BRITaIN'S CONSERVaTIVE MEPs are poised to deliver an embarrassing rejection of the Government's global warming stance today in a European Parliament vote on toughening climate targets.  Many, if not most, of the 26 Tories are likely to vote against the proposal that the EU should tighten its proposed 20 per cent cut in CO2 emissions by 2020 to 30 per cent.  The shift is the centrepiece of the Government's climate agenda - it is in the Coalition document, and British ministers have campaigned for it with other EU countries - so a rejection by Tory MEPs will be seen as a snub to David Cameron.  It is possible their votes could make the difference between the proposal being won or lost.  If it is lost it will be another blow to Europe ahead of the next global climate conference in Durban, South africa, in December.  Two weeks ago Poland blocked the EU's first attempt at agreeing on the move saying it would be too damaging for Polish industry.