Dr Rafael Leal-Arcas has been awarded a Marie Curie Fellowship to do research on the interface of climate change, trade, and energyy law. Climate change is global, long-term, and accelerating. In particular, climate change will have a substantial impact on social, economic and environmental systems, and their interactions, and thereby on aspects of human security including water, food, and health. International law is not well prepared to deal with these challenges. The Westphalian State system, dividing continents, regions and the world into different territories and jurisdictions, is challenged by the fact that the global climate as an indivisible public good. Principles and tools of coexistence and cooperation in international law face the challenge of fragmentation and the need to bring about greater coherence in combating climate change. These are formidable challenges, and the international community is far from meeting them. Changing attitudes and more effective institutional designs are required to tackle the global sustainability challenges related to the use of our natural resources. Especially in the area of climate change, new legal foundations and linkages are called for.