Humans must adopt vegetarian or vegan diets to stop climate change,

The world must turn towards healthy plant- based diets to stop climate change, a UN- backed report has warned.

Our food system accounts for between 25 and 30 per cent of greenhouse gases, and is choking the life from fresh and coastal waterways with excess nitrogen.

In order to feed the predicted 9.8 billion people on Earth in 2050, the world will need to produce 56 per cent more food compared to 2010.

If the level of meat and dairy consumption rises in line with current food habits, six million square kilometres (2.3 million square miles) of forests would need to be converted to agriculture - an area twice the size of India.

Two-thirds would be changed to pasture land, with the final third being used for crops, according to the Creating a Sustainable Food Future report.

Johan Rockstrom, former director of the Potsdam Institute of Climate Change Impact Research, said: ‘To have any chance of feeding ten billion people in 2050 within planetary boundaries, we must adopt a healthy, plant-based diet, cut food waste, and invest in technologies that reduce environmental impacts.’

The ‘great food transformation’ proposed in the report is at odds with other schemes that aim to tackle greenhouse gas emissions.

One report by the UN’s Intergovernmental Panel on Climate Change (IPCC) proposes to convert areas the size of India to biofuel crops or CO2-absorbing trees.

Nearly all Paris-compatible climate models slot in a major role for a two-step process that draws down carbon by growing biofuels, and then captures CO2 released when the plants are burned to generate energy.

The amount of ‘bioenergy with carbon capture and storage’, or BECCS, required in coming decades will depend on how quickly we sideline fossil fuels and shrink our carbon footprints.

Capping global warming at 1.5C would require converting some 7.6 million square kilometres (2.9 million square miles) to BECCS.

Even if temperatures were allowed to climb twice as high, the report concluded, biofuels would still need to cover some 5 million square kilometres (1.9 million square miles). But these proposals ‘could compromise sustainable development with increased risks - and potentially irreversible consequences - for food security, desertification and