Gold has fascinated humankind for thousands of years. Its lustrous shine, malleability, and resistance to corrosion have made it highly valued for jewelry, currency, and more. But despite all the gold that has already been mined throughout history, there is only a finite supply left on Earth.
How much gold exists?
The total amount of gold in the Earth’s crust and mantle is estimated to be between 40 and 80 million tons. To put that in perspective, all of the gold ever mined in the history of humankind totals around 190,000 tons. This means that somewhere between 20% to 47% of the planet’s gold supply has already been extracted and put to use.
Each year, around 3,000 to 3,500 tons of gold are mined globally. At this rate, even the most conservative estimate of 40 million total tons means there is enough accessible gold left to last about 11,000 more years of mining. However, extraction will become more difficult over time as sources become depleted, lowering supply.
Where is gold found on Earth?
While gold can be found almost everywhere, there are regions where it is more abundant and profitable to extract:
- South Africa – Home to the Witwatersrand Basin, this region accounts for nearly 40% of all the gold ever mined globally.
- Nevada (USA) – The Carlin Trend and other deposits contribute over 75% of U.S. gold production.
- Western Australia – Deposits in the Pilbara and Goldfields regions yield a majority of Australia’s gold.
- China – China produces the fourth most gold in the world, mostly from mines in the Shandong and Fujian provinces.
- Russia – Siberian mines provide nearly all of Russia’s gold production.
Other major sources include Peru, Mexico, Canada, Brazil, and Ghana. Together, these top 10 countries produce around 75% of the world’s annual gold supply.
Factors that affect gold deposits
The abundance of gold in specific regions has to do with how it was deposited and concentrated over geologic timescales.
On Earth, gold largely exists as a result of metallic ore bodies forming when magma cooled. Explosive volcanic eruptions dispersed gold in the surrounding rock layers and flood waters eroded gold from uplifted land and carried it downstream, allowing it to reconcentrate in certain areas.
The availability of gold in a given location depends on several factors:
- Geologic setting – Gold is found where shuffling tectonic plates created ideal conditions for ore formation and concentration. Plate boundaries, rifts, subduction zones are prime areas.
- Rock types – Gold occurs more readily in igneous rocks like granite and porphyry rather than in sediments.
- Depth – Natural processes concentrate gold closer to the Earth’s surface over time. Deposits more than a mile deep are less accessible.
- Grades – The proportion of gold relative to waste rock affects mining feasibility. Richer grades (higher concentrations) are more worthwhile to extract.
Challenges in sourcing future supply
While there is enough total gold on Earth to last many more centuries of mining, actually extracting it is becoming more challenging. Some factors limiting future gold supply include:
- Declining ore grades – Companies are mining lower quality deposits as rich sources get depleted.
- Increasing operational costs – Mines today require more energy, water, labor, and technology to operate profitably.
- Political risk – Resource nationalism and unstable governments threaten supply in some gold-rich regions.
- Environmental regulations – Stricter environmental and social standards make permitting and development costly.
- Lack of new discoveries – Few undiscovered giant gold deposits remain to replace aging mines.
These constraints mean it is getting harder and more expensive to grow gold production each year. New technologies and mining frontiers could help boost supply, but likely not fast enough to meet rising global demand.
Is Earth’s gold finite?
Absolutely – gold is a nonrenewable metal, meaning there are finite amounts in the world. The fixed quantity available and increasing challenges in sourcing more of it mean that gold should be considered a scarce commodity with a supply peak.
While recycling helps supplement supply, almost all of the gold ever extracted remains in use. Unlike other metals with significant reusage rates, virtually all gold ever mined is still available in one form or another. This also effectively shrinks the available supply each year.
Some key facts about the finiteness of Earth’s gold:
- Total reserves are uncertain, but maximum estimates only amount to around 80,000 tons remaining.
- Supplies are dwindling gradually as the most accessible deposits get depleted first.
- Most of the world’s high-grade deposits have already been found and mined.
- Gold production from mining has been relatively flat over the past two decades.
- Declining ore grades mean more material has to be mined and processed for each ounce of gold.
While gold is not at immediate risk of running out, its finite nature means scarcity issues and price volatility will intensify over time. Finding and developing new economically viable deposits is crucial for meeting the world’s future gold needs.
Could there be undiscovered gold?
The majority of the world’s gold deposits that are viable to mine with current technology have already been discovered. However, there is still potential to uncover new sources.
Possibilities that could yield more gold include:
- New exploration in under-surveyed regions and frontiers like under the ocean
- Revisiting known mineralized sites and tailings at older mines
- Using new theories of ore genesis to prospect overlooked areas
- Improved geoscience knowledge and exploration tools
- Evaluating lower grade deposits overlooked before as uneconomical
While new discoveries occur frequently, most are relatively small in size and do not significantly move the needle on global gold reserves. There is still hope for major new finds, but geological expertise suggests Earth has already given up its most readily accessible giant gold deposits.
How much undiscovered gold may exist?
Estimates vary widely on how much undiscovered gold remains around the world. According to the USGS:
- Undiscovered gold resources are estimated from 11,000 to 39,000 tons worldwide.
- This totals up to 30% of expected global reserves, meaning 70% of recoverable gold is likely already discovered.
- About 18% of this undiscovered gold potential is projected to exist in North America, specifically Canada and the U.S.
- New sources are getting harder to find and often require more remote operations.
Additionally, mineral resource assessments by various geological surveys have estimated 35,000-57,000 tons of gold remaining to be found in certain countries and regions:
| Country/Region | Undiscovered Gold Estimate (tons) |
|---|---|
| Brazil | 8,000-12,000 |
| Australia | 5,000-9,000 |
| West Africa | 8,000-13,000 |
| Former Soviet Union | 5,000-8,000 |
| Canada | 2,000-5,000 |
| United States | 1,500-3,000 |
While possibly significant, these prospects would need much more investigation to determine if mining is viable. Major new large gold deposits are unlikely, but many smaller undiscovered ones could provide incremental supply.
Can gold be created synthetically?
Gold is an element, which means its atoms cannot be broken down any further or created artificially. However, minute amounts of gold can be produced through nuclear reactions and particle accelerators. But this process is incredibly expensive and energy intensive, yielding only tiny grains of gold.
During supernovas, nuclear fusion created heavy elements like gold. The quantity of new gold made this way is infinitesimally small relative to how much exists already in the universe though. Outside of additional cosmic events, new significant gold cannot be created, only already existing atoms recycled.
Some key facts about gold synthesis:
- Nuclear transformations would have to occur on a stellar scale to create economically meaningful quantities.
- Particle accelerators can only produce single gold atoms at a time at best.
- Current methods of transmutation consume exponentially more energy than they yield in gold.
- Alchemy attempts throughout history failed because chemistry alone cannot recreate the conditions or energy levels needed.
For all practical purposes, gold cannot be synthesized in adequate commercial quantities with modern science. All of Earth’s viable gold had to come from natural stellar, geologic, and chemical processes.
Could asteroid mining expand supply?
Asteroid mining has been proposed as one possible way to increase future gold supplies, though major challenges exist:
- Finding asteroids with high enough grades and total quantities of gold is difficult.
- Only certain near-Earth asteroids would be accessible targets within reasonable cost and time frames.
- Space missions are technologically daunting for both robot and human miners.
- Extensive infrastructure for deep space travel and mining doesn’t exist yet.
- Environmental impacts from processing extraterrestrial ore would need addressing.
While asteroid mining appears promising for platinum group metals, known viable targets for gold appear rarer. But some asteroids and extraterrestrial objects could provide supplemental gold in the longer term:
- Asteroid 16 Psyche may contain $10,000 quadrillion worth of iron, nickel, and gold.
- Comet Tempel 1 has an estimated 10 million kg of gold according to NASA data.
Ultimately, asteroid mining may eventually expand reachable gold supplies by a modest degree. But overcoming the obstacles involved means its impact on the gold market is unlikely to be realized for at least a few decades.
Conclusion
Earth’s gold is ultimately finite in supply and subject to progressive depletion. While more undiscovered deposits likely exist and recycling provides additional supply, economic and physical constraints limit gold’s availability.
Given myriad challenges in finding and mining new sources, global gold production will struggle to keep pace with increasing demand. Prices will likely rise in the long run as costs increase and reserves dwindle.
The exact timeline is uncertain, but gold’s rarity means scarcity and extraction issues will intensify over the next century. The world’s remaining accessible gold reserves will be drawn down gradually until sources become too scarce, remote, or uneconomical for mining to continue.
Fortunately, decades remain to find supplemental deposits and develop sufficient replacements before gold reserves could be exhausted. But the finite nature of Earth’s gold supply means a production peak is inevitable unless new asteroids or planets can eventually be tapped at reasonable cost.