President Félix Tshisekedi said the Democratic Republic of Congo would ensure that 63% of the country, home to the world's second-largest rainforest, would remain under forest cover.

The Congolese leader also pledged to reduce emissions by 17% by 2030.

In his speech, Nigeria's President Muhammadu Buhari said his administration would develop robust action plans to counter climate change, including diversifying its energy sources, the country's Premium Times reports.

The West African nation is the continent's leading oil producer.

"We will mobilise Nigerian youths towards planting 25 million trees to enhance Nigeria’s carbon sink," he added.

The president also spoke of the Great Great Wall project, which involves 11 countries planting a wall of trees from east to west across Africa, just under the southern edge of the Sahara desert.

"In addition, our administration intends to develop a shelter-belt across 11 states of the federation spanning a distance of 1,500km [932 miles] and 15km across through the Great Green Wall initiative," he said.

President Hage Geingob of Namibia called for more attention to be given to protect oceans from global warming, saying one of the southern African nation's commitments was to spend $5m (£4m) over the next year on research.

"This includes $2.3m to facilitate research on oceans, especially on fisheries stocks and the marine ecosystem, and a further $2.7m to intensify the fight against illegal, unregulated and unreported fishing, and improve ocean governance,” the Namibian newspaper quoted the president as saying.