I welcome the agreement on the fourth carbon budget (Editorial, 18 May) and the efforts of the energy and climate secretary to secure it. Unfortunately, cabinet infighting has delivered a flawed deal, with the government failing to heed advice from the Committee on Climate Change on three key points. First, it is refusing to toughen up the existing targets for 2013-23, making the fourth budget harder and more costly to achieve and stunting ambition in the here and now. Second, the concessionary review clause slipped in by the Treasury will allow the government to backtrack on the budget in 2014, depending on progress elsewhere in the EU, reducing long-term certainty on emissions cuts and potentially harming the investor confidence in green technologies which the Climate Change act is designed to build.  and on the fundamental issue of how we meet the targets, the government has shunned the CCC's recommendation that the budget should be met through domestic action alone. Exporting carbon pollution is not the same as reducing it. allowing trading mechanisms such as offsetting is, in effect, outsourcing our responsibilities to other countries - and weakening the drive to build green industries here. With the right political leadership and commitment to ambitious reforms, the green jobs of the future can become a reality now.  Caroline Lucas MP  Green, Brighton Pavilion