The talks in Brazilian capital Brasília are part of a one-week tour Ban is making to South America and to Antarctica to see the effects of global warming firsthand, and the response by governments in the region.
During his trip to Antarctica last Friday and to a Chilean glacier field on the weekend he said he saw the "alarming" result of greenhouse gases, notably through the melting of the southern ice cap.
Ban is preparing to host a December summit in Bali that is aimed at getting the international community to agree on a successor treaty to the Kyoto agreement, which is to expire in 2012.
Brazil is one of the pioneering nations on tackling climate change. It has enacted laws to protect its Amazon rainforest, and is converting its entire fleet of cars to accept both petrol and ethanol – a biofuel it makes from sugarcane.
The Brazilian president greeted Ban with handshake and quick embrace at the foreign ministry in Brasilia. Neither said anything to the media.
The two, joined by a handful of aides, went into an office for a short discussion before joining a working lunch that included Brazilian government ministers.
Mercopress