Physicians worldwide are becoming increasingly aware of the impact climate change has on the health of humans. Consistent with previous studies in other countries, physicians who participated in this study have a strong awareness that climate change is happening and an understanding of the adverse impact that climate change has on human health (André et al. 2022, den Boer et al. 2021, Kotcher et al. 2021). The physicians also understand that physicians have a responsibility to advise their patients on the links between climate change and health; however, only some physicians put this into practice. Some of the reported barriers are lack of information/resources, lack of knowledge, lack of time, and lack of support from their facility. The physicians also reported limited opportunities to obtain education on climate change and health.

This study has four main findings. First, it highlighted that physicians have insufficient knowledge about climate change. Second, there is limited access to education on climate change and health. Third, healthcare facilities do not support enough sustainable healthcare practices. Fourth, physicians are willing to advocate for climate change policy.

Physicians have insufficient knowledge about climate change

More than half of the physicians agreed that physicians have a responsibility to advise their patients on the health impacts of climate change and that physicians can play a role in changing the behavior of their patients to engage in more environmentally sustainable lifestyle choices. However, in practice, most physicians responded that they hardly advise their patients on the links between climate change and health or on health co-benefits. When assessing the physicians' knowledge, less than half of the physicians were able to answer any of the four questions correctly. Furthermore, the majority of the physicians were unfamiliar with the term ‘planetary health.’ The data suggests that physicians have insufficient knowledge of climate change. Previous studies conducted among physicians in other countries had similar findings, that a lack of knowledge impeded physicians from engaging in more climate-related initiatives (André et al. 2022, den Boer et al. 2021, Kotcher et al. 2021).

This could be one of the reasons that although physicians recognize the need to advise patients on the links between climate change and their health, they may feel averse to doing so due to insufficient knowledge. A study conducted in Thailand on the drivers of physicians’ engagement in addressing eco-health problems showed that physicians’ knowledge of the links between the ecosystem and health is significantly associated with whether or not physicians advise their patients on how to reduce environmental health risks and increase exposure to more positive environmental factors (Völker and Hunchangsith 2018).

There is limited access to education on climate change and health

When asked about factors that reduced their action to deliver climate-specific health advice and advocacy, some of the main barriers included a lack of information/resources and a lack of knowledge. Furthermore, the majority of the physicians reported not having taken any courses in medical school or any continuing professional education on climate change and health. Moreover, more than half reported rarely seeing educational materials about climate change and health in their facility.

As adverse health impacts of climate change are expected to become more severe over the coming years, physicians must understand their important role in educating the public and their patients in mitigating and adapting to climate change and recognizing its impact on their health. Therefore, physicians must be sufficiently knowledgeable to assume greater responsibility for patients and public education to serve in that role. A German study on climate-specific health literacy and medical advice showed that patients who were informed by physicians about the links between climate change and health had a higher awareness of climate-related health risks and were more willing to engage in more environmentally sustainable lifestyle choices (Reismann et al. 2021).

The Japan Ministry of Education, Culture, Sports, Science, and Technology (MEXT) published the 2022 revisions in the Medical Education Model Core Curriculum, adding compulsory topics such as “climate change and medical care” for medical students; however, planetary health is not included (MEXT 2022). The concept of planetary health has given rise to a growing field of research focusing on the interdependencies between human health and the state of Earth’s complex natural systems and how this impacts the health and well-being of humans and our planet (Whitmee et al. 2015; Veidis et al. 2019). While climate change is a critical environmental crisis threatening the health of current and future generations, an understanding of the intricate relationship between anthropogenically induced degradation of the planet’s natural systems and the interconnectedness with human health is also essential. The integration of planetary health in the education and training of future physicians is fundamental for developing the competencies required to help address the accelerating impacts of the shifting ecosystems on human health.

A multinational study found that planetary health education was incorporated into only 15% of medical students' curricula and that the interest in learning more about planetary health among medical students is exceptionally high (Omrani et al. 2020). Therefore, it is recommended that “climate change and medical care” be taught through a planetary health approach. The ideas and concepts of what planetary health education could look like have already been outlined in several educational frameworks (Guzmán et al. 2021; Shaw et al. 2021; Stone et al. 2018). Evaluation from an elective course on planetary health delivered to medical students at the University of Oslo showed that the course provided students with enhanced knowledge and skills not offered in the current medical curriculum. In addition, some of the students expressed a greater interest in learning more about how to estimate the carbon footprint of health care, sustainable quality improvement, and health service adaptation to climate change (Aasheim et al. 2023).

Moreover, this study shows that prior education or training, knowledge, and awareness of climate change are significantly associated with physicians’ practice in delivering climate-specific advice to their patients. Therefore, the increased knowledge of future physicians could lead to a more active role in educating their patients about the health risks of climate change and health co-benefits, which could help mitigate the worsening climate crisis. Continuing professional education courses could bridge the knowledge gap of physicians currently in clinical practice.

Healthcare facilities lack environmentally sustainable healthcare practices

While more than half of the physicians feel they should advocate within their facilities to promote mitigation measures for more sustainable healthcare practices, less than half actively engage in any advocacy. The healthcare sector contributes around 4.4% to the total global greenhouse gas emissions worldwide, and if healthcare were a country, it would be the fifth-largest emitter on the planet (Pichler et al. 2019).

According to a policy paper by Health Care Without Harm, the climate footprint of Japan’s healthcare sector as a percentage of national emissions is 6.4%, placing the nation among the top major emitters by healthcare sector (Health Care Without Harm 2023). Thus, it is critical to reduce carbon emissions from the healthcare sector and focus on creating more sustainable healthcare systems. The WHO defines a ‘sustainable healthcare system’ as a system that improves, maintains, or restores health while minimizing negative impacts on the environment and leveraging opportunities to restore and improve it to the benefit of the health and well-being of current and future generations (WHO 2023).

Therefore, integrating sustainability into healthcare practice should be a priority in the healthcare sector. However, more than half of the physicians in this study responded that the facilities where they work do not support sustainable healthcare practices. Fortunately, in recent years, greening the healthcare sector has been a growing trend, and there are many promising examples in countries like England to provide guidance for developing and adopting more sustainable healthcare practices, such as the National Health Service (NHS) of England's 2020 strategy "Delivering a Net Zero National Health Service" (NHS England 2024).

Physicians could be at the forefront of shaping targeted strategies within the healthcare system, mitigating the consequences of climate change in the future by reducing greenhouse gas emissions in the facilities where they work. Increasing numbers of health professionals are aware of the need for more sustainable healthcare systems, with many moving toward engaging in climate change advocacy (Luong et al. 2021). There is already a great deal of potential, as many of the physicians in this study expressed a desire to choose more environmentally sustainable medical products and equipment.

Physicians are willing to engage in advocating for climate-specific policy changes

Despite the physicians’ high level of interest in engaging in advocacy on climate-specific issues led by health professionals, among the physicians in this study only 3.4% responded that they were aware of any climate-related initiatives or advocacy opportunities within the professional associations they are a part of. Professional associations are membership-based organizations that provide physicians with a network of peers and offer professional development, research, community health education, etc. These societies can also provide physicians with the resources and opportunities to advocate for creating more sustainable practices within healthcare systems and to engage with policymakers to strengthen their commitments to more robust climate change policy.

A multinational study that examined the factors that influence health professionals’ willingness to engage in climate advocacy showed that affective issue involvement has a strong positive association with the perception that climate advocacy is the responsibility of health professionals, which in turn has a strong positive association with willingness to advocate (Lee et al. 2021). The climate crisis must be aggressively and quickly addressed at all societal levels to mitigate its effects. Physicians from a qualitative study on motivations for advocacy work responded that most of their support for advocacy work has always come from professional associations; therefore, providing accessible opportunities through professional organizations may increase advocacy participation (Warwick et al. 2022).

Addressing climate change requires interventions both to the healthcare system and to the factors driving the demand. Thus, mitigation to reduce the source of greenhouse gases and adaptation to adjust natural and human systems is essential (Winkler et al. 2015). Globally, the health community has a vital part to play in accelerating progress to address climate change, and physicians are well-positioned to understand and communicate the implications of climate change and the necessity of taking action to protect the health of humans and the environment. Moreover, physicians can use their influence and scientific knowledge to facilitate climate-specific health education to the public through their patients, which will be good for both patient health and mitigating climate change. Additionally, physicians can advocate for more systems-level policy changes to promote sustainable healthcare practices within their facilities.

Strengths and limitations

This is the first national-level study to explore the knowledge, attitudes, and practices relating to climate change and health among physicians in Japan. The cross-sectional study design represents the views of only a sample of physicians in Japan; nevertheless, several important findings emerged, yielding tentative conclusions. Despite such limitations, the findings from the study are useful to improve the knowledge of current and future physicians on climate change and health. Moreover, this study may encourage more advocacy for climate change policy among physicians.