School Email Exchange

Do you think plastic in the ocean is affecting global warming?

Posted on November 08 2012

Question submitted by George Washington Elementary School

This is an interesting question.  Some plastics floating at the sea surface are white or light-colored, which means they reflect sunlight, in turn reducing the warming of the surface ocean by a small amount.  Because of the size of most of the particles we find, it is hard to imagine that this is having a large effect on the overall heat balance.

Another way plastics could affect climate is through generation of carbon dioxide, a greenhouse gas, as a by-product of metabolism.  Plastics are traditionally made from petroleum, although some plastics are now made from bio-renewable feedstocks such as corn or sugar cane.  Regardless of the source, all plastics contain carbon.  If microorganisms are able to break down plastics for energy, carbon dioxide would be released to the ocean in the process.  One of the major research goals of this expedition is to understand which microorganisms are living on plastic, and whether or not they are interacting with the plastic either to physically break it into smaller pieces, or to biodegrade it and use the material for energy.  While it is hard to believe that the amount of carbon dioxide produced by the breakdown of plastics would significantly alter our climate, we cannot yet do the calculation to find out.