Extinction Realisation

08 Apr 2024 Leave a comment

by oxveg in Articles

Recent reports provide further evidence that the Earth may be undergoing a sixth mass extinction. In the previous mass extinction 66 million years ago, when a giant asteroid collided with Earth, killing the dinosaurs, around four-fifths of all animal species disappeared. Environmentalist George Monbiot describes mass extinction as “a symptom of Earth systems collapse.” This was certainly the case during the Permian-Triassic extinction event 252 million years ago, colloquially known as the Great Dying, when there was a massive increase in atmospheric carbon dioxide concentration (to roughly six times the current level), and a staggering 90% of species were wiped out. So, what can we expect from the current increase in carbon dioxide concentration and concomitant rise in global temperature (to around 1.2℃ above the pre-industrial level)? Climate scientist Prof Michael Mann writes: “The IPCC [Intergovernmental Panel on Climate Change] estimates as much as fourteen percent of species could be lost at 1.5℃ (2.7℉) warming, and eighteen percent at 2℃ (3.6℉). Tragic for sure, but greater rates of extinction are expected from other unchecked human activities, including habitat destruction and human exploitation of animals. However, the number climbs to twenty-nine percent at 3℃ (5.4℉), thirty-nine percent at 4℃ (7.2℉), and forty-eight percent at 5℃ (9℉). Half of all species would, by any reasonable standard, constitute a sixth extinction event rivalling the great extinctions of Earth’s geological past.”

According to a scientific paper published in November 2023, two million plant and animal species could be at risk of extinction now, twice as many as previously thought. The researchers conducted a comprehensive analysis of 14,669 International Union for Conservation of Nature (IUCN) red list assessments for European animal and plant species and found that 24% of insect species are at risk of extinction, together with 27% of plant species and 18% of vertebrate species. Such is the abundance of insect species (97% of all animal species are invertebrates, of which 90% are classified as insects), extrapolation of the figures suggests that two million plant and animal species globally are threatened with extinction. The expansion of agriculture resulting in the loss of natural habitats is the most significant driver of extinction, followed by the overexploitation of natural resources, pollution, and residential and commercial development. Anne Larigauderie, executive secretary of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), observed: “We are losing biodiversity … at rates never before seen in human history.” For example, polar bears, one of the planet’s most iconic species, are listed as “vulnerable” by the IUCN. There are an estimated 16,000 to 26,000 polar bears left on Earth, where their biggest threats are climate change (causing a loss of habitat as sea ice melts), pollution and energy development.

Overall, more than a quarter of all the plant and animal species that have been the subject of in-depth conservation assessments are at risk of extinction, according to the IUCN red list of endangered species. Perhaps the greatest threat facing the natural world is our overconsumption; it has been estimated that humans would need 1.7 planet Earths to sustain the current level of consumption. Other major threats to biodiversity include the buildup of plastics, chemicals, pesticides and fertilisers in natural ecosystems, deforestation (the world has lost 72 million hectares of primary forest in the last 21 years), the effects of harmful ‘invasive’ (introduced) species spread by human travel and trade, and of course climate change.

The latest State of Nature report for the UK, published in September 2023, found that 16% of the 10,000 mammals, plants, insects, birds and amphibians that were assessed are threatened with extinction, including iconic species such as the turtle dove and hazel dormouse. Since 1970, the abundance of the species studied in the report has declined on average by 19%, and 26% of terrestrial mammals in Great Britain are facing extinction. There have also been declines in the distributions of more than half (54%) of flowering plant species. The report found that intensive farming and the continuing effects of climate change are the two biggest drivers of nature loss. In 2020, the UK government committed to protect at least 30% of land and sea for nature by 2030, a goal towards which it has so far made little progress according to the Wildlife and Countryside Link.

Bird populations are facing an accelerating decline in the UK according to data released by the Department for Environment, Food and Rural Affairs. Their indicator of abundance shows that UK bird populations have fallen by 6% overall in the past 5 years and by 15% since 1970, with woodland birds faring the worst in recent times, with a 15% reduction in the past 5 years alone and a 37% decline since 1970. Farmland bird populations have seen a smaller decline of 8% decline in the past 5 years, but their numbers have fallen by a shocking 60% since 1970. Although conservation efforts to save Britain’s rarest birds, including the bittern and white-tailed eagle, are showing some success, Prof Richard Gregory, head of monitoring at the RSPB Centre for Conservation Science, called on “the UK government to act urgently on its commitments to address wildlife decline, and for all politicians to stand up for nature while there is still time.”

It is no wonder that woodland bird populations are in steep decline; UK forests are heading for “catastrophic ecosystem collapse” within the next 50 years according to a study published in the journal Forestry. Disease, extreme weather, and wildfires are among the many threats facing Britain’s woodlands. Winter storms in 2021 destroyed 12,000 hectares of forest in Britain, and it is thought that the fungal disease ‘ash dieback’ will kill as many as 80% of the UK’s ash trees. The UK is one of the least forested European countries, with a total coverage of 13%, and a 2021 report from the Woodland Trust found that just 7% of the UK’s native woodland was in good condition. To help offset the losses, the UK government aims to plant 30,000 hectares of forest every year by 2025 – double the current planting rate. The governments of the world, and all of us, will need to redouble our efforts if we are to prevent a sixth, human-induced, mass extinction.

Paul Appleby

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