Petroleum (or oil) and natural gas are widely used sources of fuel. Around the world many transportation, energy, and heating infrastructures depend in large part on one or both of these hydrocarbon-rich fuels, petrochemical products. While in the past it may have seemed inconceivable that people would have to step away from fossil fuels, climate change increasingly necessitates greener alternatives. It is also hard to imagine life without plastics. For many applications, such as in healthcare, there may be no better materials. A future with zero plastic is neither warranted nor desirable, but the threats to various ecosystems are likely to force the development of greener and more sustainable materials.