Editing Hubbert peak theory (section)

==Economics==
[[File:Oil imports.PNG|thumb|300px|Oil imports by country Pre-2006]]

===Energy return on energy investment===
The ratio of energy extracted to the energy expended in the process is often referred to as the Energy Return on Energy Investment (EROI or [[EROEI]]). Should the EROEI drops to one, or equivalently the [[Net energy gain]] falls to zero, the oil production is no longer a net energy source.

There is a difference between a barrel of oil, which is a measure of oil, and a [[barrel of oil equivalent]] (BOE), which is a measure of energy. Many sources of energy, such as fission, solar, wind, and coal, are not subject to the same near-term supply restrictions that oil is.{{citation needed|date = May 2017}} Accordingly, even an oil source with an EROEI of 0.5 can be usefully exploited if the energy required to produce that oil comes from a cheap and plentiful energy source. Availability of cheap, but hard to transport, natural gas in some oil fields has led to using [[natural gas]] to fuel [[enhanced oil recovery]]. Similarly, natural gas in huge amounts is used to power most [[Athabasca tar sands]] plants. Cheap natural gas has also led{{citation needed|date = May 2017}} to [[ethanol fuel]] produced with a net EROEI of less than 1, although figures in this area are controversial because methods to measure EROEI are in debate.

The assumption of inevitable declining volumes of oil and gas produced per unit of effort is contrary to recent experience in the US. In the United States, as of 2017, there has been an ongoing decade-long increase in the productivity of oil and gas drilling in all the major tight oil and gas plays. The US Energy Information Administration reports, for instance, that in the Bakken Shale production area of North Dakota, the volume of oil produced per day of drilling rig time in January 2017 was 4 times the oil volume per day of drilling five years previous, in January 2012, and nearly 10 times the oil volume per day of ten years previous, in January 2007. In the Marcellus gas region of the northeast, The volume of gas produced per day of drilling time in January 2017 was 3 times the gas volume per day of drilling five years previous, in January 2012, and 28 times the gas volume per day of drilling ten years previous, in January 2007.<ref>US Energy Information Administration,  [https://www.eia.gov/petroleum/drilling/ Drilling productivity report], 15 May 2017, (see “Report data” spreadsheet).</ref>

===Growth-based economic models===
[[File:World energy consumption 2005-2035 EIA.png|thumb|[[World energy consumption]] & predictions, 2005–2035. ''Source: International Energy Outlook 2011.'']]
Insofar as [[economic growth]] is driven by oil consumption growth, post-peak societies must adapt. Hubbert believed:<ref>{{cite web |url=http://www.hubbertpeak.com/hubbert/wwf1976/ |title=Exponential Growth as a Transient Phenomenon in Human History |publisher=Hubbertpeak.com |access-date=2013-11-03 |archive-date=2019-06-29 |archive-url=https://web.archive.org/web/20190629214750/http://www.hubbertpeak.com/hubbert/wwf1976/ |url-status=dead }}</ref>

{{blockquote|Our principal constraints are cultural. During the last two centuries, we have known nothing but exponential growth and in parallel, we have evolved what amounts to an exponential-growth culture, a culture so heavily dependent upon the continuance of exponential growth for its stability that it is incapable of reckoning with problems of non-growth. | M. King Hubbert | "Exponential Growth as a Transient Phenomenon in Human History"}}

Some economists describe the problem as [[uneconomic growth]] or a [[false economy]]. At the political right, [[Fred Ikle]] has warned about "conservatives addicted to the Utopia of Perpetual Growth".<ref>{{cite web |url=http://dieoff.org/page68.htm |title=Our Perpetual Growth Utopia |publisher=Dieoff.org |access-date=2013-11-03 |archive-url=https://web.archive.org/web/20190428120557/http://dieoff.org/page68.htm |archive-date=2019-04-28 |url-status=dead }}</ref> Brief oil interruptions in 1973 and 1979 markedly slowed—but did not stop—the growth of world [[GDP]].<ref>{{cite web|url=http://www.imf.org/external/np/speeches/2006/pdf/050206.pdf |title=The Growth of World Trade and GDP: 1951-2005|website=IMF
|year=2006|access-date=28 June 2023}}</ref>

Between 1950 and 1984, as the [[Green Revolution]] transformed [[agriculture]] around the globe, world grain production increased by 250%. The energy for the Green Revolution was provided by [[fossil fuels]] in the form of [[fertilizers]] (natural gas), [[pesticides]] (oil), and [[hydrocarbon]] fueled [[irrigation]].<ref>{{cite web |url=http://wolf.readinglitho.co.uk/mainpages/agriculture.html |title= Agriculture - how peak oil could lead to starvation|website=wolf.readinglitho.co.uk |archive-url=https://web.archive.org/web/20070818060558/http://wolf.readinglitho.co.uk/mainpages/agriculture.html |archive-date=August 18, 2007}}</ref>

David Pimentel, professor of ecology and [[agriculture]] at [[Cornell University]], and Mario Giampietro, senior researcher at the National Research Institute on Food and Nutrition (INRAN), in their 2003 study ''Food, Land, Population and the U.S. Economy'', placed the maximum [[U.S. population]] for a [[sustainability|sustainable economy]] at 200 million (actual population approx. 290m in 2003, 329m in 2019). To achieve a sustainable economy [[world population]] will have to be reduced by two-thirds, says the study.<ref>{{cite web |last=Cynic |first=Aaron |url=http://www.energybulletin.net/281.html |title=Eating Fossil Fuels |publisher=Energybulletin.net |date=2003-10-02 |access-date=2013-11-03 |url-status=dead |archive-url=https://web.archive.org/web/20070611071544/http://www.energybulletin.net/281.html |archive-date=2007-06-11 }}</ref> Without population reduction, this study predicts an agricultural crisis beginning in 2020, becoming critical c. 2050. The [[Peak oil|peaking of global oil]] along with the decline in regional [[natural gas]] production may precipitate this agricultural crisis sooner than generally expected. [[Dale Allen Pfeiffer]] claims that coming decades could see spiraling [[food prices]] without relief and massive [[starvation]] on a global level such as never experienced before.<ref>{{cite web |url=http://www.soilassociation.org/peakoil |title= Policy Reports &#124; Soil Association|website=www.soilassociation.org |archive-url=https://web.archive.org/web/20070928035437/http://www.soilassociation.org/peakoil |archive-date=September 28, 2007}}</ref><ref>{{cite web|url=http://europe.theoildrum.com/node/2225 |title=The Oil Drum: Europe &#124; Agriculture Meets Peak Oil: Soil Association Conference |publisher=Europe.theoildrum.com |access-date=2013-11-03}}</ref>