The price surge is "irrational", according to The China Nonferrous Metals Industry Association (CNIA), which hosted a video conference of the country's top producers.
Such coded warnings are part of Beijing's campaign to tame wild commodity prices, as was Wednesday's third sale of state reserve metal, including another 70,000 tonnes of aluminium.
There is undoubtedly speculative excess in the Shanghai aluminium market. Open interest is at record highs and volumes are elevated.
But the driver of the rally is rooted in China's own supply-chain tensions. Output curbs following energy restrictions are proliferating as provincial provinces scramble to meet mandated energy efficiency targets.
Welcome to aluminium's decarbonisation paradox.
The world needs more aluminium to go green but the smelters that produce the stuff use huge amounts of power and account for around 2% of all man-made emissions each year.
Squaring that carbon circle is not going to be easy for China or the global market.
The 10 aluminium producers participating in the CNIA meeting committed to "continue to ensure supply and stabilise market expectations".
Only, however, if their power-hungry smelters have sufficient supplies of electricity. Aluminium is produced by electrolysis not by blasting it in a furnace. No power, no aluminium.
And power in China is becoming a problem.
Aluminium curtailments earlier this year in Inner Mongolia were modest but a sign of things to come as the coal-dependent province tried to meet new quarterly dual-control targets for energy usage and efficiency.
The province of Guangxi, another laggard in the energy league, last month ordered smelters to reduce run-rates to preserve power over peak demand periods.
A prefecture in Xinjiang, a massive aluminium smelter hub accounting for almost one-fifth of China's capacity, has just mandated 10% production cuts across five smelters for the rest of the year.
The power situation hasn't been helped by a long drought in hydro-electric Yunnan province, a newly emerging "green" aluminium production hub.
Since China is by far the world's largest producer of aluminium, both at a raw metal and semi-manufactured product level, this collective powering-down places a big question-mark over global supply.
A market that has lived with Chinese over-supply for two decades is starting to price in a very different future.
Look at China's headline aluminium production figures and the price reaction might seem excessive.
National output rose by 7.2% in the first seven months of the year, according to the International Aluminium Institute (IAI).
However, the year-on-year growth rate is flattered by a low COVID-19 base. Annualised run-rates have increased by just 500,000 tonnes so far in 2021, a very muted response to high prices by historical standards.
It is clear that new capacity growth is being offset by the spreading energy restrictions. Constrained output has left a shortage of primary metal in parts of the country.
Shanghai exchange inventory has fallen from over 392,000 tonnes in April to a current 248,926 tonnes.
The world's largest producer continues to suck in aluminium from the rest of the world. China imported 1.06 million tonnes of primary metal last year and another 744,000 tonnes in the first half of 2021 with no sign of any let-up in the preliminary July figures.
The country remains a large exporter of aluminium in the form of semi-manufactured products, which is starting to look increasingly anomalous as the its hunger for commodity-grade metal grows.
One obvious policy tool would be to reduce the tax refund on product exports and divert volumes into the domestic market, a tactic already used in the steel sector.
That would be welcome news for aluminium product-makers everywhere else but wouldn't alter the underlying price dynamic of China running out of production growth road.
THE ALUMINIUM PARADOX
China's top state planner, the National Development and Reform Commission, has come out and urged aluminium producers to diversify into renewable power sources other than hydro such as solar and wind.
Two forms of power that ironically require significant amounts of aluminium. Indeed, the metal accounts for 85% of the mineral input of a photovoltaic cell in the form of pannelling, according to the World Bank.
It's also used in many lithium-ion batteries and is a crucial material for light-weighting vehicles for energy efficiency. In terms of usage, it's very much a green metal.
But smelting the stuff is carbon intensive, particularly in China and the rest of Asia, where the power source is still overwhelmingly coal.
That inherent paradox - hard-wired into the metal because of the production process - is impacting the market landscape.
Stresses in China's power system have turned the world's largest supplier of aluminium into a regular net importer of primary metal.
China's problem today could be the rest of the world's problem tomorrow.
The IAI has estimated the world will need another 25 million tonnes of primary metal production to meet an expected 80% rise in demand by 2050, fuelled by the demands of decarbonisation.
That assumes a 100% recycling rate, which may be a very big ask of an industry that encompasses a wide spectrum of alloys.
Building that capacity while simultaneously "greening" existing capacity in a world that needs ever more renewable power is the conundrum facing the global aluminium industry.
The Chinese authorities may succeed in shooing away the aluminium speculators for now but they'll be back unless someone can resolve aluminium's puzzling carbon paradox.
(Editing by Barbara Lewis) ((firstname.lastname@example.org, 44-207-542-4412 and on Twitter https://twitter.com/AndyHomeMetals))