He made several important contributions to geology, geophysics, and petroleum geology, most notably the Hubbert curve and Hubbert peak theory (a basic component of peak oil), with important political ramifications.

He worked as an assistant geologist for the Amerada Petroleum Company for two years while pursuing the PhD, additionally teaching geophysics at Columbia University.

[5] Hubbert was a member of the board of governors, and served as secretary of education in that organization.

[6] Hubert died on October 11, 1989, at the age of 86 while receiving treatment for pulmonary embolism.

[1] Hubbert made several contributions to geophysics, including a mathematical demonstration that rock in the Earth's crust, because it is under immense pressure in large areas, should exhibit plasticity, similar to clay.

, that bears his name: Some years later Hubbert (1956)[8] showed that Darcy's law can be derived from the Navier–Stokes equation of motion of a viscous fluid.

He predicted that for any oil-producing area, whether a province, a nation, or the planet as a whole, the rate of petroleum production of the reserve over time would resemble a bell curve.

Based on his theory, he presented a paper to the 1956 meeting of the American Petroleum Institute in San Antonio, Texas, which predicted that overall petroleum production would peak in the United States between 1965, which he considered most likely, and 1970, which he considered an upper bound.

In 1974, Hubbert projected that global oil production would peak in 1995 "if current trends continue".

[9] He also states that "provided world population can somehow be brought under control, we may at last have found an energy supply (uranium) adequate for our needs for at least the next few centuries of the 'foreseeable future'.