Why do Repubs. fight the Global Warming issue so strongly, even if we aren't responsible for global warming

(although very strong evidence says we are), wouldn't it be wise to err on the side of caution? Is it safe to run an uncontrolled experiment on the only home we have? Why not support green technologies...why not DEMAND it? We know that emissions have a negative effect on human health (smog-filled cities have much higher rates of respiratory problems such as asthma, even cancer)...why is that not reason alone to look to other things. Not to mention the political implications related to our reliance on foreign oil. Think it can't be done? Brazil primarily uses ethanol to run their vehicles and they enjoy .90/gal ethanol prices, cleaner cities and minimal reliance on foreign oil. Brazil has offered to import ethanol to the US, but we have placed a 100% tariff on ethanol...so trade options don't look good. Tariff on oil you ask? 0%. It took Brazil 30 years to get to where they are in green technologies...why can't we at least start on the process?