Critical Minerals Investment: Copper’s Case Is Stronger Than Pitched

The popular copper pitch says demand will grow by “nearly 30%” and supply will fall 30% short. The best current research says demand growth is closer to 50% by 2040, while the supply gap is narrowing rather than widening.

That tension matters because critical minerals investment is now sold on slogans, and the slogans are drifting away from the data.

Three forces are converging on the same physical inputs: deglobalisation, decarbonisation and defence. Australian investors hold unusual exposure to the theme through the ASX, and record global military spending of US$2.887 trillion in 2025 adds a demand leg beyond electrification.

Here is where the evidence holds up (copper), where it turns cyclical (lithium), and how much portfolio weight is defensible.

Why is copper the strongest pillar of critical minerals investment?

The headline gap is easy to remember. A resources fund manager frames copper as roughly 30% demand growth against a 30% supply shortfall, which is a useful simplification but not the sharpest version of the case.

S&P Global’s study Copper in the Age of AI: The Challenges of Electrification projects demand rising about 50%, from 28 million tonnes (Mt) in 2025 to 42 Mt in 2040. Supply is projected to peak near 33 Mt in 2030 and then decline, leaving a potential 10 Mt shortfall, roughly 24-25% of demand, even with recycled scrap doubling to 10 Mt.

The International Energy Agency (IEA) adds a time-stamped correction. Analyst Shobhan Dhir warned on 1 December 2025 that the shortage could reach 30% by 2035. The agency’s Global Critical Minerals Outlook 2026, published in July 2026, says:

The copper supply gap has fallen “from around 30% to 25%” as more projects are expected to come online.

The direction is persistent but narrowing. Supply constraints explain why: declining ore grades, rising capital costs and long project lead times. Demand comes from EVs, grids, renewables, data centres and defence systems, with copper trading around US$14,430 per tonne on 5-6 October 2026.

Declining ore grades and long lead times feed directly into copper price formation, which is why a narrowing supply gap can coexist with prices holding near US$14,430 per tonne.

A gap of 25% that has narrowed still means supply must chase demand for a decade. That tells you copper’s case rests on slow-moving physical constraints rather than sentiment, and it gives you a yardstick for judging any fund pitch or broker note.

How does lithium differ, and what does history say about its booms?

The pull of the lithium story is real. The fund manager describes a third boom, with 20-30 new companies emerging, EV demand still roughly eight times higher to go, and supply taking about 10 years to develop.

Chinese manufacturers are producing cheap, high-volume vehicles, VW is cutting models, and BYD has held prices despite European trade barriers. Demand, in other words, is not the worry.

What the previous busts looked like

Supply is. Lithium went through boom and bust in 2017-2018 and again in 2021-2022, with sharp price corrections afterwards. Projects commissioned at high prices arrived into oversupply and stressed leveraged producers.

The IEA’s 2026 outlook says lithium supply gaps have narrowed as projects come online, though it gives no precise remaining percentage. Battery-grade lithium carbonate sat around 118,000-120,000 CNY per tonne in China in early October 2026.

Lithium is more cyclical than copper for several reasons:

• Supply responds quickly once prices rise, because brine and hard-rock spodumene build-outs can swing the market into surplus.
• Returns are highly sensitive to spot prices, cost curves and policy announcements.
• LFP and sodium-ion battery chemistries can temper demand growth.
• Many producers are leveraged, so price falls hit equity holders hard.

Strong EV demand does not protect lithium equity returns from supply responses. Many ASX lithium specialists are exposed to exactly this cycle, so you should treat lithium as a sized, volatile satellite position rather than a structural core.

What do defence spending and deglobalisation add to the resources case?

Three apparently separate themes act on the same inputs:

1. Deglobalisation: onshoring, stockpiles and export controls turn minerals from commodities into strategic assets.
2. Decarbonisation: EVs, grids and renewables raise demand for copper and battery metals.
3. Defence: higher military budgets add buyers who care less about price.

The starting fact is scale. The Stockholm International Peace Research Institute (SIPRI) reported on 27 April 2026 that:

World military spending rose 2.9% in real terms to US$2,887 billion in 2025, the 11th straight year of growth and 2.5% of world GDP.

The mix is also shifting from jets and tanks toward drones, software, space and cyber. S&P Global notes defence systems carry higher copper intensity, which links the spending directly to the metal.

Where Australia fits

Australia spent about US$35.3 billion in 2025, ranking 17th globally, according to SIPRI data reported by ABC News on 28 April 2026. A speaker also cited $887 billion over 10 years; that figure is the speaker’s claim only and could not be confirmed.

China dominates copper smelting and lithium processing, and has applied export controls to gallium, germanium and certain graphite products. Australia’s response includes US-Australia agreements, the Critical Minerals Strategy with government-backed finance, and a discussed Strategic Reserve whose details are still evolving.

The discussed Strategic Reserve is reported to prioritise military minerals, which would give defence-linked projects a financing floor that purely commercial developments lack.

Policy and defence demand create a price-insensitive buyer and a financing floor, so you should see these projects as partly strategic rather than purely cyclical. Announcements, though, are not revenue.

Are miners strong enough to deliver, and where could the thesis break?

What the balance-sheet argument rests on

The reassuring claim is that miners are well funded. The fund manager says they are indifferent to rates, recession or wars, with commodities sitting high on the cost curve. Large diversified miners have historically run moderate gearing and ample liquidity, and BHP is expanding copper capacity by about 50%.

That is qualitatively plausible, but unverified here. FY25-FY26 capex, guidance and balance-sheet figures for BHP, Rio Tinto, Glencore, Pilbara Minerals and Mineral Resources were not available.

Where the thesis could break

The fund manager notes resource equities beat MSCI World for seven straight years during the China cycle. The cautious counterpoint is that supercycle narratives can be priced in early, and resource stocks de-rate sharply when macro conditions soften.

ESG and permitting risk can also stall projects in both metals. The honest read is that the structural story is strong but partly priced, so check company-level numbers yourself before treating “strong balance sheets” as established fact.

Sizing the position: a practical allocation framework for Australian investors

Institutional frameworks for diversified Australian investors typically suggest 5-15% in resources, with about 10% as a central case. The fund manager suggests the top end of a roughly 10% natural rate over a five-year horizon.

Resources diversify against tech-heavy indices and inflationary regimes, but bring higher volatility and deeper drawdowns. Over multiple decades, global resources have delivered returns similar to or slightly below MSCI World, with sharp outperformance in upcycles such as the early 2000s and parts of 2020-2022.

A four-step approach follows from that:

1. Set the range: pick a figure within 5-15% that you could hold through a deep drawdown.
2. Weight copper against specialties: the fund manager’s own mix spans copper, silver, gold, specialties and an energy core, and specialties such as lithium need diversification.
3. Choose access: direct holdings or a thematic ETF.
4. Set rebalancing rules: trim after rallies and review annually.

For defence, the speaker cited the DFND ETF (45 firms, about US$250 million) purely as an example of access. Because resources suit a tactical, diversifying role rather than a dominant core, size the position to what you can tolerate losing temporarily.

Investors wanting to turn a 5-15% range into actual holdings can use our dedicated guide to sizing junior mining positions, which shows how concentration affects upside.

What the evidence supports, and what you still need to check

Copper is the highest-conviction pillar, lithium is cyclical, and defence adds demand and security. The “30%/30%” slogan understates demand growth while the supply gap is narrowing.

Verify company-level balance sheets, settle on a position size within 5-15%, and revisit it each year against IEA and S&P Global updates. Treat the $887 billion defence figure as unverified, and remember no precise lithium gap is available.

This article is for informational purposes only and should not be considered financial advice. Investors should conduct their own research and consult with financial professionals before making investment decisions. Past performance does not guarantee future results, and projections are subject to market conditions and various risk factors.