The world's population must drastically change diets in order to prevent "potentially catastrophic" damage to the planet, scientists have warned.

Global food production is the largest strain on the earth caused by humans and unsustainable farming is already driving climate change, deforestation and biodiversity loss, found a major project commissioned by The Lancet health journal.

As researchers warned that people must sharply cut the amount of meat they eat to live sustainably, here is why managing food supply is key to controlling climate change:

AGRICULTURAL EMISSIONS

Food production creates about a quarter of all greenhouse gas emissions, experts estimate. Livestock farming for meat and dairy represents more than half of that total at 14.5 percent of all emissions, with cattle the biggest offenders.

LAND USE

Agriculture is the biggest single driver of deforestation, stripping away forests that reduce climate change by absorbing and storing carbon. Livestock takes up the most space, with land used to grow animal feed and for grazing using nearly 80 percent of all agricultural land.

WATER USE

About 70 percent of the world's freshwater is used for agriculture, with climate change expected to increase the number of people facing water scarcity. More efficient farming could reduce water use, helping to meet climate challenges.

WASTE

Up to a third of all food is wasted - totalling around 130 crore tonnes per year. It results in unnecessary emissions and means food does not reach those who need it. Experts predict the amount of food waste will rise further without action.

A GROWING POPULATION

The number of people on earth is expected to grow to 9.8 billion by 2050, adding pressure on the world's resources. It is estimated that world food production may have to double to keep pace with demographic changes