The SA Cities Network and the Renewable Energy and Energy Efficiency Partnership are hosting a second round of talks at the COP17 conference in Durban on the implementation of climate-change mitigation targets.
The talks are being held as the deadline for an agreement on mitigation commitments rapidly approaches.
The event focused on financial models for city rejuvenation through the use of renewable energy sources to lower carbon emissions and slow climate change.
Stefan Schurig, of the World Future Council, said city life was powered by the use of oil in transport, agriculture, entertainment and communication.
"Oil is a finite and dirty resource. We have to [decide] now to shift to using renewable energy sources, such as the sun and wind," he said.
Half the global population lives in cities, which consume more than two-thirds of the world's energy and about 60% of its fresh water - and contribute to more than 70% of global carbon dioxide emissions.
Cities are therefore a primary cause of climate change, said Schurig, but they have the ability and opportunities to be part of the solution.
Energy efficiency is a good example of "money saved is actually money made".
The scaling up of the use of renewable energy created about 370000 jobs in Germany - twice as many as in the coal and nuclear sectors.
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