The lush vineyards, rare plant species and breathtaking scenery that make the Cape Peninsula region a tourist magnet are in danger of withering away within decades, the findings of a growing number of climate change scientists suggest.

A library of evidence - including a major UN report released on Friday - suggests that Africa will be affected more severely than any other continent by climate change this century.

Hundreds of millions of people are set to face severe shortages of food and drinkable water across the continent, but the impact may be most dramatic on the southernmost tip of Africa.

According to international and South African experts, the region's endemic plant kingdoms, fish stocks and unshielded coastal areas are to be at risk from rising sea levels, the wine region is to migrate towards the east, farming is to become more difficult and food ever scarcer.

"The prospects are dire," said Katherine Bunney, the facilitator of a grouping of global warming activist organisations, the South African Climate Action Network.

"We should be scared enough about the effects of climate change to want to do something about it. It is going to be catastrophic."

If the world succeeded in arresting and reversing carbon dioxide emissions to pre-industrial levels over the next few decades, the damage would be limited, but not averted.

"Even if we begin acting now, we will feel it. It is just a matter of degree."

British economist Nicholas Stern, author of an influential report on the economics of climate change released last year, has said Africa will be hit hardest and soonest, with more floods and droughts.

"There would be a serious threat to the water flow down the Nile on which 10 countries depend," he told environmentalists on a recent trip to Cape Point.

Stern said areas that were hotter than others would see temperature rises first, with extended droughts and more frequent and severe flash floods.

"Africa ... is more vulnerable (as) there are more people depending on agriculture and more people in poverty."

The two hottest and driest provinces, the Western Cape and Northern Cape, face the harshest impact.

Dennis Laidler, deputy director of climate change at the Western Cape Department of Environmental Affairs, said temperatures could rise by 2°C to 5°C by the end of the century and the trend in the province would "be towards desertification"

The wine regions could move towards the Garden Route and shrink as farmers sought wetter climes and chose more resistant crops, Bunney said.

Fruit, wheat, vegetable, and dairy farming in the province were also vulnerable.

Many indigenous plant species would migrate towards more water-rich parts of the province and some would become extinct.

The fynbos kingdom is one of the world's six floral kingdoms and has more species than the whole of Europe.

"The loss of biodiversity (would be) an incredible economic loss for tourism," Bunney said.

Among other prospects were increasing urbanisation as agricultural activity declined, a threat to estuaries and their unique fish species, and more wildfires.

A 2005 Western Cape climate change report warned of the potential effects of rising sea levels. With higher sea levels, storm defences would be breached more easily.

With less frequent but more severe rainfalls, flooding would become a bigger threat. On the Cape Flats, informal settlements would be especially vulnerable to flooding because of the high water table.

Laidler said the provincial government was working to curb carbon dioxide emissions by increasing renewable energy's contribution to total production to 15% by 2015.

There would be steps to limit water leaks, punish unproductive resource use and replace the government fleet with gas-powered vehicles.

"The cost of not doing anything will be huge."

Stern said he was encouraged that the threat was being taken increasingly seriously globally. "But … will we, as the world, act quickly enough and strongly enough? We will find out in the next year or two."