When I thought about my very first blog post, there was no doubt I would dedicate it to a topic that motivates my actions every single day: Environmental Change impacting Human Health - short: Planetary Health.
When looking at the past 200 years, in terms of socio-economic development, the world has certainly become a better place. The absolute number of people living in extreme poverty has halved, and the overall life expectancy has more than doubled¹. As summarized below, there have never been more people on earth as today and for 2050 the UN predicts a world population of around 10 billion². At the same time, economic growth (measured in GDP) has gone up drastically³.
Indicators for socio-economic development³ Indicators for Earth system trends³
When looking at these measures, economic growth has certainly benefited humanity and improved the lives of many people⁴. But unfortunately, everything comes at a price. In the last 11,500 years, humanity has lived in a relatively climatically stable epoch, called the Holocene³. Due to unsustainable human activities, causing widespread environmental damage in the atmosphere, on land, and in the oceans, we will leave a footprint in the earth's geological record. These major impacts have led to a definition of a new geological epoch, the Anthropocene⁵.
Human actions such as burning fossil fuels result in significant increases in atmospheric greenhouse gas concentrations⁵. The accumulation of carbon dioxide (the primary greenhouse gas, persisting in the atmosphere for centuries) leads to an increase in global temperature, commonly known as climate change. Compared to pre-industrial levels, the global average temperature has already risen by about 1.0°C and is currently increasing at a rate of 0.2°C per decade⁶. In the absence of policies, it is expected to reach 4.1°C - 4.8°C by the end of the century⁷. Even though the 2015's Paris Agreement was a major step forward to address climate change, it will not be sufficient to limit global warming to 2°C⁸. If all countries, that signed the Paris Agreement would implement its goals into their national policies, we could expect a temperature increase of approximately 3.2°C by the year 2100⁸. On the 4th of November 2020, the US has formally withdrawn from the Paris climate agreement.
But what does climate change mean for human health? And is the term climate change outdated to properly display its far-reaching consequences? Direct effects include those from increased exposure to high ambient temperatures, such as heat-related illness and death⁸. Toward the end of the century, the coolest day in summer may be warmer than the hottest day today. But, the indirect effects are way more complex. Simply speaking, greenhouse-gas emissions add energy to the climate system, resulting in increasing frequency, intensity, and duration of extreme weather events, including heatwaves, floods, and droughts⁸. The Antarctic ice sheet is melting, sea levels are rising, which exposes millions of people to flooding every year⁸. Droughts are posing increased pressure on global food safety, exacerbated by a growing world population. Interestingly, increasing evidence suggests that rising carbon dioxide concentrations have further effects on the nutritional quality of food, including lowering the levels of protein, a range of micronutrients, and B vitamins, which further stresses global food systems⁸.
And, especially connected to my profession: rising temperatures are shifting vectors, leading to an increased risk of vector-borne diseases in regions that have never been exposed before⁸. Not that funny fun fact: Half of the world population is now at risk of Dengue fever⁴. Furthermore, water is expected to be the primary medium through which we will feel the effects of climate change. Its availability is becoming less predictable in many places and droughts are further aggravating water scarcity⁹. Possible contamination resulting from floods increases the risk of water-borne diseases, such as Cholera and Hepatitis A⁹. As a result of all these factors, the risk of conflict, poverty, forced migration, depression, and anxiety grows drastically ⁸.
The World Health Organization estimates that approximately 250,000 deaths annually between 2030 and 2050 could be due to climate-change related increases in heat exposure, as well as rising burden of diarrheal disease, malaria, dengue, coastal flooding and childhood stunting⁸. It has to be pointed out, that this is a conservative estimate, not including morbidity and deaths from e.g. the disruption of health services from extreme weather events⁸. Furthermore, the World Bank projects that without the development of new coping strategies in response to climate change, more than 100 million people could be forced into extreme poverty by 2030⁸. Without higher investments in strengthening and expanding current adaptation and mitigation policies, the risk will be considerably higher, especially for the ones that have contributed the least to carbon dioxide emissions⁸.
We must now understand the interconnectedness between climate change and human health in order to properly develop actions, now and in the future. As seen over the last decades, framing the rising global temperature as a purely environmental issue has proven to be not successful. The burden of climate change-related health outcomes is not distributed evenly between the Global North and the Global South, bearing huge potential for generational as well as political conflicts all around the world. Instead, framing the destruction of our livelihood as a multi-level catastrophe for human health, a decision between life and death, could contribute to finally put global warming at the forefront of international agenda-setting.
Did I catch your interest? A Life On Our Planet - /www.attenboroughfilm.com Ice On Fire https://www.hbo.com/documentaries/ice-on-fire
ABOUT THE AUTHOR:
Sophie is a trained public health professional and is currently doing her MSc in Infectious Disease Epidemiology at UCL in training. Her scientific journey started in the rural communities of Nicaragua, took her to the Netherlands, Denmark, Chile, and India. For her, research is done for the people and its findings should be accessible to everyone, underlining the importance of science communication. Her blog is her contribution to making (epidemiological) global health research more understandable to a broader audience, outside the scientific community.
¹ Gapminder.org. (2019). Data. [online] Available at: https://www.gapminder.org/data/. ² United Nations (2018). World population projected to reach 9.8 billion in 2050, and 11.2 billion in 2100 – says UN - United Nations Sustainable Development. [online] Available at: https://www.un.org/sustainabledevelopment/blog/2017/06/world-population-projected-to-reach-9-8-billion-in-2050-and-11-2-billion-in-2100-says-un/. ³ Steffen, W. et al. (2015) ‘The trajectory of the Anthropocene: The Great Acceleration’, The Anthropocene Review, 2(1), pp. 81–98. doi: 10.1177/2053019614564785. ⁴ LSHTM. (2020). Climate Change is a Health Emergency. [online] Available at: https://www.lshtm.ac.uk/newsevents/events/climate-change-health-emergency-0. ⁵LSHTM. (2020). About. [online] Available at: https://www.lshtm.ac.uk/research/centres/centre-climate-change-and-planetary-health/about [Accessed 6 Nov. 2020]. ⁶IPCC.ch. (2018). Summary for Policymakers — Global Warming of 1.5 oC. [online] Available at: https://www.ipcc.ch/sr15/chapter/spm/. ⁷Climateactiontracker.org. (2018). Temperatures | Climate Action Tracker. [online] Available at: https://climateactiontracker.org/global/temperatures/. ⁸Haines, A. & Kristie, E. 2019, "The Imperative for Climate Action to Protect Health",The New England journal of medicine,vol. 380, no. 3, pp. 263-273. ⁹UN-Water. (2017). Climate Change | UN-Water. [online] Available at: https://www.unwater.org/water-facts/climate-change/.
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