Sick of poring over labels at the supermarket? Brace yourself: it is only going to get worse.

Trend-watchers predict that by 2030, shoppers in wealthy countries will get a breakdown of almost every aspect of their food's environmental footprint before they head for the checkout.

Far from being restricted to carbon footprints, former Parliamentary Commissioner for the Environment Morgan Williams believes supermarkets will become the arbiters of everything from how much freshwater was used to how much energy and how many nutrients went into making every piece of food on the shelves.

He believes wealthy shoppers - increasingly the mainstay of New Zealand exports - will become rapidly more worried about using up the world's finite food-growing resources.

And in a future where nutrients are scarce and plants are bred to drink as little water as possible, soil scientists may be considered as glamorous as rocket scientists are today.

Worldwide, food demand is expected to grow by 50 per cent by 2030 and double by 2050.

At the same time, wild fish stocks are expected to fall and a growing sector of the world's population is tipped to grow wealthy enough to demand access to protein from meat and dairy.

Dr Williams said farming countries such as New Zealand would have to work ever-harder to prove they could wring more sustenance from the same patch of paddock.

The agricultural scientist, who was New Zealand's Parliamentary Commissioner for the Environment from 1997 to 2007, said access to vital elements in the environment for food-growing - including nitrogen, carbon and water - would only get more expensive over the next two decades as pressure to increase food production ramped up.

Britain's chief scientist Professor John Beddington has warned of a "perfect storm" of food, water and energy shortages by 2030, where food prices would rise, more people would go hungry, and people would flee the worst-affected regions in their millions.

Work on water and carbon footprinting is already underway in New Zealand, but nutrients such as nitrogen may also be caught up in the footprinting trend.

Dr Williams believes a revolution in farming practices is inevitable - but he does not think the major driver will be slashing the fast-burning greenhouse gas methane, currently a major focus of Government spending.

He predicted farmers would learn more about how to use biochar and other new techniques to trap essential nutrients in the soil, including borrowing techniques from organic farmers.

A spin-off for swimmers and recreational fishers could be cleaner low-land lakes and rivers, as fewer wasted nutrients leak into waterways from farming.

While demand for food ramps up, access to freshwater will become more and more scarce as climate change alters rainfall patterns.

The Ministry of Agriculture and Forestry says the effects of climate change are already being seen on New Zealand's drier east coast, where the amount of freshwater available is declining.

Dr Williams said New Zealand would not dry out the way some countries would, but farmers would need to adjust to less predictable rainfall. "You're going to need more crop for your drop." Globally the reality of more variable rainfall would mean greater reliance on irrigation, he said.

Those who are attached to their lawn sprinklers should also be warned.

Pressure on freshwater supplies means all households are likely to end up paying for the tap water they use - as Aucklanders already do.

Dr Williams said a nationwide price on water was almost inevitable as virtually everywhere in the world that had tried it found that people wasted less water.