Animal Populations have Declined Nearly 70% Since 1970, Says Report

A Journal of People report

Overall, the world biodiversity scenario is not good. According to a new report, animal populations have declined by such a staggering amount, that only an overhaul of the world’s economic systems could possibly reverse the damage.

Nearly 21,000 monitored populations of mammals, fish, birds, reptiles and amphibians, encompassing almost 4,400 species around the world, have declined an average of 68% between 1970 and 2016, according to the World Wildlife Fund’s Living Planet Report 2020. Species in Latin America and the Caribbean, as well as global freshwater habitats, were disproportionately impacted, declining, on average, 94% and 84%, respectively.

Every two years, the World Wildlife Fund (WWF) releases its landmark report, revealing how far species populations have declined since 1970 — an important marker for the overall health of ecosystems. 

Broken relationship between humans and the natural world 

The latest report indicates that the rate populations are declining “signal a fundamentally broken relationship between humans and the natural world, the consequences of which — as demonstrated by the ongoing COVID-19 pandemic — can be catastrophic.”

“This report reminds us that we destroy the planet at our peril — because it is our home,” WWF U.S. president and CEO Carter Roberts said in a statement. “As humanity’s footprint expands into once-wild places, we’re devastating species populations. But we’re also exacerbating climate change and increasing the risk of zoonotic diseases like COVID-19. We cannot shield humanity from the impacts of environmental destruction. It’s time to restore our broken relationship with nature for the benefit of species and people alike.”

A donkey tied up next to a burnt area of Amazon rainforest reserve, south of Novo Progresso in Para state, on August 16, 2020. / Credit: CARL DE SOUZA/AFP via Getty Images

Humans are to blame

The report blames humans alone for the “dire” state of the planet. It points to the exponential growth of human consumption, population, global trade and urbanization over the last 50 years as key reasons for the unprecedented decline of Earth’s resources, which it says the planet is incapable of replenishing.

Overuse of finite resources 

The overuse of these finite resources by at least 56% has had a devastating effect on biodiversity, which is crucial to sustaining human life on Earth. “It is like living off 1.56 Earths,” Mathis Wackernagel, David Lin, Alessandro Galli and Laurel Hanscom from the Global Footprint Network said in the report.

Land-use change 

The report points to land-use change — in particular, the destruction of habitats like rainforests for farming — as the key driver for loss of biodiversity, accounting for more than half of the loss in Europe, Central Asia, North America, Latin America and the Caribbean.

Much of that land is now used for agriculture, which is responsible for 80% of global deforestation and makes up 70% of freshwater use. Using this much land requires a vast food system that releases 29% of global greenhouse gases, and the excessive amount of land and water that people are using has killed 70% of terrestrial biodiversity and 50% of freshwater biodiversity. Many species simply cannot survive under the new conditions forced upon them when their habitats are altered by humans. 

Destruction of ecosystems

Destruction of ecosystems has threatened 1 million species — 500,000 animals and plants and 500,000 insects — with extinction, much of which can be prevented with conservation and restoration efforts.

Healthy vegetation sits alongside a field scorched by fire in the Amazon rainforest in Rondonia state, Brazil. / Credit: Leonardo Carrato/Bloomberg/Getty Images

Food industry needs an overhaul

Where and how humans produce food is one of the biggest threats to nature, the report says. Much of the habitat loss and deforestation that occurs is driven by food production and consumption.

One-third of all terrestrial land is used for cropping and animal breeding. Of all the water withdrawn from available freshwater resources, 75% is used for crops or livestock. If current habitats remain the same, researchers predict that cropland areas may have to be 10-25% larger in 2050 than in 2005, just to accommodate increased food demand. That increase is expected, despite more than 820 million people facing food insecurity, indicating that much of the agricultural strain is wasted.

Food loss and waste 

Food loss and waste cost the U.S. $1 trillion in economic costs, $700 billion in environmental costs and approximately $900 billion in social costs, according to the report.

Around the world, an estimated one-third of all food produced for humans is lost or wasted — about 1.4 billion tons every year. Food waste is responsible for at least 6% of global greenhouse gas emissions — three times more than that from aviation — and nearly one-quarter of those emissions come from wasted food.

Cattle on a dairy farm in Saxony on June 6, 2020. / Credit: Sebastian Willnow/picture alliance via Getty Images

The role of climate crisis

Species overexploitation, invasive species and diseases and pollution are all considered threats to biodiversity, the report said. However, human-caused climate change is projected to become as, or more important than, other drivers of biodiversity loss in the coming decades.

Climate change creates an ongoing destructive feedback loop in which the worsening climate leads to the decline in genetic variability, species richness and populations, and that loss of biodiversity adversely affects the climate. For example, deforestation leads to an excess of carbon dioxide in the atmosphere, warming the planet and exacerbating forest fires.

Just a handful of countries — Russia, Canada, Brazil and Australia — contain regions without a human footprint. But these wilderness areas are facing irreversible erosion, affecting other species and humans’ ability to adapt to climate change.

According to the report, no part of the ocean is entirely unaffected by overfishing, pollution, coastal development and other human-caused stressors. Humans depend on marine ecosystems to provide food, climate regulation, carbon storage and coastal protection — all of which are affected by these activities and are exacerbated by climate change.

“These places are disappearing in front of our eyes,” said James Watson, from the University of Queensland and WCS, Brooke Williams from the University of Queensland and Oscar Venter from the University of Northern British Columbia.

Link between the health of the people and the planet

Between devastating wildfires and the COVID-19 pandemic, 2020 has made it clear that humans and nature have never been more intertwined. The report shows that the natural support for human life is rapidly declining — and that it’s up to citizens, governments and business leaders to come together at a scale never-before-seen to do something about it.

Experts expressed concern that many of the major gains in human health in the past 50 years — such as a decreased rate of child mortality and poverty and an increase in life expectancy — could be undone or even reversed due to loss of nature.

The rate of infectious disease emergence has increased dramatically over the past 80 years — and nearly half of these diseases are connected to land-use change, agriculture and the food industry. One study cited by the report suggests that diseases originating in animals are responsible for 2.5 billion cases of illness and nearly 3 million deaths every year.

“How humanity chooses to recover from the COVID-19 pandemic, and how it addresses the looming threats from global environmental change, will influence the health of generations to come,” wrote Thomas Pienkowski and Sarah Whitmee of the University of Oxford.

The current trends can be flattened 

The report urges that current trends can be flattened, and even reversed, with urgent action. It emphasizes the need for world leaders to overhaul the food production and consumption industries — taking deforestation completely out of supply chains and making trade more sustainable, among other things.

Cost: billions of dollars globally 

In just the last year alone, natural disasters, from California’s wildfires to severe droughts in Australia, have cost billions of dollars globally. Experts warn that economic decision-makers need to take into account not only produced and human capital, but also natural capital when crafting public and private policy.

Eating: Healthier way

To feed 10 billion people by 2050, humans will need to adopt a healthier way of eating — both for themselves and for the planet. Diet-related disease risk is the leading cause of premature mortality globally and food production is the main driver of biodiversity loss and water pollution, also accounting for 20-30% of greenhouse gas emissions.

Experts recommend humans adopt a diet that consists of a balanced proportion of whole grains, fruits, nuts, vegetables, beans and pulses, with animal-derived products like fish, eggs, dairy and meat consumed in moderation.

The report calls the above changes “non-negotiable” to preserve human health, wealth and security and urges world leaders gathering virtually for the U.N. General Assembly beginning September 15 to address them — only then can humans “bend the curve” of biodiversity loss.

“While the trends are alarming, there is reason to remain optimistic,” said WWF global chief scientist Rebecca Shaw. “Young generations are becoming acutely aware of the link between planetary health and their own futures, and they are demanding action from our leaders. We must support them in their fight for a just and sustainable planet.”


Following are excerpts from the report:

“In the last 50 years our world has been transformed by an explosion in global trade, consumption and human population growth, as well as an enormous move towards urbanisation. These underlying trends are driving the destruction and degradation of nature, with the world now overusing natural resources at an unprecedented rate. Only a handful of countries retain most of the last remaining wilderness areas. As a result, our natural world is transforming more rapidly than ever before. The 2020 global Living Planet Index shows an average 68% fall in monitored populations of mammals, birds, amphibians, reptiles and fish between 1970 and 2016. Species’ population trends are important because they are a measure of overall ecosystem health. Measuring biodiversity, the variety of all living things, is complex, and there is no single measure that can capture all the changes in this web of life.”

“Since the industrial revolution, human activities have increasingly destroyed and degraded forests, grasslands, wetlands and other important ecosystems, threatening human well-being. Seventy-five per cent of the Earth’s ice-free land surface has already been significantly altered, most of the oceans are polluted, and more than 85% of the area of wetlands has been lost. The most important direct driver of biodiversity loss in terrestrial systems in the last several decades has been land-use change, primarily the conversion of pristine native habitats into agricultural systems; while much of the oceans have been overfished. Globally, climate change has not been the most important driver of the loss of biodiversity to date, yet in coming decades it is projected to become as, or more, important than the other drivers. The loss of biodiversity is not only an environmental issue but a development, economic, global security, ethical and moral one. It is also a self-preservation issue. Biodiversity plays a critical role in providing food, fibre, water, energy, medicines and other genetic materials; and is key to the regulation of our climate, water quality, pollution, pollination services, flood control and storm surges. In addition, nature underpins all dimensions of human health and contributes on non-material levels – inspiration and learning, physical and psychological experiences and shaping our identities – that are central in quality of life and cultural integrity.”

“The 2020 global Living Planet Index (LPI) shows an average 68% (range: -73% to -62%) fall in monitored populations of mammals, birds, amphibians, reptiles and fish between 1970 and 2016 1.”

“Biodiversity is declining at different rates in different places.” 

“The global LPI does not give us the entire picture – there are differences in abundance trends between regions, with the largest declines in tropical areas. The 94% decline in the LPI for the tropical subregions of the Americas is the most striking result observed in any region. The conversion of grasslands, savannahs, forests and wetlands, the overexploitation of species, climate change, and the introduction of alien species are key drivers.”

“Freshwater biodiversity is declining far faster than that in our oceans or forests. Based on available data, we know that almost 90% of global wetlands have been lost since 1700 83; and global mapping has recently revealed the extent to which humans have altered millions of kilometres of rivers 84. These changes have had a profound impact on freshwater biodiversity with population trends for monitored freshwater species falling steeply. The 3,741 monitored populations – representing 944 species of mammals, birds, amphibians, reptiles and fishes – in the Freshwater Living Planet Index have declined by an average of 84% (range: -89% to -77%), equivalent to 4% per year since 1970 (Figure 3). Most of the declines are seen in freshwater amphibians, reptiles and fishes; and they’re recorded across all regions, particularly Latin America and the Caribbean.”

“Species with a larger body size compared with other species in the same taxonomic group are sometimes referred to as ‘megafauna’. In the freshwater system, megafauna are species that grow to more than 30kg, such as sturgeon and Mekong giant catfish, river dolphins, otters, beavers and hippos. They are subject to intense anthropogenic threats 3, including overexploitation 4, and strong population declines have been observed as a result 5. Mega-fishes are particularly vulnerable. Catches in the Mekong river basin between 2000 and 2015, for example, have decreased for 78% of species, and declines are stronger among medium- to large-bodied species 6. Large fishes are also heavily impacted by dam construction, which blocks their migratory routes to spawning and feeding grounds.”

“Humanity’s influence on the decline of nature is so great that scientists believe we are entering a new geological epoch, the Anthropocene. Yet, measuring biodiversity, the variety of all living things, is complex, and there is no single measure that can capture all of the changes in this web of life. The vast majority of indicators show net declines over recent decades.”

“Plant extinction risk is comparable to that of mammals and higher than for birds. The number of documented plant extinctions is twice as many as for mammals, birds and amphibians combined 21. In addition, an assessment of a sample of thousands of species representing the taxonomic and geographic breadth of global plant diversity showed that one in five (22%) are threatened with extinction, most of them in the tropics.”

“In the last 50 years our world has been transformed by an explosion in global trade, consumption and human population growth, as well as an enormous move towards urbanisation, changing how we live unrecognisably. Yet this has come at a huge cost to nature and the stability of the Earth’s operating systems that sustain us.”

“Since 1970, our Ecological Footprint has exceeded the Earth’s rate of regeneration. This overshoot erodes the planet’s health and, with it, humanity’s prospects. Both human demand and natural resources are unevenly distributed across the Earth. The pattern of human consumption of these resources differs from resource availability, since resources are not consumed at the point of extraction. The Ecological Footprint per person, across countries, provides insights into countries’ resource performance, risks and opportunities.”

“Varying levels of Ecological Footprint are due to different lifestyles and consumption patterns, including the quantity of food, goods and services residents consume, the natural resources they use, and the carbon dioxide emitted to provide these goods and services.”

“Up to one-fifth of wild species are at risk of extinction this century due to climate change alone, even with significant mitigation efforts, with some of the highest rates of loss anticipated in biodiversity ‘hotspots’.”

“Just 30 years ago, climate change impacts on species were extremely rare, but today they are commonplace. Some species are relatively buffered from changes (e.g. deep-sea fishes), but others (e.g. Arctic and tundra species) already face enormous climate change pressures. Such pressures impact species through various mechanisms including direct physiological stress, loss of suitable habitat, disruptions of interspecies interactions (such as pollination or interactions between predators and prey), and the timing of key life events (such as migration, breeding or leaf emergence) (Figure 11) 34. Recent climate change impacts on flying foxes and the Bramble Cay melomys show how quickly climate change can lead to drastic population declines, and warn of unseen damage to less conspicuous species (see boxes).”

“The Bramble Cay melomys, Melomys rubicola, made headlines in 2016 when it was declared extinct following intensive surveys of the 5-hectare coral cay in Australia’s Torres Strait where the species lived. It is the first known mammal extinction to be linked directly to climate change 35. This rodent has been lost. It will, however, remain immortalised as a stark reminder that the time to act on climate change is now.”

“Flying foxes (genus Pteropus) are not physiologically capable of tolerating temperatures above 42o C 37. At these temperatures, their usual coping behaviours – such as shade-seeking, hyperventilation and spreading saliva on their bodies (they cannot sweat) – are insufficient to keep them cool, and they begin to clump together in a frenzy to escape the heat. As they drop from the trees, many are injured or become trapped and die. Between 1994 and 2007, more than 30,000 flying foxes from at least two species, from a global population of less than 100,000, are thought to have died during heatwaves.”

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