The Executive Director of UNEP, Achim Steiner, speaks at the launch ceremony for Global Environmental Outlook on Thursday at UNEP headquarters in Nairobi. [Photo by Hou Liqiang/chinadaily.com.cn]

About 500,000 square meters of land in Africa is being degraded due to soil erosion, salinization, pollution and deforestation, posing challenges to the food security of the continent, a new UN report said.

The report, Global Environmental Outlook, published by the United Nations Environment Program on Thursday at its headquarters in Nairobi, also said over cultivation, inefficient irrigation practices, overgrazing, the exploitation of resources, uncontrolled mining activities and climate change will further degrade land in the world's second largest continent.

While reducing agricultural productivity and food security, land degradation will also initiate a chain of effects, including increasing migration, the spread of disease, infrastructure destruction, and high rates of poverty, according to the report.

It projects that forest cover in Africa is likely to shrink to less than 600 million hectares by 2050 because of a growing population and a rise in the demand for firewood.

Meanwhile, air pollution, and provisions for sanitation and safe drinking water are also challenging the continent.

Indoor air pollution is responsible for 600,000 premature deaths every year in Africa. The continent's reliance on the use of biomass for cooking, lighting and heating means that 90 per cent of the region’s population is exposed to this health threat.

The continent has seen the proportion of its population with access to clean water grow from 64 percent in 2005 to 68 percent in 2012, but more than half of the population in sub-Saharan Africa still does not have any access to improved sanitation, according to the report.

The report, released ahead of the United Nations Environment Assembly includes six separate reports, which provide highly detailed examinations of the environmental issues affecting each of the world’s six regions: the Pan-European region, North America, Asia and the Pacific, West Asia, Latin America and the Caribbean, and Africa.

The environmental change sweeping the world is occurring at a faster pace than previously thought, making it imperative that governments act now to reverse the damage being done to the planet, it concludes.

The regional assessments find that the world shares a host of common environmental threats that are rapidly intensifying in many parts of the world, including population growth, rapid urbanization, rising levels of consumption, desertification, land degradation and climate change, which have combined to leave countries suffering from severe water scarcity.

The Executive Director of UNEP, Achim Steiner, said: "Today, thanks to this report, we now know more about the state of the world's environment than ever before. With these assessments, UNEP has presented the world with the very latest evidence on the state of the world’s environment, providing them with the tools they need anticipate and avoid the damage that is being done to our planet."

"If current trends continue and the world fails to enact solutions that improve current patterns of production and consumption, if we fail to use natural resources sustainably, then the state of the world's environment will continue to decline. It is essential that we understand the pace of environmental change that is upon us and that we start to work with nature instead of against it to tackle the array of environmental threats that face us."

Involving 1,203 scientists, hundreds of scientific institutions and more than 160 governments, the report is the most authoritative study that UNEP has ever published on the state of the global environment, according to a press release from UNEP.