Soil damage fuels climate change

LONDON, Apr 29 (BBC): Climate change can't be halted if we carry on degrading the soil, a report will say.

There's three times more carbon in the soil than in the atmosphere - but that carbon's being released by deforestation and poor farming.

This is fuelling climate change - and compromising our attempts to feed a growing world population, the authors will say.

Problems include soils being eroded, compacted by machinery, built over, or harmed by over-watering.

Hurting the soil affects the climate in two ways: it compromises the growth of plants taking in carbon from the atmosphere, and it releases soil carbon previously stored by worms taking leaf matter underground.

The warning will come from the awkwardly-named IPBES - the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services - a panel studying the benefits of nature to humans.

The body, which is meeting this week, aims to get all the world's governments singing from the same sheet about the need to protect natural systems.

IPBES will formally release its report on May 06.

About 3.2 billion people worldwide are suffering from degraded soils, said IPBES chairman Prof Sir Bob Watson.

"That's almost half of the world population. There's no question we are degrading soils all over the world. We are losing from the soil the organic carbon and this undermines agricultural productivity and contributes to climate change. We absolutely have to restore the degraded soil we've got."

Prof Watson previously led the Inter-governmental Panel on Climate Change (IPCC).

"Governments have focused on climate change far more than they have focused on loss of biodiversity or land degradation. All three are equally important to human wellbeing."

Soil expert Prof Jane Rickson from Cranfield University, UK, added: "The thin layer of soil covering the Earth's surface represents the difference between survival and extinction for most terrestrial life.

"Only three per cent of the planet's surface is suitable for arable production and 75 billion tonnes of fertile soil is lost to land degradation every year." She said soils form at a rate of 1.0cm in 300 years.

There's uncertainty about the exact level of global soil degradation. But the major hotspots are reported to be in South America, where forests are being felled; sub-Saharan Africa; India and China.

Soil scientists in both the biggest Asian nations are worried that their ability to grow their own food may be compromised.

In the US, some soils are being restored as forests take over poor quality land previously worked by small farmers, but others are still being degraded.