Consumers and businesses will soon be able to buy a number of products and services that don’t cause any net greenhouse gases to be released into the environment, thanks to a program launched by the Climate Neutral Network in Underwood, Wash. The network certifies companies that reduce their greenhouse-gas emissions as much as possible and offset the rest by helping to reduce the burning of fossil fuels elsewhere. Three companies have already been certified as climate neutral: Shaklee, which markets household, personal care, and other consumer products; Interface, a commercial floor-covering company; and the Saunders Hotel Group in Boston. About a dozen Fortune 500 companies are also looking into certification.