The concept of the “technosphere” aims to reveal the immense scale of our collective impact. The concept was first introduced by US geologist Peter Haff in 2013, but paleobiologist Jan Zalasiewicz has since popularised the term through his work. The technosphere encompasses the vast global output of materials generated by human activities, as well as the associated energy consumption.
Since the agricultural revolution some 12,000 years ago (when we started building cities and accumulating goods), human enterprise has steadily grown. However, our impact has surged dramatically over the past couple of centuries. This surge has since transformed into exponential growth, particularly since 1950.
The technosphere is indicative of how humans are increasingly emerging as a global force on par with the natural systems that shape the world. The transformation that is needed to reduce our impact is therefore equally large. And yet, despite growing awareness, there has been a lack of concrete action to address humanity’s impact on the planet.
To comprehend the sheer magnitude of the technosphere, it is best visualised. So here are four graphs that capture how our collective addiction to “stuff” is progressively clogging up planet Earth.
1. Weighing the technosphere
In 2020, a group of Israeli academics presented a shocking fact: the combined mass of all materials currently utilised by humanity had surpassed the total mass of all living organisms on Earth.
According to their findings, the collective weight of all life on Earth (the biosphere) – ranging from microbes in the soil, to trees and animals on land – stands at 1.12 trillion tonnes. While the mass of materials actively used by humans, including concrete, plastic and asphalt, weighed in at 1.15 trillion tonnes.
The technosphere weighs more than all life on Earth (trillion tonnes):
The relative weights of the active technosphere and biosphere. The active technosphere includes materials that are currently in use by human activities. The biosphere includes all living things. Elhacham et al. (2020), CC BY-NC-ND
This graph offers a glimpse into the immense size of humanity’s footprint. But it likely only scratches the surface.
When accounting for the associated byproducts of the materials used by humans, including waste, ploughed soil and greenhouse gases, the geologist and palaeontologist, Jan Zalasiewicz, calculated that the technosphere expands to a staggering 30 trillion tonnes. This would include a mass of industrially emitted carbon dioxide equivalent to 150,000 Egyptian Pyramids.
2. Changing the Earth
Remarkably, human activity now dwarfs natural processes in changing the surface of our planet. The total global sediment load (erosion) that is transported naturally each year, primarily carried by rivers flowing into ocean basins, is estimated to be around 30 billion tonnes on average. However, this natural process has been overshadowed by the mass of material moved through human action like construction and mining activities.
Humans change the Earth’s surface more than natural processes (billion tonnes):
Global movement of material: average annual natural sediment transport (blue), the total mass of things transported by humans in 1994 (purple) and in 2015 (orange). Cooper at al. (2018) & ScienceDaily (2004), CC BY-NC-ND
3. Transporting ‘stuff’
Our ability to transport fuel and products worldwide has facilitated the trends shown in the preceding graphs. Humans now transport these materials over increasingly vast distances.
Shipping continues to be the primary mechanism for moving materials around the globe. Since 1990, the amount of materials that are shipped around the world has increased more than threefold – and is continuing to grow.
How shipping has grown since 1980 (million tonnes):
Plastic stands out as one of the main “wonder materials” of the modern world. Due to the sheer speed and scale of the growth in plastic manufacturing and use, plastic is perhaps the metric most representative of the technosphere.
The first forms of plastic emerged in the early 20th century. But its mass production began following the second world war, with an estimated quantity of 2 million tonnes produced in 1950. However, the global production of plastic had increased to approximately 460 million tonnes by 2019.
This surge in plastic manufacturing is a pressing concern. Plastic pollution now causes many negative impacts on both nature and humans. Ocean plastics, for example, can degrade into smaller pieces and be ingested by marine animals.
Plastic manufacturing (million tonnes) has grown exponentially since 1950:
Humanity’s escalating impact on planet Earth poses a significant threat to the health and security of people and societies worldwide. But understanding the size of our impact is only one part of the story.
Equally important is the nature, form and location of the different materials that constitute the technosphere. Only then can we understand humanity’s true impact. For example, even the tiniest materials produced by humans, such as nanoplastics, can have significant and far-reaching consequences.
What is clear, though, is that our relentless pursuit of ever-increasing material output is overwhelming our planet.
Editor’s note: Climate change can not be addressed without stopping the extinction and plastics crisis. Every day, an estimated 137 species of plants, animals and insects go extinct due to deforestation alone. Microplastics have been detected in more than 1,300 animal species, including fish, mammals, birds, and insects. A global plastic treaty will only work if it caps production. Bangladesh is about to implement its existing law regarding plastic usage by strictly banning single-use plastic and, gradually, all possible plastic uses.
Scientific models can never account for all of the interconnected relationships within planetary systems’ boundaries. That is one reason why catastrophe predictions are always being pushed ahead.
There is simply no way the current economic system can persist indefinitely on a finite planet. Unfortunately, COP16’s primary goal is critical to striking a sustainable balance between human civilization and the natural world. That is an impossibility. We must tackle the underlying causes of biodiversity loss, including fossil fuel extraction, mining, industrial agriculture, intensive livestock farming, large-scale infrastructure projects, and monoculture tree plantations, basically civilization.
It is time to end civilization. Everything that claims existence must lose it; this is the eternal law. Power never gives up power willingly; it can only be broken with struggle. Nature is struggling to survive; we should help it.
Wildlife, climate and plastic: how three summits aim to repair a growing rift with nature
By the end of 2024, nearly 200 nations will have met at three conferences to address three problems: biodiversity loss, climate change and plastic pollution.
Colombia will host talks next week to assess global progress in protecting 30% of all land and water by 2030. Hot on its heels is COP29 in Azerbaijan. Here, countries will revisit the pledge they made last year in Dubai to “transition away” from the fossil fuels driving climate breakdown. And in December, South Korea could see the first global agreement to tackle plastic waste.
Don’t let these separate events fool you, though.
“Climate change, biodiversity loss and resource depletion are not isolated problems,” says biologist Liette Vasseur (Brock University), political scientist Anders Hayden (Dalhousie University) and ecologist Mike Jones (Swedish University of Agricultural Sciences).
Earth’s fraying parasol “How hot is it going to get? This is one of the most important and difficult remaining questions about our changing climate,” say two scientists who study climate change, Seth Wynes and H. Damon Matthews at the University of Waterloo and Concordia University respectively.
The answer depends on how sensitive the climate is to greenhouse gases like CO₂ and how much humanity ultimately emits, the pair say. When Wynes and Matthews asked 211 authors of past reports by the Intergovernmental Panel on Climate Change, their average best guess was 2.7°C by 2100.
“We’ve already seen devastating consequences like more flooding, hotter heatwaves and larger wildfires, and we’re only at 1.3°C above pre-industrial levels — less than halfway to 2.7°C,” they say.
There is a third variable that is harder to predict but no less important: the capacity of forests, wetlands and the ocean to continue to offset warming by absorbing the carbon and heat our furnaces and factories have released.
This blue and green carbon pump stalled in 2023, the hottest year on record, amid heatwaves, droughts and fires. The possibility of nature’s carbon storage suddenly collapsing is not priced into the computer models that simulate and project the future climate.
However, the ecosystems that buffer human-made warming are clearly struggling. A new report from the World Wildlife Fund (WWF) showed that the average size of monitored populations of vertebrate wildlife (animals with spinal columns – mammals, birds, fish, reptiles and amphibians) has shrunk by 73% since 1970.
Wildlife could become so scarce that ecosystems like the Amazon rainforest degenerate, according to the report.
“More than 90% of tropical trees and shrubs depend on animals to disperse their seeds, for example,” says biodiversity scientist Alexander Lees (Manchester Metropolitan University).
“These ‘biodiversity services’ are crucial.”
The result could be less biodiverse and, importantly for the climate, less carbon-rich habitats.
Plastic in a polar bear’s gut
Threats to wildlife are numerous. One that is growing fast and still poorly understood is plastic.
Bottles, bags, toothbrushes: a rising tide of plastic detritus is choking and snaring wild animals. These larger items eventually degrade into microplastics, tiny fragments that now suffuse the air, soil and water.
“In short, microplastics are widespread, accumulating in the remotest parts of our planet. There is evidence of their toxic effects at every level of biological organisation, from tiny insects at the bottom of the food chain to apex predators,” says Karen Raubenheimer, a senior lecturer in plastic pollution at the University of Wollongong.
Plastic is generally made from fossil fuels, the main agent of climate change. Activists and experts have seized on a similar demand to address both problems: turn off the taps.
In fact, the diagnosis of Costas Velis, an expert in ocean litter at the University of Leeds, sounds similar to what climate scientists say about unrestricted fossil fuel burning:
“Every year without production caps makes the necessary cut to plastic production in future steeper – and our need to use other measures to address the problem greater.”
A production cap hasn’t made it into the negotiating text for a plastic treaty (yet). And while governments pledged to transition away from coal, oil and gas last year, a new report on the world’s energy use shows fossil fuel use declining more slowly than in earlier forecasts – and much more slowly than would be necessary to halt warming at internationally agreed limits. The effort to protect a third of earth’s surface has barely begun.
Each of these summits is concerned with ameliorating the effects of modern societies on nature. Some experts argue for a more radical interpretation.
“Even if 30% of Earth was protected, how effectively would it halt biodiversity loss?” ask political ecologists Bram Büscher (Wageningen University) and Rosaleen Duffy (University of Sheffield).
“The proliferation of protected areas has happened at the same time as the extinction crisis has intensified. Perhaps, without these efforts, things could have been even worse for nature,” they say.
“But an equally valid argument would be that area-based conservation has blinded many to the causes of Earth’s diminishing biodiversity: an expanding economic system that squeezes ecosystems by turning ever more habitat into urban sprawl or farmland, polluting the air and water with ever more toxins and heating the atmosphere with ever more greenhouse gas.”
Editor’s note: Mass media news about war raises concerns about death, injury, and refuge of humans, the war on nature is rarely highlighted. But warfare always means ecocide on a large scale and wildlife and nature often take more time to recover than it is capable of. In Ukraine, 80% of wildlife is already on the brink of extinction, with the Russian aggression even more species and individual animals are getting lost. Therefore it’s a relief to have organisations like UAnimals who rescue pets and wildlife in emergency situations and raise international awareness about the destruction in nature and national parks.
The Ottawa Convention also referred to as the “Mine Ban Treaty,” prohibits the use, stockpiling, production, and transfer of anti-personnel landmines (APLs). Some key current and past producers and users of landmines, including the United States, China, India, Pakistan, and Russia, have not signed the treaty.
For Ukrainian activists, rescuing the dogs of war — not to mention the cats, swans, bats, bears and other wildlife — often means putting their own lives on the line.
Saving Ukraine’s injured and displaced animals during wartime often means seeing the worst elements of Russian cruelty.
“When a territory is liberated, our team goes there and we speak with the people who survived the occupation,” says Olga Chevhanyuk, chief operating officer of UAnimals, Ukraine’s largest animal-rights organization. “And each time we hear that when the Russians entered the town, they started shooting animals for fun, starting with dogs just walking the streets and ending with huge farms and shelters. Sometimes it’s probably a matter of manipulation, getting people scared. But mostly it’s no reason at all, just because they can.”
Originally founded to oppose inhumane conditions in circuses, the nonprofit UAnimals has shifted its mission to rescuing and caring for domestic animals and wildlife devastated by Russian aggression.
Working with local volunteers and shelters, they’ve helped tens of thousands of animals since the war began a year ago, including dogs and cats, horses, deer, swans, birds of prey and bats — even large predators like bears. In January alone they rescued more than 9,600 animals, provided food and medicine to thousands more, rebuilt shelters, and helped fund operations throughout the country.
They’ve also found themselves purchasing supplies not traditionally used in animal rescues.
“Before the war, you never think of buying helmets for your team,” Chevhanyuk says.
And then there’s the human toll: The nonprofit has contracted with psychologists to provide on-demand assistance to its team in the field. “So now they can have a session with the psychologist when they’re overwhelmed,” she says.
But this is all about saving more than individual animal lives and human minds. It’s about saving the soul of a country.
UAnimals has started calling the Russian war an ecocide — the deliberate destruction of the natural environment.
“Nowadays 20% of Ukraine’s nature conservation areas are affected by war,” Chevhanyuk says. “Russians occupy eight national reserves and 12 national parks, and some of the national parks are land-mined. Holy Mountains National Park is 80% destroyed. Some of them are destroyed 100%, meaning there are no plants, no animals, and no buildings which people use to heal animals. The land is littered with remains of destroyed objects, like tons of oil and burned products.”
Landmines are among the worst problems. They kill humans and animals indiscriminately, start fires, and will take years to mitigate. About 62,000 square miles of Ukraine may be contaminated with landmines. “This is greater than the size of Illinois,” according to information provided by a U.S. State Department official. “The United States is investing $91.5 million over the coming year to help the government of Ukraine address the urgent humanitarian challenges posed by explosive remnants of war created by Russia’s invasion.”
Cleaning up the pollution will require even more funding and effort. The war has caused at least $37 billion in environmental damage, a Ukrainian NGO said in November.
UAnimals predicts it could take more than a decade to repair the damage, but Ukraine’s wildlife doesn’t have that much time. “More than 80 species of animals in our country are on the verge of extinction and may completely cease to exist due to Russian aggression,” Chevhanyuk says. “Some of them are the steppe eagle, black stork, brown bear, Eurasian lynx, barn owl and eared hedgehog.”
While many of these species also exist in other countries, Chevhanyuk says wildlife has been an important element of Ukrainian folksongs, art and symbology — the very fabric of its culture — for centuries. “Being humane and treating animals as something really important and equal — this is one of the things which differs us a lot from Russians. And that’s, I believe, a part of our future victory.”
UAnimals continues to ramp up its fundraising and recovery efforts while expanding its network of shelters outside the country — a necessary step, as Ukrainian shelters and reserves are rapidly filling to capacity with animals too wounded ever to be released back into the wild.
“We have big shelters for bears, for example,” Chevhanyuk says, “but they are already full. I’m afraid that if something happens, we’ll need to bring these animals abroad. So we are very grateful to all our partners in different countries because there’s a big need right now.”
The organization is also tapping back into its activist roots to bring international attention to conditions in Ukraine. In February they organized Stop Ecocide Ukraine rallies in four U.S. cities — Atlanta, Austin, New York and San Antonio — that each attracted hundreds of people.
In a way, this is a return to form. “We used to create huge animal-rights marches in 30 Ukrainian cities every September,” Chevhanyuk says. “But since the war started, we are more focused on the emergency.”
And the international community has started to take notice. Last month the Parliamentary Assembly of the Council of Europe passed a resolution to “build and consolidate a legal framework for the enhanced protection of the environment in armed conflicts” — steps that support establishing ecocide as a new international crime.
“From a legal perspective, this is really encouraging,” says Jojo Mehta, cofounder and executive director of Stop Ecocide International, “because if you put severe harm to the living world on the same level as severe harm to people, if you say ecocide is as bad, wrong and dangerous as genocide, you’re creating a mental rebalance.”
It could still take years for ecocide to become international law. Meanwhile, the destruction of Ukraine continues, as do recovery efforts.
“If our team knows there is an animal to rescue,” Chevhanyuk says, “they will go in.”
Editor’s Note: Since main stream media gives so much attention to COP28 UN Framework Convention on Climate Change (UNFCCC), a lot of people are familiar with it. Climate change is posed as the main environmental issue that we are facing right now. While DGR believes that climate change is a threat, it is by far not the worst. Other pressing issues, like biodiversity loss, are often sidelined by mainstream media. As a result, many people do know what COP14 UN Convention on the Conservation of Migratory Species of Wild Animals (CMS) is. Biodiversity preservation requires habitat restoration, hardly something that anyone could gain profit from. Climate change, on the other hand, has provided many opportunities for corporations, in the name of “green” energy transition. We believe that climate change is a symptom of industrial civilization. Continuation of the process via “renewable” energy will only worsen all the ecological crisis that we are facing now, including climate change. Ending industrial civilization, protecting species and restoring habitats is the only way to actually address these issues.
Nearly Half of Migratory Species Populations Decline
While some migratory species listed under CMS are improving, nearly half (44 per cent) are showing population declines.
More than one-in-five (22 per cent) of CMS-listed species are threatened with extinction.
Nearly all (97 per cent) of CMS-listed fish are threatened with extinction.
The extinction risk is growing for migratory species globally, including those not listed under CMS.
Half (51 per cent) of Key Biodiversity Areas identified as important for CMS-listed migratory animals do not have protected status, and 58 per cent of the monitored sites recognized as being important for CMS-listed species are experiencing unsustainable levels of human-caused pressure.
The two greatest threats to both CMS-listed and all migratory species are overexploitation and habitat loss due to human activity. Three out of four CMS-listed species are impacted by habitat loss, degradation and fragmentation, and seven out of 10 CMS-listed species are impacted by overexploitation (including intentional taking as well as incidental capture).
Climate change, pollution and invasive species are also having profound impacts on migratory species.
Globally, 399 migratory species that are threatened or near threatened with extinction are not currently listed under CMS.
Click to download full report. (PDF 15.0 MB)
Until now, no such comprehensive assessment on migratory species has been carried out. The report provides a global overview of the conservation status and population trends of migratory animals, combined with the latest information on their main threats and successful actions to save them.
Billions of animals make migratory journeys each year on land, in rivers and oceans and in the skies, crossing national boundaries and continents, with some travelling thousands of miles across the globe to feed and breed. Migratory species play an essential role in maintaining the world’s ecosystems, and provide vital benefits, by pollinating plants, transporting key nutrients, preying on pests, and helping to store carbon.
The main focus of the report is the 1,189 animal species that have been recognized by CMS Parties as needing international protection and are listed under CMS, though it also features analysis linked to over 3,000 additional non-CMS migratory species. Species listed under the Convention are those at risk of extinction across all or much of their range, or in need of coordinated international action to boost their conservation status.
Most worryingly, nearly all CMS-listed species of fish – including migratory sharks, rays and sturgeons – are facing a high risk of extinction, with their populations declining by 90 per cent since the 1970s.
Analyzing the threats to species, the report shows the huge extent to which the decline in migratory species is being caused by human activities.
The two greatest threats to both CMS-listed and all migratory species were confirmed as overexploitation – which includes unsustainable hunting, overfishing and the capture of non-target animals such as in fisheries – and habitat loss, degradation and fragmentation – from activities such as agriculture and the expansion of transport and energy infrastructure.
The State of the World’s Migratory Speciesreport will provide scientific grounding and policy recommendations to set the context and provide valuable information to support the deliberations of the UN wildlife conservation conference (CMS COP14) starting today in Samarkand, Uzbekistan.
The convention also adopted a resolution urging parties not to engage with or support deep-sea mining until more scientific evidence is acquired. This resolution garnered criticism from the secretary-general of the International Seabed Authority (ISA), the U.N.-mandated body that governs deep-sea mining in international waters.
While attendees say COP14 had many successes, some experts say that more action and resources are required to keeping species from sliding toward extinction. – Mongabay
Editor’s Note: After exploiting almost every land on Earth, the industrial economy has now moved on to exploit the sea. Exploiters do not view the sea as many of us do: a deep body of water that is home to unimaginably large number of creatures. They see the sea as they view any other place on Earth: a huge reservoir of resources that might profit them. These profits come in many forms: greater wealth, which in turn is control over even more resources, and an ability to surround oneself with and have power over more people to do their bidding. It is for this that they are destroying life on Earth.
But, of course, that is not something they could publicly acknowledge. They have to create a more “righteous” justification for their not-so-righteous action. This is why they, in a cruel twist of words, claim to exploit the sea to protect the environment. In the following piece, Julia Barnes explains how the blue economy is just another form of greenwashing. Julia Barnes is the director of the award-winning documentaries Sea of Life and Bright Green Lies. She is a co-founder of Deep Sea Defenders, a campaign dedicated to protecting the marine environment from seabed mining. deepseadefenders.org
The Blue Economy and Greenwashing
By Julia Barnes
The term “blue economy” was first introduced in 2012, at the United Nations climate change conference in Qatar, COP18.
It has become a buzzword used by ocean conservationists and industry alike. But what does this term actually mean? And more importantly, what are the implications for the ocean?
Definitions vary. For some, the term simply describes economic activities taking place at sea. However, most interpretations include language around sustainability, conservation, or better stewardship.
According to Google/Oxford Languages, the blue economy is defined as:
blue economy
noun
an economic system or sector that seeks to conserve marine and freshwater environments while using them in a sustainable way to develop economic growth and produce resources such as energy and food.
Embedded in this definition are the values and assumptions of the dominant culture: the idea that economic growth is desirable, that the ocean consists of resources to be exploited, and that these resources can be “developed” in a sustainable way.
Sustainable has become perhaps the most meaningless word in the English language. It has been pasted in front of nearly every destructive activity imaginable; used as a rhetorical shield to deflect criticism. We now have sustainable mining, sustainable forestry, sustainable fisheries, and sustainable energy. Yet, the real world effects of these activities remain the same: they are destroying the planet.
Some examples of sectors within the blue economy include: industrial fishing, aquaculture, shipping, coastal and marine tourism, energy (wind, waves, tidal, biofuel, offshore oil and gas), ocean-based carbon credits, mineral resources (deep sea mining, dredging, sand mining), and biotechnology (marine genetic resources, industrial enzymes) – all of which the ocean would be better off without.
The problem isn’t that these industries are being done in an unsustainable way and can somehow be tweaked to become sustainable; unsustainability is inherent to what they are, and to the economic model under which they operate – a model that demands infinite extractive growth despite the fact that our planet is finite and has already been largely denuded of life, a model that objectifies the ocean and values it only for the profit humans can extract from it.
The notion of a sustainable blue economy provides the illusion of protection. Meanwhile, industry and corporations are doubling down on their efforts to exploit the sea, extracting living organisms faster than the rate at which they can reproduce, destroying habitat, wiping out vulnerable species, and pushing new frontiers of extraction. Carbon capture schemes are popping up, abusing the sea in a shell game that legitimises continued emissions through supposed carbon “offsets”. Genetic prospecting threatens to privatize and commodify the very DNA of our nonhuman kin. Deep sea mining threatens to disrupt the ocean on a scale not previously seen. Offshore energy projects (for fossil fuels and so-called renewables) impose damage on the sea while providing power to the system that is at the root of the problem.
At a time when we should be pulling back, reducing our impact, and allowing the ocean to regenerate, the blue economy offers instead to continue business as usual, only rebranded.
As with so many of the things that have been marketed to us as “green”, the blue economy is primarily about sustaining a gluttonous way of life at the expense of life on the planet.
What if instead of defining the ocean as a resource, we valued it for what it really is? A living community vital to the functioning of our planet. The foundation of life on Earth. An entity with volition of its own. A force much older, larger, and wiser than we are. Something so powerful, beautiful, and magical, it cannot be described in words but can certainly be felt. Something sacred and deserving of respect.
The ocean is already collapsing under the many assaults of the global industrial economy. Further commodifying it under a vague claim of sustainability will not solve the problem.
Editor’s note: We all know the word mammal, but not many people may have heard about tetrapod species. This group of wild animals includes amphibians, birds and reptiles in addition to mammals. Most people love jaguars and monkeys, but an ecosystem is thriving with all kinds of particular species, also with the ones that are green and greasy or look like little dinosaurs.
Because of their importance researchers want to find out how many tetrapod species have gone extinct in comparison to how many can be rediscovered; just because nobody saw them in between a few years, doesn’t mean that they’re gone. With this “lost and found” method scientists can prove how bad the extinction rate really is, and, in a case of rediscovery, get funding for protection measures.
In our so called civilization there’s no real protection for other than humans, wildlife has to make way when human needs appear. In a natural world where nonhumans needs were also considered we wouldn’t need to count for lost and found species. We would give them their own space and let them be. Yet it seems nowadays the only way to get funding for nature conservancy projects is by research, a method that only speaks to the mind.
But the mind is limited, human brains cannot grasp wholeness, beauty and true meaning of a healthy environment with only thoughts. Often it hinders us to connect to the special beings surrounding us. So in addition to science we as a society need a culture of connection and heartfelt unity to not lose more.
Lost species are those that have not been observed in the wild for over ten years, despite searches to find them. Lost tetrapod species (four-limbed vertebrate animals including amphibians, birds, mammals and reptiles) are a global phenomenon – there are more than 800 of them, and they are broadly distributed worldwide.
Our research, published today in the journal Global Change Biology, attempts to pin down why certain tetrapod species are rediscovered but others not. It also reveals that the number of lost tetrapod species is increasing decade-on-decade. This means that despite many searches, we are losing tetrapod species at a faster rate than we are rediscovering them. In particular, rates of rediscovery for lost amphibian, bird and mammal species have slowed in recent years, while rates of loss for reptile species have increased.
This is not good news. Species are often lost because their populations have shrunk to a very small size due to human threats like hunting and pollution. Consequently, many lost species are in danger of becoming extinct (in fact, some probably are extinct). However, it is difficult to protect lost species from extinction because we don’t know where they are.
Rediscoveries lead to conservation action
In 2018, researchers in Colombia successfully searched for the Antioquia brush-finch (Atlapetes blancae), a bird species unrecorded since 1971. This rediscovery led to the establishment of a reserve to protect the remaining population of the brush-finch, which is tiny and threatened by habitat loss caused by agricultural expansion and climate change.
The Antioquia brush-finch, which was rediscovered in Colombia in 2018, and protected through the establishment of a new reserve.Victor Manuel Arboleda/iNaturalist
The Victorian grassland earless dragon (Tympanocryptis pinguicolla) was rediscovered in Australia last year. It hadn’t been recorded for 54 years, and was presumed to be extinct, due to the loss of its grassland habitat and predation by invasive alien species including feral cats. Its rediscovery resulted in government funding to trial new survey techniques to find further populations of the species, a breeding program, and the preparation of a species recovery plan.
The Victorian grassland earless dragon was rediscovered in Australia last year.CSIRO/Wikimedia
Thus, rediscoveries are important: they provide evidence of the continued existence of highly threatened species, prompting funding for conservation action. The results of our study may help to prioritise searches for lost species. In the image below, we mapped their global distribution, identifying regions with many lost and few rediscovered species.
The global distribution of lost and rediscovered tetrapod species. Grey shading and text = the number of species within a region (a country or an island) that are currently lost (globally). Orange text: the number of rediscovered species with a range incorporating this region. White regions without orange numbers: no data on lost or rediscovered species. White regions with orange numbers: regions where lost species have been rediscovered and no (known) lost species remain.Thomas Evans, Global Change Biology, 2024
What factors influence rediscovery?
Sadly, many quests to find lost species are unsuccessful. In 1993, searches in Ghana and the Ivory Coast over seven years failed to rediscover a lost primate, Miss Waldron’s red colobus (Piliocolobus waldronae). The research team concluded that this noisy and conspicuous monkey, unrecorded since 1978, may well be extinct. Its demise has been caused by hunting and the destruction of its forest habitat. Further searches in 2005, 2006 and 2019 were also unsuccessful, although calls that were possibly by this species were heard in 2008.
Searches for the Sinú parakeet in the Upper Sinú Valley recorded the presence of ten other parrot species including the great green macaw (Ara ambiguus) (pictured) which is critically endangered.Grigory Heaton/iNaturalist
So why is it that some species are rediscovered while others remain lost? Are there specific factors that influence rediscovery? We aimed to answer these questions in our study, in order to improve our ability to distinguish between the types of lost species we can rediscover, from those that we cannot, because they are extinct.
We compiled a database of 856 lost and 424 rediscovered tetrapod species (amphibians, birds, mammals and reptiles). We then proposed three broad hypotheses about factors that might influence rediscovery: characteristics of (i) tetrapod species, and (ii) the environment influence rediscovery, and (iii) human activities influence rediscovery.
For example, body mass (a species characteristic) may positively influence rediscovery, as larger lost species should be easier to find. Lost species occupying dense forests (a characteristic of the environment) may not be rediscovered as searching for them is difficult. Lost species affected by threats associated with human activities (e.g., invasive alien species, which are being spread to new locations by global trade) may not be rediscovered, as they may be extinct.
Based on these hypotheses, we collected data on a series of variables associated with each lost and rediscovered species (for example, their body mass), which we then analysed for their influence on rediscovery.
Hard to find + neglected = rediscovered
On the upside, our results suggest that while many lost species are difficult to find, with some effort and the use of new techniques, they are likely to be rediscovered. These species include those that are very small (including many lost reptile species), those that live underground, those that are nocturnal, and those living in areas that are difficult to survey.
In fact, since the completion of our study, De Winton’s Golden Mole (Cryptochloris wintoni) has been rediscovered in South Africa. This species hadn’t been recorded in the wild since 1937. It lives underground much of the time, so searches were conducted using techniques including environmental DNA and thermal imaging.
Our results also suggest some species are neglected by conservation scientists, particularly those that are not considered to be charismatic, such as reptiles, small species and rodents. Searches for these species may also be rewarded with success. Voeltzkow’s chameleon (Furcifer voeltzkowi), a small reptile species, was rediscovered in Madagascar in 2018.
The Bramble Cay melomys – once considered to be a lost species, but now declared extinct.State of Queensland/Wikimedia
Lost or extinct?
Unfortunately, our results also suggest that some lost species are unlikely to be found no matter how hard we look, because they are extinct. For example, remaining lost mammal species are, on average, three times larger than rediscovered mammal species. Some of these large, charismatic, conspicuous species should have been rediscovered by now.
Furthermore, one third of remaining lost mammal species are endemic to islands, where tetrapod species are particularly vulnerable to extinction. The Bramble Cay melomys (Melomys rubicola), which was once considered to be a lost species, has recently been declared extinct by the Australian Government. It occupied a small island that has been extensively surveyed – if it still existed it should have been rediscovered by now.
Lost bird species have, on average, been missing for longer than those that have been rediscovered (28% have been missing for more than 100 years), and many have been searched for on several occasions – perhaps some of these species should also have been rediscovered by now.
Nevertheless, unexpected rediscoveries of long-lost species like the Cebu flowerpecker (Dicaeum quadricolor) do occur, so we shouldn’t lose hope, and we should definitely keep searching. However, some searches are being carried out for long-lost species that are considered to be extinct, such as the thylacine (Thylacinus cynocephalus). Perhaps the limited resources available for biodiversity conservation would be better used to search for lost species likely to still exist.
Thomas Evans is a Research scientist at Freie Universität Berlin and Université Paris-Saclay
The relative weights of the active technosphere and biosphere. The active technosphere includes materials that are currently in use by human activities. The biosphere includes all living things.
Global movement of material: average annual natural sediment transport (blue), the total mass of things transported by humans in 1994 (purple) and in 2015 (orange).
Shipping capacity growth between 1980 and 2022.
Annual plastic production.
