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An increasingly unhealthy planet affects the well-being of billions. Promoting a healthy planet promotes healthy people.

2. A healthy planet supports healthy people

During the last thousands of years, the Earth has provided a hospitable environment for human societies to flourish. The natural greenhouse effect provides a comfortable climate, and water flows across the globe support humans and their activities. Humans are so used to exploiting the resources of the planet and enjoying the free clean air, water and climate the biosphere provides that the latter are simply taken for granted, unvalued and unaccounted for by our socio-political and economic systems – the ‘externality’ concept that is at the heart of environmental economics and that leads, as was noted many years ago, to the tragedy of the commons (Hardin, Reference Hardin1968). The tendency as societies ‘develop’ is for the environment to be seen increasingly as something that can be controlled, commodified and used to serve human needs while at the same time serving as a receptacle of discarded wastes.

Everyone depends on a healthy environment for good human health, with health understood as physical, social and psychological well-being. However, the poor are fundamentally dependent on nature for its direct supply of air, water, land and food to sustain their livelihood activities as well as their day-to-day survival and health. There are estimates that approximately 70% of the poor depend directly on the land, water and air for their lives and livelihoods (Sukhdev et al., Reference Sukhdev, Wittmer, Schröter-Schlaack, Nesshöver, Bishop, ten Brink and Simmons2010). More than 2 billion people work in the informal sector, including 85.8% of workers in the African labour force, 68.2% of workers in Asia and the Pacific and 40% of the Latin American labour force (ILO, 2018). They depend on predictable weather and healthy pollinators for their subsistence agriculture, on stable as opposed to extreme weather events for their lives and livelihoods, on a steady flow of water in their rain-fed or glacier-fed rivers and on the fish in rivers and coastal waters for much of their protein.

Indigenous peoples and local communities have long revered the forests and waters and have treated these resources as gifts from God – in fact, these communities who live on approximately one-fifth (22%) of the global land surface have actually still managed to conserve approximately four-fifths of the global biodiversity (Sobrevila, Reference Sobrevila2008). However, only 10% of the 2.5 billion people who are directly dependent on the land actually own their land (Oxfam, International Land Coalition, Rights and Resources Initiative, 2016), and in particular women farmers own only a fraction of the land they work on (FAO, 2011). These communities are increasingly under pressure as their lands become polluted and their livelihoods are put at risk through, for example, the impacts of extractive industries (extracting 84 billion tonnes in 2015; Ekins & Hughes, Reference Ekins2017) or because they are forced off their properties through distress sales or land-grabbing (Rulli et al., Reference Rulli, Saviori and D'Odorico2013). Even in cities, approximately 1 billion people in growing urban slums have no property rights (Habitat for Humanity, 2016). Slum-dwellers face specific challenges with respect to excessive exposure to air pollution, water pollution and waste, with 3 billion people worldwide having no access to proper waste management facilities (Wilson et al., Reference Wilson, Rodic, Modak, Soos, Rogero, Velis and Simonett2015). Insecure tenure and property rights affect the motivation and abilities of communities to invest in their lands or properties.

Those in the formal market economy are also dependent on a healthy planet, but differently so, through global investment and trade in extracted resources that are then used to produce a variety of goods and services for commercial ends. The technologies of all goods and services use the minerals and other resources of the Earth and produce a steady stream of waste. Thus, NCP supports a growing global world product of more than USD 75 trillion in 2017. As just one example of NCP, pollinators are conservatively estimated to provide a service of USD 351 billion to the commercial agricultural sector (Lautenbach et al., Reference Lautenbach, Seppelt, Liebscher and Dormann2012). Another calculation of the contribution of ecosystems to human welfare puts the value at USD (2007) 125 trillion annually, significantly more than the global world product (Costanza et al., Reference Costanza, de Groot, Sutton, van der Ploeg, Anderson, Kubiszewski and Turner2014). More important than this notional aggregate value is the calculation from the same source that USD 4–20 trillion worth of ecosystem services have been lost between 1995 and 2011. Clearly, these numbers do not reflect the huge value that these ecosystems have for humans, but at least they serve to indicate the order of magnitude of damage being caused and to relate this in some way or other to the global economic system.

We conclude that a healthy planet and a stable climate are critical for supporting healthy people in both the informal and formal economies.

3. An unhealthy planet leads to unhealthy people

Just as a healthy planet contributes to human health and well-being, the increasingly poor health of the planet is harming the well-being of humans as well as the rest of life on Earth.

Local environmental thresholds practically everywhere are being crossed with respect to different ecosystems through uncontrolled grazing or resource extraction in or excessive use of the commons and the uncontrolled emissions of solid, liquid and gaseous wastes into the lithosphere, atmosphere and hydrosphere. Emissions of persistent, bio-accumulative and toxic pollutants, greenhouse gases (GHGs) and others are changing the composition of the atmosphere, leading to concentrated urban air pollution, household air pollution in rural homes in developing countries and climate change. Groundwater is being extracted beyond recharge levels and heavily polluted in specific locations and is affected by changing freshwater supplies, reduced recharge zones and localized scarcity or floods with long-lasting impacts. More than 100 million chemical substances have been released into the environment. The mismanagement of antibacterial drugs, pesticides, endocrine disrupting chemicals and persistent organic pollutants threaten both humans and wildlife, particularly in aquatic systems. The oceans are warming and acidifying, killing coral reefs especially, but not only, in tropical areas. Coral reefs, which are among the most biodiverse ecosystems in the world, provide services worth USD 29 billion annually, so their loss will have significant impacts on coastal populations (Burke et al., Reference Burke, Reytar, Spalding and Perry2011). The oceans are being drained of their fish resources. They are also subject to growing pollution, especially from the 8 million tonnes of plastic that enter the oceans annually (Jambeck et al., Reference Jambeck, Geyer, Wilcox, Siegler, Perryman, Andrady, Narayan and Law2015), as well as from offshore oil pollution and hydrocarbon accidents.

Globally, scientists are increasingly warning that human behaviour is seriously affecting the planet, which some scientists express in terms of crossing planetary boundaries (Steffen, Reference Steffen, Richardson, Rockström, Cornell, Fetzer, Bennett and Sörlin2015). One of these ‘boundaries’ is related to biodiversity – genes, species and ecosystems – which is disappearing at rates that have caused scientists to conclude that the sixth global mass extinction event (with earlier events long ago identified from the fossil record) either is, or could be, underway (Barnosky et al., Reference Barnosky, Matzke, Tomiya, Wogan, Swartz, Quental, Marshall and Ferrer2011; Ceballos et al., Reference Ceballos, Ehrlich and Dirzo2017). Between 1970 and 2014, populations of vertebrates – mammals, birds, fish and reptiles – fell by an average of 60%, with freshwater species exhibiting a decline of 83% (WWF, 2018). Another key global marker is climate change: global average temperatures have increased by 0.8–0.9°C since 1880, and 8 years in the last decade have been the warmest on record (Climate Central, 2018). Current climate policies will only achieve a third of what is needed to meet the 1.5–2.0°C objective of the Paris Agreement on Climate Change (Xu & Ramanathan, Reference Xu and Ramanathan2017). Warming has cascading effects on the polar climate system, with sea ice in the Arctic retreating, permafrost thawing, snow cover extent decreasing and ice sheets, ice shelves and mountain glaciers continuing to lose mass, all of which trigger other changes across the planet. Thawing peat lands contribute 5% of GHGs annually (Joosten, Reference Joosten2015). Increasingly, it seems that environmental stresses, along with other socio-political factors, are contributing to migration (Ekins et al., Reference Ekins and Gupta2019).

These environmental changes are negatively affecting human health and well-being. Air pollution is the number one cause of environment-related sickness causing premature death, as well as chronic ill health and loss of income (approximately USD 5 trillion annually) (World Bank & Institute for Health Metrics and Evaluation, 2016). In 2015 alone, 9 million people died prematurely from long-term exposure to air pollution (Landrigan et al., Reference Landrigan, Fuller, Acosta, Adeyi, Arnold, Basu and Zhong2017); 103 million years of healthy life were lost due to heart disease, stroke, lung cancer, chronic lung disease and respiratory infections (Cohen et al., Reference Cohen, Brauer, Burnett, Anderson, Frostad, Estep and Forouzanfar2017; Health Effects Institute, 2017). This is probably because more than 50% of the global population lives in cities, but only approximately 12% of such cities meet World Health Organization air quality standards (World Health Organization, 2014). In rural areas, household air pollution affects 2.8 billion people (Smith et al., Reference Smith, Bruce, Balakrishnan, Adair-Rohani, Balmes and Chafe2014), and in 2012, between 2.9 and 4.3 million people died as a result (Landrigan et al., Reference Landrigan, Fuller, Acosta, Adeyi, Arnold, Basu and Zhong2017), with an estimated gross domestic product (GDP) loss of 0.68% in low-income countries (Landrigan et al., Reference Landrigan, Fuller, Acosta, Adeyi, Arnold, Basu and Zhong2017). Air pollution especially affects vulnerable people because of their age, health, living circumstances or occupation (Crimmins et al., Reference Crimmins, Balbus, Gamble, Beard, Bell, Dodgen and Ziska2016). Air pollution costs USD 225 billion in lost labour income, most of which occurs in poorer countries (World Bank & Institute for Health Metrics and Evaluation, 2016).

Water insecurity (quantity and quality) affects health and livelihoods. Melting glaciers reduce the security of flow in rivers potentially affecting 1 billion people (UNEP, 2016a), and a high percentage of these people confront acute water shortage for at least 1 month annually. Mostly poorer women spend approximately 40 billion hours on collecting water (UNDP, 2006). Contaminated water causes 1.7 million fatalities from treatable diseases annually (Ashbolt, Reference Ashbolt2004). Such diseases cost USD 140 billion in revenues lost and USD 56 billion in medical costs annually (Lixil/Water Aid/Oxford Economics, 2016). Rising contamination from chemicals, including antibiotics and endocrine disruptors, and fracking could lead to water becoming the number one cause of death by 2050 (O'Neill, Reference O'Neill2012). Wetlands conservatively valued at up to USD 800,000 ha/year (2007 price levels; de Groot et al., Reference de Groot, Brander, van der Ploeg, Costanza, Bernard, Braat and van Beukering2012) are being lost rapidly (40% in 1997–2011, at a loss of USD 2.7 trillion to local people; Costanza et al., Reference Costanza, de Groot, Sutton, van der Ploeg, Anderson, Kubiszewski and Turner2014). Poor ocean health affects access to cheap protein (i.e., fish) for approximately 275 million people (Wilkinson et al., Reference Wilkinson, Salvat, Eakin, Brathwaite, Francini-Filho, Webster and Harris2016) and the access to 20% of the animal protein supply for 3.1 billion people in total (FAO, 2011), potentially affecting small-scale fisheries that support 58–120 million people (World Bank, 2012). It also threatens livelihoods in the tourism (USD 2.3 trillion) and commercial fishing sectors (USD 252 billion) (Ferreira, Reference Ferreira, Rice and Rosenberg2016).

Land degradation (29%) and related loss of biodiversity affects (subsistence) agriculture for approximately 3.2 billion people (Le et al., Reference Le, Nkonya, Mirzabaev, Nkonya, Mirzabaev and von Braun2016; UNCCD, 2017). Growing soil salinization could reduce agricultural revenues by USD 27.3 billion (Qadir et al., Reference Qadir, Quillérou, Nangia, Murtaza, Singh, Thomas and Noble2014) and exacerbate famine. Deforestation particularly affects poor local communities and indigenous peoples (WWF, 2016), and unsanitary waste collection and disposal expose 2 billion people mostly in the developing world to health hazards (Kuehr, Reference Kuehr2014), especially the 15 million waste pickers (Binion & Gutberlet, Reference Binion and Gutberlet2012).

Biodiversity loss is linked to the rise in zoonotic diseases and may be responsible for 60% of human infectious diseases (CDC, 2017; Karesh et al., Reference Karesh, Dobson, Lloyd-Smith, Lubroth, Dixon, Bennett and Heymann2012), for the fall in the resilience of agricultural systems because of loss of pollinators and genetic diversity and hence for food insecurity and for invasive species that lead to hundreds of billions of USD losses globally (approximately USD 22 and 120 billion a year in the EU (Kettunen et al., Reference Kettunen, Genovesi, Gollasch, Pagad, Starfinger, ten Brink and Shine2009) and the USA (Pimentel et al., Reference Pimentel, Zuniga and Morrison2005), respectively). The illegal trade in species, conservatively valued at USD 150 billion annually, is also a major contributor to the loss of genetic, species and ecosystem diversity (Higgins & White, Reference Higgins, White, Pink and White2016).

Creeping and sudden disasters further undermine the ability of farmers, fishers and coastal residents in particular to cope, often displacing people (2016: 24.2 million; IDMC/NRC, 2017) and otherwise adversely affecting them (1995–2015: 4.2 billion) and killing them (1995–2015: 600,000), all with huge economic (1995–2016: USD 1.4 trillion; ELD, 2015), psychological and well-being costs. Between 1995 and 2015, 700,000 people died and 1.7 billion people were affected by extreme weather events, costing USD 1.4 trillion (UNISDR/CRED, 2015). Approximately 90% of the economic losses were faced by upper-middle- and high-income countries. However, the loss to the poorest countries at only 1% of the global total is significant as this latter loss was equivalent to 1.5% of the GDP of the poorest countries, and over 99% of it was uninsured (Watts et al., Reference Watts, Amann, Ayeb-Karlsson, Belesova, Bouley, Boykoff and Costello2017). This number is significantly higher for small island (1–8% of GDP on average over 1970–2010; UNEP, 2016b) and coastal states, who also face existential threats. Vulnerability to climate change is far from equally distributed: 20 of the 36 highest GHG-emitting countries have the least vulnerability, while 11 out of the 17 low to moderate emitters have the highest vulnerability (Althor et al., Reference Althor, Watson and Fuller2016).

In total, approximately 25% of current mortality is caused by environmental factors (Prüss-Üstün & Neira, Reference Prüss-Üstün and Neira2016), and this excludes the loss of life, home and livelihoods of those affected by extreme weather events and possibly the rise in zoonotic diseases. The costs to global welfare as a consequence of air pollution alone is estimated at USD 4.6 trillion annually (Landrigan et al., Reference Landrigan, Fuller, Acosta, Adeyi, Arnold, Basu and Zhong2017).

4. Causes of an unhealthy planet

What are the causes of all this? Two key drivers of environmental pressures are the continued prioritization of ‘growth’ and technological development without accounting for the environmental consequences. The tendency for countries to seek to ‘grow now, clean up later’ may have increased incomes worldwide, but in ignoring environmental values has increased welfare much less, and may have reduced it in some countries, while the same model has also delivered growing inequality. ‘Cleaning up later’ is also becoming more difficult, or is impossible when change is irreversible. Similarly, technology and innovation have enhanced productivity and some aspects of lifestyles, but have also exposed humans to increasing risks. Furthermore, the rising population (which, according to some estimates, could be approximately 7.5 billion in 2018, 10 billion in 2050 and 12 billion in 2100; Samir & Lutz, Reference Samir and Lutz2017) and the increasing proportion of the world living in urban areas (50% today to possibly 66% in 2050; UN DESA, 2014) are creating additional demands on the Earth's resources, although clearly those with access to the most resources have a larger environmental footprint. Finally, climate change is no longer a future possibility, but a present reality, with the Earth committed to further climate change from past emissions that will also act as an important driver and amplifier of environmental pressures.

In terms of environmentally intensive sectors, the energy sector is responsible for most GHG emissions, which are strongly correlated with incomes. The richest 10% of households globally emit 66% of the GHGs, while the poorest 50% emit 15% (Hubacek et al., Reference Hubacek, Baiocchi, Feng, Castillo, Sun and Xue2017). Much material extraction is associated with environmental damage and is also strongly correlated with incomes: the wealthiest countries use ten times more materials per capita per year than the poorest (Schandel et al., Reference Schandel, Fischer-Kowalski, West, Giljum, Dittrich, Eisenmenger and Fishman2016).

Agriculture accounts for 70% of water use, with aquifers being used beyond recharge rates (Hoekstra & Mekonnen, Reference Hoekstra and Mekonnen2012). Approximately 56% of the land footprint of the EU's consumption is from other countries (EEA, 2015). While 2 billion people have food deficiencies (Global Panel on Agriculture and Food Systems for Nutrition, 2016), over 2 billion people are overweight (NCD Risk Factor Collaboration, 2017) or obese. Current meat production (including feed for animals) accounts for 70% of farmland, drives deforestation, emits approximately a fifth of GHGs and uses approximately 8% of water resources (FAO, 2006), as well as causing massive chemical pollution and biodiversity loss. Meat consumption per capita in 2017 in the USA was double that of India and the continent of Africa (OECD, 2018). Food waste is 95–115 kg per capita annually in rich countries and 6–11 kg per capita annually in poor countries (Wilson et al., Reference Wilson, Rodic, Modak, Soos, Rogero, Velis and Simonett2015), at a global rate of 33%, with 56% occurring in rich countries (Lipinski et al., Reference Lipinski, Hanson, Lomax, Kitinoja, Waite and Searchinger2013).

Approximately 30% of urban dwellers have no access to basic services, and coastal city dwellers are particularly vulnerable to sea-level rise (UN-Habitat, 2003). In terms of environmental and resource efficiency – that is, environmental impact and resource use per unit of GDP – cities do better than rural areas and richer countries do better than the developing world (Yale Center for Environmental Law & Policy, 2018), but in absolute terms, cities and richer countries have greater negative environmental impacts and resource uses than rural areas and developing countries, respectively.

There is therefore a clear rich–poor dimension in the causes of environmental problems. There is also a strong gender dimension to the production, distribution, trade, transportation and consumption systems and waste streams that lead to heavy environmental pressures (Angeles, Reference Angeles and Cohon2017; Cohen, Reference Cohen, Lipsig-Mummé and McBride2015).

In the arena of population dynamics, from 1950 to 2017, total fertility rates decreased by 49.4% (Christopher et al., 2018). High fertility and population growth rates impede development and are associated with low income, low human development indicators and gender inequality. Addressing these issues, as well as enhancing education, especially for girls and women, and reducing infant mortality are likely to reduce population growth (Do & Kurimoto, Reference Do and Kurimoto2012; van Bavel, Reference van Bavel2013).

5. Policies for a healthy planet

The evidence for action is now incontrovertible. Scientific assessments in different fields (see Section 1) are presenting coherent messages of an increasingly unhealthy planet that is also on the brink of dangerous anthropogenic climate change with globally cascading impacts on land, water, oceans and biodiversity, and hence human health and well-being.

Current trends show that despite increasing efficiencies in production and consumption, the volume of degradation will increase. Despite expected improvements in water and food production, the SDGs regarding these and other environmental issues will not be achieved. As GEO-6 states: ‘Overall, the world is not on track to achieve the environmental dimension of the SDGs and related [multilateral environmental agreements] by 2030 and 2050’.

While incremental policy to address individual problems is necessary, it will not be sufficient. Going beyond symptoms and end-of-pipe solutions requires addressing the underlying drivers – the undifferentiated pursuit of growth; the potential negative impacts of technology; the gender inequality and social inequity that drive population growth and urbanization; and mitigating and adapting to climate change.

What is clear from GEO-6 is that there has been considerable innovation in environmental policy. The evidence suggests that no policy instrument is a priori better than another, that policy design (including vision, baselines and targets and feedback mechanisms for ratcheting up/down) is critical and that countries learn from each other. Not surprisingly, policy diffusion is slower and less ambitious where there are conflicting interests, and redistributive policies are needed. There is a need for policies that are both credible and flexible over the medium and long term as policy-makers discover what works and how quickly. Policy-makers urgently need better evidence for the effectiveness of policy through both the application of traditional scientific methods and the generation of new and disaggregated data and knowledge using citizen science, big data, Earth observation and indigenous and community knowledge, taking a strongly gendered and equity-sensitive approach throughout (Sutherland et al., Reference Sutherland, Gardner, Haider and Dicks2014; UNEP, 2016c).

It is also clear that environmental policy alone will not be enough to resolve environmental problems. The integration of environmental policy into other policy areas will also be required. This will not be successful without adequate attention being paid to potential co-benefits and trade-offs and substantial political will to see through the transformative change and reconfiguration of systems and institutions that are needed.

GEO-6 concludes that meeting the SDGs by 2030 and achieving broader environmental sustainability goals by 2050 are possible. Though very challenging, it is possible to achieve the necessary decoupling between economic growth and resource use (resource decoupling) and pollution (impact decoupling) through investing in decarbonization, dematerialization and detoxification within a circular economy in respect to both the land and the oceans. According to GEO-6, the Paris Agreement targets require low-carbon technologies to reduce carbon emissions in the global economy by 4–6% annually in order to approach near-zero emissions from the energy sector by 2050. Achieving the 1.5°C target would also require deep reduction in short-lived climate pollutants (Haines et al., Reference Haines, Amann, Borgford-Parnell, Leonard, Kuylenstierna and Shindell2017; Shindell et al., Reference Shindell, Borgford-Parnell, Brauer, Haines, Kuylenstierna, Leonard and Srivastava2017; Xu & Ramanathan, Reference Xu and Ramanathan2017). In the agricultural sector, a shift away from meat consumption could have multiple benefits – it could reduce the pressure on deforestation, water consumption and chemical pollution; it could release land to feed far more people directly; and for nature protection, and it could enhance human health. These effects would be reinforced by policies to reduce food wastage. Decoupling water from economic growth (e.g., through reusing grey water, increasing water efficiency and reducing demand through smart and drip irrigation) is also essential, as is managing the water in an integrated manner. In the transport sector, a focus on public transport, electric vehicles and active transport (walking and cycling) is required. Combining a healthy lifestyle with decentralized and improved technologies could make a key difference.

The spatial planning of urbanization could achieve greater well-being with lower land use and reduce the rate of increase of pollutants. Increased investment in green infrastructure including ecosystem- and resilience-based approaches and protected areas could enhance both biodiversity and local resilience to extreme weather events. The latter also requires an adaptive governance strategy that pays full attention to disaster management.

Already there are indications of many local initiatives worldwide to address these issues. There are many stories of investment in nature-based solutions, in the circular economy and in promoting smart and sustainable cities, of raising social awareness and of demanding the decentralization of systems. Some initiatives are amalgamating in larger social movements and using different tools, including litigation. In the Netherlands, the court has ruled that the government must increase its GHG reduction target because of the validity of the science and the recognition that continued emissions violate the human rights of others (Court Case 200.178.245, 2018).

At the global level, treaties on biodiversity, transboundary waters, oceans and climate change have been negotiated and continue to be subject to negotiations. These have mobilized action – 180 countries have submitted their National Biodiversity Strategies and Action Plans in implementation of their responsibilities under the Convention on Biological Diversity, and the Climate Change regime has spawned more than 1500 laws and policies worldwide (Nachmany & Setzer, Reference Nachmany and Setzer2018). However, as has already been noted, despite these treaties, biodiversity is under severe threat, and the 1.5°C target appears out of reach. The transboundary water agreements have scarcely been ratified and global regulation is lacking on marine litter, plastic pollution, chemical safety (including antibiotic pollution and endocrine disruptors), electronic waste, military-related waste, pesticides and sand mining.

Doubtless, the global vision and goals that have been outlined in the SDGs are a start. Goal-setting in itself can have positive impacts: for example, between 1990 and 2010, 2 billion people are reported to have gained access to potable water in fulfilment of the Millennium Development Goals (World Health Organization/UNICEF, 2012). But the far more ambitious SDGs require much more than goal-setting for their achievement. It is hard to see how they can be reached without legally binding multilateral environmental agreements that minimize the opportunities for free-riders.

A set of principles to govern policies was adopted in the Rio Declaration on Environment and Development of 1992. In May 2018, the UN General Assembly adopted a Resolution to begin negotiations on a legally binding Global Pact for the Environment (UN General Assembly, 2018) based on key principles. Although it is early days, this is a step in the right direction and could provide the impetus to steer investments into more sustainable pathways through a proactive, precautionary and equitable approach.

Although GEO-6 provides some good news regarding policy choices and implementation, the nature and scale of the damage calls for a wholesale re-examination of the fundamental drivers of the economic system, most notably its prioritization of ever-greater material consumption without adequately taking into account the contribution to human health and well-being of greater equity and environmental quality, as expressed through the SDGs. These contributions are entirely omitted from the money-based measures of production and consumption that drive the investments of the financial sector, and governments everywhere struggle to get the mandate to redress the balance in the face of the relentless pressures of commercialization and consumerism. Moving towards the sustainable consumption and production of SDG12 will require the political assertion and expression of values that emphasize the promotion of environmental and human health in a context of reduced material inequality, rather than undifferentiated economic growth.

6. Healthy people and a healthy planet are mutually supportive

There is compelling evidence in GEO-6 that a healthy planet is vital for all life, underpinning the very existence and well-being of the poorer half of the world's population and the economic welfare of the richer half. Evidence has also been presented here that the planet's health is deteriorating fast, with biodiversity loss and climate change as key global indicators. Locally, air, water and land pollution are cumulatively exposing billions of people to loss of heath, livelihoods and well-being. While air pollution is the number one environmental cause of deaths and disease worldwide today, water may become the number one cause by 2050. And failure to reduce GHG emissions in line with the Paris Agreement targets could cause ongoing climate change, compromising global human health irreversibly.

Conversely, redesigning societies and institutions to promote healthy consumption, healthy production and healthy spatial planning could be greatly beneficial for society. More conscious consumption, less meat in diets, less food waste and a more active lifestyle (more cycling and walking) could greatly enhance human health while promoting a healthier environment. And human well-being more widely could be promoted through more energy and environmentally efficient compact city design, renewable energy and moves towards a circular economy.

However, mobilizing men, women and children to want to change their behaviour away from actions that threaten their and future generations’ long-term health and well-being will require approaches that are sensitive to gender, age and culture and incorporate policy mixes across the full range of available instruments: goals such as the SDGs, knowledge, education, subsidies, rewards, environmental taxes, standards, environment impact assessments, the adoption of treaties and the Global Pact. And because policies are seldom neutral and because people will experience losses as well as gains, the politics of such a transformation will not be straightforward. At the most fundamental level, the hope must be that recognizing human rights to basic resources could have multiplier effects by enhancing the legitimacy of policy, mobilizing biodiversity protection through empowering local communities and indigenous peoples (Forest Peoples Programme/The International Indigenous Forum on Biodiversity/The Secretariat of the Convention on Biological Diversity, 2016) and increasing food security by providing tenure security, including for women (Croppenstedt et al., Reference Croppenstedt, Goldstein and Rosas2013). Comprehensive sustainable development education will also be required in order to enable the next generation to manage the problems they will inherit.

Finally, there are sound economic reasons for taking action. Perhaps surprisingly, the evidence is mounting that the approach outlined above, combined with the current trend of automation and data exchange in manufacturing technologies, could enable frontrunner countries to become more competitive and enter a new age of economic growth. UNEP's landmark 2011 report on the Green Economy found that switching from existing investment patterns by investing 2% of global GDP in restoring natural capital could result in a higher economic growth outcome from 2017 onwards (UNEP, 2011).

Investment in greater resource efficiency could also deliver substantial economic gains. Two of the many estimates of the benefits to be gained from greater resource efficiency are set out in detail by Dobbs et al. (Reference Dobbs, Oppenheim, Thompson, Brinkman and Zornes2011) and the Business and Sustainable Development Commission (BSDC, 2012). Dobbs et al. estimate that, in 2030, implementing all of the technologies considered would save private investors USD 2.9 trillion per year, a figure that rises to USD 3.7 trillion from a social perspective if financial subsidies to the energy, agriculture and water sectors, as well as energy taxes, are removed, and carbon is priced at USD 30 per tonne. Some 70% of these savings would offer a rate of return of greater than 10% per year.

The BSDC estimates that achieving the SDGs ‘opens up an economic prize of at least US$12 trillion for the private sector, and potentially 2–3 times more’ across the four broad sectors of food and agriculture, cities, energy and materials, and health and well-being (BSCD, 2012).

The Global Commission on the Economy and Climate (2014) finds that more than half and as much as 90% of the global emissions reductions required to get onto the 2°C climate pathway could generate net benefits to the economy. These include health benefits from reductions in urban pollution and traffic congestion, increases in efficiency and improvements in energy security and supply. Another estimate is that economic investment in achieving the 2°C target could leverage health benefits that are 1.4–2.5 times greater than the cost of mitigation. A 2.5-fold health benefit implies that for a cost of USD 22.1 trillion in climate policy, a return of USD 54.1 trillion in health benefits is possible. Research shows that increasing the target to 1.5°C could be very beneficial for China and India (Markandya et al., Reference Markandya, Sampedro, Smith, Van Dingenen, Pizarro-Irizar, Arto and González-Eguino2018). A reduction of global food waste of 33% could make further substantial savings (Lipinski et al., Reference Lipinski, Hanson, Lomax, Kitinoja, Waite and Searchinger2013; UNEP/UNITAR, 2013). These kinds of estimates suggest that the costs of inaction to the global community and nations in the face of current environmental challenges run into trillions of dollars and significantly exceed the costs of action to address them effectively.