Researchers Identify Top Biological Conservation Issues of 2024

In the 2024 biodiversity horizon scan, the ocean features prominently, both as a harbringer of climate crisis and as the key to mitigating global warming. Photo by KAL VISUALS on Unsplash

If you hope to catch a glimpse of what life on Earth will be like in the future, forget the time machine — all you need is a horizon scan.

Since 2009, a group of researchers have come together annually to predict the top issues in the global conservation sphere for the year ahead before their impacts are yet to be fully documented. 

In the biodiversity horizon scan for 2024, published this past December in Trends in Ecology & Evolution and coordinated by the Cambridge Conservation Initiative, 15 issues made the list, from emerging technologies like artificial photosynthesis to the climate effects of wildfires.

“It seems that we are reasonably good at saying here are some of the issues that seem to be coming up over the horizon that might have consequences and that you might want to be thinking about,” said William Sutherland, lead author of the scan and a conservation biology professor in the zoology department at the University of Cambridge in England. 

To conduct the scan, a team of 31 authors, including those working for environmental nonprofits and experts in specific fields, first consulted both scientific literature and wider networks to search for ideas. 

With a list of 96 topics produced as a result, every person scored each one on the basis of three criteria: importance, likelihood and novelty.

“A lot of the aim of that is to reduce the influence of single individuals. They have very little say and can't sway the system, and it's anonymous,” said Sutherland. “You can't have one person with strong views that will have much influence. They've got to convince other people that they're right.”

From there, the list was narrowed down to 37 issues, which were ranked again through in-person and virtual discussions held last September. Three artificial intelligence models proposed 20 topics, but none ended up in the final list, making the remaining 15 issues the sole product of collaboration and a shared focus on the future.

“The whole ethos and idea of horizon scanning is to start to identify and prioritize what's next to come, so we can be more proactive,” said Nafeesa Esmail, a conservation scientist and co-author on the scan.

According to Laura Heady, who was not involved in the horizon scan, talking about biodiversity is of significant local interest. As conservation and land use program coordinator for the Hudson River Estuary Program, she has witnessed a shift in thinking over time. 

“When I started doing this work, which was about 20 years ago, we were just getting out there and educating municipal decision-makers and leaders on what biodiversity is and why it was important in the Hudson Valley,” said Heady. “We don't really need to emphasize that as much anymore because a lot of people get that now.”

Pros and Cons Abound

Many of the issues included in the published list suggest both positive and negative effects, with some hidden more under the surface than others.

For instance, the industrial chemical ammonia, used mostly as fertilizer, contributes 2% of the world's carbon dioxide emissions during production. Alternatively, nitrogen from the air can be combined with hydrogen from water microdroplets, as opposed to hydrogen from natural gas, to create what is called green ammonia.

And yet, this green ammonia still makes fertilizer, which in and of itself has negative environmental impacts. When soil microbes break down fertilizer, the potent greenhouse gas nitrous oxide is unleashed in the process, while fertilizer run-off can prompt freshwater algal blooms and kill fish. 

Another example would be basalt, which, when pulverized into dust and added to agricultural soils, releases nutrients that aid in plant growth and may reduce soil acidity. But it's not the only trick the volcanic rock has up its sleeve — basalt can serve as a form of geologic carbon capture through a chemical reaction known as carbon mineralization. 

Once basalt and carbon dioxide make contact, the carbon turns into a solid mineral and cannot re-enter the atmosphere; if widely implemented, this technique could mineralize up to 2 gigatons of carbon dioxide every year. Still, if the origins of the basalt dust come from mining waste or building materials, that could spell trouble for aquatic ecosystems in the form of pollution.

But as the authors of the scan note throughout the list of issues, biodiversity doesn’t just operate in a vacuum. It is shaped by external forces, most of which involve us humans.

Take neonicotinoids, commonly known as neonics — a class of insecticides that cause bugs to become paralyzed and die. In addition, neonics can be applied directly to plants, making them toxic in turn, and can spread throughout an ecosystem via runoff. Bees are especially susceptible to neonics, as they can lose their sense of smell, undergo tremors and eventually die prematurely. 

With the Environmental Protection Agency expected to review interim decisions on neonics only this year, states have been issuing their own regulations, including New York's Birds and Bees Protection Act, signed into law by Gov. Kathy Hochul in December. 

As the horizon scan indicates, identifying the toxicity of new chemicals in a precautionary approach can assist in further regulating neonics. Tools like the EPA's SeqAPASS can be used by researchers to evaluate a plant or animal's susceptibility to toxic chemicals through data already available for other organisms.

According to Sutherland, this method stands in contrast to traditional LD50 tests, which administer a lethal dose of material to half a group of test animals. In this way, evaluating other options for measuring toxicity offers a consideration of the consequences.

“If it's easier for us to say this is likely to be damaging, this is likely to be benign, that is a very useful thing to be able to do,” said Sutherland. “And then for those that are harmful, you may well end up doing more sophisticated work.”

Beyond this controversy, perhaps one of the most publicized issues on the list, as seen in futuristic television commercials, is a threat posed by NEOM, a modern community currently in development in Saudi Arabia and funded by the country's Kingdom. 

Touted as friendly to nature and centered on "planetary regeneration," NEOM will consist of twelve regions in total. One of those regions, called THE LINE, will function as a skyscraper city towering over 1,600 feet above sea level and running on renewable energy sources. But at the same time, its mirrored exterior and possible wind turbines on the roof present a collision risk for the migratory pathway of 2 billion birds who fly between Europe and Africa each fall. 

Similarly, with the Hudson River Valley region in high demand for those seeking a desirable place to call home between New York City and the State Capital of Albany, increased development to account for higher populations can either help or harm the local landscape.

“If that is planned well, it can be done in a way that has a manageable amount of impact on the environment, but if it's done in a way that's out of sync with the environmentally sensitive areas we want to avoid, then it can have a real impact on biodiversity,” said Heady.

Earthworm populatins are dwindling -- but soil ecoacoustics can allow scientists to listen in before it's too late. "Earthworm" by pfly is licensed under CC BY-SA 2.0.

High-Tech Future in Store 

With the horizon scan’s focus on anticipating what is to come in biodiversity conservation, the potentials and pitfalls of emerging technologies remain to be fully assessed and implemented. But what we do know can advance suggestions for what might be possible.

For instance, brown hydrogen releases carbon dioxide by heating fossil fuels and white hydrogen involves drilling into the Earth's crust with invasive infrastructure. In contrast, green hydrogen renders a promising premise — in effect, it uses electricity from renewable sources of energy through the chemical process of electrolysis, which splits water molecules into its separate elements. 

Although green hydrogen production is designed to operate in salt-free environments, scientists are testing its capabilities in seawater to reduce the strain on freshwater use. Even so, excess oxygen from seawater electrolysis could still present a hazard to marine ecosystems. In addition, any leakage from hydrogen production could contribute to emissions of methane, a greenhouse gas that is much more effective than carbon dioxide when it comes to warming potential. 

While over 40 countries have national hydrogen strategies in place, including the U.S., low-emissions hydrogen makes up less than 1% of the global hydrogen marketplace, as per the International Energy Agency's latest Global Hydrogen Review. And like many innovative technologies yet to be adopted on a wide scale, limited financial resources do play a role. 

“Until some of these technologies become a little bit more mainstream, often the cost is still quite prohibitive for your average conservation project to employ,” said Esmail.

With agriculture's rapid conversion of habitat to cropland and the polluting qualities of fertilizer established by the scan, one of those technologies not yet completely adopted lies in the procedure behind autotrophic hydrogen-oxidizing bacteria. 

Put simply, when bacteria are grown in an environment supplied only by hydrogen, nitrogen and carbon dioxide, the tasteless organic matter generated as a result is nutritionally similar to fish and can be incorporated into protein. Products originating from this bacteria have already been approved in Singapore. 

Then, there's the fascination behind artificial photosynthesis in the laboratory, where an acetate made out of carbon dioxide, water and electricity replaces the glucose sugar plants make for energy. And forget about direct light from the sun — solar panels can fuel the production of the acetate, which is then added to plants growing in vials. No need for soil and land equates to a process that is 18 times more efficient than natural photosynthesis.

Moving ever further into the future, benchtop DNA printers, which literally print DNA in a mostly unregulated capacity, could do so on demand within the next few years. In the conservation sector, this may be applicable to developing disease immunity for at-risk species or aiding in "de-extinction" by reviving extinct animals through genetic modification of similar species. But DNA printing could also trigger cultivated invasive species or the unintentional transfer of genes to wildlife.

A less risky up-and-coming technology known as soil ecoacoustics, which could possibly be combined with environmental DNA, can be utilized by scientists to monitor invertebrates and listen in on the sounds they make. One of those soil invertebrates — the small but mighty earthworm — might require that monitoring more than others.

These so-called ecosystem engineers create tunnels for oxygen and stimulate plant growth through nutrient cycling, but according to one study, an earthworm population decline of up to 41% over the last 25 years has been observed in U.K. soils. It implies pesticide use in farmland may be to blame.

But still, all this advanced technology is not always needed to advance biodiversity goals. For example, conservation planning allows local municipalities and other organizations to work with the Hudson River Estuary Program to establish Conservation Advisory Councils, conduct inventories of natural resources and create land protection funds. 

“You wouldn’t jump into planning a policy without first taking stock of what you have and setting priorities,” said Heady. “I always think of it like an insurance plan — you wouldn't buy an insurance plan without knowing what you're trying to insure first.”

Biodiversity Amidst Human Influence

Of course, the conversation around biodiversity is impossible without a reference to climate change.

“We are in a climate crisis, but we're also in a biodiversity crisis. And so, ways we can think about being resilient and adapting for both is really the important strategy as we think of the years ahead in our conservation work,” said Heady. 

With the connection between wildfires and global warming expected to become ever more apparent, the effects of burned forests are having a sizable influence on the El Niño-Southern Oscillation, a regularly occurring climate pattern based on Pacific Ocean temperatures. 

In fact, one study found that aerosols and dust released from the Australian wildfires at the end of the last decade cooled the sea surface and triggered a three-year La Niña period, with intense drought in Eastern Africa and an active tropical hurricane season following suit. 

And gone are the days when biodiversity and climate change were separate issues. Indeed, severe wildfires quite obviously have local consequences as well, including negative impacts on biodiversity — after a severe fire, carnivores lose prey, wildlife corridors disappear and tree roots burn.

“In the wider dialogues and forums, there is a lot of disentanglement between biodiversity and climate change impacts, but at the end of the day, there is so much in which they interact,” said Esmail. 

Beyond climate impacts on land alone, the ocean tends to fuel the bigger fire, which makes perfect sense, considering the fact that it constitutes 70% of Earth's surface. “It’s a lot of habitat, and if things happen in the marine environment, often they then happen at scale,” said Sutherland.

So far, all eyes have been on the Atlantic meridional overturning circulation, a crucial system of currents that carries salt and heat throughout the ocean and also influences the climate as a whole. A study published in Science Advances this month estimated the AMOC is on its way to tipping sooner than previously thought and could result in catastrophic occurrences like massive precipitation shifts in the Amazon rainforest and significant drops in temperature across Europe.  

But the horizon scan argues that Antarctic abyssal overturning deserves more attention. 

As the Antarctic ice sheet melts at a rate of 150 billion tons annually and water density and salt concentrations reduce, the overturning of currents in the oceanic abyss could decrease at a rate of 40% by 2050. And so, problems could be in store for both the climate and the environment, while the ocean's limited ability to absorb carbon dioxide hangs in the balance. If a high-emissions scenario is in place, abyssal warming could escalate over the next three decades.

Moreover, individual organisms are predicted to experience severe climate woes. ​​In January 2022, mass die-offs of sea urchins occurred in both the Caribbean and Mediterranean, and in the former, up to 99% of the long-spined sea urchin population died due to the presence of scuticociliate, a microorganism that can act as a pathogen and spread disease. 

If left unchecked, macroalgae smother coral reefs in the Caribbean — which is why it's up to the sea urchins to remain in abundance and keep the algae at bay. 

According to a research analysis of the die-off, heavy rainfall preceded the mortality event, and this indicates that other environmental stressors like heat, which is already known to stunt sea urchin eggs and larvae, could spell trouble for tropical ecosystems worldwide.

But the ocean can also serve as the climate hero we all need, as it absorbs a third of carbon dioxide emissions. Taking advantage of the ocean’s carbon-sinking abilities presents a range of approaches, both chemical and biological in nature. 

For instance, adding minerals to the ocean can enhance its ability to dissolve carbon and adding iron can fertilize phytoplankton, which absorb carbon dioxide via photosynthesis. Risks like increased metal toxicity or reduced oxygen availability are both possible and unclear at the same time.

In the ocean's twilight zone, the first layer after the sunlight zone, a vast biodiversity of marine creatures thrive, from the confetti squid to the pelican eel and the largest amount of fish in the ocean — and the zone also plays a tremendous role in the biological carbon pump, whereby carbon at the surface is transferred to deeper waters. 

When phytoplankton absorb carbon during photosynthesis and are then consumed by larger animals up the food chain, organisms in the twilight zone that venture to the surface bring that phytoplankton — and carbon — back down with them. However, warmer temperatures may mean less good-quality food available for consumption, which equates to less carbon sequestered overall.

Whether in the sea or on land, examining all these biodiversity issues and their associated complexities and nuances couldn’t come at a better time. With a global target in place to protect 30% of the world's land and waters by 2030, the horizon scan emphasizes that actions to conserve biodiversity can speak just as loud as the words researchers divulge to teach us about it.

“The whole idea is for these scans and the topics to get into mainstream media,” said Esmail, “bringing that awareness and that push for change to happen before it’s too late.”