- Email: [email protected]
Is peakoilism coming?
ARTICLE IN PRESS Energy Policy 37 (2009) 2136–2138
Contents lists available at ScienceDirect
Energy Policy journal homepage: www.elsevier.com/locate/enpol
Is peakoilism coming? Lin Zhao a,b,, Lianyong Feng a,b, Charles A.S. Hall c,d a
China University of Petroleum, Beijing, China The Association for the Study of Peak Oil and Gas, China State University of New York, College of Environmental Science and Forestry, USA d The Association for the Study of Peak Oil and Gas, USA b c
a r t i c l e in f o
a b s t r a c t
Article history: Received 13 April 2008 Accepted 19 February 2009 Available online 27 March 2009
Peak oil research and the Association for the Study of Peak Oil and Gas (ASPO) have contributed a great deal to improve people’s recognition of peak oil. Although peak oil is becoming a part of public recognition, it is still hard to say whether peak oil discussion will develop into a theory such as ‘‘peakoilism’’. On one hand, there are still some difficult problems in peak oil research. On the other hand, the peakoilers have the potential for scientific research and have their allies: the climate change researchers and the new energy advocates. Oil is a limited, non-renewable resource, and an oil peak is inevitable. Peak oil theory is a kind of development theory rather than a crisis theory, which promotes reasonable utilization of the limited oil resources, promotes conservation, and encourages the development of renewable energy. & 2009 Elsevier Ltd. All rights reserved.
Keywords: Peak oil Oil production Resource depletion
The world famous writer Victor Hugo wrote on his last night that ‘‘the forthcoming thought is stronger than all the armies of the world’’. Peak oil is a new concept and thought, at least to the majority of people who have heard about it (See Kjell, 2006). The essence of the peak oil issue is to expose the largest number of people possible to the objective phenomenon that the world’s petroleum resources are becoming depleted, to marshal the empirical data that support the concept and probable imminence of a global oil peak, to explore the advent of an oil peak in many countries where it has already occurred and to attempt to understand and quantify the impact of an oil peak on society, the economy, and the lives of ordinary people, etc. People have discussed the limits of mineral resources and of the possibilities for sustainable development of economies for years. The concept of peak oil was first proposed by the geologist M. King Hubbert in a talk to the American Petroleum Institute in 1956. He developed even in 1949 and in subsequent papers the idea that the production and use of any non-renewable resource such as oil would grow slowly at first, then exponentially as more uses were found for it, and then reach a peak in production when roughly half of the total extractable reserves had been used. This would be followed by a gradual decline until it was not produced at a rate that was especially economically useful (See Hubbert, 1949, 1962, 1967). Hubbert predicted in 1956 that oil production of the lower 48 United States would peak either in 1965 or 1970 depending
Corresponding author at: China University of Petroleum, Beijing, China.
E-mail addresses: [email protected] (L. Zhao), [email protected] (L. Feng), [email protected] (C.A.S. Hall). 0301-4215/$ - see front matter & 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.enpol.2009.02.017
upon an ultimate reserve of 150 or 200 Gb (billion barrels). He was met with derision, but nevertheless the peak did in fact occur in 1970, and despite the addition of Alaska and a tremendous increase in technology, the US now produces only 50% of the oil that it did in 1970. The concept was more or less ignored by the majority of academia and business until 1998, when geologists Dr. Colin J. Campbell and Jean Laherrere published their paper ‘‘The end of cheap oil’’ in Scientific American, followed by a speech on oil depletion at Clausthal University of Technology in Germany. Then Colin Campbell hit upon an idea to build an organization or network structure with other scientists interested in oil depletion. This brought the beginning of the Association for the Study of Peak Oil and Gas (ASPO). In May, 2002, Professor Kjell Aleklett from Uppsala University of Sweden organized the first international conference on oil depletion in Uppsala, in which experts gave a definition to peak oil and set the substantial framework for ASPO organization. Thanks to the devotion and activities of ASPO, the peak oil concept became well known in the world after only a few years. The missions of ASPO are as follows: (a) define and evaluate the world’s endowment of oil and gas. (b) model depletion, taking due account of demand, economics, technology and politics. (c) raise awareness of the serious consequences of peak oil for mankind. One of the important ways in which ASPO completes its missions as an international organization is by holding international conferences. ASPO has held seven international workshops. Each of them has received great attention from experts, governmental officers and medias. ASPO tries to answer such questions as: when will (or has) peak oil occur(ed)? Will oil production fall at once or stay at a ‘‘bumpy plateau’’ for a certain time after the peak? What
ARTICLE IN PRESS L. Zhao et al. / Energy Policy 37 (2009) 2136–2138
are the changing economic and energy costs of obtaining oil and its possible replacements? What kind of political consequences will follow oil peak? Will the global oil peak bring wars? What will the consequences be if governments do not carry out proper countermeasures to release the tension caused by oil peak? What position will governments choose to take in making energy policies? When, it at all, will renewable energy be available to use at a large scale and to what extent can renewable energy substitute for petroleum? ASPO is trying to arouse people’s interest, even to raise an alarm, regarding the consequences of oil depletion by bringing forward such questions and searching for possible answers. From the first annual workshop to the seventh, the ASPO has attracted more and more attention and attendees. Its coverage has extended to many countries, and the level of attendees is increasing. Currently, more than 26 countries have their own additional ASPO national groups, including Austria, Australia, China, France, Germany, Holland, Ireland, Italy, Norway, Portugal, Spain, Switzerland, Sweden, USA, etc. Peak oil research and the ASPO have contributed a great deal to improving people’s recognition of peak oil, by promoting reasonable utilization of the limited oil resources, promoting conservation and encouraging the development of renewable energy. Many governments in the world are taking some measures to address the peak oil issue. For example, the research of the ASPO has persuaded the Swedish government to recognize peak oil and to be willing to take some countermeasures, starting with the appointment of a committee to develop proposals for Sweden on decreasing its oil dependency. As for America, the Congress invited Kjell Aleklett, Chairman of the ASPO to give a speech titled ‘‘A World Addicted to Oil’’ in October 2005. Furthermore, President Bush announced that America is addicted to oil, which is often imported from unstable parts of the world, in his 2006 State of the Union address on January 31, 2006. The US Government Accountability Office (GAO) wrote a report titled ‘‘Uncertainty about Future Oil Supply Makes it Important to Develop a Strategy for Addressing a Peak and Decline in Oil Production’’ and submitted it to the US Congress in February 2007. In July 2007, the US Department of Energy brought forward a draft report on the peak oil issue. (Nevertheless, the overwhelming majority of Americans have no concept of ‘‘peak oil’’.) Australia is also very keen on peak oil issues. The ASPO Australia branch was set up in November 2005 and has presented more than 200 valuable proposals to the Australian Institute of Energy National Conference. The Upper House of Australia held a conference on the future oil supply in Australia in February 2007 and added the peak oil issue to the agenda. Peak oil is becoming an important part of public recognition, but it is still hard to say whether peak oil discussion will develop into a theory such as ‘‘peakoilism’’. In our opinion, the so-called peakoilism contains two layers of meanings. First of all, it should cover a series of systematic and specific theories and thoughts. Secondly, the theories should be accepted and spread widely throughout the public. There are still five difficult problems in peak oil research. The first is insufficient systematic methodology. Although different kinds of models and ideas are emerging in a number of countries, as Feng et al. (2006) mentioned, there is no systematic structure or research method yet. Second, there is difficulty in determining the nature, limits and extent of the disciplines. Peak oil researchers are from many specialties and backgrounds, including petroleum exploration and exploitation, oil refining, oil markets, new energy, finance, economics, ecology, and occasionally just interested citizens. Third, there is the problem of the definition of oil. Colin Campbell’s forecast has changed from 66 Mb/d (million barrels per day) for regular oil to 85 Mb/d for all liquids in 2007. The oil demand includes all liquids. Although the production from conventional oil (easy oil) is
2137
declining, the production from non-conventional oil (like oilsands) and other resources (like biofuels) is increasing, and the forecast of oil supply should address when the latter will fail to fill the oil demand. Fourth, there is the problem of getting reliable data on oil production and reserves. As Campbell and Laherre`re, (1998) pointed out, OPEC members cheat on quotas based on reserves. Fifth, peak oil has not been accepted by the mainstream public. Therefore, the so-called peakoilism has a very large charge in front of it. The peakoilers, who are strongly focused on empirical and objective research on peak oil, have good potentials for scientific research. There are three main reasons for this. The first is that the ASPO has an unbiased orientation and thus freedom. The ASPO is not affiliated with any political party and does not advocate for any environmental association or industrial organization. Its objective is to do research and give scientific judgments, to release to governments and the public the analyses and opinions of experts, and to provide, to the degree possible, correct estimations and predictions to explore the influence of oil depletion on the society, economy and policy and to recommend appropriate countermeasures. The second is the cross-discipline platform for peak oil debate. It can be said that most researchers feel that different approaches and disciplines add strength to the overall analysis of peak oil. For example, the concept of energy return on investment (EROI), originally developed in ecology, may have enormous applications for the peak oil issue because the most important issue is not how much oil is left in the ground, but how much can be developed at a substantial energy profit. The latter is a much smaller amount than the former. The third is interest. There is an old proverb in China, which says that interest is the best teacher. Peakoilers can typically be divided into two groups. One group is made up of mostly retired experts or scholars. The other contains people undertaking a profession to make a living and doing research on peak oil according to their professional interests. Thus, what stimulates many of the peakoilers is their interest, independent of salary or other benefits. From another perspective, the lack of no-stringsattached governmental or other funding of the researchers involved is an international scandal. The peakoilers have their allies: the climate change researchers and the new energy advocates. The subject of peak oil brings pressure to governments and oil companies. However, it is a popular topic for climate change researchers and new energy advocators. An ideal solution to the peak oil problem, if possible, must be undertaken with these other important issues (the climate change and the new energy development) in mind. As Zhao and Feng (2007) pointed out, the objectives for those involved in resource depletion, climate change and new energy development are similar. That is, they seek to promote the development of renewable energy, which includes the evolution of techniques and reduction in their costs. In addition, as a kind of scientific research, peak oil study has similarities with climate change. The climate change propagators met with cold criticism from their opponents and encountered severe debate when they began the research in early days. Currently, many people are aware of climate change, and many governments around the world are taking measures to ameliorate it. What people care about is how to deal with the phenomenon and how to decrease the emission of greenhouse gases even though the academic debate is ongoing. Contrastingly, peak oil is undergoing ardent debate. Will it become another climate change issue and form a global movement or bring forward a new field of peakoilism? The arrival of peak oil will probably force many people who wish to ignore the issue to confront it and hopefully other issues as well. In human history, there have been many ‘‘-isms’’ and perhaps ‘‘peakoilism’’ will be embraced as yet another, even followed by
ARTICLE IN PRESS 2138
L. Zhao et al. / Energy Policy 37 (2009) 2136–2138
peakgasism, peakcoalism, peak everything, eventually perhaps forming peakism. In our current society, most business plans are based on consumption of oil, and usual economic forecasts are based on a constant growth of the GDP. Thus, maybe projecting the decline of oil is politically unpopular, and we can understand why peak oil is rejected by many politicians or managers of oil companies. However, oil is a limited, non-renewable resource, and oil peak is inevitable. Furthermore, peak oil theory is a kind of development theory rather than a crisis theory. Perhaps what we need to do is to accept the eventual depletion of oil sooner or later and to develop renewable energy while limiting populations and their excessive material aspirations to realize sustainable development of society. If we do not adopt that path through our own planning, it will inevitably be imposed upon us, probably in a much less desirable way. The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China (NSFC) under
Grant 70841024. We also would like to thank Editor Nicky France and the anonymous referees for their helpful suggestions and corrections on the earlier draft of our manuscript according to which we improved the content. References Campbell, Colin J., Laherre`re, Jean H., 1998. The end of cheap oil. Scientific American 278 (3), 78–83. Feng, Lianyong, Zhao, Lin, Zhao, Qingfei, Wang, Zhiming, 2006. Peak oil theory and forecast on world peak oil. Acta Petrolei Sinica 27 (5), 139–142 (in Chinese). Hubbert, M. King, 1949. Energy from fossil fuels. Science 109 (2823), 103–109. Hubbert, M. King, 1962. Energy resources. Publication 1000-D, Natl. Academy of Science/Natl. Research Council. Hubbert, M. King, 1967. Degree of advancement of petroleum exploration in the United States. AAPG Bulletin 52 (11), 2207–2227. Kjell, Aleklett, 2006. The global energy supply situation today and tomorrow. The Energy and Environment Conference. Shijiazhuang, China. Zhao, Lin, Feng, Lianyong, 2007. Research status of peak oil and evocable consideration. International Petroleum Economics 15 (11), 29–35 (in Chinese).
Contents lists available at ScienceDirect
Energy Policy journal homepage: www.elsevier.com/locate/enpol
Is peakoilism coming? Lin Zhao a,b,, Lianyong Feng a,b, Charles A.S. Hall c,d a
China University of Petroleum, Beijing, China The Association for the Study of Peak Oil and Gas, China State University of New York, College of Environmental Science and Forestry, USA d The Association for the Study of Peak Oil and Gas, USA b c
a r t i c l e in f o
a b s t r a c t
Article history: Received 13 April 2008 Accepted 19 February 2009 Available online 27 March 2009
Peak oil research and the Association for the Study of Peak Oil and Gas (ASPO) have contributed a great deal to improve people’s recognition of peak oil. Although peak oil is becoming a part of public recognition, it is still hard to say whether peak oil discussion will develop into a theory such as ‘‘peakoilism’’. On one hand, there are still some difficult problems in peak oil research. On the other hand, the peakoilers have the potential for scientific research and have their allies: the climate change researchers and the new energy advocates. Oil is a limited, non-renewable resource, and an oil peak is inevitable. Peak oil theory is a kind of development theory rather than a crisis theory, which promotes reasonable utilization of the limited oil resources, promotes conservation, and encourages the development of renewable energy. & 2009 Elsevier Ltd. All rights reserved.
Keywords: Peak oil Oil production Resource depletion
The world famous writer Victor Hugo wrote on his last night that ‘‘the forthcoming thought is stronger than all the armies of the world’’. Peak oil is a new concept and thought, at least to the majority of people who have heard about it (See Kjell, 2006). The essence of the peak oil issue is to expose the largest number of people possible to the objective phenomenon that the world’s petroleum resources are becoming depleted, to marshal the empirical data that support the concept and probable imminence of a global oil peak, to explore the advent of an oil peak in many countries where it has already occurred and to attempt to understand and quantify the impact of an oil peak on society, the economy, and the lives of ordinary people, etc. People have discussed the limits of mineral resources and of the possibilities for sustainable development of economies for years. The concept of peak oil was first proposed by the geologist M. King Hubbert in a talk to the American Petroleum Institute in 1956. He developed even in 1949 and in subsequent papers the idea that the production and use of any non-renewable resource such as oil would grow slowly at first, then exponentially as more uses were found for it, and then reach a peak in production when roughly half of the total extractable reserves had been used. This would be followed by a gradual decline until it was not produced at a rate that was especially economically useful (See Hubbert, 1949, 1962, 1967). Hubbert predicted in 1956 that oil production of the lower 48 United States would peak either in 1965 or 1970 depending
Corresponding author at: China University of Petroleum, Beijing, China.
E-mail addresses: [email protected] (L. Zhao), [email protected] (L. Feng), [email protected] (C.A.S. Hall). 0301-4215/$ - see front matter & 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.enpol.2009.02.017
upon an ultimate reserve of 150 or 200 Gb (billion barrels). He was met with derision, but nevertheless the peak did in fact occur in 1970, and despite the addition of Alaska and a tremendous increase in technology, the US now produces only 50% of the oil that it did in 1970. The concept was more or less ignored by the majority of academia and business until 1998, when geologists Dr. Colin J. Campbell and Jean Laherrere published their paper ‘‘The end of cheap oil’’ in Scientific American, followed by a speech on oil depletion at Clausthal University of Technology in Germany. Then Colin Campbell hit upon an idea to build an organization or network structure with other scientists interested in oil depletion. This brought the beginning of the Association for the Study of Peak Oil and Gas (ASPO). In May, 2002, Professor Kjell Aleklett from Uppsala University of Sweden organized the first international conference on oil depletion in Uppsala, in which experts gave a definition to peak oil and set the substantial framework for ASPO organization. Thanks to the devotion and activities of ASPO, the peak oil concept became well known in the world after only a few years. The missions of ASPO are as follows: (a) define and evaluate the world’s endowment of oil and gas. (b) model depletion, taking due account of demand, economics, technology and politics. (c) raise awareness of the serious consequences of peak oil for mankind. One of the important ways in which ASPO completes its missions as an international organization is by holding international conferences. ASPO has held seven international workshops. Each of them has received great attention from experts, governmental officers and medias. ASPO tries to answer such questions as: when will (or has) peak oil occur(ed)? Will oil production fall at once or stay at a ‘‘bumpy plateau’’ for a certain time after the peak? What
ARTICLE IN PRESS L. Zhao et al. / Energy Policy 37 (2009) 2136–2138
are the changing economic and energy costs of obtaining oil and its possible replacements? What kind of political consequences will follow oil peak? Will the global oil peak bring wars? What will the consequences be if governments do not carry out proper countermeasures to release the tension caused by oil peak? What position will governments choose to take in making energy policies? When, it at all, will renewable energy be available to use at a large scale and to what extent can renewable energy substitute for petroleum? ASPO is trying to arouse people’s interest, even to raise an alarm, regarding the consequences of oil depletion by bringing forward such questions and searching for possible answers. From the first annual workshop to the seventh, the ASPO has attracted more and more attention and attendees. Its coverage has extended to many countries, and the level of attendees is increasing. Currently, more than 26 countries have their own additional ASPO national groups, including Austria, Australia, China, France, Germany, Holland, Ireland, Italy, Norway, Portugal, Spain, Switzerland, Sweden, USA, etc. Peak oil research and the ASPO have contributed a great deal to improving people’s recognition of peak oil, by promoting reasonable utilization of the limited oil resources, promoting conservation and encouraging the development of renewable energy. Many governments in the world are taking some measures to address the peak oil issue. For example, the research of the ASPO has persuaded the Swedish government to recognize peak oil and to be willing to take some countermeasures, starting with the appointment of a committee to develop proposals for Sweden on decreasing its oil dependency. As for America, the Congress invited Kjell Aleklett, Chairman of the ASPO to give a speech titled ‘‘A World Addicted to Oil’’ in October 2005. Furthermore, President Bush announced that America is addicted to oil, which is often imported from unstable parts of the world, in his 2006 State of the Union address on January 31, 2006. The US Government Accountability Office (GAO) wrote a report titled ‘‘Uncertainty about Future Oil Supply Makes it Important to Develop a Strategy for Addressing a Peak and Decline in Oil Production’’ and submitted it to the US Congress in February 2007. In July 2007, the US Department of Energy brought forward a draft report on the peak oil issue. (Nevertheless, the overwhelming majority of Americans have no concept of ‘‘peak oil’’.) Australia is also very keen on peak oil issues. The ASPO Australia branch was set up in November 2005 and has presented more than 200 valuable proposals to the Australian Institute of Energy National Conference. The Upper House of Australia held a conference on the future oil supply in Australia in February 2007 and added the peak oil issue to the agenda. Peak oil is becoming an important part of public recognition, but it is still hard to say whether peak oil discussion will develop into a theory such as ‘‘peakoilism’’. In our opinion, the so-called peakoilism contains two layers of meanings. First of all, it should cover a series of systematic and specific theories and thoughts. Secondly, the theories should be accepted and spread widely throughout the public. There are still five difficult problems in peak oil research. The first is insufficient systematic methodology. Although different kinds of models and ideas are emerging in a number of countries, as Feng et al. (2006) mentioned, there is no systematic structure or research method yet. Second, there is difficulty in determining the nature, limits and extent of the disciplines. Peak oil researchers are from many specialties and backgrounds, including petroleum exploration and exploitation, oil refining, oil markets, new energy, finance, economics, ecology, and occasionally just interested citizens. Third, there is the problem of the definition of oil. Colin Campbell’s forecast has changed from 66 Mb/d (million barrels per day) for regular oil to 85 Mb/d for all liquids in 2007. The oil demand includes all liquids. Although the production from conventional oil (easy oil) is
2137
declining, the production from non-conventional oil (like oilsands) and other resources (like biofuels) is increasing, and the forecast of oil supply should address when the latter will fail to fill the oil demand. Fourth, there is the problem of getting reliable data on oil production and reserves. As Campbell and Laherre`re, (1998) pointed out, OPEC members cheat on quotas based on reserves. Fifth, peak oil has not been accepted by the mainstream public. Therefore, the so-called peakoilism has a very large charge in front of it. The peakoilers, who are strongly focused on empirical and objective research on peak oil, have good potentials for scientific research. There are three main reasons for this. The first is that the ASPO has an unbiased orientation and thus freedom. The ASPO is not affiliated with any political party and does not advocate for any environmental association or industrial organization. Its objective is to do research and give scientific judgments, to release to governments and the public the analyses and opinions of experts, and to provide, to the degree possible, correct estimations and predictions to explore the influence of oil depletion on the society, economy and policy and to recommend appropriate countermeasures. The second is the cross-discipline platform for peak oil debate. It can be said that most researchers feel that different approaches and disciplines add strength to the overall analysis of peak oil. For example, the concept of energy return on investment (EROI), originally developed in ecology, may have enormous applications for the peak oil issue because the most important issue is not how much oil is left in the ground, but how much can be developed at a substantial energy profit. The latter is a much smaller amount than the former. The third is interest. There is an old proverb in China, which says that interest is the best teacher. Peakoilers can typically be divided into two groups. One group is made up of mostly retired experts or scholars. The other contains people undertaking a profession to make a living and doing research on peak oil according to their professional interests. Thus, what stimulates many of the peakoilers is their interest, independent of salary or other benefits. From another perspective, the lack of no-stringsattached governmental or other funding of the researchers involved is an international scandal. The peakoilers have their allies: the climate change researchers and the new energy advocates. The subject of peak oil brings pressure to governments and oil companies. However, it is a popular topic for climate change researchers and new energy advocators. An ideal solution to the peak oil problem, if possible, must be undertaken with these other important issues (the climate change and the new energy development) in mind. As Zhao and Feng (2007) pointed out, the objectives for those involved in resource depletion, climate change and new energy development are similar. That is, they seek to promote the development of renewable energy, which includes the evolution of techniques and reduction in their costs. In addition, as a kind of scientific research, peak oil study has similarities with climate change. The climate change propagators met with cold criticism from their opponents and encountered severe debate when they began the research in early days. Currently, many people are aware of climate change, and many governments around the world are taking measures to ameliorate it. What people care about is how to deal with the phenomenon and how to decrease the emission of greenhouse gases even though the academic debate is ongoing. Contrastingly, peak oil is undergoing ardent debate. Will it become another climate change issue and form a global movement or bring forward a new field of peakoilism? The arrival of peak oil will probably force many people who wish to ignore the issue to confront it and hopefully other issues as well. In human history, there have been many ‘‘-isms’’ and perhaps ‘‘peakoilism’’ will be embraced as yet another, even followed by
ARTICLE IN PRESS 2138
L. Zhao et al. / Energy Policy 37 (2009) 2136–2138
peakgasism, peakcoalism, peak everything, eventually perhaps forming peakism. In our current society, most business plans are based on consumption of oil, and usual economic forecasts are based on a constant growth of the GDP. Thus, maybe projecting the decline of oil is politically unpopular, and we can understand why peak oil is rejected by many politicians or managers of oil companies. However, oil is a limited, non-renewable resource, and oil peak is inevitable. Furthermore, peak oil theory is a kind of development theory rather than a crisis theory. Perhaps what we need to do is to accept the eventual depletion of oil sooner or later and to develop renewable energy while limiting populations and their excessive material aspirations to realize sustainable development of society. If we do not adopt that path through our own planning, it will inevitably be imposed upon us, probably in a much less desirable way. The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China (NSFC) under
Grant 70841024. We also would like to thank Editor Nicky France and the anonymous referees for their helpful suggestions and corrections on the earlier draft of our manuscript according to which we improved the content. References Campbell, Colin J., Laherre`re, Jean H., 1998. The end of cheap oil. Scientific American 278 (3), 78–83. Feng, Lianyong, Zhao, Lin, Zhao, Qingfei, Wang, Zhiming, 2006. Peak oil theory and forecast on world peak oil. Acta Petrolei Sinica 27 (5), 139–142 (in Chinese). Hubbert, M. King, 1949. Energy from fossil fuels. Science 109 (2823), 103–109. Hubbert, M. King, 1962. Energy resources. Publication 1000-D, Natl. Academy of Science/Natl. Research Council. Hubbert, M. King, 1967. Degree of advancement of petroleum exploration in the United States. AAPG Bulletin 52 (11), 2207–2227. Kjell, Aleklett, 2006. The global energy supply situation today and tomorrow. The Energy and Environment Conference. Shijiazhuang, China. Zhao, Lin, Feng, Lianyong, 2007. Research status of peak oil and evocable consideration. International Petroleum Economics 15 (11), 29–35 (in Chinese).