il ▁fuel ▁coal , ▁natural ▁gas ▁is ▁only ▁ 5 0 % ▁as ▁dirty . ▁Fra ck ing ▁issues ▁exist ▁when ▁producing ▁the ▁gas , ▁and ▁if ▁as ▁little ▁as ▁ 3 ▁percent ▁of ▁the ▁gas ▁produced ▁esc apes , ▁effects ▁upon ▁the ▁climate ▁are ▁close ▁to ▁equivalent ▁as ▁when ▁burning ▁coal . ▁Despite ▁this , ▁it ▁is ▁often ▁presented ▁as ▁a ▁' clean er ' ▁foss il ▁fuel ▁in ▁environmental ▁disc ourse ▁and ▁is ▁often ▁used ▁to ▁balance ▁the ▁inter mitt ent ▁nature ▁of ▁solar ▁and ▁wind ▁energy . ▁Environment al ists ▁have ▁argued ▁that ▁the ▁Bush ▁Administration ' s ▁Clear ▁Sk ies ▁In iti ative ▁actually ▁weak ens ▁air ▁poll ution ▁laws . ▁Many ▁food ▁products ▁have ▁pack aging ▁that ▁ev okes ▁an ▁environment ally ▁friendly ▁imag ery ▁even ▁though ▁there ▁has ▁been ▁no ▁attempt ▁made ▁at ▁lower ing ▁the ▁environmental ▁impact ▁of ▁its ▁production . ▁In ▁ 2 0 0 9 , ▁European ▁Mc Donald ' s ▁changed ▁the ▁colour ▁of ▁their ▁log os ▁from ▁yellow ▁and ▁red ▁to ▁yellow ▁and ▁green ; ▁a ▁sp okes man ▁for ▁the ▁company ▁explained ▁that ▁the ▁change ▁was ▁" to ▁clarify ▁[ the ir ] ▁responsibility ▁for ▁the ▁pres ervation ▁of ▁natural ▁resources ." ▁ ▁Ex isting ▁published ▁consumption ▁figures ▁tend ▁to ▁under est imate ▁the ▁consumption ▁seen ▁in ▁practice ▁by ▁ 2 0 ▁to ▁ 3 0 %. ▁The ▁reason ▁is ▁partly ▁that ▁the ▁official ▁fuel ▁consumption ▁tests ▁are ▁not ▁sufficiently ▁representative ▁of ▁real ▁world ▁usage . ▁Auto ▁mak ers ▁optim ise