The global wildlife populations have declined by an average 68% in over four decades, a World Wide Fund for Nature, or WWF, report has revealed. The WWF was formerly known as the World Wildlife Fund and remains the planet’s largest conservation organisation.

The “Living Planet Report 2020”, published on Thursday, said that environmental degradation, climate change, overexploitation of species, invasive species and population are the major contributing factors in the decline in biodiversity between 1970 and 2016.

The report presents an overview of the state of the world through contributions from more than 125 experts and the Living Planet Index, or LPI, which is based on trends in global wildlife abundance.

“These findings are devastating, and a stark reminder that a healthy planet is a precondition for a healthy human society, and that the European Green Deal is as relevant as ever,” said Ester Asin, director of WWF’s European Policy Office. “Urgent action is needed to halt and reverse the loss of nature and tackle climate change, both within the EU [European Union] and globally.”

The report showed that freshwater species were the most affected with an 84% decline in their populations. One out of every three freshwater species was threatened with extinction and species with larger body size, called megafauna, were more at risk than smaller ones, it said.

Further, the rate of decline of wildlife populations is different across various regions. Biodiversity in Latin America and the Caribbeans was the worst affected with a 94% drop, while in Europe and Central Asia the decline was the least at 24%. There was 33% slump in North America, 65% in Africa and 45% in the Asia-Pacific region.

In Latin America, over 2,000 amphibian species face extinction, which is the highest estimate among vertebrates. The main reason for them was diseases.

On plants, the report said the rate of their extinction was double that of mammals, birds and amphibians combined. “Agriculture, including expansion or intensification of crop or livestock farming, plantations and aquaculture, is the most frequently identified threat to plants in IUCN [International Union for Conservation of Nature] Red List assessments,” it said. “Consistent with these assessments, habitat destruction and land use changes, mainly urbanisation and agriculture-related, are the major causes reported for plant extinctions 59.”

The report, however, added that the reason behind the extinction for most of the plant species remained unknown.

On illnesses affecting humans and wildlife, it said that about 60% of infectious diseases come from animals and nearly two-thirds of them are wild animals. “The emergence of these diseases correlates with high human population density and high wildlife diversity, and is driven by anthropogenic changes such as deforestation and the expansion of agricultural land, the intensification of livestock production, and the increased harvesting of wildlife,” the publication said. It added that this was the reason behind the outbreak of Nipah virus in Malaysia in 1998, Serial Acute Respiratory Syndrome or SARS in China in 2003 and many others.

It cited that human activity was the major factor behind the decline of wildlife populations. “That’s because [the recent decline] 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,” the report said. “Until 1970, humanity’s Ecological Footprint was smaller than the Earth’s rate of regeneration. To feed and fuel our 21st century lifestyles, we are overusing the Earth’s biocapacity by at least 56%.”

Fishing was the largest factor affecting the ocean’s biodiversity, followed by climate change, pollution and coastal development, among others.

The report urged that protecting biodiversity was “more than an ethical commitment”, and that it was “non-negotiable” for the survival of humanity as nature and humans are intertwined. The report also pointed out that biodiversity was important for food security.

The report cited measures that can be taken to protect wildlife, including forming strategies at the national level, ranging from dietary changes to land-use conservation.

“Our 2019 results show that at least 50% of the Earth’s terrestrial area could be managed to support biodiversity conservation by 2050,” it said. “This target for biodiversity conservation could be achieved while also ensuring food security, reducing carbon emissions, and supporting reforestation initiatives. Major caveats are that we do not consider biodiversity supported by habitat on agricultural land, the management intensity of grassland, or uncertainties related to rates and levels of biodiversity reestablishment on afforested and abandoned agricultural land.”