تحلیل نقش جزر و مد در قلمروسازی دریایی و تأثیرات تغییر اقلیم بر آن

نوع مقاله: مقاله پژوهشی

نویسندگان

1 استاد جغرافیای سیاسی، دانشگاه تهران

2 دکترای تخصصی و پژوهشگر ارشد مرکز پژوهش های مجلس شورای اسلامی

3 دانشیار آب و هوا شناسی، دانشگاه تهران

4 استادیار حقوق بین الملل دانشگاه تهران

10.22131/sepehr.2019.37495

چکیده

بنیان و پایۀ فضاسازی، قلمروگستری، تحدید حدود و مرزبندی در دریاها بر اساس عوامل جغرافیایی (بویژه جغرافیای طبیعی) صورت میگیرد. در میان عوامل متعدد جغرافیای طبیعی، جزر و مد در تحدید حدود و قلمروسازی دریایی نقش بسیار تعیینکنندهای دارد. با این وجود، کشورهای جهان هرکدام از سطح مبنای مشخصی برای تعیین خط جزر خود بهره گرفته و این موضوع مسائل و چالشهایی را در قلمروسازی دریایی به همراه داشته است. در این زمینه تغییرات اقلیمی که به افزایش سطح دریاها منجر می­شود، پدیدۀ مزبور را با تغییراتی مواجه خواهد ساخت. هدف پژوهش حاضر که با استفاده از روش توصیفی- تحلیلی انجام یافته و از نرمافزار GIS و محاسبهگر ریاضی نقشه به نامRaster calculator برای ترسیم نقشههای مورد نیاز بهره گرفته شده، این است که ضمن بررسی نقش و اهمیت جزر و مد در تحدید حدود دریایی، تأثیرات افزایش سطح دریاها را بر آن و فرایند قلمروسازی دریایی، تحلیل و واکاوی کند. نتایج تحقیق نشان میدهد افزایش دو متری سطح دریا که در این تحقیق به آن توجه شده است، جزر و مد را در مناطقی که عقبنشینی ساحلی در آن صورت میگیرد، به شدت تحت تأثیر قرار خواهد داد، لذا با توجه به ترسیم خطوط مبدأ عادی بر اساس این عامل جغرافیایی، باید انتظار داشت در این مناطق، خطوط مذکور دچار عقبنشینی شوند؛ اما چنانچه نقاط پایۀ در نظر گرفته شده برای خطوط مبدأ مستقیم در اثر بالا آمدن سطح دریاها به میزان دو متر، غرق شوند، این خطوط نیز عقبنشینی خواهند کرد. این امر تا حدود زیادی به سطح مبنای در نظر گرفته شده برای ترسیم خطوط مبدأ، بستگی خواهد داشت. شایان ذکر است خط جزر ترسیم ­شده در نقشهها بویژه در مناطقی که تحدید حدود دریایی صورت گرفته، بیشتر از خط جزر واقعی قابل استناد است و به این ترتیب در آینده نقشه به عنوان مهمترین ابزار جغرافیایی، میتواند نقش ثبات­سازی را ایفا کند.

کلیدواژه‌ها


عنوان مقاله [English]

The role of tides in maritime territoriality and the impact of climate change on it

نویسندگان [English]

  • Doreh Mirheidar 1
  • Bahador Gholami 2
  • Zahra Pishgahifard 1
  • Ghasem Azizi 3
  • Amirhossein Ranjbarian 4
1 Professor of political geography, University of Tehran
2 Ph.D. of political geography, University of Tehran
3 Associate Professor of physical geography, University of Tehran
4 Assistant Professor of international law, University of Tehran
چکیده [English]

Extended Abstract
Introduction
Maritime territories and quasi-territories are, in fact, continuation of territories underwater,formedbased on rules and principles governing political systems,international law and international relationsin maritime environment.Place making, territoriality, delimitation and demarcation of territories in the seas are performed based on geographical factors (particularly physical geography). As one of many different physical geographic factors, tideplays a decisive role in maritime delimitation and territoriality. It is considered as the basis upon which boundaries of different maritime territories and quasi-territories in different countriesare demarcated and delimited and formalnautical maps are drawn. Each country of the worldapplies a different basisfor determining low water lineand thisresults in many issues and challenges in maritime territoriality. Meanwhile, sea level has risen due toclimate changesand is expected to increase in the future. Thiswill also affect the above mentioned phenomenon, and may cause serious challenges for demarcation of the existing boundaries. Thus, the present study employs a descriptive-analytical method toinvestigate the role and significance of tides in maritime delimitation andanalyze the impact of sea levelrise on delimitationand maritime territoriality process.
 
Materials & Methods:
The present study is an applied research following a descriptive-analytical method. Related data was collected through library and internet-based methods and the research follows a qualitative method of analysis. Moreover, GIS and mathematical map calculator known as the “Raster Calculator” were used to draw the maps required for therise of sea levels. Based on the existing scenarios and their average values,the present study considers a two-meter rise for the sea level rise by the end of the 21st century.
 
Results & Discussion:
Tideis the most significant factor based on which baselines are drawn. Setting low water line as a fixed basisused for delimitation of maritime territories and quasi-territories is only possible ifcoastline is stabilized at one level or in other words at a definite plate during tide. This function is carried out by the tidal datum. Datum is the reference level based on which all depths andcorresponding elevations are plotted. Therefore, tides play a significant role in determining the Law of the Sea. On flat coastlines, baseline is determined based on the low water line. On dented and jagged beaches, the base points are also determined according to the same phenomenon. Moreover, some features such as the low–tide elevations and islands are also identified based on the datum used. Selection of low water line (as opposed to high water line) leads outer limits of the territorial sea and consequently other areas toward the sea. This will expandmaritime area under sovereignty and jurisdiction of different countries. The country which uses a lower datum will expand its marine sovereignty and jurisdiction. In Persian sources, terms such as the lowest tide line have been used mistakenly as a translation for the term “Low Water line” stipulated in Article 5 of the 1982 Convention. This is while lowest tide is only one type of low water lines, and though this concept plays the most important role in maritime territoriality, no clear reference has been mentioned for datum in the 1982 Convention. The convention stipulates thatdatum used in the official nautical charts published by different states is the tidal datum based on which normal baseline must be defined. Although the International Hydrographic Organization has proposed the lowest astronomical tide as the basis for determining the datum, there is a major difference between states in this regard and they use a variety of tidal base lines. However, coastal countries usually prefer to use the lowest datum. It seems that sea level rise, as the most important phenomenon resulting from climate change, has significant impacts on tides and boundaries delimitated based on tides. This is because low water line may retreat due to sea level rise, and as a result base points upon which baselines are drawn, along with marine territories and quasi-territories might also move closer to the land. However, states which have based their datum on higher averages oflow water will encounter fewer challenges caused by the retreating baseline compared to those that have selected the lowest low water line. However, evaluating a two-meter rise in sea level by the end of the 21st century shows that in different coastal regions of the world,the impact of sea level rise on low water line is not balanced and similar. Thus, given the spatial-geographical variations, only flat regions of the world will encounter submersion of coastlines and retreating low-water line.
 
Conclusion
Results indicate that sea level rise has dramatically changed tides and will challenge Political Geography of the Sea. However, a two-meter sea levelrise will severely affect tides in areas facing coastal retreat, and since normal baselines are drawn based on this geographic factor, a retreat in those baseline should also be expected. In case ofstraight baselines, if base points immerse due to two-meter rise in sea level, these lines will also retreat. Yet, this largely dependson the datum considered for drawing the baselines. On the other hand, the approach used bydifferent states, especially in areas in which maritime boundaries have been delimited, shows that low-water line drawn onformal maps is more referable than the actual low-water line and, therefore, maps can play a stabilizing role as the most important geographic instrumentin the future.

کلیدواژه‌ها [English]

  • Tides
  • Coastal geomorphology
  • Maritime territoriality
  • Climate change
1- برد، اریک (1392) ژئومورفولوژی ساحلی، ترجمه مجتبی یمانی و وحید محمدنژاد، انتشارات دانشگاه تهران.
2- چرچیل، لو؛ رابین، آلن (1383)، حقوق بین‌الملل دریاها، ترجمه: بهمن آقایی، چاپ دوم، تهران، کتابخانه گنج دانش.
3-حافظ نیا، کاویانی راد؛ محمدرضا، مراد (1383) افق‌های جدید در جغرافیای سیاسی، تهران: انتشارات سمت.
4- صیرفی، ساسان (1392) حقوق بین‌الملل عرفی خط مبدأ مناطق دریایی؛ با نگاه ویژه به خط مبدأ ایران در خلیج فارس و دریای عمان، استاد راهنما؛ امیرحسین رنجبریان، رساله دکتری، دانشگاه تهران، دانشکده حقوق و علوم سیاسی.
5- میرحیدر، دره و همکاران (1386) روند قلمروسازی کشورهای ساحلی در بستر خلیج فارس، فصلنامه ژئوپلیتیک، سال سوم، شماره اول، بهار.
6- میرحیدر، دره (1394) مراحل تکوین مباحث و مفاهیم جغرافیای سیاسی دریاها در دوران مدرن، خبرنامه انجمن ژئوپلیتیک ایران، شماره 37، بهار.
7- میرحیدر، راستی، میراحمدی؛ دره، عمران، فاطمه سادات (1393) مبانی جغرافیای سیاسی، انتشارات سمت.
8- Antunes, Nuno Sérgio Marques (2000) the Importance of the Tidal Datum in the Definition of Maritime Limits and Boundaries, International Boundaries Research Unit, Department of Geography, University of Durham.
9- Blake, Gerald (2000) Geographers and international boundaries, IBRU Boundary and Security Bulletin, winter.
10-Cámara Stougaard-Andresen, Roberto A. (2010) Climate change and the Law of the Sea Convention, Master thesis, FACULTY OF LAW, Lund University,
11- Di Leva, Charles & Morita, Sachiko (2007) Maritime Rights of Coastal States and Climate Change: Should States Adapt to Submerged Boundaries? The legal vice presidency, the World Bank.
12- Dundua, Nugzar (2007) Delimitation of maritime boundaries between adjacent States, United Nations – The Nippon Foundation Fellow.
13- Glassner, Martin Ira(1986) The new political geography of the sea, Political Geography Quarterly, Volume 5, Issue 1, January.
14- Gottmann, Jean(1951) Geography and International Relations, World Politics, Vol. 3, No. 2, Jan, pp. 153-173.
15- Huang, Lei(2010) International Law Relating to the Outer Limits of Maritime Zones in the Context of Sea Level Rise, Master Thesis, university of Tromsø.
16- IPCC WGII AR5 (2014) Do Not Cite, Quote, or Distribute Prior to Public Release on 31 March.
17- Johnson, Barbara (1976) the Political Geography of the Oceans, by: Prescott, J. V. R., the Western Political Quarterly, Vol. 29, No. 3 (Sep), pp. 481-482.
18-Kalin, Walter (2011) Climate Change Induced displacement – A Challenge for international law, published by: Mahanirban Calcutta Research Group.
19- Lerner, Brenda Wilmoth & Lerner, K. Lee (2008) Climate Change: In Context, library of congress cataloging in publication data.
20- Lusthaus, Jonathan (2010) Research and Analysis Shifting Sands: Sea Level Rise, Maritime Boundaries and Inter-state Conflict, POLITICS, NO: 30(2),
21- Menefee, Samuel pyeatt (1991) Half Seas Over”: The Impact of Sea Level Rise on International Law and Policy, UCLA Journal of Environmental Law and Policy, 9(2).
22- Noone, Kevin J. (2012) Sea-Level Rise, Managing Ocean Environments in a Changing Climate, Department of Applied Environmental Science, Stockholm University, Stockholm, Sweden.
23- Pratt, Martin (2004) Geographical analysis in maritime boundary delimitation, International Boundaries Research Unit, Durham University.
24- Prescott, Victor and Schofield, Clive (2005) The Maritime Political Boundaries of the World, Second Edition, martinus nijhoff publishers, Leiden / Boston.
25- Schofield, Clive (2012) defining areas for joint development in disputed waters, Australian Centre for Ocean Resources and Security, University of Wollongong.
26- Schofield, Clive and Arsana, Andi (2012) Climate change and the limits of maritime jurisdiction, Climate Change and the Oceans, Edward Elgar Publishing Limited.
27- Schofield, Clive Howard (2009) the trouble with island, a thesis master of laws, The Faculty of Graduate Studies, the University of British Columbia.
28- Schofield, Clive (2013) Holding back the waves? Sea level rise and maritime Claims, Climate Change: International Law and Global Governance: Legal Responses and Global Responsibility Vol.1, pp: 593-614.
29- U. S. Army Corps of Engineers (2011) Sea level change considerations for civil works program, Department of the Army, Washington, District of Columbia.
30- Vidas, Davor (2013) fundamental challenges for the law of the sea, lecture at the University of Tromsø Faculty of Law, 20 September.
31- Warner, Robin and Schofield, Clive (2012) Climate change and the oceans: legal and policy portents for the Asia Pacific region and beyond, Climate Change and the Oceans, Edward Elgar Publishing Limited.
32- Yoskowitz, David W. & Gibeaut, James & McKenzie, Ali (2009) The Socio-Economic Impact of Sea Level Rise in the Galveston Bay Region, A report for Environmental Defense Fund, Harte Research Institute for Gulf of Mexico Studies.