I heard the other day that our oil exports now exceed our oil imports. My question: why aren't we just using the oil we have, instead of shipping it across the ocean? Economics aside for a minute... this is having a huge impact to global warming, yet I'm the one being blamed?
No you didn't hear the word "oil". You heard that the US is a net exporter of Gasoline, Diesel, and other fuels. These are refined products, not crude oil. Since 2008, the cunsumption rates (demand) for gasoline, diesel, and other fuels has fallen, as part of enonomic contraction. Thus, large refineries, especially on the Gulf coast near Houston, TX (Galveston, Texas City) have spare refining capacity. So, they buy crude, and refine it to produce gasoline and other products. Just as crude oil is traded globally, so is gasoline. The purchasers are nations with no refineries, like the Bahamas, or areas will less refining capacity than needed, like Equador or Argentina.
US consuption of oil has fallen from about 21 Mbbl/day to 18 Mbbl/day (rough). US production of oil is about 5 Mbbl/day. The US is nowhere near being an oil exporter. But, the US is importing some oil, refining it, and then exporting the refined products, like this:
1. Import oil
2. Refine into gasoline, diesel, jet fuel, etc
3. Export for profit!
So, this is a good business for the oil refiners, and puts money into the US economy. It does not mean that the US is oil independent, not even close.
Also, the cost of shipping oil across the ocean is insignificant compared to the value of the product to the end user. Ocean transportation is a tiny component of carbon emissions. I'd guess less than 1% off the top of my head.