In 1869, two Cornish miners prospecting in the dusty hills of Victoria, Australia, hit something unusually hard just beneath the roots of a tree. What they uncovered was a single lump of gold that weighed about as much as an adult man. The nugget, later named Welcome Stranger, came in at roughly 72 kilograms and was so large the local bank had to have it broken apart on an anvil before it could even be weighed.
For that glittering mass of metal, John Deason and Richard Oates received just under ten thousand pounds, a life changing sum at the time. A nugget of similar size today would be worth in the region of a couple of million pounds according to later estimates, yet the original was melted down into anonymous bullion and disappeared from view.
The story of “Welcome Stranger” sounds like a prospector’s dream. A lucky swing of the pick, a fortune overnight, a place in mining folklore. But it also raises a question that feels more urgent in a warming world. If one nugget can make headlines a century-and-a-half later, what is the hidden cost of the countless tonnes of gold we extract today?
From lucky strike to global industry
In Deason and Oates’s day, gold was dug from shallow alluvial deposits with hand tools and muscle. Today, that dream has scaled up into a global industrial system that feeds record demand from jewelry buyers, investors, and technology manufacturers. Total gold demand in the third quarter of 2025 reached more than 1,300 tonnes, the highest quarterly level recorded by the World Gold Council.
To supply that appetite, modern mines move entire hillsides. Ore grades are often low, so huge volumes of rock must be crushed, treated, and stored as waste. Industry analysis indicates that primary gold production emitted around 50 million tonnes of carbon dioxide equivalent in 2023 from direct operations alone. When processing, transport, and downstream use are included, some studies put the total footprint of the gold sector above 100 million tonnes of emissions each year.
For most of us, the link between a wedding ring or a small bar in a safety deposit box and those emissions is easy to forget. Yet the electricity that powers crushers and mills, the diesel burned by heavy trucks, and the fuel that keeps off-grid mines running all show up later on the climate balance sheet and, eventually, on household energy bills and insurance premiums.
Toxic chemicals and poisoned rivers
Gold’s environmental footprint is not just about carbon. Extracting the metal often relies on chemicals that can be devastating if they escape into soil and water. Large-scale mines commonly use cyanide solutions to separate gold from crushed ore. European Union research has highlighted that uncontrolled cyanide leaching can contaminate groundwater, forcing operators to build lined leach pads and recovery systems to reduce the risk.
At the smaller end of the industry, millions of people work in artisanal and small-scale gold mining. This sector is now the single largest source of human-made mercury emissions, responsible for almost 38 percent of the global total according to a report for WWF. Mercury is used to form an amalgam with fine gold particles, then burned off, releasing toxic vapors and leaving residues in river sediments and fish.
Recent investigations show how this pressure is reshaping entire landscapes. In the Peruvian Amazon, illegal gold mining has cleared around 140,000 hectares of forest since the mid-1980s, with hundreds of rivers and streams contaminated by mercury. A separate probe into mercury production in Mexico traced tonnes of the metal being smuggled to South American gold fields, where it is used in unregulated mining and lingers in ecosystems for decades.
The health toll is becoming harder to ignore. In Ghana, a recent study found soil mercury concentrations in some mining communities more than five times higher than World Health Organization safety thresholds, with arsenic levels thousands of percent above recommended limits. Children in these areas are already showing signs of kidney damage and mercury exposure. Scientific surveys in other mining regions confirm that cyanide and heavy metals accumulate in agricultural and residential soils near gold sites, with the highest free cyanide levels consistently found in mine waste.
The image of a gleaming nugget in a miner’s hand sits uncomfortably beside the reality of murky rivers and poisoned fish on someone else’s dinner plate.
Can gold be mined more responsibly?
The picture is not entirely bleak. Because gold is durable and easily recycled, it can circulate for generations. In 2024, recycled gold supplied around thirty percent of global demand, and its share of total annual supply has climbed from roughly twenty four percent in 2022 to more than twenty seven percent in 2024 according to recent market analyses. That means every gram recovered from old jewelry or electronic waste can substitute for ore that would otherwise have to be mined.
Some large mines are starting to rework their energy use as well. In Mali, for example, the off-grid Fekola gold mine now draws much of its daytime power from a hybrid solar and battery system, which allows the operator to rest several heavy fuel generators and avoid burning more than thirteen million liters of diesel each year. That project alone cuts an estimated thirty nine thousand tonnes of carbon dioxide annually. Industry wide studies suggest that shifting mine power to renewables and improving efficiency could put the sector on a pathway more aligned with global climate goals, although progress remains uneven.
Still, as long as the price of gold stays high and regulations remain patchy, illegal and high impact operations are likely to keep spreading, especially in remote forests and along vulnerable rivers. Recent enforcement sweeps in Latin America uncovered illegal gold sites tied to child labor, human trafficking, and severe mercury contamination, underlining how environmental crime and organized crime often move together.
What that man-sized nugget can teach us
The “Welcome Stranger” nugget vanished into the furnaces of the nineteenth century, leaving behind only sketches, replicas, and a memorial obelisk in rural Victoria. Its story still captures imaginations because it feels like a pure stroke of luck, a once-in-a-lifetime windfall pulled almost intact from the ground.
Modern gold production is different. It is less about surprise and more about scale. The metal in a simple ring might come from explosives, cyanide leach pads, diesel engines, and long supply chains that stretch from tropical riverbanks to urban refineries.
At the end of the day, the question for consumers is simple. When we buy or invest in gold, are we content to chase the shimmer, or do we want some assurance that the river downstream and the forest canopy are not paying the price?
Choosing recycled gold, asking jewelers about sourcing, and supporting stronger rules on mercury and cyanide will not erase the footprint of the world’s favorite precious metal overnight. But each of those steps helps shift the industry away from the most damaging practices and toward a version of gold that glitters a little less for the planet.
The main study referenced on gold’s environmental footprint was published on The Impact of Gold.
