The European Council decided 23 October 2014 to reduce emissions of green house gasses with 40%. However, the Commisisons draft was supplemented with many derogations.
The greenhouse effect is thought to be causing a worldwide increase in temperature, estimated to be between 2 and 6 degrees over the next 100 years. The greenhouse effect is caused by the emission of "greenhouse gases".
The Kyoto Protocol is a commitment to reduce the emissions of such gases. The EU and the member states are part of The Kyoto Convention on Climate Change and regret that the USA has refused to sign. It has later been reviewed.
The Lisbon Treaty from 2009 has added the fight against climate change to the international objectives of the Union. See Article 191 TFEU.
Environment for young Europeans: http://ec.europa.eu/environment/youth/index_en.html
Greenhouse gas monitoring and reporting: http://ec.europa.eu/environment/climat/gge.htm