UNEP also said land degradation, air pollution, and the provision of sanitation and safe drinking water were among the main problems on the continent.
Also, many of the region’s fisheries, both inland and marine, face over-exploitation from illegal, under-reported and unregulated fishing.
It, however, said that the continent had an opportunity to use its large young population to drive its growth.
“Low-carbon, climate-resilient choices can develop the continent’s infrastructure, accelerate industrialization, increase energy and food production, and promote sustainable natural resource governance,” it said.
On water and sanitation, the report said the proportion of the population served with “clean water is increasing and grew from 64 per cent in 2005 to 68 per cent in 2012.”
UNEP said that absolute numbers of people without safe drinking water remain high.
“More than half of the population in sub-Saharan Africa still does not have any access to improved sanitation, compared to 90 per cent coverage in North Africa, with a vast difference between urban and rural areas,” the report said.
It listed African megacities such as Cairo, Kinshasa and Lagos, and emerging mega cities such as Dar es Salaam, Johannesburg and Luanda, as facing challenges from poor management of sanitation services.
The report said those challenges arose from inadequate and deteriorating infrastructure resulting from under-investment.
According to it, land-based activities causing pollution of freshwater bodies ultimately impact coastal and marine resources.
On land and forest, it noted that Africa had the second largest continent in the world, but most prized asset for food production, nutritional health and economic development.
“Worryingly, about 500 000 square meters of land in Africa is being degraded due to soil erosion, pollution and deforestation,” it said.
“This land degradation can damage agricultural productivity, nutrition and human health.
“A growing population and a rise in the demand for firewood will mean that forest cover in Africa is likely to continue shrinking, declining to less than 600 million hectares by 2050.
“Over cultivation, inefficient irrigation practices, overgrazing, the over-exploitation of resources, uncontrolled mining activities and climate change will further degrade land in Africa”.
The report said these challenges lead to reduced agricultural productivity, reduced food security, which could increase migration and spread disease, destroy infrastructure such as roads and bridges, and high rates of poverty.