It’s when the tide goes out that you see who’s been swimming naked.

That’s the issue commodity investors should be focusing on right now, as the shadow of China’s Communist Party congress fades and winter anti-pollution shutdowns start to bite.

At the heart of the global metals trade is a powerful mystery. China accounts for about half of consumption of most industrial commodities, but its appetites are ruled by unpredictable diktats from Beijing. That engenders a degree of Kremlinology, as analysts attempt to predict how Xi Jinping’s green-tinged party congress speech will mesh with an economic model that’s traditionally leaned on state-owned heavy industry for growth.

Right now, it’s the environmental theme that appears to be winning out. Electricity generation from fossil-fuel burning thermal power plants fell year-on-year in October for the first time in 15 months, as output from hydroelectric dams roared back after a lean period.

Metals that rode the China demand wave have been taking on water. Nickel forwards on the London Metal Exchange are down 6.9 percent over the past week and steel rebar has slipped 1.7 percent in Shanghai. Since the start of the month, London-traded zinc is off 3.5 percent and copper has fallen 1.2 percent.

That’s caused factors neglected amid the strength of the recent commodities price surge to regain salience.

Aluminum, the poster-child for hopes of a Beijing-led supply shutdown, has been piling up in Shanghai at a worrying pace. The stockpile of metal available for order has hit a record 634,000 metric tons, taking some of the shine off the remarkable decline in comparable inventories on the LME.

That, combined with the relatively modest pace of output declines, suggests that the market isn’t being so much starved as sated.

There’s a similar pattern in copper, where stocks are on the high side of their seasonal cycle. Meanwhile cement — often a useful indicator because of its role as an early-use product in the construction cycle and its relative immunity to market-driven speculation — is looking distinctly weak. After running at record levels through the start of the year, output slumped to a five-year seasonal low in August and October.

There’s a problem here in separating the signal from the noise. With Xi’s promise of an “ecological civilization” still ringing in cadres’ ears, no one wants Beijing to start resembling a Blade Runner-esque hellscape when smog season starts in earnest over the coming weeks. So how much of the current weakness comes from the underlying economy, and how much from seasonal constraints?

Fixed-asset investment data present some worrying signs. As a percentage of the total, infrastructure spending is running at its strongest levels since 2009 and 2010, Bloomberg Intelligence analysts Tom Orlik and Fielding Chen wrote this week. That suggests that state stimulus is currently responsible for an unusually large degree of economic activity, a scenario that’s unlikely to persist as winter sets in and Beijing’s priorities switch from making the economy run hot to cutting debt.

Consumers may save the day but in a commodity market that’s been supported more by supply cuts and speculation than demand growth over the past few years, that’s a thin reed. The last time China tried to rebalance from heavy industry toward consumption, the eventual result was the commodity crash of late 2015.

We may escape that fate, but those hoping we’re in the foothills of a renewed boom are likely to be disappointed.

This column does not necessarily reflect the opinion of Bloomberg LP and its owners.

David Fickling is a Bloomberg Gadfly columnist covering commodities, as well as industrial and consumer companies. He has been a reporter for Bloomberg News, Dow Jones, the Wall Street Journal, the Financial Times and the Guardian.

To contact the author of this story: David Fickling in Sydney at [email protected]

To contact the editor responsible for this story: Matthew Brooker at [email protected]

©2017 Bloomberg L.P.