Aluminium is the best and cheapest heat conductor for cookware. Only copper is more conductive, but also much more expensive.
This range is named after the Kyoto convention: In 1997, Kyoto, Japan, a protocol was designed to regulate worldwide emissions of CO2. The protocol set clear guidelines and targets for all countries. It is one of the most famous international agreements due to the legally binding targets for reduction in greenhouse gas emissions for countries that ratified the protocol (and for the fact that it has still not ratified by the United States).