SINGAPORE - Like a debt that only grows larger, mankind is fuelling economic growth at the expense of the planet and living on borrowed time as a consequence, scientists say.

A UN report to be published this week is likely to show in very stark terms how humanity's growing food demands and industrial agricultural practices are conspiring to threaten future food supplies and global efforts to fight climate change.

Land is a vital resource for growing crops, timber and other resources but poor management of farmlands, wholesale clearing of forests and other landscapes is leaving mankind dangerously exposed to the ravages of climate change, the report by the UN Intergovernmental Panel on Climate Change (IPCC) will say on Thursday (Aug 8).

That is because forests, mangroves, grasslands and healthy soils soak up large amounts of planet-warming carbon dioxide (CO2), the main greenhouse gas, and are therefore a key tool in slowing the pace of climate change.

Yet land clearing and land degradation are exacting a huge toll and it is only set to get worse unless farming practices are overhauled to become more sustainable and food waste eradicated. At present agriculture and forestry produce about a quarter of mankind's greenhouse gas emissions.

The solution: make agriculture part of the solution, not the problem.

But that requires a radical shift in the way food is grown, changing diets, ending food waste and rehabilitated damaged farmlands.

All of that is doable, scientists say. But so far, the damage continues as demand for more grains, meat and vegetable oils keeps growing.

Last year, primary forests covering 3.6 million hectares, an area larger than the size of Belgium, were chopped down, according to a study released in April by Global Forest Watch.

This was driven mainly by agriculture, mining and infrastructure. Brazil lost 1.3 million hectares, Democratic Republic of Congo 481,200 hectares and Indonesia 339,900 hectares.

Globally, about a third of the Earth's soil is badly degraded from agriculture, cutting land productivity and increasing soil loss, a 2017 report backed by the UN Convention to Combat Desertification said. This raises the risks of conflict and migration to more productive lands elsewhere.

Already, more than 820 million people do not have enough to eat, the UN Food and Agriculture Organization says. That's about one in every nine people in the world.

Unless food production becomes more sustainable and fairer, the risks of greater mass migration are set to increase, driven by resource-intensive economies.

Each year, humanity is consuming more, placing ever greater pressure on the planet.

This year, the World Overshoot Day arrived earlier, on July 29. This is the day when humanity has used more from nature than the planet can renew in a single year.

In 2010, it was Aug 9, and in 1980, it was Nov 4. It presently takes 1.75 Earths to meet humanity's demands.

Wealthier countries are consuming much more. Australia's overshoot day this year was March 31, Singapore's April 12, while Japan's was May 13. Indonesia's is Dec 18.

Intensifying demands for resources comes as more extreme weather is causing devastation across the globe, from record-breaking heatwaves and floods to intense droughts and wildfires. This is pushing nature to the brink and reducing its ability to adapt and recover from wilder swings in the weather.

Last month was the hottest month across the globe ever measured, and 2019 is on track to be one of the warmest years, according to data released on Monday (Aug 5) by the European Union's Earth observation network.

The world has already warmed 1 deg C since pre-industrial times and is on track to warm by more than 3 deg C by the end of the century based on current emission reduction pledges globally.

The IPCC last October looked at the steps needed to limit global warming to 1.5 deg C, a key goal of the Paris Climate Agreement.

It concluded that deep emission cuts are needed before 2030 to achieve this.

But there are no signs of those deeper cuts kicking in.

Last year, a record 41.5 billion tonnes of planet-warming CO2 was added to the atmosphere, up two per cent from the previous record, set the year before.