Editing Non-renewable resource (section)

== Fossil fuels ==
{{Main|Fossil fuel}}
{{Further|Oil depletion}}

Natural resources such as [[coal]], [[petroleum]] (crude oil) and [[natural gas]] take thousands of years to form naturally and cannot be replaced as fast as they are being consumed. It is projected that fossil-based resources will eventually become too costly to harvest and humanity will need to shift its reliance to [[renewable energy]] such as solar or wind power.

An alternative hypothesis is that carbon-based fuel is virtually inexhaustible in human terms, if one includes all sources of carbon-based energy such as methane hydrates on the sea floor, which are much greater than all other carbon-based fossil fuel resources combined.<ref>{{cite web | url=http://worldoceanreview.com/en/wor-1/energy/methane-hydrates/ |title=Methane hydrates |website=Worldoceanreview.com |access-date=17 January 2017}}</ref> These sources of carbon are also considered non-renewable, although their rate of formation/replenishment on the sea floor is not known. However, their extraction at economically viable costs and rates has yet to be determined.

At present, the main energy source used by humans is non-renewable [[fossil fuels]]. Since the dawn of [[internal combustion engine]] technologies in the 19th century, petroleum and other fossil fuels have remained in continual demand. As a result, conventional [[infrastructure]] and [[transport]] systems, which are fitted to combustion engines, remain predominant around the globe.

The modern-day fossil fuel economy is widely criticized for its lack of renewability, as well as being a contributor to [[climate change]].<ref>{{cite book|author=America's Climate Choices: Panel on Advancing the Science of Climate Change|author2=National Research Council|title=Advancing the Science of Climate Change |year=2010|publisher=The National Academies Press|location=Washington, D.C.|isbn=978-0-309-14588-6|url=http://www.nap.edu/catalog.php?record_id=12782|doi=10.17226/12782 }}</ref>