There has been a 73% decline in the average size of monitored wildlife populations in just 50 years (1970-2020), according to World Wildlife Fund‘s (WWF) Living Planet Report 2024. The report warns that parts of our planet are approaching dangerous tipping points driven by the combination of a loss of nature and and climate change.
The Living Planet Index, provided by the Zoological Society of London, tracks almost 35,000 vertebrate populations of 5,495 species from 1970-2020. The Index shows an average 73% decline in monitored vertebrate wildlife populations (mammals, birds, amphibians, reptiles and fish).
(The percentage change in the index reflects the average proportional change in monitored animal population sizes at sites around the world, not the number of individual animals lost, nor the number of populations lost.)
The steepest decline is in freshwater populations (85%), followed by terrestrial (69%) and then marine (56%).
Habitat loss and degradation and over-harvesting, driven primarily by our global food system are the dominant threats to wildlife populations around the world, followed by invasive species, disease and climate change.
Significant declines in wildlife populations negatively impact the health and resilience of our environment and push nature closer to disastrous tipping points – critical thresholds resulting in substantial and potentially irreversible change.
Regional tipping points, such as the decimation of North American pine forests, the destruction of the Amazon rainforest, and the mass die-off of coral reefs, have the potential to create shockwaves far beyond the immediate region, impacting food security, livelihoods, and economies.
For example, losses of populations of large fruit-eating animals (tapirs, toucans, tamarins, deer), which provide an essential seed-dispersal function in the Brazilian Atlantic Forest, can lead to a decline in tropical forest carbon storage.
When these animals are lost through hunting and illegal trade, they can no longer disperse the seeds of larger, hardwood trees and the forest becomes dominated by smaller, softwood trees. The smaller trees store less carbon, exacerbating climate change.
North America
North America shows a 39% decline between 1970 and 2020 (range: -14% to -57%), which is equivalent to 1% decline per year. In North America, large-scale impacts on nature were already apparent before 1970, which partly explains why there is less of a negative trend than in other regions: many populations have stabilized but starting from a lower baseline.
There have also been some conservation successes for individual species, including certain mammals such as bighorn sheep, and groups such as raptors (birds of prey), many of which have recovered from historical declines.
However, in western North America, a century of wildfire suppression allowed the forest understory to grow thick and dense. When a climate change-driven, multi-year drought took hold in the late 20th century, many adult pine trees and understory plants succumbed. The pine trees that did survive the drought were weakened by it, making them more susceptible to infestation by growing populations of the pine bark beetle.
As the climate warmed further, the pine bark beetle population expanded its range northward and upslope, killing 3.8 billion trees in its migration path. The subsequent firestorms burned the forests with such ferocity that the ecosystem is now irreparably altered, resulting in the loss of ecosystem function including water holding capacity and carbon storage.
Today, forest fires are more frequent, more intense and cover larger areas than at any point in the last 900 years for which records are available. This dynamic, which has become self-driven, is expected to eventually lead to western pine forests being replaced by shrubland and grassland.
The Living Planet Report findings, which WWF calls “catastrophic,” come on the heels of more local studies showing major losses in birds, many from building collisions, and especially mountain birds.
Major losses in amphibians and insects have also been reported, especially among pollinators.
World leaders are gathering next week for COP 16, the United Nations Biodiversity Conference, in Colombia, to discuss how to restore nature.
New York State has joined almost 200 countries committed to a landmark 2022 UN agreement on nature loss, including setting aside 30% of the planet for nature by 2030.
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