Environment can be protected through Corporate Social Responsibility, as provided in principles 7 to 9 of the Global Compact adopted by the United Nations in 2000. More precisely, within this frame the Caring for Climate initiative details how private actors can play an active role to mitigate and get adapted to climate change. Therefore, private sector does contribute to the construction of rules of law in this field. This implication is favoured by the failure of international traditional actors (States) to negotiate and adopt a new legal instrument to replace the Kyoto Protocol. Climate change is dealt with through Corporate Social Responsibility because many instruments are now existing, offering to private actors all the devices to get involved : universal methods to measure their green gas emissions and to certify these measures, international forums to publish their carbon footprint and to find solutions to reduce it, various domestic or regional markets to mitigate their green gas emissions using financial means. As a result, soft law created by private actors to deal with climate change illustrates once more the very complex and multiform nature of Corporate Social Responsibility