Two South African banks are the biggest "climate killers" among African banks, environmental activists said on Wednesday.

Standard Bank was the biggest culprit, while Nedbank, which claimed to be a carbon neutral bank, was ranked number 60, activists said on the sidelines of the 17th Conference of the Parties to the United Nations Framework Convention on Climate Change (Cop17) in Durban.

The two banks were mentioned during the release of a report showing that banks around the world had lent EU232 billion (about R2.5 trillion) to the coal industry, which is regarded as the major source of greenhouse gases.

In response, Nedbank said it was a proud conservation partner of the World Wide Fund for Nature South Africa (WWF-SA)

"Together we aspire to reduce the consumption of our natural resources. Nedbank is also the first African bank to adopt the Equator Principles," the bank said in a statement.

The Equator Principles are a voluntary set of standards for determining, assessing and managing social and environmental risk in project financing.

Comment from Standard Bank could not be immediately obtained.

Bobby Peek, of Groundwork, said Standard Bank had financed projects worth EU99 million (about R1bn) "that destroyed the environment".

Nedbank had financed Eskom's environmentally unfriendly coal projects to the tune of EU86m (about R941m).

"Since 2005, the year the Kyoto Protocol came into force, Standard Bank has provided over EU447m [about R4.89bn] to the coal industry, the single largest source of CO2 [carbon dioxide] emissions heating up our planet," he said.

The Kyoto Protocol, which came into effect on February 16, 2005, is an international agreement which sets binding targets for 37 industrialised countries and the European community on the reduction of greenhouse gas emissions.

Peek said that although Nedbank claimed to be a carbon neutral bank, there was nothing to show it was environmentally friendly.

The news about the bank's financing of coal projects came at a time when it has put banners around its building which read "a greener future needs a greener bank with green answers".

The building is next to the Inkosi Albert Luthuli Convention Centre where the Cop17 talks are taking place.

Peek said many public debates in South Africa during the "aggressive coal energy development" of the past few years had focused on the devastation coal extraction had caused.

"Presently, Johannesburg is ‘floating' above a lake of acidic waste water which is an accumulation of years of gold mining," he said.

Aggressive coal mining would also lead to disastrous consequences, as acid and toxins from abandoned mines would leak into the environment.

"Abandoned coal mines are ticking timebombs for the environment, mainly due to acid mine drainage, whereby water draining from the mines is filled with heavy metals and carcinogenic substances like benzene," Peek said.

Eskom was currently building a coal power station in Mpumalanga which would be one of the biggest in the world.

"Where the Eskom Kusile plant is situated, there are 10 other Eskom power stations. The air pollution monitoring in May to August 2010 highlighted that the air pollution ambient standards were transgressed on more than 500 occasions," he said.

South Africa was the 11th biggest emitter of carbon dioxide worldwide.

"The state utility Eskom accounts for a large part of these emissions as it generates over 90 percent of its electricity in coal-fired power plants," Peek said. -Sapa