The resulting inflexible limitations on GHG growth could entail substantial costs, perhaps running into many trillions of dollars globally if countries have to solely rely on their own domestic measures – one important economic reality recognised by many of the countries that signed the Kyoto Protocol. As a result, international mechanisms which would allow developed countries flexibility to meet their targets were included in the Kyoto Protocol. The purpose of these mechanisms is to allow the parties to find the most economical ways to achieve their targets. These international mechanisms are outlined under Kyoto Protocol.