Humanity has made the planet sick, unleashing climate change, stripping forests, causing mass extinctions of wildlife and polluting air and waterways while the earth buckles under the strain of a population surging towards the 10 billion mark.

This is the warning contained in the sixth Global Environment Outlook, the most comprehensive report of its kind, released in Nairobi, Kenya, this week by the UN Environment Programme.

The 745-page report offers a grim assessment of the planet’s ill health - but remarkably, it also provides some hope for the future.

“GEO-6 is an essential check-up for our planet,” writes UN secretary-general António Guterres. “Like any good medical examination, there is a clear prognosis of what will happen if we continue with business as usual and a set of recommended actions to put things right.”

The theme, “Healthy Planet, Healthy People”, highlights the “inextricable link between the environment and our survival and progress”.

Yet the challenges its authors - 250 scientists and experts - outline are multiple.

“From climate change to the extinction of species, economies too dependent on the wasteful use of resources and unprecedented pressure on terrestrial and marine ecosystems, we are at a decisive moment in our role as custodians of the planet,” he notes.

Though there has been some progress, “we need a significant shift in trajectory - the kind of transformational change prescribed by the Intergovernmental Panel on Climate Change in its recent report on limiting global warming to 1.5degrees” but missing ingredient is “collective resolve”.

Economically, says the GEO-6, countries are still guided by an approach of “grow now, clean up later.

“This is simply not sustainable in a world already crossing planetary boundaries on a number of dimensions, which threatens to undermine economic growth if not addressed.”

It’s often costlier than preventing damage in the first place.

“It creates stranded assets which lose their value, and is now leading to irreversible negative impacts, including on human health.

“This renders an economy un- productive and uncompetitive compared with a flexible and proactive approach, capable of managing the transition to a sustainable, innovative and resource-efficient economy that can take advantage of opportunities in fast-growing, environmentally aware markets.”

Protecting the environment, and preventing and mitigating pollution, “are major sources of economic opportunity, providing jobs, reducing poverty, driving innovation and addressing resource availability/scarcity and depletion”.

Humanity has been seriously affected by ongoing systemic ecological changes, such as climate change and deforestation.

“These have reached the point that the ecological foundations of human society and natural systems that support other species and provide invaluable ecosystem services are in great danger.

“Human activities are causing increasing amounts of pollution, to the extent this is now recognised as the biggest single risk to human health worldwide.” Continuing to live on the brink of, or outside ecological limits, will “make it more difficult to achieve prosperity, justice, equity and a healthy life for all”.

Unsustainable production and consumption patterns, inequality and population growth-driven increase in resource use are “deteriorating planetary health at unprecedented rates with increasingly serious consequences especially for poorer people and regions”.

Evidence of current global climate change is unequivocal. Eight of the 10 warmest years on record have occurred within the past decade.

“The impacts are much wider than temperature increase, affecting water availability, ecosystems, energy demand and production and transportation. Shifts in weather patterns, extreme events (heatwaves and droughts) and environmental disruptions (crop failures) result in greater risks to human health and well-being, and livelihoods, especially among the poorest and most vulnerable groups.”

Time is running out to combat these impacts, which also include changes in disease vectors, slowdowns in economic growth, and an increased potential for violent conflict.

Air pollution, which causes 6million to 7million premature deaths a year, is projected to continue to have significant negative effects on health and lead to between 4.5million and 7million premature deaths by mid-century.

Biodiversity loss from land use change, and habitat fragmentation, overexploitation and illegal wildlife trade, invasive species, pollution and climate change are driving a mass extinction of species, including critical ecosystem service providers such as pollinators. “This compromises Earth’s ecological integrity and capacity to meet human needs.”

Marine plastic litter, including microplastic, is found in all levels of the marine ecosystem and shows up in fisheries and shellfish at “alarming” levels and frequency.

“The adverse impact of micro- plastic on the marine system is unknown, with a potential health impact through the consumption of fish and marine products,” yet there is still no global agreement in force to tackle marine litter.

Natural resources, including freshwater and oceans, are too often over-exploited, poorly managed and polluted.

GEO-6 shows how about 1.4million people die annually from preventable diseases, such as diarrhoea and intestinal parasites, associated with pathogen-polluted drinking water and inadequate sanitation.

Antibiotic-resistant infections are projected to become a main cause of death worldwide by 2050. “Even greater efforts should be made to control the mismanagement of antibacterial drugs at source, in human and agricultural use.”

Modern society, too, is living in the most chemical-intensive era in human history.

“The pace of production of new chemicals largely surpasses the capacity to fully assess their potential adverse impacts on human health and ecosystems.

“The harmful impact of the inappropriate use of pesticides, heavy metals, plastic and other substances are of significant concern as such compounds appear in alarmingly high levels in our food supply. They primarily affect vulnerable members of society, such as infants exposed to elevated levels of chemicals. The impact of neurotoxins and endocrine-disrupting chemicals are potentially multi-generational.”

Nanotechnology, by decreasing the particle size of materials and increasing its reactivity, “may give a material some interesting properties, but these may be toxic”.

Unprecedented global urbanisation can present an opportunity to increase citizens’ well-being while decreasing their environmental footprint through improved governance, land-use planning and green infrastructure.

Low-meat diets and a big cut in food waste will halve the amount of food that needs to be produced to feed the projected 9billion to 10billion people on the planet in 2050.

Consider a third of global edible food is wasted and more than half of the food produced in industrialised countries is thrown away.

The world, says the UN, has the science, technology and finance to move towards a more sustainable development pathway, but there is still inadequate support from the public, business and political leaders “who cling to outdated production and development models”.

It says green investment of just 2% of countries’ gross domestic product would deliver long-term growth “as high as we presently projected but with fewer impacts from climate change, water scarcity and loss of ecosystems”.