SINGAPORE - Intensive agriculture, deforestation, mining and pollution have degraded up to 40 per cent of the planet's land surface, threatening economies and the ability to grow enough food to feed billions more people in the future, a United Nations report says.
Global Land Outlook 2, from the UN Convention to Combat Desertification (UNCCD), outlines the stark realities of damage to landscapes, which is compounding the twin crises of climate change and biodiversity loss.
But the report, five years in the making, says large-scale ecosystem restoration can put the world on a safer path by helping fight global warming, reverse the loss of nature and make agriculture more efficient, ensuring food for an increasingly hungry world.
Shifting to a regenerative restoration economy that reduces greenhouse gas emissions, land degradation and biodiversity loss has huge potential returns, the report says, estimating it to be worth between US$125 trillion (S$173 trillion) and US$140 trillion annually - up to 1.5 times the global gross domestic product (GDP).
"Investing in large-scale land restoration is a powerful, cost-effective tool to combat desertification, soil erosion and loss of agricultural production. As a finite resource and our most valuable natural asset, we cannot afford to continue taking land for granted," said Mr Ibrahim Thiaw, UNCCD executive secretary.
"Modern agriculture has altered the face of the planet more than any other human activity," he added, calling for an urgent rethink of global food systems, which are responsible for 80 per cent of deforestation and 70 per cent of freshwater use.
Land resources - soil, water and biodiversity - provide the foundation for the wealth of societies and economies, the report says. That makes them essential to meeting humanity's needs for food, water and fuel. Roughly US$44 trillion of economic output - more than half of global annual GDP - is moderately or highly reliant on nature.
But stripping the land bare of its vegetation, planting industrial-scale crops and creating vast cattle and sheep farms leave the soil exposed to wind and water erosion as well as pollution from chemicals such as fertilisers. Huge mining operations to meet the ever-growing needs of a global consumer society are also taking a toll.
The global food system is also a major source of greenhouse gas emissions, producing about a third of all such emissions annually from livestock and crops as well as food supply chains, including retail, transport and waste management. And yet despite the high environmental cost of producing and transporting food, a third of all food produced for human consumption goes to waste, the UN Environment Programme says.
The UNCCD report warns that if things continue as they are, by 2050, an additional 16 million sq km, an area almost the size of South America, will be degraded, leading to lower crop yields and high greenhouse gas emissions.
The report outlines plenty of things that can be done to halt and start to reverse the damage.
First, nations need to make good on pledges to restore one billion degraded hectares by 2030. Doing so will cost an estimated US$1.6 trillion, a fraction of the annual US$700 billion in fossil fuel and agricultural subsidies.
Upping this restoration effort to about five billion hectares (or 35 per cent of the global land area) by 2050 using measures such as agro-forestry, grazing management and assisted natural regeneration, delivers major benefits.
Crop yields increase by 5 per cent to 10 per cent in most developing countries compared to the baseline. Improved soil health leads to higher crop yields, with the largest gains in the Middle East and North Africa, Latin America and sub-Saharan Africa, limiting food price increases.
Soil water-holding capacity would increase by 4 per cent in rain-fed croplands and carbon stored in the soils rises, while carbon emissions are cut.
Already there are efforts under way in many countries to curb land degradation and protect nature. The report outlines dozens of programmes across the world involving the creation of protected areas and national parks, restoration of damaged or destroyed ecosystems and conservation efforts involving farmers.
Since 2016, Indonesia has embarked on a major programme of peatland rewetting and restoration involving hundreds of local communities and recently expanded the initiative to restore mangroves.
Pakistan has worked with farmers to rehabilitate degraded rangelands through reseeding and community-based grazing, plus sustainable rain-fed agriculture and water conservation and creating shelter belts. The country more recently launched its billion trees reforestation initiative and in 2018, expanded this to the Ten Billion Tree Tsunami Programme.
Singapore has a large-scale tree planting programme as well as efforts to create forest corridors and replanting of mangroves along parts of the coastline.
But much more remains to be done. Global efforts are under way to get nations to agree to set aside 30 per cent of the planet's land and seas as protected areas by 2030 - up from about 17 per cent and 7.75 per cent, respectively, from the present.
"Restoring long-term health and productivity in food landscapes is a top priority to ensure future sustainability," said Ms Louise Baker, UNCCD managing director of global mechanism.
"Much as an investor uses financial capital to generate profits, regenerating a forest or improving soil health provides returns in the form of a future supply of timber or food."