{"id":2728,"date":"2014-08-11T10:34:14","date_gmt":"2014-08-11T15:34:14","guid":{"rendered":"http:\/\/sciencemediacentre.ca\/site\/?p=2728"},"modified":"2014-08-11T10:41:36","modified_gmt":"2014-08-11T15:41:36","slug":"reactions-dexperts-du-ccsm-keystone-xl-emissions-de-gaz-carbonique","status":"publish","type":"post","link":"http:\/\/sciencemediacentre.ca\/site\/reactions-dexperts-du-ccsm-keystone-xl-emissions-de-gaz-carbonique\/","title":{"rendered":"Keystone XL : \u00e9missions de gaz carbonique"},"content":{"rendered":"

Une nouvelle \u00e9tude publi\u00e9e dimanche dans Nature Climate Change<\/span>\u00a0 utilise un mod\u00e8le \u00e9conomique pour quantifier l\u2019impact qu\u2019aurait la construction de l\u2019ol\u00e9oduc Keystone XL sur les \u00e9missions de gaz \u00e0 effet de serre. Le projet Keystone XL permettrait le transport de p\u00e9trole brut de l\u2019industrie des sables bitumineux en Alberta jusqu\u2019\u00e0 raffineries am\u00e9ricaines.<\/p>\n

Les auteurs expliquent que les analyses pr\u00e9c\u00e9dentes ne tenaient pas compte que la construction du pipeline pourrait diminuer les prix du p\u00e9trole \u00e0 l\u2019\u00e9chelle de la plan\u00e8te. Cela aurait comme cons\u00e9quence d\u2019augmenter la consommation de p\u00e9trole et l\u2019\u00e9mission de gaz \u00e0 effet de serre. Ils estiment donc que les \u00e9missions de gaz carbonique associ\u00e9es \u00e0 la r\u00e9alisation de Keystone XL se situent entre z\u00e9ro et 110 millions de tonnes de CO2 annuellement. En comparaison, le U.S. Department of Energy pr\u00e9dit une hausse annuelle des \u00e9missions entre 1 et 27 millions de tonnes de CO2 annuellement.<\/p>\n

Voici des r\u00e9actions d\u2019experts que nous avons recueillis au cours des derniers jours pour vous aider \u00e0 comprendre les enjeux soulev\u00e9s par cet article.<\/p>\n

***<\/p>\n

Patrick Gonzalez<\/span><\/p>\n

Professeur agr\u00e9g\u00e9, Directeur du Centre de recherche en \u00e9conomie de l\u2019environnement, de l\u2019agroalimentaire, des transports et de l\u2019\u00e9nergie (CREATE)<\/span><\/p>\n

D\u00e9partement d’\u00e9conomique, Universit\u00e9 Laval<\/span><\/p>\n

L\u2019article n\u2019apporte rien de nouveau. Comme le pr\u00e9cisent d\u2019ailleurs bien prudemment les auteurs : <\/em>This Letter offers no new insights on whether Keystone XL will ultimately enable higher oil sands production levels.<\/p>\n

Le point des auteurs est que le D\u00e9partement d\u2019\u00c9tat am\u00e9ricain consid\u00e8re sans justification que le p\u00e9trole circulant par Keystone XL ne ferait que d\u00e9placer du p\u00e9trole v\u00e9n\u00e9zu\u00e9lien, sans augmentation de la production mondiale, mais avec substitution du p\u00e9trole v\u00e9n\u00e9zu\u00e9lien par le p\u00e9trole plus sale de l’Alberta. Les auteurs soulignent que ce p\u00e9trole pourrait en fait ajouter \u00e0 la production mondiale par un effet de prix. Ils illustrent ce sc\u00e9nario avec un exemple plausible (mais extr\u00eame) o\u00f9 la construction de Keystone XL se traduit par une augmentation de la production mondiale de p\u00e9trole correspondant \u00e0 la moiti\u00e9 de sa capacit\u00e9.<\/em><\/p>\n

***<\/p>\n

Claude Villeneuve<\/span><\/p>\n

Professeur titulaire, Directeur de la Chaire en \u00e9co-conseil<\/span><\/p>\n

D\u00e9partement des sciences fondamentales, Universit\u00e9 du Qu\u00e9bec \u00e0 Chicoutimi<\/span><\/p>\n

L’article est int\u00e9ressant, mais il faut comprendre qu’il ne fait que soulever une hypoth\u00e8se qui n\u2019a pas \u00e9t\u00e9 consid\u00e9r\u00e9e dans le rapport du U.S. Department of Energy (DOE) fait pour r\u00e9pondre \u00e0 la question “Est-ce que Keystone XL va augmenter les \u00e9missions de GES s’il est construit et mis en service?”<\/em><\/p>\n

La r\u00e9ponse du DOE est que le r\u00e9sultat va \u00eatre peu significatif, parce que les \u00e9missions li\u00e9es \u00e0 la construction et \u00e0 l’op\u00e9ration d’un pipeline sont relativement faibles et se comparent aux autres modes de transport. Les auteurs ajoutent un effet d’\u00e9lasticit\u00e9 de la demande sur le march\u00e9 mondial du p\u00e9trole en supposant que l’apport de nouveau carburant, en contribuant \u00e0 maintenir bas le prix mondial du p\u00e9trole, va entra\u00eener une hausse relativement plus grande de la demande. (En gros, si l’essence est moins ch\u00e8re, on voyage plus loin pour ses vacances, donc on consomme plus de carburant dans le m\u00eame temps et on produit plus d’\u00e9missions que si l’essence est plus ch\u00e8re\u2026)<\/em><\/p>\n

C’est une hypoth\u00e8se, mais elle comporte beaucoup d’incertitudes. Cela conduit les auteurs \u00e0 postuler un effet d’\u00e9lasticit\u00e9 qui va se traduire par une demande accrue pour du p\u00e9trole. Selon la source de ce p\u00e9trole, Moyen-Orient ou Venezuela, les \u00e9missions suppl\u00e9mentaires devraient \u00eatre imput\u00e9es \u00e0 la construction du Keystone XL selon les auteurs, alors que le DOE consid\u00e8re que le p\u00e9trole serait produit de toute fa\u00e7on et transport\u00e9 autrement (autres pipelines ou train) et donc que l’effet est le m\u00eame et ne peut \u00eatre imput\u00e9 au Keystone XL.<\/em><\/p>\n

C’est un article de la section “Letters”, donc un \u00e9l\u00e9ment de discussion l\u00e9gitime, mais qui ne donne pas une r\u00e9ponse d\u00e9finitive au probl\u00e8me.<\/em><\/p>\n

***<\/p>\n

Mark Jaccard<\/strong><\/p>\n

Professeur, \u00c9cole de gestion des ressources et de l’environnement<\/span><\/p>\n

Universit\u00e9 Simon Fraser<\/span><\/p>\n

The paper seems to have sound analysis and its conclusions seem reasonable. To reiterate its main point, expanding oil supply infrastructure is likely to have some effect on oil prices by providing market access to more oil supply for consumers. Unless the production cost of that supply exactly matches current prices, its competitive availability will have some downward pressure on oil prices, which in turn increases oil consumption and associated GHG emissions (depending on what economists call the demand elasticity). Of course, there is considerable uncertainty about the magnitude of the effect. The authors represent this uncertainty by selecting from high and low points of a probability distribution – showing that the effect on oil consumption and emissions can range from 0 to 110 MtCo2 per year.<\/em><\/p>\n

Overall, the paper suggests a flaw in the analysis of the US State Department because it did not consider this effect when addressing President Obama\u2019s request to know the incremental effect of the pipeline on emissions.<\/em><\/p>\n

***<\/p>\n

Werner Antweiler<\/span><\/p>\n

Professeur associ\u00e9, \u00c9cole de commerce Sauder<\/span><\/p>\n

Universit\u00e9 de la Colombie-Britannique<\/span><\/p>\n

I am sympathetic to the findings in the forthcoming paper in the sense that extra supply of oil will have an impact in equilibrium that results in more consumption (and thus more greenhouse gas emissions). The analysis in the paper makes use of conventional supply and demand model using generally recognized assumptions about long-term supply and demand elasticities. So far so good. The full effect of the Keystone XL pipeline (as well as others such as the proposed Enbridge Northern Gateway, the Kinder-Morgan Trans Mountain Expansion, and the TransCanada Energy East project) depends on four additional considerations, however:<\/em><\/p>\n

1. The impact of additional pipeline capacity on production. The assumption is that every extra barrel of capacity in transportation leads to a one-to-one increase in production. This assumption may be rather strong because capacity utilization may vary over time, and capcity that is currently using more expensive transportation modes (i.e., rail) may shift back to a lower-cost transportation mode (i.e., pipeline). Furthermore, refining capacity may also constrain any increase in output. In particular, the Keystone XL pipeline depends crucially on refining capacity in the southern US that is not expected to increase.<\/em><\/p>\n

2. An increase in supply of (cheaper) oil may displace other more costly or more polluting energy sources such as coal. This means that there is a substitution effect across fuel sources. A change in oil prices affects prices in related markets (gas, coal) at least in the long term.<\/em><\/p>\n

3. \u00a0Oil markets are oligopolistic. There is the possibility that cheaper Canadian oil may lead to market-stabilizing actions by major oil producers that have an interest in maintaining prices. They can withdraw or withhold production capacity to offset new supplies. Thus, Canadian oil merely displaces other oil sources.<\/em><\/p>\n

4. The GHG intensity of bitumen production is higher than the corresponding GHG intensity of conventional types of oil sources (about 20%). To the extent that Canadian heavy oil displaces other conventional oil sources in the market, it may lead to an overall increase of GHG intensity of oil production even if the total amount of oil consumed remains unchanged.<\/em><\/p>\n

Quantifying these additional mechanisms is likely to be rather tricky, and I do not claim to have any deep insights empirically into these mechanisms.<\/em><\/p>\n

Despite these caveats that I\u2019ve pointed out, I reckon that additional pipeline capacity will ultimately lead to a net increase of greenhouse gases. The exact amount may be uncertain, but it is certainly not a negligible amount.<\/em><\/p>\n

In conclusion, the new paper by Erickson and Lazarus is a welcome contribution to the debate even if the numbers will continue to be debated hotly. I agree with the authors that we need greater transparency of the economic models that are used to determine global impact, such as the EnSys WORLD model they refer to in the paper.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

Une nouvelle \u00e9tude publi\u00e9e dimanche dans Nature Climate Change\u00a0 utilise un mod\u00e8le \u00e9conomique pour quantifier l\u2019impact qu\u2019aurait la construction de l\u2019ol\u00e9oduc Keystone XL sur les \u00e9missions de gaz \u00e0 effet de serre. Le projet Keystone XL permettrait le transport de p\u00e9trole brut de l\u2019industrie des sables bitumineux en Alberta jusqu\u2019\u00e0 raffineries am\u00e9ricaines. Les auteurs expliquent […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[488],"tags":[388,402,1513,683],"class_list":["post-2728","post","type-post","status-publish","format-standard","hentry","category-liste-dexperts","tag-changements-climatiques","tag-colombie-britannique","tag-economie","tag-environnement"],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p4DqbN-I0","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"http:\/\/sciencemediacentre.ca\/site\/wp-json\/wp\/v2\/posts\/2728","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/sciencemediacentre.ca\/site\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/sciencemediacentre.ca\/site\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/sciencemediacentre.ca\/site\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/sciencemediacentre.ca\/site\/wp-json\/wp\/v2\/comments?post=2728"}],"version-history":[{"count":6,"href":"http:\/\/sciencemediacentre.ca\/site\/wp-json\/wp\/v2\/posts\/2728\/revisions"}],"predecessor-version":[{"id":2736,"href":"http:\/\/sciencemediacentre.ca\/site\/wp-json\/wp\/v2\/posts\/2728\/revisions\/2736"}],"wp:attachment":[{"href":"http:\/\/sciencemediacentre.ca\/site\/wp-json\/wp\/v2\/media?parent=2728"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/sciencemediacentre.ca\/site\/wp-json\/wp\/v2\/categories?post=2728"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/sciencemediacentre.ca\/site\/wp-json\/wp\/v2\/tags?post=2728"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}