Editing Hubbert peak theory (section)

==Hubbert peaks==
{{See also|The Limits to Growth}}
Although Hubbert's peak theory receives the most attention concerning [[peak oil|peak oil production]], it has also been applied to other natural resources.

===Natural gas===
{{Main|Peak gas}}
Doug Reynolds predicted in 2005 that the North American peak would occur in 2007.<ref>{{cite news |first=Bill |last=White |url=http://dwb.adn.com/money/industries/oil/v-printer/story/7296501p-7208184c.html |title=State's consultant says nation is primed for using Alaska gas |date=December 17, 2005 |newspaper=Anchorage Daily News |url-status=dead |archive-url=https://web.archive.org/web/20090221153321/http://dwb.adn.com/money/industries/oil/v-printer/story/7296501p-7208184c.html |archive-date=February 21, 2009 }}</ref>  Bentley predicted a world "decline in conventional gas production from about 2020".<ref>{{cite journal |title=Viewpoint - Global oil & gas depletion: an overview |first=R.W. |last=Bentley |journal=Energy Policy |volume=30 |issue=3 |pages=189–205 |year=2002 |url=http://www.oilcrisis.com/bentley/depletionOverview.pdf |doi=10.1016/S0301-4215(01)00144-6 |access-date=2005-02-23 |archive-date=2008-05-27 |archive-url=https://web.archive.org/web/20080527233844/http://www.oilcrisis.com/bentley/depletionOverview.pdf |url-status=dead }}</ref>

===Coal===
{{Main|Peak coal}}
Although observers believe that peak coal is significantly further out than peak oil, Hubbert studied the specific example of [[Anthracite coal|anthracite]] in the US, a high-grade coal, whose production peaked in the 1920s. Hubbert found that anthracite matches a curve closely.<ref>{{cite web |url=http://www.geo.umn.edu/courses/3005/resource.html |title= Home|website=www.geo.umn.edu |archive-url=https://web.archive.org/web/20041031184216/http://www.geo.umn.edu/courses/3005/resource.html |archive-date=October 31, 2004}}</ref> Hubbert had recoverable [[Coal#World coal reserves|coal reserves worldwide]] at 2.500 &times; 10<sup>12</sup> metric tons and peaking around 2150 (depending on usage).

More recent estimates suggest an earlier peak. ''Coal: Resources and Future Production'' (PDF 630KB<ref>{{cite web |url=http://www.energywatchgroup.org/files/Coalreport.pdf |title=Startseite |publisher=Energy Watch Group |access-date=2013-11-03 |url-status=dead |archive-url=https://web.archive.org/web/20130911224731/http://www.energywatchgroup.org/files/Coalreport.pdf |archive-date=2013-09-11 }}</ref>), published on April 5, 2007 by the Energy Watch Group (EWG), which reports to the German Parliament, found that global coal production could peak in as few as 15 years.<ref name="energybulletin.net">{{cite web |last=Phillips |first=Ari |url=http://www.energybulletin.net/29919.html |title=Peak coal: sooner than you think |publisher=Energybulletin.net |date=2007-05-21 |access-date=2013-11-03 |url-status=dead |archive-url=https://web.archive.org/web/20080522155229/http://www.energybulletin.net/29919.html |archive-date=2008-05-22 }}</ref> Reporting on this, Richard Heinberg also notes that the date of peak annual energetic extraction from coal is likely to come earlier than the date of peak in quantity of coal (tons per year) extracted as the most energy-dense types of coal have been mined most extensively.<ref>{{cite web|url=http://www.richardheinberg.com/museletter/179 |title=Museletter |publisher=Richard Heinberg |date=2009-12-01 |access-date=2013-11-03}}</ref> A second study,
''The Future of Coal'' by B. Kavalov and S. D. Peteves of the Institute for Energy (IFE), prepared for the European Commission Joint Research Centre, reaches similar conclusions and states that "coal might not be so abundant, widely available and reliable as an energy source in the future".<ref name="energybulletin.net"/>

Work by [[David Rutledge (engineer)|David Rutledge]] of [[Caltech]] predicts that the total world coal production will amount to only about 450 [[gigatonne]]s.<ref name=NS>"Coal: Bleak outlook for the black stuff", by David Strahan, [[New Scientist]], [https://www.newscientist.com/channel/earth/mg19726391.800-coal-bleak-outlook-for-the-black-stuff.html January 19, 2008, pp. 38–41].</ref> This implies that coal is running out faster than usually assumed.

===Fissionable materials===
{{Main|Peak uranium}}
In a paper in 1956,<ref>{{cite web |url=http://www.hubbertpeak.com/hubbert/1956/1956.pdf |title=Nuclear Energy And The Fossil Fuels |author=M. King Hubbert |date=June 1956 |publisher=[[Shell Development Company]] |access-date=2013-12-27 |url-status=dead |archive-url=https://web.archive.org/web/20080527233843/http://www.hubbertpeak.com/hubbert/1956/1956.pdf |archive-date=2008-05-27 }}</ref> after a review of US fissionable reserves, Hubbert notes of nuclear power:

{{cquote|There is promise, however, provided mankind can solve its international problems and not destroy itself with nuclear weapons, and provided world population (which is now expanding at such a rate as to double in less than a century) can somehow be brought under control, that we may, at last, have found an energy supply adequate for our needs for at least the next few centuries of the "foreseeable future."}}

As of 2015, the identified resources of uranium are sufficient to provide more than 135 years of supply at the present rate of consumption.<ref name="Red Book">{{cite book |author=[[Nuclear Energy Agency|NEA]], [[IAEA]] |year=2016 |title=Uranium 2016 – Resources, Production and Demand |url=https://www.oecd-nea.org/ndd/pubs/2016/7301-uranium-2016.pdf |isbn=978-92-64-26844-9 |publisher=[[OECD|OECD Publishing]] |doi=10.1787/uranium-2016-en}}</ref> Technologies such as the [[thorium fuel cycle]], [[nuclear reprocessing|reprocessing]] and [[Fast breeder reactor|fast breeders]] can, in theory, extend the life of [[uranium]] reserves from hundreds to thousands of years.<ref name="Red Book"/>

Caltech physics professor [[David Goodstein]] stated in 2004<ref>{{cite web|last=Jones|first=Tony|title=Professor Goodstein discusses lowering oil reserves|url=http://www.abc.net.au/lateline/content/2004/s1249211.htm|publisher=Australian Broadcasting Corporation|access-date=14 April 2013|date=23 November 2004|archive-url=https://web.archive.org/web/20130509063107/http://www.abc.net.au/lateline/content/2004/s1249211.htm|archive-date=2013-05-09|url-status=dead}}</ref> that

{{cquote|...&nbsp;you would have to build 10,000 of the largest power plants that are feasible by engineering standards in order to replace the 10 terawatts of fossil fuel we're burning today ... that's a staggering amount and if you did that, the known reserves of uranium would last for 10 to 20 years at that burn rate. So, it's at best a bridging technology ... You can use the rest of the uranium to breed plutonium 239 then we'd have at least 100 times as much fuel to use. But that means you're making plutonium, which is an extremely dangerous thing to do in the dangerous world that we live in.}}

===Helium===
[[File:US Helium Production and Storage 1940-2014.png|thumb|Helium production and storage in the United States, 1940–2014 (data from USGS)]]
Almost all [[helium]] on Earth is a result of [[radioactive decay]] of [[uranium]] and [[thorium]]. Helium is extracted by [[fractional distillation]] from natural gas, which contains up to 7% helium. The world's largest helium-rich natural gas fields are found in the United States, especially in the [[Hugoton Natural Gas Area|Hugoton]] and nearby gas fields in Kansas, Oklahoma, and Texas. The extracted [[Helium storage and conservation|helium is stored]] underground in the [[National Helium Reserve]] near [[Amarillo, Texas|Amarillo]], [[Texas]], the self-proclaimed "Helium Capital of the World". Helium production is expected to decline along with natural gas production in these areas.

Helium, which is the second-lightest chemical element, will rise to the upper layers of Earth's [[atmosphere]], where it can forever break free from Earth's gravitational attraction.<ref>{{cite journal
|title=Helium in the Terrestrial Atmosphere
|author=Kockarts, G.
|volume=14| issue = 6
|bibcode=1973SSRv...14..723K
|year=1973
|pages=723ff
|journal=Space Science Reviews
|doi=10.1007/BF00224775
|s2cid=120152603
}}</ref> Approximately 1,600 tons of helium are lost per year as a result of [[atmospheric escape]] mechanisms.<ref name="techdaily">{{cite web|url=http://scitechdaily.com/earth-loses-50000-tonnes-of-mass-every-year/|title=Earth Loses 50,000 Tonnes of Mass Every Year|work=SciTech Daily|date=5 February 2012 }}</ref>

===Transition metals===
{{Main|Peak copper}}
Hubbert applied his theory to "rock containing an abnormally high concentration of a given metal"<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=2013-07-12 |archive-url=https://web.archive.org/web/20130712115025/http://www.hubbertpeak.com/hubbert/wwf1976/ |url-status=dead }}</ref> and reasoned that the peak production for metals such as [[copper]], [[tin]], [[lead]], [[zinc]] and others would occur in the time frame of decades and [[iron]] in the time frame of two centuries like coal. The price of copper rose 500% between 2003 and 2007<ref>{{cite web|url=http://minerals.usgs.gov/minerals/pubs/commodity/copper/mcs-2008-coppe.pdf |title=Copper |author=Daniel L. Edelstein |publisher=[[U.S. Geological Survey]], Mineral Commodity Summaries |date=January 2008 |access-date=2013-12-27}}</ref> and was attributed by some{{who|date=December 2013}} to [[peak copper]].<ref name=Leonard2006>{{cite web
 |url=http://www.salon.com/tech/htww/2006/03/02/peak_copper/index.html 
 |title=Peak copper? 
 |work=Salon 
 |author=Andrew Leonard 
 |date=2006-03-02 
 |access-date=2008-03-23 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20080307042349/http://www.salon.com/tech/htww/2006/03/02/peak_copper/index.html 
 |archive-date=2008-03-07 
}}</ref><ref>{{cite web|url=http://news.silverseek.com/CharlestonVoice/1135873932.php|title=Peak Copper Means Peak Silver|publisher=News.silverseek.com|access-date=2013-11-03|url-status=dead|archive-url=https://web.archive.org/web/20131104020042/http://news.silverseek.com/CharlestonVoice/1135873932.php|archive-date=2013-11-04}}</ref> Copper prices later fell, along with many other commodities and stock prices, as demand shrank from fear of a [[Late 2000s recession|global recession]].<ref>{{cite web|url=http://uk.reuters.com/article/oilRpt/idUKN2747917920090129 |archive-url=https://web.archive.org/web/20200920185939/https://uk.reuters.com/article/oilRpt/idUKN2747917920090129 |url-status=dead |archive-date=September 20, 2020 |title=Commodities – Demand fears hit oil, metals prices  |publisher=Uk.reuters.com |date=2009-01-29 |access-date=2013-11-03}}</ref> [[Lithium]] availability is a concern for a fleet of [[Li-ion battery]] using cars but a paper published in 1996 estimated that world reserves are adequate for at least 50 years.<ref>{{cite journal |last1=Will |first1=Fritz G. |title=Impact of lithium abundance and cost on electric vehicle battery applications |journal=Journal of Power Sources |date=November 1996 |volume=63 |issue=1 |pages=23–26 |doi=10.1016/S0378-7753(96)02437-8 |bibcode=1996JPS....63...23W |id={{INIST|2530187}} }}</ref> A similar prediction<ref>{{cite web|url=http://www.dft.gov.uk/stellent/groups/dft_roads/documents/page/dft_roads_024056-01.hcsp |title=Department for Transport  |publisher=Dft.gov.uk |access-date=2013-11-03}}</ref> for [[platinum]] use in fuel cells notes that the metal could be easily recycled.

===Precious metals===
{{Main|Peak gold}}
In 2009, Aaron Regent president of the Canadian gold giant Barrick Gold said that global output has been falling by roughly one million ounces a year since the start of the decade. The total global mine supply has dropped by 10 percent as ore quality erodes, implying that the roaring bull market of the last eight years may have further to run. "There is a strong case to be made that we are already at 'peak gold'," he told The Daily Telegraph at the RBC's annual gold conference in London. "Production peaked around 2000 and it has been in decline ever since, and we forecast that decline to continue. It is increasingly difficult to find ore," he said.<ref>{{cite web|url=https://www.telegraph.co.uk/finance/newsbysector/industry/mining/6546579/Barrick-shuts-hedge-book-as-world-gold-supply-runs-out.html |title=Barrick shuts hedge book as world gold supply runs out |date=11 November 2009 |publisher=Telegraph |access-date=2013-11-03}}</ref>

Ore grades have fallen from around 12&nbsp;grams per tonne in 1950 to nearer 3&nbsp;grams in the US, Canada, and Australia. South Africa's output has halved since peaking in 1970. Output fell a further 14 percent in South Africa in 2008 as companies were forced to dig ever deeper – at greater cost   – to replace depleted reserves.

World mined gold production has peaked four times since 1900: in 1912, 1940, 1971, and 2001, each peak being higher than previous peaks. The latest peak was in 2001 when production reached 2,600 metric tons, then declined for several years.<ref>Thomas Chaise, [http://news.goldseek.com/Dani/1273767071.php World gold production 2010], 13 May 2010.</ref> Production started to increase again in 2009, spurred by high gold prices, and achieved record new highs each year in 2012, 2013, and 2014, when production reached 2,990 tonnes.<ref>US Geological Survey, [http://minerals.usgs.gov/minerals/pubs/commodity/gold/mcs-2016-gold.pdf Gold], Mineral commodity summaries, Jan. 2016.</ref>

===Phosphorus===
{{Main|Peak phosphorus}}
[[Phosphorus]] supplies are essential to farming and depletion of reserves is estimated at somewhere from 60 to 130 years.<ref>{{cite web |url=http://www.apda.pt/apda_resources/APDA.Biblioteca/eureau%5Cposition%20papers%5Cthe%20reuse%20of%20phosphorus.pdf |title= APDA - Home|website=www.apda.pt |archive-url=https://web.archive.org/web/20061006120520/http://www.apda.pt/apda_resources/APDA.Biblioteca/eureau%5Cposition%20papers%5Cthe%20reuse%20of%20phosphorus.pdf |archive-date=October 6, 2006}}</ref> According to a 2008 study, the total reserves of phosphorus are estimated to be approximately 3,200 MT, with peak production at 28 MT/year in 2034.<ref>
{{cite web |author=White |first1=Stuart |last2=Cordell |first2=Dana |author-link2=Dana Cordell |year=2008 |title=Peak Phosphorus: the sequel to Peak Oil |url=http://phosphorusfutures.net/peak-phosphorus |access-date=2009-12-11 |publisher=Global Phosphorus Research Initiative (GPRI)}}</ref> Individual countries' supplies vary widely; without a recycling initiative America's supply<ref>{{cite web|url=http://minerals.usgs.gov/minerals/pubs/commodity/phosphate_rock/phospmcs06.pdf |title=Phosphate Rock|author=Stephen M. Jasinski |publisher=[[U.S. Geological Survey]], Mineral Commodity Summaries |date=January 2006 |access-date=2013-12-27}}</ref> is estimated around 30 years.<ref>{{cite web |url=http://www.ecosanres.org/PDF%20files/Fact_sheets/ESR4lowres.pdf |title=Closing the Loop on Phosphorus |author=Ecological Sanitation Research Programme |publisher=[[Stockholm Environment Institute]] |date=May 2008 |access-date=2013-12-27 |url-status=dead |archive-url=https://web.archive.org/web/20060805112847/http://ecosanres.org/PDF%20files/Fact_sheets/ESR4lowres.pdf |archive-date=2006-08-05 |author-link=Ecological Sanitation Research Programme }}</ref> Phosphorus supplies affect agricultural output which in turn limits alternative fuels such as biodiesel and ethanol. Its increasing price and scarcity (the global price of rock phosphate rose 8-fold in the 2 years to mid-2008) could change global agricultural patterns. Lands, perceived as marginal because of remoteness, but with very high phosphorus content, such as the [[Gran Chaco]]<ref>{{cite news
 |title=A postcard from the central Chaco 
 |author=Don Nicol 
 |access-date=2009-01-23 
 |url=http://www.breedleader.com.au/images/chaco%20postcard%20.pdf 
 |quote=alluvial sandy soils have phosphorus levels of up to 200–300 ppm 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20090226104329/http://www.breedleader.com.au/images/chaco%20postcard%20.pdf 
 |archive-date=2009-02-26 
}}</ref> may get more agricultural development, while other farming areas, where nutrients are a constraint, may drop below the line of profitability.

===Renewable resources===

===Wood===
Unlike fossil resources, forests keep growing, thus the Hubbert peak theory does not apply. There had been wood shortages in the past, called [[Holznot]] in German-speaking regions, but no global [[peak wood]] yet, despite the early 2021 "[[Lumber]] Crisis". Besides, [[deforestation]] may cause other problems, like erosion and drought by ending forests' [[Biotic pump]] effect.

===Water===
{{Main|Peak water}}
Hubbert's original analysis did not apply to renewable resources. However, [[over-exploitation]] often results in a Hubbert peak nonetheless. A modified Hubbert curve applies to any resource that can be harvested faster than it can be replaced.<ref>{{cite web
  |url=http://www.worldwater.org/data20082009/ch01.pdf
  |title=The World's Water 2008–2009, Ch 1.
  |publisher=[[Pacific Institute]]
  |author=Meena Palaniappan and Peter H. Gleick
  |year=2008
  |access-date=2009-01-31
  |url-status=dead
  |archive-url=https://web.archive.org/web/20090320104604/http://www.worldwater.org/data20082009/ch01.pdf
  |archive-date=2009-03-20
  }}</ref>

For example, a reserve such as the [[Ogallala Aquifer]] can be mined at a rate that far exceeds replenishment. This turns much of the world's underground water<ref>{{cite web |url=http://www.uswaternews.com/archives/arcsupply/6worllarg2.html |title= World?s largest acquifer going dry|website=www.uswaternews.com |archive-url=https://web.archive.org/web/20060913031104/http://www.uswaternews.com/archives/arcsupply/6worllarg2.html |archive-date=September 13, 2006}}</ref> and lakes<ref>{{cite web |url=http://www.earth-policy.org/Updates/2005/Update47_data.htm |title= April 7, 2005: Disappearing Lakes, Shrinking Seas - DATA|website=www.earth-policy.org |archive-url=https://web.archive.org/web/20060903213215/http://www.earth-policy.org/Updates/2005/Update47_data.htm |archive-date=September 3, 2006}}</ref> into finite resources with peak usage debates similar to oil. These debates usually center around agriculture and suburban water usage but generation of electricity<ref>http://www.epa.gov/cleanrgy/water_resource.htm {{dead link|date=November 2013}}</ref> from nuclear energy or coal and tar sands mining mentioned above is also water resource intensive. The term [[fossil water]] is sometimes used to describe aquifers whose water is not being recharged.

===Fishing===
{{Main|
Fishing down the food web}}
At least one researcher has attempted to perform Hubbert linearization ([[Hubbert curve]]) on the [[whaling]] industry, as well as charting the transparently dependent price of caviar on sturgeon depletion.<ref>{{cite web|url=http://www.aspoitalia.net/index.php?option=com_content&task=view&id=34&Itemid=39 |title=How General is the Hubbert Curve? |publisher=Aspoitalia.net |access-date=2013-11-03}}</ref>  The [[Collapse of the Atlantic northwest cod fishery|Atlantic northwest cod fishery]] was a [[renewable resource]], but the numbers of fish taken exceeded the fish's rate of recovery. The end of the cod fishery does match the [[Exponential decay|exponential]] drop of the Hubbert bell curve. Another example is the [[cod]] of the North Sea.<ref>{{cite web |url=http://www.hubbertpeak.com/laherrere/multihub.htm |title=Laherrere: Multi-Hubbert Modeling |publisher=Hubbertpeak.com |access-date=2013-11-03 |archive-date=2013-10-28 |archive-url=https://web.archive.org/web/20131028052636/http://www.hubbertpeak.com/laherrere/multihub.htm |url-status=dead }}</ref>

===Air/oxygen===
Half the world's [[oxygen]] is produced by [[phytoplankton]]. The plankton was once thought to have dropped by 40% since the 1950s.<ref>{{cite web|url=http://www.nbcnews.com/id/38451744/ns/us_news-environment#.UgzfIdKOSrN |archive-url=https://web.archive.org/web/20130925132822/http://www.nbcnews.com/id/38451744/ns/us_news-environment#.UgzfIdKOSrN |url-status=dead |archive-date=September 25, 2013 |title=Plankton, base of ocean food web, in big decline  |publisher=NBC News |date=2010-07-28 |access-date=2013-11-03}}</ref> However, the authors reanalyzed their data with better calibrations and found plankton abundance dropped globally by only a few percent over this time interval ([http://wormlab.biology.dal.ca/publication/view/boyce-etal-2014-estimating-global-chlorophyll-changes-over-the-past-century/ Boyce et al. 2014])