Are humans largely responsible for a looming mass extinction of species? Of the estimated eight million species on earth, around a million face extinction.
According to biodiversity specialists from around the world many of the eight million species are now threatened with extinction within decades — a situation humans have not faced before. The rate of species extinctions is accelerating, with grave impacts on people around the world, warns a report from the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). The average abundance of native species in most major land-based habitats has fallen by at least 20%, mostly since 1900. More than 40% of amphibian species, almost 33% of reef-forming corals and more than a third of all marine mammals are now threatened. The picture is less clear for insect species, but available evidence supports a tentative estimate of 10% being threatened. At least 680 vertebrate species had been driven to extinction since the 16th century and more than 9% of all domesticated breeds of mammals used for food and agriculture had become extinct by 2016, with at least 1,000 more breeds still threatened.
The first global assessment of biodiversity and ecosystem services has held humans accountable and has urged immediate action to avert disaster. The report is dedicated to providing the world with an objective, scientific view of climate change, its natural, political and economic impacts and risks, and possible response options.
While more food, energy and materials than ever before are now being supplied to people in most places, it is increasingly at the expense of nature’s ability to provide such contributions in the future and frequently undermines nature’s many other contributions, which range from water quality regulation to sense of place.
The biosphere, upon which humanity depends, is being altered to an unparalleled degree across all spatial scales. Biodiversity — the diversity within species, between species and of ecosystems — is declining faster than at any time in human history, says the report.
Nature is essential for human existence and good quality of life. Most of nature’s contributions to people are not fully replaceable, and some are irreplaceable. Nature plays a critical role in providing food and feed, energy, medicines and genetic resources and a variety of materials fundamental for people’s physical well being and for maintaining culture.
For example, more than two billion people rely on wood fuel to meet their primary energy needs, an estimated four billion people rely primarily on natural medicines for their health care and some 70% of drugs used for cancer are natural or are synthetic products inspired by nature.
Over 75% of global food crop types, including fruits and vegetables and some of the most important cash crops such as coffee, cocoa and almonds, rely on animal pollination.
Marine and terrestrial ecosystems are the sole sinks of the greenhouse gases now causing climate change. These ecosystems soak up around 60% of the emissions. Ecosystems, species, wild populations, local varieties and breeds of domesticated plants and animals are shrinking, deteriorating or vanishing. The essential, interconnected web of life on Earth is getting smaller and increasingly frayed. This loss is a direct result of human activity and constitutes a direct threat to human well-being in all regions of the world.
Five main culprits
To authors have ranked the five direct drivers of change in nature with the largest relative global impacts so far. In descending order of importance, they are changes in land and sea use; direct exploitation of organisms; climate change; pollution and invasive alien species. The report says climate change is already impacting nature from the level of ecosystems to that of genetics, and these impacts are expected to increase over the coming decades, in some cases surpassing the impact of land and sea use change and other drivers.
The report says global goals for conserving and sustainably using natural resources and achieving sustainability cannot be met by the current business-as-usual approach. The scientists point out that loss of biodiversity is not only an environmental issue but also a developmental, economic, security, social and moral issue as well.
Three-quarters of the land-based environment and about 66% of the marine environment have been significantly altered by human actions, though on average these trends have been less severe or avoided in areas held or managed by indigenous peoples and local communities.
With more than a third of the world’s land surface and nearly 75% of freshwater resources now devoted to crop or livestock production, the value of agricultural crop production has increased by about 300% since 1970, raw timber harvest has risen by 45% and approximately 60 billion tonnes of renewable and non-renewable resources are now extracted globally every year, having nearly doubled since 1980.
But land degradation has reduced the productivity of 23% of the global land surface, up to USD 577 billion in annual global crops are at risk from pollinator loss and 100-300 million people are at increased risk of floods and hurricanes because of loss of coastal habitats and protection.
Local varieties and breeds of domesticated plants and animals are disappearing. This poses a serious risk to global food security by undermining the resilience of many agricultural systems to threats such as pests, pathogens and climate change. By 2016, 559 of the 6,190 domesticated breeds of mammals used for food and agriculture had become extinct and at least 1,000 more are threatened.
In addition, many crop wild relatives that are important for long-term food security lack effective protection, and the conservation status of wild relatives of domesticated mammals and birds is worsening.
In 2015, 33% of marine fish stocks were being harvested at unsustainable levels; 60% were maximally fished, with just 7% harvested at levels lower than what can be sustainably fished.
Plastic pollution has increased tenfold since 1980, 300-400 million tonnes of heavy metals, solvents, toxic sludge and other wastes from industrial facilities are dumped annually into the world’s waters, and fertilisers entering coastal ecosystems have produced more than 400 ocean “dead zones” totalling more than 245,000 square kilometres.
The report presents a wide range of illustrative actions for sustainability and pathways for achieving them across and between sectors such as agriculture, forestry, marine systems, freshwater systems, urban areas, energy, finance and others. It highlights the importance of adopting integrated management and cross-sectoral approaches that take into account the trade-offs between food and energy production, infrastructure, freshwater and coastal management, and biodiversity conservation. It also stresses the importance of moving to a more holistic economic paradigm than one concentrated solely on growth.