Global and Planetary Health
Global health describes human population health on a global scale and focuses particularly on health improvement internationally. The World Health Organization (WHO) is the main international agency linked to global health. Global health is measured in relation to global disease burden, the reduction in health from all causes of death or illness globally. Disability-Adjusted Life Years and Quality-Adjusted Life Years (DALYs/QALYs) are commonly used metrics in measuring global health.
Planetary health describes the health of humanity globally and the health of the natural planetary systems on which it depends. Holistic planetary health has been defined as the “achievement of the highest attainable standard of health, wellbeing, and equity worldwide through judicious attention to the human systems …that shape the future of humanity and the Earth’s natural systems that define the safe environmental limits within which humanity can flourish” (Whitmee et al. 2015). Global and planetary health is inextricably linked, as present-day human civilization is dependent on the health of multiple planetary systems for its survival.
Introduction: Human Development, Planetary Boundaries, and Global Health
The Holocene epoch, beginning just under 12,000 years ago and comprising the major time period during which human society has developed, is the only known planetary epoch capable of supporting modern human civilizations. Within this epoch, planetary changes were effectively buffered by earth’s natural regulatory feedback loops, meaning that global temperatures and other planetary conditions remained relatively constant. However, the start of the industrial revolution (bringing heavy reliance on fossil fuels and industrial farming, as well as population growth) ushered in a new era: the Anthropocene. This epoch marks the time at which human activities started to have a significant effect on earth systems, moving the planet away from the stable Holocene state. Although the precise start date for the Anthropocene is yet to be defined, it is widely accepted as a concept by the scientific community. The Holocene-Anthropocene shift is resulting in environmental change on a scale that can harm human societies.
In broad terms, human health is in better condition in the present day than at any period during the development of human societies (e.g., with a higher life expectancy and lower death rate in children – You et al. 2014). There has also been a large reduction in extreme poverty in recent decades (Olinto et al. 2013), which have also seen rapid advances in healthcare, education, and technology development. The recent development of humanity is underpinned by earth systems such as the atmosphere, oceans, forests, wetlands, tundra, and more (Whitmee et al. 2015). These earth systems provide direct goods and services, such as food, fuel, and water, as well as indirect goods and services such as nutrient cycling and climactic stability. The present-day global population stands at ~7.6 billion, and, in reaching these levels, large changes have occurred in earth systems. It is predicted with 95% certainty that, by 2100, the global population will have reached between 9 and 13.2 billion people (Gerland et al. 2014). The continuation of unsustainable resource use, coupled with expanding population, risks irreversible alteration to earth systems, which in turn could undermine human societal development and existence.
The boundaries do not represent defined thresholds at which change will occur, but are positioned prior to zones of uncertainty (where, with current data, the reaction of earth systems to changes cannot be reliably predicted) in which earth systems are liable to dramatic changes. Moving past the high-risk boundary indicates a high likelihood of earth system change with potential for large negative impacts on humanity. The further planetary boundaries are transgressed beyond the safe operating space, the more likely conditions for human survival are to be diminished.
It is unlikely that earth’s systems will change in a linear fashion as boundaries are transgressed. Rather, they are likely to react in an abrupt, nonlinear fashion, which could result in irreversible environmental change, manifesting at a regional or global level (Whitmee et al. 2015). What is more, boundaries are not independent, meaning that changes to one earth system can have knock-on effects on multiple others, exacerbating damaging effects for humanity. The understanding of early warning signs around large earth system perturbations remains in its infancy, but includes monitoring system variance and “flickering” between states (Steffen et al. 2015).
Impacts on health caused by environmental change pose serious risks to the increases in global health statuses achieved in recent decades and look set to become the dominant driver of adverse global health effects this century. Therefore, global and planetary health cannot be separated. This entry will examine the planetary boundaries and changing earth systems (as outlined in Fig. 1), highlighting their effects on global health.
Climate and Biosphere Changes and Global Health Effects
Climate change represents the greatest threat to humanity of the twenty-first century. Anthropogenic climate change is mostly caused by greenhouse gas (GHG) emissions, and therefore modeling future climate scenarios is largely based on GHG emission predictions. Important GHGs for climate change include carbon dioxide, methane, and nitrous oxide. The burning of fossil fuels and conversion of wilderness areas to agricultural or settlement land drive the majority of these emissions. Climate change itself is defined as the human-driven changes to radiative forcing (the rate of energy change per unit area of the globe measured at the top of the atmosphere, caused by GHG emissions and other factors effecting changes, Rockström et al. 2009; Steffen et al. 2015). The current global emission trajectory is higher than the highest-end scenarios modeled by the Intergovernmental Panel on Climate Change (IPCC) and, if this trajectory is maintained, predicts a temperature increase of 2.6–4.8°C by the end of this century in comparison to 1986–2005 levels. Such a temperature increase would trigger, as is already being observed, decreases in planetary surface ice and vegetation cover. Such reinforcing feedbacks could push temperatures even higher, threatening the viability of natural systems upon which human societies depend. The lower carbon dioxide boundary (used as the normalizing factor for climate change, Fig. 1) is currently set at 350 parts per million (ppm), designed to ensure the maintenance of the polar ice sheets. However, atmospheric carbon dioxide concentrations currently stand at ~399 ppm (Steffen et al. 2015). With current levels of climate change, there have already been recorded increases in heavy rainfall events, drought in other regions, and loss of polar ice sheets.
Biological diversity (biodiversity) is a key component of earth systems and their ability to provide goods and services important for human societies. While species extinction occurs naturally and is seen throughout the fossil record, the rate of biodiversity loss (and biosphere change) has increased hugely during the Anthropocene. The present planetary extinction rate is over 100 times the extinction rate observed in the fossil record (Pimm et al. 2014), meaning species extinctions are occurring with an incidence unseen since the last mass extinction events. It is estimated that the population sizes of vertebrate species have halved in the last 50 years (WWF International 2014). Major threats to biodiversity include loss or degradation of habitats, overfishing, pollution, and climate change (Whitmee et al. 2015). Population growth places additional strain on global biodiversity.
In measuring biodiversity impacts more precisely, Steffen et al. (2015) developed the concept of the biodiversity intactness index (BII), assessing changes in biota abundance resulting from human impact in relation to the pre-industrial era. A 100% score indicates abundance across all population subgroups at pre-industrial levels. However, when applied to seven countries in Africa, BII scores were between 69% and 91%, demonstrating considerable biodiversity loss (Scholes and Biggs 2005). Biosphere integrity (the sum of ecosystems and their biodiversity) is crucial in regulating and maintaining earth systems. It plays a key role in regulating material and energy flows and buffers terrestrial and marine systems. As the majority of the biosphere’s planetary regulation capacity is fulfilled by the biota inhabiting it, loss of biodiversity is an important concern for the state of other earth systems. A rich biosphere and biodiversity provide multiple services beneficial to health, such as reducing air pollution, regulating temperature, providing natural medicines, protecting against landslides, and having positive effects on mental health in the case of green spaces (Whitmee et al. 2015). Biosphere degradation places all of these at risk.
The rate of climate change is likely to increase the rate of species extinction in the twenty-first century. Analysis of the climate change and biosphere boundaries indicates that the two are integrated and connected to all other PBs. While under the influence of other PBs, they provide the most important framework under which other PBs function (Steffen et al. 2015). Therefore, climate change and biosphere integrity can be seen as central PBs. Transgressing the safe boundaries of either one of these, as is already the case (see Fig. 1), has large potential to negatively impact humanity and increases the likelihood of other boundaries being crossed. A key example of the interdependence of climate change and biosphere integrity can be seen with global agriculture. Agriculture is the largest consumer of freshwater globally, can negatively impact terrestrial systems and biodiversity, and is also responsible for ~32% of global GHG emissions annually. It is also the largest source of aquatic nitrogen and phosphorus loading, which can lead to eutrophication (nutrient overloading leading to plant blooming and so-called dead zones for marine life) and biodiversity loss.
In addition to this, broad climate change such as that caused by intensive farming can negatively impact on food security (the ability to feed the global population reliably). This can result from temperature changes to which crops are not adapted, degradation of soil quality (drought, erosion, flooding, increasing salt content, etc.), and loss of pollinators for plant reproduction, among others. A study by the IPCC (2014) has found that, while crop yields are likely to decrease by up to 2% per decade for the remainder of the century due to climate change, demand is forecast to increase 14% per decade up to 2050. People living in poverty (of which there are ~1.2 billion at present, United Nations 2005) are more likely to live in climate hazardous locations with inadequate healthcare and resource access and are more prone to undernutrition due to lack of wealth. These factors contribute to leave the poor at highest risk of the negative health effects of climate change and biosphere degradation-driven food insecurity (Whitmee et al. 2015).
Negative health impacts from climate change arise principally because of direct impact from weather events, alterations in ecological systems, and economic dislocation of communities (as can be seen in climate refugees). A 2006 WHO report estimated that ~25% of disease burden globally could be attributed to negative environmental factors (Prüss-Ustün and Corvalán 2006).
Global temperature increases provide a clear example of human health impact. In the case of vector-borne diseases, the rate of pathogen development in vectors can increase with rising temperature. There is evidence to show that tick-borne diseases, malaria, and Ross River virus disease have increased their range as temperatures have increased in recent decades (McMichael et al. 2003). Numerous mathematical models have forecast increases in the distribution of malaria-/dengue-fever-carrying mosquitos and leishmaniasis-carrying sand flies. Even under IPCC climate change scenario A1B (where a balanced mixture of fossil fuels and renewable energy sources are used moving forwards), it is estimated that an additional 200 million people will be at risk of malaria by 2050 (Béguin et al. 2011). Warmer temperatures can also increase summer peaks of food-borne infections such as salmonella and increase child diarrheal disease (McMichael et al. 2003).
Gasparrini et al. (2017) recently showed that, under high emission scenarios, there will be an increase in overall temperature-related mortality globally. What is more, the negative health effects of increasing temperature will disproportionally affect poorer regions of the world. These effects include not only disease increase and food insecurity but also migration and conflicts and extreme weather events. Large-scale climate change is associated with economic instability, civil strife, and creation of climate refugees who have higher exposure to infectious disease, mental health problems, and malnutrition (McMichael et al. 2003).
Land System Change, Freshwater Use, and Human Impact
Over 30% of the non-ice or desert land on the planet has been converted to agricultural use (Foley et al. 2007). In Southeast Asia this is much higher, at ~50%. Growing demand for animal produce and nonfood plant products (such as biofuels) is driving continued global habitat conversion. Palm oil plantations have been shown to possess significantly reduced species diversity in comparison to primary or secondary forests (Savilaakso et al. 2014). Therefore, many land use changes are driving biodiversity loss. Burning of forests to make way for agriculture increases air pollution and GHG emissions, and intensive farming techniques degrade soil, which can be thought of as a nonrenewable resource on human time scales. Such degradation results in 1–2.9 million hectares of soil per year becoming unusable for agriculture (Lambin and Meyfroidt 2011). This decreases food security, increases flooding risk, and removes natural carbon sinks.
Regarding tropical forests, they have strong mitigating effects on temperature increases through evapotranspiration (where water is transferred from the land or plants to the atmosphere through evaporation), which has an overall environmental cooling effect. Deforestation in Africa occurs at double the average global rate (FAO 2012), and in West Africa, ~90% of forest cover has been lost. Africa is also the world’s most rapidly urbanizing region, and urban sprawl threatens existing primary land areas. Rapid urbanization without appropriate planning and provision of amenities may also increase the incidence of slum dwelling, which carries significantly worse health outcomes than other forms of living (African Population and Health Research Center (APHRC) 2014). In São Paulo, Brazil, forest cover around key watersheds has been reduced ~70%, increasing watershed sedimentation and reducing water security.
Intact ecosystems provide significant protection against climactic variation. Coastal forests provide flood protection, as can floodplains and rivers. Such ecosystems can also regulate disease transmission, though these interactions remain to be fully understood. However, increased zoonotic (animal to human) disease transmission has been reported in degraded habitats (CBD-WHO 2015). In addition, forest loss and loss of plant biodiversity can increase malaria transmission. Following deforestation in sub-Saharan regions, an increase in malarial vector density and malaria transmission was observed (Yasuoka and Levins 2007). Interactions between climate change, biodiversity loss, and land use change PBs are expected to increase the occurrence of emerging infectious diseases this century (Whitmee et al. 2015).
A well-known tool for reducing forest loss is the reducing emissions from deforestation and forest degradation (REDD) system, which places monetary value on a forest’s carbon store and encourages investment in low carbon development. REDD+ (with an extra emphasis on conservation and enhancement of forests) has helped Costa Rica reach conservation targets in biodiversity, water services, and carbon sequestration (Whitmee et al. 2015).
Fifty percent of available planetary freshwater is diverted for human use annually, much of which comes from groundwater. In many areas the groundwater is being used faster than it is being replenished, with the highest disparities occurring in agriculturally intensive areas. In the Arab world, freshwater availability stood at 743m3 per person per year in 2011, below the defined water poverty level of 1000m3 (El-Zein et al. 2014). From 2000 to 2050, water demand is forecast to rise 55% globally (mostly due to rising manufacturing and energy demands). Forty percent of the global population are forecast to be living under severe water stress in 2050 (Whitmee et al. 2015). Reductions in water availability will impact food security, economic growth, and the planetary water cycle, in turn negatively impacting on other PBs. Water-rich and water-poor nations are increasingly competing for the same resources. Suweis et al. (2013) highlighted that food import is associated with an invisible “transfer” of water, used to grow the food, known as the virtual water trade. Climate change and water scarcity may soon reduce the virtual water exported by water-rich nations which may bring them in to conflict with water-poor nations.
Insufficient or unclean freshwater can also promote disease. In 2012 ~700,000 deaths globally were caused by diarrheal disease from unclean drinking water (Prüss-Ustün et al. 2014), and the incidence of this is forecast to increase ~10% globally by 2040 due to climate change. River degradation is also associated with increased schistosomiasis (a parasitic worm infection) by, along with eutrophication and overfishing, increasing the abundance of their vectors in areas where they are endemic (Myers and Patz 2009). Droughts can also increase vector-borne disease spread by encouraging informal water stockpiling, providing new mosquito breeding grounds.
Biogeochemical Flows in Global and Planetary Health
Perturbations in the nitrogen and phosphorus cycle are particularly relevant to global and planetary health and are major drivers of ecosystem change. Human activities (such as fertilizer production for intensive agriculture) convert more nitrogen gas from the atmosphere into reactive forms per year than all of the planet’s terrestrial processes combined (Rockström et al. 2009). While nitrogen fertilizer has been crucial for increasing global food yields and allowing population growth, only 30–50% of nitrogen applied to fields ever reaches the intended crops (Tilman et al. 2002). Excess nitrogen leaches into terrestrial and aquatic ecosystems, leading to biosphere degradation through decreased plant biodiversity and eutrophication, among others.
Phosphorus is mined and also used in fertilizers. However, similarly to reactive nitrogen, huge amounts of phosphorus leach into unintended ecosystems. The oceans are now subject to an influx of phosphorus >8 times the natural background rate (Rockström et al. 2009). Fossil records indicate that major ocean anoxia and extinctions occur at a critical phosphorus influx level. Previous models have suggested that increasing phosphorus flow into the ocean beyond 20% above the natural background could trigger anoxic ocean events if sustained (Handoh and Lenton 2003). More recent analysis has indicated that, to avoid widescale water degradation, phosphorus application to soil for fertilizer should not exceed 6.2 teragrams (1 teragram being 1 million tonnes) per year. However, the current global rate of application is ~14.2 teragrams per year.
As well as polluting water sources, reducing biodiversity, and being a key driver of GHG emissions (the production of nitrogen fertilizer is fossil fuel intensive), perturbed biogeochemical flows can also indirectly reduce food security (by harming marine food stocks and being part of an industrial agricultural system, which often degrades soil) and increase vector-borne disease incidence (by contributing to biosphere degradation).
The increasing concentrations of carbon dioxide in the atmosphere have caused the acidity of the oceans to increase as a result of an accumulation of free hydrogen ions in seawater. While the pH of the oceans has decreased approximately 0.1 in the last quarter of a century, due to the logarithmic nature of the pH scale, this in fact represents an increase in ocean acidity of 26% (IPCC 2014). The acidity of the oceans is forecast to increase by ~170% in relation to pre-industrial revolution levels by 2100 (IGBP, IOC, SCOR 2013). The major effects of increased ocean acidification include a reduction in survival of marine animals, rapid loss of coral reefs (major ecosystem buffers) and reduction in survival of mollusks due to combined corrosive actions of an acidified ocean on their shells, and inability to form shells (Whitmee et al. 2015). The latter arises from a reduction in calcium carbonate in available forms for mollusks and shelled animals as ocean acidity increases. Kawaguchi et al. (2013) predict that the population of Southern Ocean Antarctic krill is at high risk of collapsing in the next 300 years due to the adverse effects of increasing ocean acidity on krill hatching. Such a population collapse would effectively remove the bottom of the food chain in this ecosystem, threatening not only the survival of human food sources from marine environments but also the survival of organisms at the top of the food chain, such as whales.
Aquatic food sources represent a key protein source in the human diet. They can also be rich sources of omega three fatty acids, which reduce the risk of heart disease. Increasing ocean acidity is likely to disrupt human food sources in the oceans and fuel food insecurity as this century progresses. The loss of coral reefs, associated with increasing temperature and acidification of the oceans, will also disrupt coastal food security as well as economic stability in communities relying on the reefs for their livelihoods. Ocean acidification has already produced tangible negative impacts on shellfish harvesting in the Pacific. Combined with the Food and Agriculture Organization assessment (FAO 2014) that, as of 2015, 90% of global fish stocks are exploited at their maximum yield or overfished, and the coming decades will be crucial for changing oceanic conditions and may represent a wider tipping point into marine food insecurity and global health impact.
Stratospheric Ozone Depletion
The stratospheric ozone layer, extending from around 17 to 50 km above the earth’s surface, is a crucial absorber of high-energy solar ultraviolet radiation. Such radiation is highly dangerous to biological organisms, and without the stratospheric ozone layer, human existence in its current form would not be possible. Stratospheric ozone remains one of the only PBs moving into the defined safe boundary (Fig. 1) of the PB, rather than in the opposite direction. The boundary for the safe operating space for stratospheric ozone is only breached seasonally over Antarctica. Stratospheric ozone concentrations are actually predicted to rise globally in the coming decades as the hole in the ozone layer is slowly repaired by natural buffering processes following the reduction in usage of chlorofluorocarbons and other ozone-depleting substances. These substances, widely used from the 1950s to the later part of the twentieth century, were emitted on earth’s surface where they had been used as propellants, solvents, refrigerants, etc. Upon transport to the stratosphere by planetary winds, they photodissociate (are broken apart by photons) releasing halogen atoms which destroy ozone. Following increased understanding of ozone-depleting substances’ harmful impact on the ozone layer, they have been broadly phased out, allowing the PB of stratospheric ozone to undergo a process of repair.
Atmospheric Aerosol Loading and Novel Entities
Aerosols (suspensions of particles in air) display a range of human health effects and are the causative agent of ~7.2 million deaths per year (Steffen et al. 2015) as well as having adverse effects on other earth systems. Aerosol optical density (AOD) is the measure used to define the atmospheric aerosol loading PB and has a safe operating space boundary of 0.25. In South Asia, the background AOD is ~0.15, but soot particulate emissions from cooking and heating, diesel particulate pollution, fossil fuel emissions, and volcanic eruptions can drive this value as high as 0.4 (Chin et al. 2014). This can decrease the intensity of the sunlight reaching the earth’s surface by 10–15% (Steffen et al. 2015). The annual average AOD globally is ~0.3, above the proposed safe operating boundary. Reducing aerosolized climate pollution would be beneficial for human health; ~2.4 million premature deaths annually could be avoided. In poorer rural areas of the world, clean energy in the home has the highest potential to reduce pollution exposure (Wilkinson et al. 2009).
Novel entities are defined as new substances (such as chemicals) or modified life forms with the potential for unwanted geophysical and/or biological effects (Steffen et al. 2015). Chlorofluorocarbons and stratospheric ozone depletion (see subsection “Stratospheric Ozone Depletion”) are key examples of how novel entities can bring about harmful planetary impacts. There are well over 100,000 substances traded globally at present (Egeghy et al. 2012), and this number is increasing. Persson et al. (2013) have provided the most comprehensive assessment of the criteria novel entities must meet in order to be potential threats to planetary boundaries. Firstly, the novel entity has an unknown disruptive effect on earth systems. Secondly, this effect is not discovered until the problem is of a planetary scale. Finally, the disruptive effect is not easily reversible. It is important that novel entities are thoroughly tested before release for activities which may allow them to threaten earth systems and PBs, but at present this is not routinely the case. Important sources of environmental chemical contamination include agricultural leaching, heavy metals and dioxins used in electronics production and recycling, heavy metals from mining, asbestos release from older buildings and structures, and pharmaceutical pollution through natural excretion or inappropriate disposal, among many others (Whitmee et al. 2015). While the total chemical waste released into the environment globally is unknown, in 2009 ~5 million tonnes of chemicals were released into the environment in North America. 1.5 million tonnes of these were classed as somehow toxic, and nearly 1 million tonnes of these were known or potential carcinogens (UNEP 2013).
Such pollution promotes biosphere degradation and can enter food chains, particularly in marine environments, causing cumulative toxicity effects in ecosystems as they move up the food chain (which can include humans at the top). For example, methylmercury, a toxic chemical which harms fetal brain development, is known to bioaccumulate in oceanic food chains and reach humans. Children are at particular risk from toxic chemical pollution due to the susceptibility of developmental processes to harm and generally reduce ability to detoxify chemicals in comparison to adults (Grandjean and Herz 2011).
The detrimental health effects of toxic chemical exposure can occur via inhalation, skin exposure, and ingestion in food or water, among others. Those living in poverty are most at risk as they are statistically more likely to be exposed to the toxins. Almost all children exposed to toxic levels of lead are found in low-income or impoverished settings (Whitmee et al. 2015). Exposure to endocrine (hormone) disrupting chemicals increases genital abnormalities and poor-quality semen in men and endocrine-linked cancer incidence, as well as thyroid perturbations, which can lead to behavioral disorders (Tilman et al. 2002). In one of the most comprehensive studies in the field, Huang et al. (2016) analyzed the associations between farmer’s exposure to pesticides in china and adverse health effects. Examining short- and medium-term effects of exposure to organophosphate and organosulfur pesticides, among others, indicated a range of health impacts, including liver damage, peripheral nerve impairment, and renal dysfunction. This indicates the importance of considering not only accidental but also occupation exposure to novel entities on a planetary scale and their impacts on global health.
In order to combat the negative effects of harmful novel entities on both earth systems and human health, improved chemical evaluation is needed prior to environmental release, as well as use of safer alternative chemicals wherever possible. Shifting toward a circular economy (minimizing waste and maximizing reuse and recycling) would also be of use (see subsection “Future Perspectives”).
Global and planetary health is inextricably linked, and, in developing modern societies, humans have had enormous impact on earth’s natural systems, leading to the entering of a new planetary epoch, the Anthropocene. Multiple PBs (see Fig. 1) have been perturbed to the point of risking major degradation of earth systems supporting human civilization, bringing risks of increasingly negative health effects on humans. Continued unsustainable resource usage and expanding populations will exacerbate planetary boundary perturbation, further increasing the magnitude of negative global health effects and disproportionately affecting the world’s poorest. Health risks of planetary degradation come not only from extreme weather events but also from undernutrition, increases in the range and spread of vector-borne diseases, and exposure to harmful environmental pollutants, among others. Should the current trajectory of emissions and global temperature increases continue, the ability of present-day human societies to survive will be under great threat.
Whitmee et al. (2015) have outlined the three main challenges that face humanity with regard to a changing planet. The first are “conceptual and empathy failures,” or so-called imagination challenges. These include overreliance on gross domestic product (GDP) as a measure of societal progress, failing to take future generations’ health and well-being into account with present-day policies, and the disproportionate effect of earth system degradation on the poor. The second are “knowledge failures” such as research that does not take social or environmental factors into account, lack of resources made available to healthcare systems, and the obsolete nature of some decision-making frameworks when faced with the present challenges. The third are “implementation failures,” or so-called governance challenges, including government response to threats (compounded by uncertainty in, e.g., PBs), the potential for global resources to represent triggers of international conflict, and the inertia between problem recognition, action, and tangible effects.
Reductions in natural capital and harm to earth systems should be accounted for in economic terms, such that monetary economics and natural resources are not seen as separate. The Natural Capital Initiative (Holt and Hattam 2009), Economics of Ecosystems and Biodiversity (Sukhdev et al. 2014), and Genuine Savings (Dasgupta 2010) initiatives provide frameworks for identifying the financial value of all ecosystem components utilized in the delivery of products or services, providing ways to physically account for them and optimize processes in terms of reducing unsustainable natural capital usage. Wider adoption of such principles in industry would provide greater economic incentives for environmental protection. Coupled with this, redefining of prosperity to mean increased quality of life and healthcare globally would help reduce inequities in current health and economic systems and could help avoid future conflicts. The wider realization of the moral obligations of the present, resource-intensive society to safeguard the well-being of future generations is also imperative for future global health and links in practical terms to natural capital concepts and reduction of present inequity.
In providing food security for a growing population, resilient and sustainable agricultural systems are required. They must be able to withstand environmental variation, provide food price stability, and challenge the health burdens from inadequate diets. Additionally, they must tackle food waste, which currently stands at 30–50% of all global food produced per year (Whitmee et al. 2015). This waste not only reflects inequities in global distribution systems but causes biosphere degradation, excessive water use, and high GHG emissions.
In the near term, adequately meeting family planning needs could lessen the strain on earth systems from a burgeoning population. Over 80% of the forecast growth in population to 2100 will occur in Africa, which risks exacerbating poverty and negative health prevalence. One in four African women still has an unmet need for family planning, and meeting this could reduce or delay the population growth until such time as it is more sustainable (Ezeh 2016).
Further to this, planetary health metrics should be incorporated into healthcare systems. At present, healthcare expenditure is largely focused on noncommunicable disease burden (Jamison et al. 2013). However, environmental and planetary health challenges (such as clean water and tackling air pollution) remain underfunded and should be seen as a higher priority health spending area in light of a changing planet.
In achieving holistic global and planetary health, scientific understanding of the precise links between planetary boundary changes and human health impacts must be refined. By developing this understanding and showcasing the positive health outcomes that can be achieved by developing sustainable societies, greater action may follow.
In the meantime there is an urgent requirement to enhance the resilience of current systems to rapid environmental perturbations by ensuring, for example, that healthcare systems can be responsive under varying conditions, flood and drought protections are in place, and adequate buffers around food security exist. Understanding of global and planetary health and their inseparable nature should come to represent the most important political policy driver globally in the twenty-first century, in order to preserve the planet and human civilization for generations to come.
- African Population and Health Research Center (APHRC) (2014) Population and health dynamics in Nairobi’s informal settlements: report of the Nairobi Cross-Sectional Slums Survey (NCSS) 2012. APHRC, NairobiGoogle Scholar
- CBD-WHO (2015) Connecting global priorities: biodiversity and human health, a state of knowledge review. https://www.cbd.int/health/SOK-biodiversity-en.pdf. Accessed 15 Mar 2018
- EU Commission (2014) Towards a circular economy: a zero waste programme for Europe. https://www.oecd.org/env/outreach/EC-Circular-econonomy.pdf. Accessed 15 Mar 2018
- FAO (2012) State of the world ‘s forests. http://www.fao.org/3/a-i3010e.pdf. Accessed 15 Mar 2018
- FAO (2014) The state of world fisheries and aquaculture http://www.fao.org/3/a-i3720e.pdf. Accessed 15 Mar 2018
- IGBP, IOC, SCOR (2013) Ocean acidification – summary for policymakers. http://www.igbp.net/download/18.30566fc6142425d6c91140a/1385975160621/OA_spm2-FULL-lorez.pdf. Acessed 15 Mar 2018
- IPCC (2014) Climate change 2014: impacts, adaptation, and vulnerability. https://www.ipcc.ch/pdf/assessment-report/ar5/wg2/WGIIAR5-IntegrationBrochure_FINAL.pdf. Accessed 15 Mar 2018
- McMichael AJ, Campbell-Lendrum DH, Corvalan CF et al (2003) Climate change and human health. World Health Organisation. http://www.who.int/globalchange/publications/climchange.pdf. Accessed 15 Mar 2018. https://doi.org/10.2307/2137486
- Myers SS, Patz JA (2009) Emerging threats to human health from global environmental change. Annu Rev Environ Resour 34:223–252. https://doi.org/10.1146/annurev.environ.033108.102650CrossRefGoogle Scholar
- Olinto P, Beegle K, Sobrado C, Uematsu H (2013) The state of the poor: where are the poor, where is extreme poverty harder to end, and what is the current profile of the world’s poor? World Bank. http://siteresources.worldbank.org/EXTPREMNET/Resources/EP125.pdf. Accessed 15 Mar 2018
- Prüss-Ustün A, Corvalán C (2006) Preventing disease through healthy environments. World Health Organisation. http://www.who.int/quantifying_ehimpacts/publications/preventingdisease.pdf. Accessed 15 Mar 2018. https://doi.org/10.1590/S1413-41522007000200001
- Sukhdev P, Wittmer H, Miller D (2014) The economics of ecosystems and biodiversity (TEEB): challenges and responses. http://img.teebweb.org/wp-content/uploads/2014/09/TEEB-Challenges-and-Responses.pdf. Accessed 15 Mar 2018. https://doi.org/10.1093/acprof:oso/9780199676880.003.0007
- UNEP (2013) Global chemicals outlook: towards sound management of chemicals. https://sustainabledevelopment.un.org/content/documents/1966Global%20Chemical.pdf. Accessed 15 Mar 2018
- WWF International, Zoological Society of London, Global Footprint Network, Water Footprint Network (2014). https://www.wwf.or.jp/activities/data/WWF_LPR_2014.pdf. Accessed 15 Mar 2018
- You D, Hug L, Chen Y, et al (2014) Levels and trends in child mortality. Unicef. https://www.unicef.org/media/files/Levels_and_Trends_in_Child_Mortality_2014.pdf. Accessed 15 Mar 2018