PLANETARY HEALTH DESCRIBES THE STATE OF HEALTH OF HUMAN CIVILISATION AND THE ENVIRONMENT ON WHICH IT DEPENDS.
Rockefeller Fondation and The Lancet
Climate change : a threat for health
Climate change in a few words
- Over the last 10,000 years, the Earth’s average temperature has never fluctuated by more than 2°C. This stable climate has been a prerequisite for the development of human civilisation.
- Since 1850, the average global temperature has risen by an average of 1.1°C, with an exponential upward trend. With the Paris Climate Agreement in 2015, many countries agreed to limit global warming to well below +2°C, or even +1.5°C.
- But the trend is moving in a different direction: according to the latest IPCC report, a temperature rise of more than 3°C is expected by 2100. The most pessimistic scenarios predict a temperature rise of 6 to 7 degrees more if CO2 emissions continue to rise at the current rate, which would make living conditions on Earth impossible for human beings.
- In parallel with global warming, tipping points threaten to be triggered, such as the thawing of permafrost, the melting of the Greenland ice cap or fires in tropical forests. If these tipping points are triggered, feedback loops can be set in motion, with unpredictable and potentially dramatic consequences for temperature trends and rising sea levels.
- Only if global CO2 emissions are cut in half by 2030 and to zero by 2050 is there a 50% chance of staying within the 1.5 degree warming target.
- At present, emissions are continuing to rise. A climate catastrophe can only be slowed by decisive action. The “window of opportunity” is getting smaller and smaller – every tenth of a degree counts!
- But climate change and CO2 emissions are not the only issue. To preserve life, we need to respect the nine planetary boundaries established by the scientific community, six of which have already been exceeded. Preserving biodiversity is an absolute necessity: we are one living species among many.
Threats to health from climate change
- Man does not live in isolation on Earth, but depends on and is connected to the many ecosystems of water, air and land.
- Climate change is causing sea levels to rise, leading to flooding in coastal regions and extreme weather events such as storms, heavy rain, heat waves, droughts and fires. The consequences are the destruction of infrastructure, food and water shortages, political and social instability, conflicts over resources, migration and evictions. All these factors have a major impact on human health and well-being. According to the IPCC, between 3.3 and 3.6 billion people are highly vulnerable to climate change. The 2015 Lancet Commission states that climate change threatens the global public health gains of recent decades. Climate change is already having an impact on the health of the population in Switzerland, particularly through increased mortality and morbidity due to heat and air pollution. A recent study estimates that 380 people will die in Switzerland in 2023 as a result of global warming.
- Heatwave days are increasing all over the world, including in Switzerland: from 5 heatwave days per year between 2000 and 2010, there were 15 in 2018 according to this study. The impact of heat on health is well known. Hyperthermia increases the risk of cardiovascular disease, kidney damage and heatstroke, and affects mental health by increasing aggressive behaviour and reducing sleep quality. The most vulnerable people are children, the elderly, people working outdoors and people living in poorly insulated and therefore precarious housing. The heatwave of 2003 killed almost 1,000 people in Switzerland. According to the Lancet Countdown, a further 30,000 heat-related deaths are already expected in the EU by 2030.
- Climate change is leading to a deterioration in the agricultural system and food security. Thanks to improved living conditions, developments in agriculture and better access to primary care, malnutrition has declined in recent decades. But since 2014, malnutrition has been on the rise again. The WHO predicts that there could be 77,000 to 131,000 additional deaths among the under-5s in 2030 if no mitigation strategy is put in place.
- Air pollution and climate change have a common cause: the burning of fossil fuels. Air pollution shortens a European’s life expectancy by an average of two years. It is the greatest environmental risk to health – ahead of even tobacco! – and is a major contributor to cardiovascular, respiratory and lung diseases and asthma.
- Global warming is leading to an increase in the number and severity of allergies and longer periods of exposure to pollen.
- Mosquito-borne diseases such as malaria, dengue fever and chikungunya are at greater risk because of climate change. The areas where disease-causing mosquitoes live are expanding because of the increased heat. Ticks also benefit from rising temperatures, and with them the spread of viruses and bacteria, responsible for Lyme disease and tick-borne encephalitis, for example.
- Mental health is also affected by climate change. Extreme weather events and forced migrations lead to post-traumatic stress and depression. Being confronted with the destruction or modification of one’s environment is the cause of solastalgia or eco-anxiety, a phenomenon that affects 75% of 16-25 year-olds worldwide.
- The climate crisis particularly affects the most vulnerable (the elderly and disabled, people with pre-existing conditions, children and pregnant women). Above all, it has consequences for those countries that have contributed least to the climate crisis. Climate justice must therefore be an absolute priority.
- The economic and health consequences of climate change will be many times greater than the cost of protecting the climate.
An opportunity for our health!
In the face of climate disruption and other environmental degradation, a number of strategies can be put in place to set targets for reducing greenhouse gas emissions. Many of these measures have direct and immediate health benefits: these are known as health and environment co-benefits, and here are a few examples. Bringing together environmental and health objectives can encourage synergies and maximise the potential of joint actions, whether individual or collective.
Active mobility
Motorised mobility is a major source of greenhouse gas emissions worldwide: transport is responsible for 14% of direct emissions in Switzerland, nearly three-quarters of which are due to private cars. At the same time, motorised mobility increases air pollution and noise, prevents healthy urban planning and contributes to a sedentary lifestyle.
Active modes of transport are those that use human energy as their main source of power, such as walking and cycling. They increase physical activity in daily life, while reducing the pollution caused by transport. Active mobility is associated with a reduction in cardiovascular disease, cancer and all-cause mortality, as well as having psychological and well-being benefits. However, to promote cycling and walking, public spaces need to be designed so that they are safe and attractive. Health professionals must encourage these practices on an individual basis, and can assist with structural interventions by public authorities.
Healthy and sustainable food
Agriculture and livestock farming are responsible for 20-30% of global greenhouse gas emissions. They also contribute to deforestation, the fragmentation of natural habitats and the loss of biodiversity. The use of fertilisers and pesticides contributes to the decline in biodiversity and soil and water pollution. Global trends show an increase in the consumption of animal products, which consume more resources and emit more CO2. At the same time, we are seeing a double burden on a global scale: both an increase in malnutrition, particularly in certain developing countries, and an increase in the number of overweight and obese people, linked to a diet too rich in calories, sugar, meat and fats of animal origin. With a growing population, there is an urgent need to implement a transition towards diets that are good for health, consume less for the planet, and are capable of feeding the whole of humanity. The EAT-Lancet commission has examined these issues and is proposing a diet consisting mainly of fruit and vegetables, wholegrain cereals, pulses, nuts and unsaturated oils. Fish and poultry are considered in small quantities, and red meat, sugar, dairy products and saturated fats should be the exception. The nutritional intake of this diet covers nutrient and micro-nutrient requirements, while taking into account the environmental impact of food choices, which is often not the case in national recommendations, such as those of the Swiss Society of Nutrition.
As well as choosing the right foods, we need to give preference to local, seasonal and minimally processed products. Healthcare professionals need to help their patients make these choices, and inform them of the risks and benefits of diet.
As well as individual diets, it’s important to promote these food choices in the catering industry and reduce food waste.
Contact with nature
Around the world, we are witnessing a massive loss of biodiversity: it is estimated that 25% of animal and plant species are threatened with extinction. This concerns all species in all habitats. This massive erosion of biodiversity is compromising nature’s ability to provide the ecosystem services on which many species, including humans, depend to live in good conditions. In addition, we are seeing a loss of sensitivity of humans to the rest of the living world, with populations – particularly urban – increasingly disconnected from their natural habitats and their species. To remedy this, spending time in nature, being exposed to green spaces, blue spaces and biodiversity is beneficial to health: there is a reduction in cardiovascular risk, stress hormones and overall mortality. Children’s contact with natural environments also has a positive effect on their development and immunity. Community gardens and other forms of urban agriculture can contribute to this trend by raising awareness of soils, dependence on weather elements and the natural rhythms of plants. With this in mind, the concept of the “green prescription”, defined as the prescription of an activity involving spending time outdoors with benefits for health and well-being, should be disseminated within healthcare structures.
To promote these health and environment co-benefits, the “12 months – 12 actions” campaign has been launched by the University of Geneva and the Geneva Paediatric Society, with the participation of several members of Health for Future. The aim is to encourage family doctors to take the opportunity each month to talk about these issues with their patients, in order to raise their awareness, motivate them and involve them in the global change needed to halt the deterioration of our planet and thus of our own health.
Text inspired of Santé et environnement -, Vers une nouvelle approche globale, Part 3, by Nicolas Senn, Marie Gaille, María del Río Carral, Julia Gonzalez Holguera, 2022, available in pdf on : https://www.revmed.ch/content/download/868017/6912948/1?fileName=Sante%20et%20environnement_RMSeditions-9782880495022.pdf