis.

  • Competing interests: We have read and understood BMJ policy on declaration of interests and do not have any conflicts of interest to declare.