People smile at the tale of The Emperor’s New Clothes. The crowds cheer the soldiers and monarch going past, ignoring the fact that they are stark naked until a child sees and states the obvious.

Something like this is going on in the food world. Most academic analysts know the food system must change quite radically. Yet nothing is leading the systems change. A bit of CSR here or there, some companies pushing slightly differently. But three recent reports suggest we must push harder.

The fifth IPCC report on climate change is 2,216 pages and represents five years of data collection. Irreversible change gets more likely. And Lord Stern’s report showed food’s role as crucial - firstly, as source of greenhouse gas emissions, and secondly as a sector threatened by the impact of climate change.

Last week, the FAO published its latest livestock and climate change report. Livestock has uses. Animals make food from harsh terrain. They’re capital. They’re food. But numbers are rocketing. Consumers aspire to meat and dairy daily, so the scale of demand becomes the problem. Even if emissions are reduced by 30%, rising demand outpaces it.

“The metrics of what we want from the food system must change”

The third report is arguably the most important but least publicised. Emily Cassidy and Minnesota colleagues reviewed major crops and land use. Thirty six per cent of global crop calories grown are fed to animals. Only 12% of those feed calories ultimately contribute to the human diet. If the crops currently fed to animals were fed to humans, another four billion people could be fed adequately. US-style agriculture is inefficient. A new measure of efficiency is proposed: people fed per acre.

Here lies the policy and cultural challenge. It can be profitable not to feed people and unprofitable to feed them. The metrics of what we want from the food system must change. CSR is not enough. We need to re-engineer whole systems.

Wise heads know this. Hence the push to shave energy, materials, contents out of products. Part of this is motivated by brand protection. But the systemic problem these reports highlight is still missed. Is another children’s tale appropriate? The child crying wolf so often, it’s ignored.

Tim Lang is professor of food policy at City University London