Billions face arid future as climate change turns land to desert

Report marking Cop16 summit in Saudi Arabia says more quarter of humans face conditions that 'redefine life on Earth'

Workers look after trees planted in the green belt outside Karbala in central Iraq. The UN says billions of people are affected by an 'aridity crisis' that demands an urgent response. Reuters

More than three quarters of the Earth have become irreversibly drier over the past three decades, according to a UN report which says there is an existential crisis that could affect billions more worldwide.

About 77.6 per cent of Earth’s land was under drier conditions during the three decades up to 2020 compared to the 30 years before, according to the report from the UN Convention to Combat Desertification (UNCCD).

The report was released as part of the UN Cop16 summit in Riyadh, Saudi Arabia, on combating desertification which concludes on Friday. It is the first UNCCD summit to be held in the Middle East.

The report, which tracks the years between 1990 and 2020, said that aridity was increasing, turning humid regions into drylands, with serious implications for agriculture, ecosystems, and the people.

Delegates arrive at the conference centre for the United Nations Convention to Combat Desertification, Cop16, in Riyadh. AFP

Drylands have expanded by 4.3 million km2 in the past 30 years. That means that 40 per cent of the world's surface area not including Antarctica is now considered to be drylands.

About 2.3 billion people – more than 25 per cent of the world’s population – are living in areas affected by desertification. The report said up to five billion could be living in drylands by 2100 if trends continue.

“This analysis finally dispels an uncertainty that has long surrounded global drying trends,” said Ibrahim Thiaw, UNCCD executive secretary. “For the first time, the aridity crisis has been documented with scientific clarity, revealing an existential threat affecting billions around the globe.

“Droughts end. When an area’s climate becomes drier, however, the ability to return to previous conditions is lost. The drier climates now affecting vast lands across the globe will not return to how they were and this change is redefining life on Earth.”

Water availability in the Middle East and North Africa had declined more than 75 per cent since the 1950s, the report said. It also highlighted that the aridity crisis was linked to Middle East's more frequent and larger sand and dust storms.

The research said that failure to attain carbon neutrality would result in a further 3 per cent of the world’s humid areas becoming drylands by the end of this century.

Farming is particularly at risk, with drier land being less productive, leading to food insecurity, further fuelling migration.

UNCCD executive secretary Ibrahim Thiaw addresses the opening session of Cop 16 in Riyadh, Saudi Arabia. AFP

Aridification hotspots include the western US and Brazil, central Africa and in Europe, 95 per cent of which has become permanently drier, particularly in the south during the period studied.

In contrast, less than a quarter of land (22.4 per cent) experienced wetter conditions, with areas in the central US, Angola’s Atlantic coast, and parts of South-east Asia becoming wetter.

Barron Orr, UNCCD chief scientist, said drier land could lead to “catastrophic impacts affecting access to water that could push people and nature even closer to disastrous tipping points”, where humans are no longer able to reverse damaging effects of climate change.

Sergio Vicente-Serrano, one of the authors of the report, said that as the atmosphere heats up because the burning of coal, oil and gas spews planet-warming emissions, it leads to more evaporation on the ground. That makes water less available for humans, plants and animals.

The UN report urged countries to improve land use and become more efficient at using water. Planting crops that need less water and irrigation methods that are more efficient, like drip irrigation, would be needed on a much larger scale.

It also backed the building of a Great Green Wall, a land restoration project in Africa, which proponents said would help reverse aridity and restore ecosystems while creating jobs and stabilising affected economies.

In addition, better monitoring was needed so that communities can plan ahead, and large-scale reforestation projects to protect the Earth and its moisture.