Initially, EU environmental policy was rather introspective. More recently, however, the Union has considered global environmental governance. The role of the EU in securing the ratification and entry into force of the Kyoto Protocol in the face of US opposition is an example in this regard. This international dimension is reflected in the EU's Sixth Environmental Action Programme, which recognises that its strategic objectives can only be achieved if a series of key international environmental agreements are actively supported and properly implemented both at an EU level and worldwide. The entry into force of the Lisbon Treaty further strengthens the EU's global environmental leadership ambitions. The vast body of EU environmental law which now exists has played a vital role in improving habitat and species protection in Europe as well as contributed to improvements in air and water quality and waste management. However, significant challenges remain, both to meet existing EU targets and aspirations and to agree new targets and actions that will further improve the environment and the quality of life in Europe and beyond.