Whence Plastics? Why Worry About My Plastic Water Bottle?

"Plastics are made from natural materials such as cellulose, coal, natural gas, salt and crude oil through a polymerisation or polycondensation process. ... In a polymerisation reactor, monomers such as ethylene and propylene are linked together to form long polymer chains." (From www.plasticseurope.org).  The whole thing starts with crude oil that has been refined to provide the foundation for plastics manufacturing.
So how does crude oil refining--which is essential part of the manufacturing of plastics, effect our planet.
Let's start this discussion with some basic science: surrounding the earth are five layers of atmosphere. The "troposphere" is where humans operate, where we live and breathe.  Above the troposphere there are two layers, the stratosphere and the mesophere--the space where commercial jets fly.  Finally, there's the thermosphere and the exosphere.  Carbon dioxide emissions are thickening all layers (except the exosphere).  Quite simply, the earth has become a "heat trap".  The carbon dioxide buildup has allowed the radiation that would normally exit our "troposphere" be captured--no longer escaping into the exosphere.
According to the National Resources Defense Council (nrdc.org) "In the United States, the burning of fossil fuels to make electricity is the largest source of heat-trapping pollution, producing about two billion tons of CO2 every year. Coal-burning power plants are by far the biggest polluters. The country’s second-largest source of carbon pollution is the transportation sector, which generates about 1.7 billion tons of CO2 emissions a year."
And, according the the Federal EPA: "approximately one ounce of carbon dioxide is emitted for each ounce of polyethylene (PET) produced. PET is the type of plastic most commonly used for beverage bottles. Other sources pin the production ratio of carbon emissions to plastic production closer to 5:1."
So, where you start is simple: start by stopping the use of plastic bags and plastic bottles.
We have to start somewhere.