The world needs to improve the way it values land in order to halt degradation, which is estimated to lose 24 billion tons of fertile soil and 15 billion trees every year, according to a new report from a UN panel on Friday, the World Day to Combat Desertification.

The International Resource Panel, under the United Nations Environment Program (UNEP), released the report titled Unlocking the Sustainable Potential of Land Resources: Evaluation Systems, Strategies and Tools. It was a way to help policy makers and land managers unlock the full potential of land and allow them to use resources more efficiently, said Jefferey Herrick, a research scientist at the US department of Agriculture and the report's author.

Erosion, nutrient depletion, acidification, salinization, compaction and chemical pollution have left 33 percent of the world's soils either moderately or highly degraded, the report said.

If current conditions continue, 320-849 million hectares of land will be converted to cropland by 2050 at the expense of the world's savannahs, grasslands and forests. As a result, greenhouse gas emissions from agriculture may increase from 24 to 30 percent.

The report said a better understanding of the potential of the world's land resources – at farm, watershed, country and regional levels – could raise food productivity, promote biodiversity, and increase resilience to climate change.

"To feed the world's people, we will need to get the best we can out of the land," said Ibrahim Thiaw, Deputy Executive Director of UNEP.

"The International Resource Panel, in this study of the benefits of land evaluation, has again shown us a way to do more and better with less, and, at the same time, deliver on the Sustainable Development Goals that the world agreed to last year."