Healthcare leaders: We need new global norms, policies and actions to survive as a species

By Charlotte Owen-Burge | July 6, 2021

It is beyond doubt that climate change is the greatest threat to human health in the 21st Century. As we try to emerge from COVID-19, the need to rapidly rebuild a society that can adapt and respond to the climate crisis has therefore never been greater.

Dr Claire Bayntun, Vice President of the Royal Society of Medicine and Clinical Consultant in Global Public Health, with input from leading healthcare professionals, discusses the role of the health sector in this transformation and explains what we must all do if we are to live in a fairer, heathier and more resilient society.

The topic will be explored further at 18:00-19:00 BST on Tuesday July 6 as part of the Royal Society of Medicine’s Health Emergency of Climate Change series.

Charlotte Owen-Burge: What do we currently know about the relationship between planetary health and pandemics? 

Dr Claire Bayntun: By definition, a pandemic is impactful across national and regional boundaries of the planet, all be it that some regions may disproportionately suffer. The planetary nature means that the damage is across sectors – local and global economies, travel, trade and health are all affected with a pandemic.

Human activity greatly increases the risk of pandemics, through multiple mechanisms.

Ecosystem destruction depletes biodiversity (one of the nine planetary health boundaries), forcing predation patterns to be altered, resulting in animals to come into closer proximity than they otherwise would.

Studies suggest that we are more likely to get zoonotic diseases from animals that live and thrive in human adapted landscapes, and therefore as we transform natural landscapes, such as for food production, we inadvertently increase the risk for zoonotic disease transmission, such as Ebola and Lassa Fever. Subsistence farmers who work the land have high levels of neglected zoonotic diseases.

Human ingress into previously wild areas pushes humans into contact with animals that they would otherwise rarely encounter. Human hunting of ‘bushmeat’ does the same, as do ‘wet markets’, which mix animals and humans at a high density in a manner never seen in the wild.

Once zoonotic pathogens transmit in humans, the spread is exacerbated by our globalized travel. Pre-pandemic, we had 142 people boarding a jet plane every second – this not only spreads the pathogen to new susceptible populations, but also impacts climate change directly through the flight travel.

Human ingress into previously wild areas pushes humans into contact with animals that they would otherwise rarely encounter. Image: Wikipedia Commons.

Does climate change affect the transmission of zoonotic diseases? 

Already, approximately 60% of emerging human pathogens are zoonoses – and this will increase.

Atmospheric energy gain increases surface and water temperatures, which in turn increases vector borne diseases. The heat increases the evaporation of water, which also drives increased rainfall.

Outbreaks of Rift Valley fever (a disease of cattle transmitted by mosquitoes) follow heavy rainfall. Aedes spp. (the main mosquito vectors) are floodwater breeders. Chikungunya and West Nile outbreaks may be associated with heavy rainfalls.

The additional rainfall also increases the range of land and water in which vectors can live and thus the geographical area for vector-borne diseases. Examples are mosquitos for dengue and malaria; snails for schistosomiasis.

Raised temperatures also mean the vectors breed faster and feed more often, while the parasites replicate more rapidly in their stomachs.

New emerging infections – for example, Zika and chikungunya – also appear, allowing otherwise unusual diseases in some areas to become more prevalent. An example is leishmaniasis.

Higher temperatures also increase the developmental rate of ticks, and the over-winter survival rate is also increased. Another example is rodent survival rates, increasing hantavirus transmission.

Moreover, rising sea levels and extreme weather events will lead to coastal flooding and risks for water- and vector borne zoonoses.

Rising sea levels and extreme weather events will lead to coastal flooding and risks for water- and vector borne zoonoses. Image: Photo Stock.

Does air pollution increase the risk of getting COVID-19? Does it make symptoms worse?

Air pollution includes infectious and non-infectious components. Air pollutants increase the risk of other lungs diseases like COPD and persons with COPD are at increased risk for catching COVID-19.

It’s also important to note that poverty is a major factor associated with Covid-19, and may confound the association of Covid mortality with air pollution, as the most disadvantaged tend to live in the areas with the highest pollution.

However, even when such factors are adjusted for, the association remains.

How likely are we to see infectious disease spread as a result of climate change?

This is near certain – all climate change modelling shows an increase of infectious diseases linked to climate change.

Why are emerging infectious diseases on the rise?

Emerging infectious diseases are the end-result of the interaction amongst infectious agents, the hosts and the environment.

Climate change can affect all three – the host can be weakened and more susceptible to emerging infections; the agent can mutate and alter its host range or geographic spread; the environment can be altered directly through rising temperature, adverse weather and indirectly by affecting the ecosystem.

As well as the examples of force multipliers above which capture the impacts of climate change, there is also an increasing resistance to multiple antibiotics which poses a challenge to the effective treatment and management of some infectious diseases.

What actions can we take to prevent future outbreaks?

Preparedness for future outbreaks of infectious diseases are managed under different disciplines currently. There needs to be multi-disciplinary approaches.

The health security response is to create robust surveillance systems and strengthen health systems, nationally and regionally, in order to detect, respond and recover effectively and efficiently to outbreaks when they occur. This is achieved through prevention and preparedness strategies, systems, infrastructures and activities.

However, due to the recognition of the links between climate and planetary health with outbreaks, there is a second part to this response which focuses on that interaction, involving mitigation and adaptation for the health and well-being of our planet in order to prevent an increase in future outbreaks.

Climate change and global health policy have traditionally been treated as separate issues. Do we need to adjust our thinking? And if so, why?

Yes. This is a false dichotomy – as in our prevention of future outbreaks, and managing the health and well-being of individuals, human health and climate/planetary health are interdependent.

Further, the management is global-wide. Although we need individual, local and national level action, the issues of climate and planetary health need the global community to engage with solutions and change our current trajectory of mega-trends.

We need new global norms, policies and actions to survive as a species, and as a planetary biosphere with ecosystems of which humans are only a (destructive) part.

To achieve this, we have a responsibility to train, educate, advocate and influence decision and policy-makers, collaborate widely through our research work, and engage the youth in inclusive programmes.

Both COVID-19 and climate change are causing the deaths of thousands of people. Why do you think the scale of actions to combat them are so different?

COVID-19 is an infectious disease that is widely reported in the world, and it visibly affects people, driving government and citizens to take action. The pace of Covid-19 sits within an electoral cycle, whereas global energy gain / global heating does not.

By contrast, the impacts of poor climate and planetary health are often initially challenging to diagnose with clarity, yet affecting those without a voice the hardest.

Who are the most at-risk communities from the dual threats of zoonotic diseases and climate change? 

Equity challenges prevail with pandemics and climate change. The most vulnerable and socially disadvantaged are least able to adapt, and thus are always disproportionately affected. This includes those with low or no income, those with disabilities and co-morbidities, migrant workers, refugees, and often women and children are at more risk of all threats.

For example, due to the flooding in the region of Lake Victoria, Kenya, children have to wade through water to go to school, without protective shoes, and often unable to swim. They face the increased health risks from the high prevalence of water- and vector borne diseases, as well as skin conditions. Women in the region are typically most affected by the flooding of the agricultural land which they depend upon for providing food and income security, and many have been left homeless on their own trying to manage the welfare of their children.

Some marginalized communities, such as the Turkana community in Kenya, often lack the required infrastructure, training and representation to adapt as their environment and climate changes. These traditional, rich cultures, which are some of the most sustainable of the human species, are at risk.

While these societal and demographic inequities result in disproportionate suffering, we are all at risk – consider Zika in Europe, and Leishmaniasis in the USA.

Lake Victoria, Kenya.

What role should the healthcare sector be playing in mitigating and adapting to climate change and the prospect of future pandemics?

The healthcare sector has a duty to take on adaptation activities – working to identify, prevent and prepare for the threats, creating resilient health systems and early detection surveillance structures.

However, as trusted professionals, health workers have an important role in mitigation – advocating for change in national and global legislation, re-setting policy and targets, and increasing the pace and scale of delivery to match the need. For example, we need to aim for true zero [emissions], to prevent problems from continuing. Environmental impact assessments should be part of all health procurement.

Why is it so important for health officials to talk about climate change now?

The Royal Society of Medicine’s series, the Health Emergency of Climate Change, aims to support health professionals to understand the various diseases that are directly associated with climate change. However, the series has an additional role.

Health officials have a voice, and our role is to protect health and well-being. Our lives, and those of future generations, are threatened. One fifth of what we emit today will be still heating our planet in 33,000 years.

We must support others to reduce their carbon footprint, bringing immediate co-health benefits for individuals in areas that we work – through active transport (walking, cycling) and improved diets (less meat and dairy, more fruit and vegetables).

We must radically shift from the mindset and investment at the level of ‘doing less damage’ to ‘positively healing our planet’. This involves consuming and using less. We must actively protect and restore wild areas, stop deforestation, change our agricultural patterns and limit our international travel.

We must work to become truly carbon zero in years, rather than planning to do so over decades, and we must also re-capture CO2, making sustainability of the planet and its resources core to all policies.

Dr Bayntun drew from the expertise of contributors to the Royal Society of Medicine’s upcoming episode: Planetary Health through the lens of the Pandemic. The episode will be broadcast 18:00-19:00 London BST on Tuesday July 6 2021, and will be available afterwards at – Health Emergency of Climate Change Series.

Professor Hugh Montgomery – Professor of Intensive Care Medicine, University College London (UCL), and Director, UCL Institute for Human Health and Performance

Dr Peninah Murage – Co-Deputy Director of the LSHTM Centre on Climate Change and Planetary Health, from Kenya

Dr Deoraj Caussy, Epidemiologist and Lead Researcher for Network of African Science Academics (NASAC), Mauritius

Melvine Otieno, Planetary Health Alliance Next Generation Fellow, University of Eldoret, Kenya

Dr Rob Dellink, Co-ordinator Modelling and Outlooks at the Environment and Economy Integration Division of the OECD Environment Directorate, France

Professor Sabine Gabrysch, Head of Research Department 2 on Climate Resilience of the Potsdam Institute for Climate Impact Research, Germany

Dr Kris Murray,  Lead, Ecological Health Lab in the School of Public Health, Imperial College London and Associate Professor, Environment and Health, LSHTM Lead of the Planetary Health theme, MRC Unit, The Gambia 

Dr Cathryn Tonne, Environment epidemiologist and Associate Research Professor at Barcelona Institute for Global Health, Spain

Dr John Amuasi, Co-Chair, The Lancet One Health Commission and Group Leader of the Global Health and Infectious Diseases Research Group, Kumasi Collaborative Center for Research in Tropical Medicine, Ghana

Professor Dame Anne Johnson, Professor of Infectious Disease Epidemiology, University College London, Co-Director, UCL Health of the Public

Main references

Intergovernmental Panel on Climate Change (IPCC), “Climate Change 2007: Impacts, Adaptation and Vulnerability: Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change” (Cambridge: Cambridge University Press, 2007), 433-467

United nations environment programme (UNEP) Preventing the next pandemic: Zoonotic diseases and how to break the chain of transmission. Available at https://wedocs.Unep.Org/bitstream/handle/20.500.11822/32316/zp.Pdf?Sequence=1&isallowed=y. [accessed 26 July 2020]

World health organization (WHO) Protecting health from climate change: Vulnerability and adaptation assessment. World Health Organization: 2013.

Watts, N.; Amann, M.; Ayeb-Karlsson, S.; Belesova, K.; Bouley, T.; Boykoff, M.; Byass, P.; Cai, W.; Campbell-Lendrum, D.; Chambers, J.; et al. The Lancet Countdown on health and climate change: From 25 years of inaction to a global transformation for public health. Lancet 2017, 391, 581–630.

Gibb R, Redding DW, Chin KQ, Donnelly CA, Blackburn TM, Newbold T, et al. Zoonotic host diversity increases in human-dominated ecosystems. Nature. 2020;584(7821):398–402.

Ostfeld RS, Keesing F. Species that can make us ill thrive in human habitats. Nature. 2020;584(7821):346–7 doi:

Lancet Commission on Climate Change:

Planetary Health boundaries – Steffen, W., K. Richardson, J. Rockström, S.E. Cornell, I. Fetzer, E.M. Bennett, R. Biggs, S.R. Carpenter, et al. 2015. Planetary boundaries: Guiding human development on a changing planet. Science 347: 6223.

Other key resources that address these issues

Pandemics: and air pollution:

UNEP Frontiers 2016 Report – Emerging Issues of Environmental Concern

OECD papers:

Youth & Civil Society

The Climate Champions Youth Fellowship 2024

Find out if you are eligible for our paid fellowship programme, and apply before 10pm GMT on Wednesday 10th April   Young people and future generations are environmental stewards of the future. Many are also leaders and subject matter experts today. The Climate Champions Team, in support of the UN Climate Change High-Level Champions, are […]

Youth & Civil Society

Upcoming: UN Commission on the Status of Women (CSW67)

The 67th annual Commission on the Status of Women (CSW67), the UN’s largest annual gathering on gender equality and women’s empowerment, will take place this year from 6 – 17 March under the theme, “Innovation and technological change, and education in the digital age for achieving gender equality and the empowerment of all women and girls”.