Some pen pusher,sorry,button pusher sits in an office with a computer,works out the how to reduce pollution.Looks great on a screen but the problem arises when you put it on the ground.No allowance made for various factors,in cities,traffic lights 20mph speed limits,numskulls filling yellow boxes etc.etc.etc..In the country,large slow moving agriculture vehicles,some which are bigger than Tam's a 40' on a road where two cars have bother meeting,never mind trying to overtake.
There was ethanol introduced to petrol,10% here,to reduce pollution,but I don't think the extra fuel that needs to be burned to cover the same distance to make up the reduced power of ethanol loaded petrol was taken into account.
Lately I have been reading that they,the scientists,are now blaming the cows in the fields for being a large contributor to global warming.What are they going to do,put bloody catalytic converters on the animals arses? I wonder what kept the CO2 at bay when the millions of animals that roamed the world before man set about slaughtering them in the 19th and 20th centuries? Yes I have seen farmers cause damage with their slurry,but as in all walks of life and industry you will find a gobshite.
I am not a "Global Warming" disbeliever but I do believe that the "Green" taxes are a means to line the government's coffers.If they were really worried about global warming ,they would be taking steps against big business in chemical,plastics etc. production.One of those factories probably expels more pollution into the atmosphere in a day than all of our 2stroke outboards put together will do in our lifetime,even if we used them all day everyday.Rant over

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I'm sure someone will be able to contradict my theory,I'm no scientist,but to draw a comparison,if you reduce the quantity of a core element in a concrete product,cement,you need to increase the quantity of the product to meet the same weight bearing specification.