MEDIUM: The tiny parasitic wasp that saved an industry
Before chemical pesticides were invented, farmers relied upon local predators to control crop-devastating pests for millennia, but now the practice is getting a modern revival.
S
Scattered among the highly biodiverse forests of South East Asia, millions of farmers eke out their livelihoods by growing cassava. This cash crop — grown by both small-scale farmers who own just one or two hectares and industrial farms spread across thousands of hectares — is sold mainly to manufacturers who use its starch in plastics and glues.
When cassava was first imported to South East Asia from South America (as it was to Africa a few decades earlier), it was able to grow without the help of pesticides. Then in 2008, the cassava mealybug followed the root vegetable to the region and began devastating the crops. To compensate for the losses, farmers began encroaching into the forests around their plots to try to get a little bit more produce from their land.
“Some of those areas are under significant pressure from deforestation,” says Kris Wyckhuys, an expert in biological controls at China Academy of Agricultural Sciences’ Institute of Plant Protection in Beijing. “Cambodia has some of the highest rates of tropical deforestation.”
The arrival of the cassava mealybug not only had major impacts on the livelihoods of those who grow cassava, it affected the national economies of the countries in the region and might have had rippling effects elsewhere.
Substitute products in the starch market like corn and potato rose in price. There was a threefold increase in the price of cassava starch in Thailand — the world’s number one exporter of cassava starch.
“When an insect reduces crop yields by 60–80%, you have a major shock,” says Wyckhuys. The solution was to find the mealybug’s natural enemy, a 1mm-long parasitic wasp (Anagyrus lopezi), in its native South America. This wasp is extremely selective about using the cassava mealybug as a host for its larvae. By late 2009 it had been introduced to the cassava cropland in Thailand and had started working its way through the mealybugs.
There’s no detailed information on how quickly the wasp drove mealybug populations down in the country. But by mid-2010, “parasitic wasps were being reared by the millions and mass-released throughout Thailand, including by airplane, and we can assume that their impacts on mealybug populations could be felt fairly quickly,” says Wyckhuys.
The cassava crop is incredibly important to the economies of South East Asia (Credit: Getty Images)
The cassava crop is incredibly important to the economies of South East Asia (Credit: Getty Images)
When the same wasp was used to control mealybugs in West Africa in the early 1980s, it promptly suppressed the pest population levels from more than 100 individuals on each cassava tip to fewer than 10–20. Less than three years later, the wasp had effectively dispersed over 200,000 sq km (77,220 sq miles) in southwestern Nigeria and could be found on the vast majority of cassava fields in the area.
This type of intervention is called classical biological control. You find a natural predator and introduce it to a crop to curb the spread of a pest. Wyckhuys calculated the economic benefit to the farmers across 26 countries in Asia-Pacific at $14.6bn to $19.5bn (£11.4bn to £15.2bn) per year. “The action of a 1mm wasp helped to resolve a major financial shock in the global starch market,” he says.
Biological control was the default for thousands of years, so it’s funny to think of it as new — Rose Buitenhuis
Our understanding of the benefits of the right predator in cropland stretches back millennia, though biocontrol has largely fallen out of fashion in modern farming practices. “Biological control was the default for thousands of years, so it’s funny to think of it as new,” says Rose Buitenhuis, a scientist at the independent horticulture science organisation, Vineland Research and Innovation Centre, in Ontario, Canada.
If biocontrol can be so successful, why is it now an uncommon method of fighting pests? What happens when it goes wrong? And why are researchers pushing to change that?
You might also like:
Planting trees doesn’t always help with climate change
The ‘pandemic’ destroying the world’s favourite fruit
The farms growing beneath our cities
To the people of pre-Columbian Mesoamerica, cane toads existed somewhere between life and death, and were revered as a mediator to the underworld. The amphibians produce a powerful toxin capable of inducing hallucinogenic experiences that priests used in rituals to communicate with their deceased ancestors. The Maya people are famous for worshipping snakes and birds of prey, which feature in exquisite examples of Mesoamerican art. But the Maya, and other indigenous peoples, also portrayed the humble toad in artworks, often grinning cheerily as if enjoying the effects of their own psychedelic toxin.
The Maya carved toads and frogs into pots and vessels. As semi-aquatic animals and harbingers of rain — essential to the health of crops — they are synonymous with water and therefore life. Their metamorphosis from eggs to tadpoles to toadlets indicated the beginning of the rainy season, emerging from the water as if they were emerging from the underworld.
This ancient Maya vessel in the shape of a cane toad celebrates the amphibians water-bringing characteristics (Credit: Justin Kerr/K5935/Dumbarton Oaks)
This ancient Maya vessel in the shape of a cane toad celebrates the amphibians water-bringing characteristics (Credit: Justin Kerr/K5935/Dumbarton Oaks)
The toad was also seen a powerful ally in keeping crop-destroying pests at bay. They were welcomed in cornfields and storage bins, where they are a naturally-occurring predator of beetles and small rodents that might decimate a crop. But the same neurotoxin, bufotenin, that the priests used as a hallucinogen was also the cane toad’s primary defence against its own predators and it is poisonous enough to kill a human if they are careless.
The indigenous peoples of Mesoamerica understood the duality of the natural world. The cane toad represented both life and death. Painted on one Maya vessel is a cane toad presenting a platter with a human eye, bone and hand to a jaguar and serpent who dance joyously in the underworld. The Maya respected the toad’s potency and welcomed its presence. They also knew that messing with nature could have grave consequences.
In 2007, the cane toad was estimated to cover about 1.2 million sq km of Australian wilderness
The cane toad is hated in Australia. Imported from the Americas as a biocontrol in 1935, it thrived in its new environment on the sugarcane crops of the northeastern states. The abundance of its favourite prey, the cane beetle, along with other native Australian insects, and the absence of suitable predators meant that cane toad numbers exploded. In 2007, the cane toad was estimated to cover about 1.2 million sq km of Australian wilderness and number 1.5 billion individuals. Its range is likely to increase with climate change.
A. https://downloadmp3diamondplatnumzwaah.substack.com/p/download-mp3-diamond-platnumz-waah
B. https://downloadmp3otilebrownjamila.substack.com/p/download-mp3-otile-brown-jamila-ft
C. https://downloadmp3diamondplatnumzwaahftkoffiolomide.wordpress.com/
D. https://issuu.com/download-mp3-diamond-platnumz-waah-ft-ko
E. https://issuu.com/download-mp3-otile-brown-jamila-reekado
F. https://issuu.com/download-mp3-berita-ndlovu-youth-choir
The result was devastating. Predator populations crashed — species that would normally prey on native toads, like quolls, a type of marsupial, and goannas, types of large monitor lizard, died from the cane toad’s toxin. The Australian government and local campaigners destroy millions of toads each year. The cane toad’s reputation is so poor in the country that the amphibian’s plight has been the subject of ironic children’s books.
“The toads were released contrary to scientific advice at the time,” says Wyckhuys. Releasing the toads “was something that should never have been done and is entirely impossible in modern biocontrol — you don’t release generalist, polyphagous, vertebrate predators. It is not a tiny red flag, it is a massive red banner”.
The cane toad is not alone. There are at least ten instances of biocontrols becoming invasive species throughout history. In World War Two, Japanese and Allied forces released mosquitofish to prey on mosquito larvae in an effort to reduce the spread of malaria among troops on Pacific islands. These small, innocuous-looking fish are now an invasive species in that area, where they dispersed quickly and outcompeted local species. The same applies to the Asian ladybug in Europe, introduced to control aphids.
A cane toad secretes its dangerous bufotoxin from glands behind its head (Credit: Getty Images)
A cane toad secretes its dangerous bufotoxin from glands behind its head (Credit: Getty Images)
As a result of high-profile failures like this, the use of chemical controls — pesticides — instead of biocontrols gathered momentum in the first half of the 20th Century. But, with a handful of exceptions, the controversial image of biocontrols is largely unfounded. Successful introductions of biocontrols outnumber the failures at least twenty-five-fold.
Now, some researchers are trying to change biological controls’ perception. They say the days of pesticides are numbered.
The end of pesticides?
“Chemical controls solved a lot of problems in the 1930s, 1940s and 1950s,” says Buitenhuis. “Farmers didn’t have to work as hard. They could just go to their cabinet, find a spray and the pests would die.”
The issue with chemical controls is that pest species breed quickly, which means that an individual who is resistant to a pesticide can very quickly produce resistant offspring. Pesticide producers then have to constantly refine their products just to keep up with the pest — what Buitenhuis refers to as a pesticide resistance treadmill and is elsewhere called the “red queen effect”, after the Red Queen from Through the Looking Glass.
The number of pesticides available to farmers is running out. In 2018, three pesticides from a class of chemicals called neonicotinoids were banned outright by the EU having already had their use severely restricted in 2013. These chemicals, which are similar in structure to nicotine, coat seeds to protect them from pests in the soil. However, as the crop grows, the pesticide is absorbed and spreads throughout the plant’s tissue where it collects in the pollen and nectar. Both wild and domesticated pollinators feeding on those plants are then exposed to the pesticide.
Critics of the ban point out that limiting seed-treatment pesticides could end with them being replaced by spray-on pesticides, which can be equally damaging to pollinators and are more expensive to farmers.
If pesticide use is to decrease, might more farmers turn to biological controls like this parasitic wasp? (Credit: Getty Images)
If pesticide use is to decrease, might more farmers turn to biological controls like this parasitic wasp? (Credit: Getty Images)
“There is a whole range of negative social and ecological factors tied to pesticides,” says Wyckhuys. “From the greenhouse gases used to produce and distribute chemicals — substantial greenhouse gas emissions — to human health implications for farmers and consumers. The impacts are not just restricted to the fields or to the farm but they are amplified across the landscape [by leaching], propagated through surface water or dust, taken up in the air by aerosols.”
Pesticide residues have been found in the cloud forest of Costa Rica and the Great Barrier Reef in Australia. And when pesticides appear in the wrong place, they become biocides — something that kills life. When they leach into the environment around farm land, they simplify biological communities and degrade ecosystems. What appeals to scientists like Wyckhuys about biocontrols is that their application can be much more targeted.
Caroline Reid, senior technical lead from Bioline Agrosciences, a biological control producer in the UK , agrees. Add to the specificity of biocontrols a reduction in the number of chemicals that are safe to use and a push across the EU towards sustainable farming and you can see why biocontrols are becoming increasingly mainstream. But how do they work?
Biological controls
There are broadly three types of biocontrols: predators, parasitoids and pathogens. Cane toads are an example of a predatory biocontrol. They prey on cane beetles, but unfortunately they are not overly choosy (they are “polyphagous”) and in Australia they began preying on other native insects which were not pests.
Parasitoids are a little more gruesome. Often these types of biocontrol are species of parasitic wasp or fly who lay their eggs inside caterpillars or beetles only for the resulting larvae to break out of their host’s abdomens, killing it in the process.
Successful biocontrols should have a high reproduction rate, so they can multiply quickly when they detect a pest
Pathogens can take the form of fungi, viruses or bacteria that kill or make their host infertile. These tend to target quite specific species of pest, making them a popular choice for modern biocontrol research because there is a lower risk of them attacking other harmless species with unintended consequences. Though, as we have all found out recently, viruses do from time to time jump species quite successfully.
Successful biocontrols should have a high reproduction rate, so they can multiply quickly when they detect a pest, be very specific in which species they target and able to seek their prey efficiently. In practice no biocontrol is perfect. Instead, researchers finely balance the risks associated with each of these.
There are also three ways that biological controls can be applied to a crop: classical, conservation and an augmented approach.
The cane toad is an example (if rather a bad one) of classical biocontrol — in which a new species is introduced into the environment.
A parasitic wasp (Cotesia congregata) climbs onto the back of a tobacco hornworm caterpillar where it will lay eggs in the host, eventually nullifying it (Credit: Getty Images)
A parasitic wasp (Cotesia congregata) climbs onto the back of a tobacco hornworm caterpillar where it will lay eggs in the host, eventually nullifying it (Credit: Getty Images)
“The classical form of biocontrol is specifically geared to invasive species management,” says Wyckhuys.
Biocontrol offers the option to go back to the region of origin of that pest, study the co-evolved natural enemies and choose the organisms that are highly effective at controlling them. “We don’t want to introduce an organism that is going to attack other organisms. We select an effective biocontrol that is highly specific,” says Wyckhuys.
Alternatively, in conservation approaches, predators that already exist within the environment are promoted by protecting their habitat. This can be done by increasing the amount of hedgerow or meadow around a field.
In a study on cabbage farming, where there was a high proportion of meadows surrounding a cabbage plot, numbers of cabbage-eating caterpillars were lower. This was likely due to the greater presence of parasitic wasps in those environments, the researchers say. However, in other instances, meadows promoted the presence of pest species like aphids and flea beetles. It’s not as simple as introducing more meadow to cut down on pests — the dynamics between farmland and wild land need to be carefully managed.
Conservation biocontrols like this are also limited to controlling pests which are native to their local environment. Like classical biocontrols, many pest species were first introduced to their environment by humans — they weren’t necessarily already there. As countries import seeds and crops from across the world, it is easy to assume that the odd accidental pest tagged along. Now, finding themselves in a new environment without a natural predator, they flourish.
Finally, in augmented approaches a pathogen or parasite is introduced to a crop at a key time — perhaps when pests begin to breed or lay eggs, or even before the pest arrives — so that the control species quickly nullifies their threat before their own numbers dwindle and they too die out in that area. The advantage of this approach is that you can be very specific with how you tackle the pest species.
“Augmented control is very popular in the European greenhouse sector,” says Wyckhuys. “In some areas pesticide use is zero.”
Greenhouses have been the domain of biocontrols for decades, even while chemical pesticides had their boom years. They have a big advantage of being a more or less closed system, so a predatory biocontrol is not going to fly away. Then there is the fact that greenhouse crops tend to be higher value — tomatoes, peppers and cucumbers sell for more per unit area than cereals, for instance.
A. https://downloadmp3diamondplatnumzwaah.substack.com/p/download-mp3-diamond-platnumz-waah
B. https://downloadmp3otilebrownjamila.substack.com/p/download-mp3-otile-brown-jamila-ft
C. https://downloadmp3diamondplatnumzwaahftkoffiolomide.wordpress.com/
D. https://issuu.com/download-mp3-diamond-platnumz-waah-ft-ko
E. https://issuu.com/download-mp3-otile-brown-jamila-reekado
F. https://issuu.com/download-mp3-berita-ndlovu-youth-choir
In more recent years the popularity for biocontrols has spread to other sectors such as floraculture, viticulture and outdoor fruits like strawberries.
“In Canada we did a survey in 2017/ 2018, 92% of flower growers use biocontrol as the main pest control strategy,” says Buitenhuis. “It is an amazing success story and came about because of pesticide resistance, especially in Canada.”
Buitenhuis and Reid know that when large surface area crop farmers switch to biocontrols for their cereals and grains, the momentum will have swung back in their favour. “If an arable farmer decided that a biocontrol is usable on wheat or barley that is us cracked it,” says Reid. Likewise, Buitenhuis says that persuading countries like Colombia, Ecuador and Kenya to adopt such approaches would be “big wins”.
“It is coming,” says Buitenhuis. “Using chemicals only is not a long-term sustainable strategy.”
—
Join one million Future fans by liking us on Facebook, or follow us on Twitter or Instagram.
If you liked this story, sign up for the weekly bbc.com features newsletter, called “The Essential List”. A handpicked selection of stories from BBC Future, Culture, Worklife, and Travel, delivered to your inbox every Friday.
Share using Email
Share on Twitter
Share on Facebook
Share on Linkedin
Similar Articles
Smart Guide to Climate Change
1
The smart way to stay warm this winter
future
2
Why it’s getting harder to mine gold
future
3
Why wildfire smoke causes harm far away
future
4
Why clothes are so hard to recycle
Mining
Why it’s getting harder to mine gold
Share using Email
Share on Twitter
Share on Facebook
Share on Linkedin
(Image credit: Jeff J Mitchell/Getty Images)
Descending a gold mine in Scotland (Credit: Jeff J Mitchell/Getty Images)
By Chris Baraniuk
27th October 2020
The price of gold has rocketed during the pandemic, but mining it is getting more difficult. Chris Baraniuk reports on challenges and controversy at one of the UK’s biggest planned mines.
F
For 1,000 days, the caravan stood with banners and placards pinned to its side: “We are not afraid. This is our land. This is our home. We will die for it.” Irish flags flutter in the wind. This is the anti-gold mine protest site set up by a group of locals in County Tyrone, Northern Ireland.
With 460 million-year-old veins of gold strewn hither and thither in the rock deep underfoot, the prospect of a mine in Curraghinalt, in a remote corner of the Sperrin mountains, has been talked about for decades — but it has never yet materialised. A recent application by a mining company to extract the seams of precious metal, has brought the prospect closer still. If successful, the firm says it could bring new jobs and money to the area. But many here want to keep things the way they are.
“I devote all my time to this campaign, I just feel it’s our future,” says Fidelma O’Kane, a retired social worker and lecturer who is concerned about the potential environmental impacts of the mine.
“My main worry is that the water will be poisoned, the air will be poisoned, the land will be contaminated — and ultimately people’s health will suffer,” she adds, explaining that she would never accept a mine, of any kind, in this area.
The company hoping to extract precious metals here, Dalradian Gold, says that it has put in place a swathe of environmental safeguards, and promises several economic benefits for locals. Still, the online planning proposal for the mine has attracted tens of thousands of comments, mostly negative, and a public inquiry will now take place to decide what will happen next.
Some in the nearby settlement of Gortin have objected to the planned gold mine (Credit: Alamy)
Some in the nearby settlement of Gortin have objected to the planned gold mine (Credit: Alamy)
Heralded by some as a potential boon for Northern Ireland, where jobs and investment opportunities stagnated during the 30-year period of conflict known as the Troubles, experts say Curraghinalt could become home to the largest gold mine in the UK, were it to go ahead.
The question now hovering over the rolling Sperrins is, what is more valuable: keeping the gold in the ground, or taking it out?
This query could hardly be voiced at a more pivotal moment. The price of gold rocketed during the pandemic, spurring renewed interest in excavation projects and even an illegal mining boom in parts of the Amazon rainforest. Yet gold is proving ever-more difficult to release from the ground. The technical challenges may be well known, but environmental protests and local politics are less predictable. At what point does mining gold stop being worth the effort?
You may also like:
The controversial plan to fill a mine with nuclear waste
Inside the hunt for a million-dollar haul of ocean gold
The gold mine at the end of the world
Last year, global gold production fell by 1%, the first decline in a decade, according to the World Gold Council, which promotes the gold industry. Some analysts argue we have reached “peak gold” — which means that the maximum rate of extraction has passed and the production of gold will continue to fall until, eventually, mining for it shall cease entirely.
However, demand for the stuff shows no sign of slowing down.
“It’s kind of a perfect storm,” says Matt Miller, vice president of equity research at CFRA Research, an investment analysis company. “Or, a better way to say it is, the fundamentals for gold may never be stronger than they are now.”
According to CFRA, about half of the world’s gold, excluding that still buried in the ground, is used in jewellery. As for the other half, one quarter is held by central banks and a final quarter is owned by private investors or used in industry.
Miller is among those who believe we have reached peak gold. The price of a single ounce of the glittering yellow metal breached $2,000 (£1,550) this summer and still rests comfortably above $1,900 (£1,470). Twenty years ago, the same ounce would sell for less than a quarter of that amount. The latest surge, following the emergence of Covid-19, has been linked to weakening currencies, including the US dollar. Governments are borrowing huge sums to pay for their pandemic response plans and printing money to fill the gap, say analysts, which means that the value of currency has become more volatile. Gold on the other hand is viewed as a stable asset, of which there are finite amounts, meaning that investors deem it trustworthy.
Questions and protests from some in the local Gortin community have led to a public inquiry (Credit: Alamy)
Questions and protests from some in the local Gortin community have led to a public inquiry (Credit: Alamy)
But Covid-19 has also caused disruption to gold mining operations themselves and supply is not likely to bounce up to meet rising demand any time soon. As such, the gold mining industry is actually sitting on the makings of a “major crisis”, argues Miller.
“My view is that gold demand will continue to trend upwards,” he says. “More and more of that is going to come from the recycling, which basically means that gold is trading hands.”
A. https://downloadmp3diamondplatnumzwaah.substack.com/p/download-mp3-diamond-platnumz-waah
B. https://downloadmp3otilebrownjamila.substack.com/p/download-mp3-otile-brown-jamila-ft
C. https://downloadmp3diamondplatnumzwaahftkoffiolomide.wordpress.com/
D. https://issuu.com/download-mp3-diamond-platnumz-waah-ft-ko
E. https://issuu.com/download-mp3-otile-brown-jamila-reekado
F. https://issuu.com/download-mp3-berita-ndlovu-youth-choir
He predicts that recycling old jewellery, coins or even the seemingly miniscule amounts of gold in the circuit boards of electronic devices, will become an increasingly significant source of the metal in the future. CFRA’s data suggests that around 30% of the world’s gold supply in the past 20 years was actually recycled, not mined. Refineries that recycle “scrap” gold — old jewellery, coins and bars — do use toxic chemicals and energy in their processes, but some environmental impacts may be much lower than mining. One recent study of gold refineries in Germany found that, kilogram for kilogram, the production of 99.99% pure gold via recycling was 300 times less carbon intensive than mining it from underground or open pit mines.
This means that obtaining one kilogram of recycled gold would produce 53kg of CO2 equivalent — but to mine a kilogram of the same material would cause 16 tonnes of CO2 equivalent to be emitted. Recycling scrap gold from electronics fell in between the two but was still better than mining — at one tonne of CO2 equivalent for every kilogram of gold turned out.
Like any large-scale industrial operation, gold mining can also have local effects on the environment. Public opposition to gold mines in some parts of the world has become a barrier to gold production, says Miller. Such resistance does not only exist in Tyrone. Take the Pascua-Lama mine in Chile, for instance. After years of protests from local activists on environmental grounds, the project was halted by regulators.
Gold is in high demand, but supply from mines is dwindling (Credit: Charles O’Rear/Getty Images)
Gold is in high demand, but supply from mines is dwindling (Credit: Charles O’Rear/Getty Images)
But where gold mines have become established, they can become giant operations. The world’s largest produce many tonnes of gold annually and the biggest of them all, Nevada Gold Mine in the US, churns out more than 100 tonnes every year. Even smaller gold mines can support the livelihoods of many people within the communities that bloom around them. Take the city of Val d’Or (Valley of Gold) in Quebec, Canada. There’s been a town there ever since gold was discovered in 1923. Various other metals including copper and lead are now also extracted in the area and a surplus of mining jobs has attracted people to Val d’Or in recent years. The town’s ice hockey team, the Foreurs, even has a mascot with a hard hat named “Dynamit” — a reference to the dynamite used to blast away rock in mining.
Political barriers
As for Curraghinalt, it was bloodshed that kept the gold in the ground for many years. During the Troubles, several political and sectarian groups in Northern Ireland turned to violence, carrying out shootings and bombings, for example. So when one company eyed the potential for a mine at Curraghinalt in the 1980s, it struggled to obtain a permit for explosives, given the security risks of keeping them on-site at the time.
But a decade later, Curraghinalt seemed to promise a more hopeful future, remembers Adrian Boyce, professor of applied geology at Scottish Universities Environmental Research Centre. Around the time of the Good Friday Agreement (the political accord signed in April 1998 that helped bring an end to the Troubles), Boyce and colleagues took part in an initiative to study the geology of Curraghinalt and assess its commercial potential.
“It was really a fresh hope for the people of Northern Ireland and that’s the impact that I saw for it,” he recalls. “At a time when, you know, not a lot of people were investing in Northern Ireland.”
He mentions the Omagh bombing, in which a group calling itself the Real IRA detonated a car bomb on a Saturday afternoon in August 1998, killing 29 people, including a woman who was pregnant with twins. Omagh is a 20-minute drive from Curraghinalt. In the minds of some, the economic opportunities of a brand new gold mine offered Northern Ireland a chance to escape the horrors of the past — and still offers the local area economic hope for the future.
After protestors objected to Dalradian’s proposed use of cyanide, the company dropped that plan (Credit: Alamy)
After protestors objected to Dalradian’s proposed use of cyanide, the company dropped that plan (Credit: Alamy)
Back in the 1990s, it was the price of gold that ultimately stymied the mine’s prospects, says Boyce. But that is no barrier now. And, he says, the size of the mine — Dalradian estimates it could produce 130,000 ounces (4 tonnes) annually for 20 years or more — makes it unique in the UK.
“For gold, Curraghinalt is far and away the biggest gold mine that’s ever been found in the UK,” says Boyce. “It dwarfs everything else.”
Yet the story of Curraghinalt speaks to the challenges of industrial gold mining in 2020, especially when operating near existing communities in an area of natural beauty. The mine is situated in a fairly remote part of Northern Ireland surrounded by farms and wilderness. Omagh, for instance, has a population of fewer than 20,000 people.
Since 2009, Dalradian has been excavating samples from below ground at its site in Curraghinalt while promoting plans for the mine to locals. The proposals include building an underground mine, rather than an open pit-style project, and extracting ore that would be processed partly in Tyrone, partly overseas.
Following fierce opposition, in 2019 Dalradian dropped its plan to use cyanide at the site. In some gold mining operations, solutions containing cyanide are used to dissolve gold from ore mined out of the ground so that the metal can be extracted and collected. Dalradian also says it has reduced water usage by 30% and gas emissions by 25% as part of its aim to become Europe’s first carbon neutral mine.
But campaigners continue to express concerns that chemicals could be washed into nearby rivers and harm local wildlife. Pollution from the mine could also negatively affect people’s health, they claim. And they also fear that a large heap of “tailings” — waste material extracted from the mine and left aboveground — would blight the area’s scenery.
BBC Future had arranged to tour Dalradian’s site in Tyrone but the company cancelled the visit two days before it was due to take place without explanation.
In a statement, a spokesman for Dalradian said: “This is a safe and environmentally responsible project which will emulate the successes of other modern mines in Europe.”
The company says it has listened to the community, offering tours and changing its mining processes when concerns were raised.
“People can also be assured that the project is being scrutinised by an independent, robust planning process and that it has been designed to meet exacting standards. We’ve held around 100 meetings with regulators so far and the local Public Health Agency has made no objection to the project on public health grounds.”
And regarding the tailings: “The dry stack will have an average thickness of 17m (56 feet), will be replanted during operations, is located in a natural hollow and will be blended into the local landscape.”
Human activity in the Sperrins dates back thousands of years (Credit: Alamy)
Human activity in the Sperrins dates back thousands of years (Credit: Alamy)
In a recent application for permission to discharge materials including heavy metals into a nearby stream, Dalradian also mentioned corrosive substances such as sulphuric acid and sodium hydroxide. On this point, the spokesman said, “Although it’s not expected that they will be used routinely, as they will be stored on-site they must be listed in the discharge consent.”
A treatment plant would be used for water management, he added, and noted that the mine offered a “massive opportunity” at a time when Northern Ireland’s economy faced uncertainty over Brexit.
While campaigners like O’Kane say they will not accept the mine under any circumstances, there are certainly some who would. It is difficult to get a sense of exactly how many in Tyrone are for or against. The Northern Ireland Department for Infrastructure planning portal contains more than 41,000 public comments about Dalradian’s proposals, more than 90% of which are objections. When asked by BBC Future why many of these responses appeared to be duplicates, the department said it believed the figures were an “accurate summary” of representations received.
Duplicates can arise for a number of reasons, a spokesman said: “They can relate to individuals making a representation on more than one occasion given there has been various amendments to the proposal.”
With a public inquiry now looming over the plans, it’s up to the authorities to investigate and represent the interests of local people before coming to a decision about whether the works ought to go ahead, suggests Boyce. “Let the politicians do what politicians are paid to do,” he adds.
In recent years, across the Irish Sea in Scotland, local objections were raised over plans for a different mine, at Cononish, in Loch Lomond National Park. Boyce notes that environmental concerns were voiced there, too, but ultimately the project gained support and was granted planning permission. The first gold from the mine could be produced as early as November.
A mine at Curraghinalt that proved to be productive would certainly attract interest from investors, argues Chris Mancini, a research analyst at Gabelli Gold Fund, which invests in gold. And he argues that it would be safe, environmentally speaking.
But it won’t do for some. For Fidelma O’Kane and her fellow campaigners, the mine has become anathema — a threat to the very character of the place where they live.
“The area is a beautiful area, it’s designated an Area of Outstanding Natural Beauty,” insists O’Kane. “We don’t want it industrialised with heavy industry.
“The clean, green image of our country would be gone forever.”
Whatever happens next at Curraghinalt, there’s no doubt that Dalradian’s efforts have sparked many discussions locally about what people would be willing to accept. It’s the sort of debate that could well become more common if the price of gold remains high and companies seek out small but nonetheless lucrative gold deposits in places that may have little or no tradition of gold mining.
Then again, if we really have reached peak gold, the rush might not last very long.
—
Join one million Future fans by liking us on Facebook, or follow us on Twitter or Instagram.
If you liked this story, sign up for the weekly bbc.com features newsletter, called “The Essential List”. A handpicked selection of stories from BBC Future, Culture, Worklife, and Travel, delivered to your inbox every Friday.
Advertisement
Environment
The long distance harm done by wildfires
Share using Email
Share on Twitter
Share on Facebook
Share on Linkedin
(Image credit: AFP/Getty Images)
Wildfires can release huge amounts of greenhouse gases and harmful smoke particles that affect human health (Credit: AFP/Getty Images)
By Allison Hirschlag
23rd August 2020
Smoke from burning forests and peat can linger in the atmosphere for weeks, travelling thousands of miles and harming the health of populations living far away.
A. https://downloadmp3diamondplatnumzwaah.substack.com/p/download-mp3-diamond-platnumz-waah
B. https://downloadmp3otilebrownjamila.substack.com/p/download-mp3-otile-brown-jamila-ft
C. https://downloadmp3diamondplatnumzwaahftkoffiolomide.wordpress.com/
D. https://issuu.com/download-mp3-diamond-platnumz-waah-ft-ko
E. https://issuu.com/download-mp3-otile-brown-jamila-reekado
F. https://issuu.com/download-mp3-berita-ndlovu-youth-choir
From far above, they almost look beautiful. Golden yellow tendrils etched across the dark forest landscape below. But in daylight, at close range, the devastation wrought by the fires in the Krasnoyarsk region of Siberia is harrowing.
A wall of blistering flames engulfs the vegetation. Behind it, charred trees stand like blackened toothpicks while columns of smoke choke the air, rising high up into the atmosphere. Since the start of 2020, Russia has seen an estimated 19 million hectares (73,359 square miles) consumed by wildfires, according to Greenpeace International’s analysis of satellite images. Nasa has warned that abnormally warm temperatures in eastern Siberia — particularly in the Sakha Republic, more than 1,250 miles (2,000km) away from Krasnoyarsk — have led to more intense and widespread fires than normal.
The destruction this leads to is undeniable. Swathes of forest and peatland are destroyed. Countless animals caught up in the flames and smoke perish. And when the flames reach areas inhabited by people, they can claim many lives and homes of those unlucky enough to be caught in their path.
In the first few months of 2020, Australia grappled with the worst wildfire season in its history. It claimed the lives of 33 people, destroyed thousands of homes and saw 18 million hectares (69,500 square miles) burned. Three billion animals were killed or displaced. And this August, thousands of lightning strikes triggered hundreds of fires across California, leading to a state of emergency being declared as the flames threatened densly populated residential areas. Beset by a prolonged drought, the state experienced its most destructive and deadliest fires in recorded history during 2017 and 2018. This year California, Washington and Oregon are fighting deadly wildfires that have burned millions of acres of land — up to 400 hectares (1,000 acres) are burning every 30 minutes — and destroyed thousands of homes.
You might also like:
Why the arctic is ablaze
Could this bring wildfires under control?
Five common myths about wildfires
These impacts on the ground can be hard to bear, but wildfires can have another far-reaching effect on our lives.
Rising up to 14 miles (23km) into the air, well into the stratosphere, plumes of smoke from large wildfires can spread all over the globe thanks to currents of air. Smoke from this summer’s Siberian wildfires has been choking nearby cities for months now and has spread across the Pacific Ocean to reach Alaska. The smoke has even been reducing air quality by creating hazes in cities as far away Seattle.
Smoke from the recent fires on the west coast of the US — where blazes have already claimed several lives in Oregon and California — has blown across the continent as far as New York and Washington DC on the east coast.
In dry summer conditions forest fires can sweep across huge areas, but they can also smoulder underground waiting to burst back into flame (Credit: Julia Petrenko/Greenpeace)
In dry summer conditions forest fires can sweep across huge areas, but they can also smoulder underground waiting to burst back into flame (Credit: Julia Petrenko/Greenpeace)
The Arctic wildfires in Siberia this summer have set a record: for releasing more pollution into the air in a single month than any other in 18 years of record keeping, according to the European Centre for Medium-Range Weather Forecasts.
It is in part down to what’s burning — resin-rich boreal forest, peat buried in bogs and melting tundra permafrost all release high concentrations of carbon dioxide into the atmosphere along with methane and toxic contaminants such as mercury. But it’s also because the fires are more widespread — a byproduct of record-breaking heat waves that gripped the Arctic in early summer. This helped thaw parts of the tundra, making it much more susceptible to burning.
Carried with the gases released by wildfires, however, are also tiny, lightweight particles of soot. Such “particulate matter” (PM) is a common component in air pollution in cities, where it can be released from vehicle exhausts and heavy industry. But smoke from wildfires can lead to dramatic spikes in the amount of particulate matter in the air compared with average air pollution.
Wildfire causes episodes of the worst air quality that most people living in high income countries are ever going to see — Sarah Henderson
For example, during wildfire season in Canada, cities in British Columbia have seen particulate levels that are 20 times higher than would be expected on an average day.
“Wildfire causes episodes of the worst air quality that most people living in high income countries are ever going to see,” says Sarah Henderson, senior scientist in environmental health services at the British Columbia Center for Disease Control. The small size and large amount of particulate matter has a lot to do with this.
Wildfires tend to produce large quantities of finer particulates known as PM2.5 and even finer nanoparticles, which are known to be particularly harmful to human health. This is largely because the tiny particles — which are more 30 times smaller than the width of a human hair and so too small to see — can penetrate the lung membranes when breathed in, damaging the respiratory system and passing into the blood stream.
Smoke from fires in Siberia has blown as far as Alaska, Canada and US cities including Seattle (Credit: Julia Petrenko/Greenpeace)
Smoke from fires in Siberia has blown as far as Alaska, Canada and US cities including Seattle (Credit: Julia Petrenko/Greenpeace)
In the short-term, that can lead to coughing, shortness of breath and exacerbate asthma attacks. During the bushfires at the end of 2019 in Australia, hospital admissions due to breathing problems increased by 34% in the state of New South Wales.
One study estimated that between 2004 and 2009, around 46 million people in the western US were exposed to at least one wave of smoke from wildfires. On days where smoke had caused high PM2.5 levels, there was a 7.2% increase in hospital admissions due to respiratory illnesses. Increases in PM2.5 have also been found to be accompanied by a spike in cases of cardiac arrest.
The potential long-term effects, however, are just as worrying.
Firefighters have been fighting to defend homes after thousands of lightning strikes started forest fires in California (Credit: Reuters)
Firefighters have been fighting to defend homes after thousands of lightning strikes started forest fires in California (Credit: Reuters)
Particulate matter has been linked to a range of long-term problems, including increased inflammation, and a greater risk of heart disease and stroke.
But wildfire smoke carries an added danger compared with other particulate pollution. It is filled with reactive chemical compounds that can be carcinogenic, and that can also lead to premature births. These compounds can also stress the body’s respiratory tract, leaving it more vulnerable to deadly respiratory pathogens such as Covid-19. One study found that particulate matter from wildfire smoke was especially harmful to a type of immune cell called macrophages in the lungs. It showed that wildfire particulates were four times more toxic to these immune cells than particulate matter from other air pollution. (Read more about the link between air pollution and respiratory disease)
Henderson, who’s currently conducting two studies on the long-term health effects of wildfire smoke, says people with pre-existing respiratory conditions are often the most impacted by the smoke. Her work suggests that some may never completely recover after experiencing just one severe wildfire season. Newborn babies, however, may face the most life-altering impacts, because their lungs are still developing and therefore highly vulnerable to smoke toxicity.
Wildfires in California have quickly spread to threaten homes and vehicles after they were sparked by lightning strikes (Credit: Reuters)
Wildfires in California have quickly spread to threaten homes and vehicles after they were sparked by lightning strikes (Credit: Reuters)
Perhaps most alarming is that the toxicity of these smoke particles also appears to increase the further they get from the site of a fire. As they are carried in the wind, the particles undergo chemical reactions in the air that cause them to “age” in a process known as oxidation. This converts the particles into highly reactive compounds that have an even greater capacity to damage cells and tissue than when they were first produced.
A recent study conducted in Greece showed that this process can lead to the toxicity of smoke compounds doubling in the hours after they are first emitted from a fire and that they have the potential to become up to four times as toxic over the following days.
Wildfire smoke can hang in the atmosphere for days, weeks or even months depending on how long the fires burn
“Even if someone is far away from a fire source, they may still experience adverse health outcomes from the inhalation of highly diluted and oxidised smoke,” says Athanasios Nenes, an atmospheric chemist at the Swiss Federal Institute of Technology Lausanne and the Institute of Chemical Engineering Sciences in Patras, Greece, who led the study. “We have seen that the oxidative potential of wildfire smoke can be up to four times higher when smoke has been atmospherically processed.”
Wildfire smoke can hang in the atmosphere for days, weeks or even months depending on how long the fires burn. One reason it’s able to do that is because the superheated smoke and ash rising into the air can trigger pyrocumulonimbus events, or fire-induced thunderstorms.
These thunderstorms form at least 10 miles (16 km) above the ground in the stratosphere. Here they are moved by the winds and weather in the jetstream, allowing smoke particles to “stay in the stratosphere for weeks, because it’s a very stable layer,” says Mike Flannigan, director of the Canadian Partnership for Wildland Fire Science at the University of Alberta.
This also allows wildfire smoke to travel huge distances. Large wildfires can send smoke billowing across whole continents and even oceans. In 2019, smoke from forest fires in Alberta, Canada, was tracked spreading across the Atlantic and into Europe. Smoke from the recent Australian fires was carried by pyrocumulonimbus events over New Zealand, where it impacted air quality and visibly darkened snow on mountains. The smoke even made it to South America.
Experts like Henderson and Nenes fear this spread of wildfire smoke may be exacerbating the harmful health effects of existing air pollution in busy, overpopulated cities. Globally wildfire smoke has been estimated to cause over 339,000 premature deaths a year — far more than those who lose their lives directly in these blazes. It could also be shortening life expectancies for populations that experience fire seasons regularly, Henderson warns.
The smoke from fires in Australia in 2019 and early 2020 led to a spike in hospitalisations in New South Wales (Credit: NASA/Maxar Technologies)
The smoke from fires in Australia in 2019 and early 2020 led to a spike in hospitalisations in New South Wales (Credit: NASA/Maxar Technologies)
“It really has an impact if you live under poor air quality conditions,” says Henderson. “If that translates to these populations that are living for four months at a time in these really smoky conditions, you know that’s going to have an impact on their life expectancy.”
Wearing masks such as the N95 respirator can help people to protect themselves when they venture outside during wildfire smoke events. Investing in air purifiers with HEPA filters can also help reduce fine particles indoors too, says Henderson.
“If we can keep the indoor air as smoke-free as possible, it will go a long way to protecting people from these exposures,” she says.
But the longer-term impact of wildfires is not just on human health, but the health of the planet as a whole. Burning forests and peat release huge amounts of carbon dioxide and other greenhouse gases into the atmosphere.
“Peat fires are important because it’s legacy carbon,” says Flannigan. “It’s been built up over thousands of years. And it can be emitted to the atmosphere in a matter of hours or days.” One study estimated that during the 2015 fire season in Indonesia, biomass fires that included a significant amount of peat released the equivalent of 1.5 billion tonnes of carbon dioxide into the atmosphere while fires in 1997 released so much carbon it was equivalent to 13–40% of all emissions from fossil fuels that year.
As climate change causes these Arctic territories to warm, the risk of more carbon-spewing peat fires will only increase
According to Flannigan, the soil in Russia, Alaska and Canada contains 30 times the amount of peat found in Indonesia’s soil. As climate change causes these Arctic territories to warm twice as fast as the rest of the planet, the risk of more carbon-spewing peat fires will only increase.
If that wasn’t enough, these areas are regularly experiencing so-called Zombie fires, which are slow-burn peat fires that can smoulder just under the ground for months and even years, only to roar back to life when temperatures climb, as happened in Siberia this year.
With climate change bringing warmer, dryer summer conditions, it could lead to a vicious cycle of fire.
“The warmer we get, the more fire we get,” says Flannigan. “The more fire we get, the more greenhouse gas emissions we get, which feeds the warming and this keeps on going until something changes.”
The haze generated by forest fire smoke can impact the air quality in cities nearby and also thousands of miles away (Credit: EPA)
The haze generated by forest fire smoke can impact the air quality in cities nearby and also thousands of miles away (Credit: EPA)
Nasa researchers discovered another effect wildfire smoke may be having on the climate. They found the Earth is surrounded by a haze of old smoke hanging in the troposphere over places like Antarctica. It accounts for roughly one-fifth of the aerosols from global fires.
“On a global scale, these smoke particles cool the Earth, but only slightly,” says Gregory Schill, a research associate at the National Oceanic and Atmospheric Administration’s Chemical Sciences Laboratory where the study was conducted. “On a regional scale, however, and in climate-sensitive places like the Arctic, these particles can cause a regional warming effect.”
One reason for this is that black and brown carbon in smoke absorbs heat, causing the air temperature to rise and warm the area below. In areas like the Arctic, this could only exacerbate the problem, creating the conditions that would make wildfires even more likely.
In a world already struggling against wildfires, it is a worrying prediction.
—
Join one million Future fans by liking us on Facebook, or follow us on Twitter or Instagram.
If you liked this story, sign up for the weekly bbc.com features newsletter, called “The Essential List”. A handpicked selection of stories from BBC Future, Culture, Worklife, and Travel, delivered to your inbox every Friday.
A. https://www.reddit.com/user/Fakazagod_s/comments/k0zmr8/download_mp3_diamond_platnumz_waah_ft_koffi/
