چکیده:
استفاده گسترده از سوختهای فسیلی در بخشهای مختلف حملونقل، صنعت، مصرف خانگی، نیروگاهها و... با انتشار آلایندههای متعدد در اتمسفر، بروز تبعات مختلفی را برای محیط زیست و سلامتی انسان به دنبال داشته است. در به وجود آمدن چنین شرایطی عوامل مختلفی از جمله صنعتی شدن جوامع، رشد اقتصادی، رشد جمعیت، رشد شهرنشینی، تغییر سبک زندگی و ... نقش دارند. شناخت عوامل مهم تاثیرگذار و تعیین سهم هرکدام میتواند در مواجهه بهتر با این معضل زیستمحیطی کمک کند. ازاینرو هدف از پژوهش حاضر بررسی عوامل موثر بر تغییرات انتشار دیاکسید کربن با تاکید بر دو عامل مهم تغییرات جمعیتی و شهرنشینی در ایران است. این تحقیق از نظر ماهیت روش، جزو تحقیقات کمی و از نظر شیوه گردآوری دادهها، جزو تحقیقات کتابخانهای محسوب میشود. دادههای مورداستفاده در این تحقیق، آمار مربوط به میزان دیاکسید کربن هوا، مصرف انرژی، تعداد جمعیت و نرخ شهرنشینی بین سالهای 1376 تا 1395 در کشور میباشد که از گزارشهای مرکز آمار ایران استخراج شده است. برای تحلیل دادهها از مدل محاسباتی تحلیل تجزیه استفاده شده است. نتایج تحقیق نشان میدهد هم جمعیت و هم شهرنشینی بر افزایش مصرف انرژی و انتشار دیاکسید کربن هوا نقش مهم داشته است.
1. Introduction
The need to energy for doing economic activities, and meeting the growing population demand have increased in the recent years. Energy consumption is a prerequisite for economic progress in societies, and its increasing consumption has led to environmental problems, the most important of which is air pollution emissions resulting from fossil fuel combustion. Due to the wide range of effects of air pollution on local to planetary scales, identifying the factors affecting pollution like carbon dioxide and determining the share of each can be a guide for environmental management in any country. Therefore, this study seeks to investigate and analyze the share of factors affecting the emissions of air pollution in Iran. The innovation of this study is emphasizing on the effect of urbanization along with population growth on air pollution. There are many theories about the effect of urbanization on the environment. Some believe that urbanization is an important factor in increasing environmental pollution and climate change. Others believe that urbanization is a factor in improving the quality of the environment due to high efficiency in energy consumption, and can lead to air pollution reduction. In this study, the amount of CO2 emissions is considered as an indicator of air pollution, and the impacts of factors including population change, urbanization growth and energy intensity on CO2 emissions changes in Iran is analyzed during the period 1997 -2016.
2. Study Area
In Iran, per capita carbon dioxide emissions in 2014 was equal to 8.4 metric tons, and its emission growth during 1990-2014 was about 127 percent, i.e., more than doubled (World Bank, 2014). Energy consumption and energy intensity in Iran have decreased in some years due to the relatively low increase in energy consumption compared to the urban population and have increased in some other years. Considering increasing energy consumption, carbon dioxide emissions have increased by the whole economy.
3. Materials and Methods
The first method (IPAT) for analyzing the main factors of environmental degradation is determined by the destructive effect on the environment (I), multiplied by population (P), economic prosperity in terms of the level of production or consumption (A), and technology as the environmental effect of economic activity (T). Some studies replaced the concept of IPAT with IMPACT. In IMPACT model, technology is divided into two parts; the term technology (T) and another term in the sense of energy relative to GDP (C). In this study, complete decomposition method was used to analyze the factors affecting the emission changes. Four factors have been selected in this study: the pollution coefficient effect, energy intensity effect, population structure (urbanization) effect, and population effect. The pollution coefficient effect is determined by the rate of carbon dioxide emission and energy consumption, which is called the carbon dioxide emission intensity. This variable evaluates fuel quality, fuel change (fuel replacement), and the installation of pollution reduction technologies. The energy intensity of urban household effect is determined by the rate of energy consumption and urban population. The energy consumption is mostly related to some variables such as economic and urban structure, transportation efficiency and energy systems of the city, energy use technologies, energy prices, energy saving policy and investment to reduce energy consumption. Urbanization effect is determined by the ratio of urbanization to population. This coefficient measures the relative position of the urban and rural population in an economy and changes with the evolution of urban structure. The population effect is expressed in the size of the total population in an economy.
4. Results and Discussion
The results show that the effect of carbon intensity is the most important factor influencing on the increase of carbon emissions. This shows that fossil fuels are widely used, and substitution for clean fuels and pollution reduction technologies in the economy are low. During the considered period, the energy consumption of the urban population has decreased. Decreases in the energy intensity can be due to increased energy efficiency, acceptance of new manufacturing technologies, reduced use of fossil fuels, or changes in fossil energy prices. Despite the declining energy consumption of the urban population, there is still great potential for reducing energy intensity due to the gap in the production process, technology, and level of management.
In the whole period of 1997 to 2016, both population and urbanization changes have increased the emissions of carbon dioxide. Urbanization has contributed 52% to carbon emissions change over the entire period. Although urbanization has had a declining effect on carbon emissions between 2007 and 2011, it has had a positive effect throughout the whole period. So, it can be said that the expansion of urbanization in Iran is a factor in increasing air pollution. In previous studies done on Iran, less attention has been paid to the effect of these two variables, and more attention has been paid to the effect of economic growth and the structure of society's products.
5. Conclusion
Considering the rapid growth of industrial activities and urbanization, the consumption of different types of energy plays an important role in influencing the local environment and changing the global climate. Increasing environmental degradation at the local, national and global levels has raised policymakers' concerns about the side effects of energy consumption and related social welfare. Recognizing the important factors influencing on pollution emissions, and determining the share of each can help in better dealing with this environmental problem. Therefore, the purpose of this study was to investigate the factors affecting changes in carbon dioxide emissions with emphasis on two important factors of demographic change and urbanization in Iran. For data analysis, the computational model of decomposition analysis has been used. The results show that both population and urbanization have played an important role in increasing energy consumption and carbon dioxide emissions. According to the results, strategies such as reducing pollution by changing fuel and switching to cleaner energy, implementing energy optimization plans and upgrading equipment technology, guiding household consumption toward improving fuel consumption patterns, and enforcing pricing and incentive policies should be considered for carbon decrease and sustainable development.
خلاصه ماشینی:
مصرف انرژي گرچـه لازمـه پيشـرفت اقتصـادي جوامـع اسـت ولـي مصـرف رو بـه افـزايش آن معضـلات زيست محيطي را نيز در پي داشته است که از جمله مهم ترين آن ها آلودگي هوا به دليل انتشار و نشت گازهاي ناشي از احتراق سوخت هاي فسيلي است (نصرالهي و غفاري گولک ، ١٣٨٩).
2 World Bank 3 Intergovernmental Panel on Climate Change خاطرنشان شده است که افزايش انتشار دي اکسيد کربن (CO٢) ناشي از مصرف انرژي فسيلي عامل اصلي تغييرات جهاني آب وهواست (فن و لي ١، ٢٠١٧).
2 Zhang & Ang 3 Paul & Bhattacharya 4 Lee and Oh. 5 Liaskas et al.
معيار آلودگي هوا نيز ميزان انتشار گـاز CO٢ –بـه عنوان يکي از مهم ترين گازهاي گلخانه اي - در نظر گرفته مي شود و سعي مي شود سهم عواملي چون تغيير جمعيت ، رشد شهرنشيني و مصرف انرژي در ميزان انتشارCO٢ در کشور طي دوره ١٣٧٦ تا ١٣٩٥ موردبررسي و تحليل قرار گيرد.
پژوهش حاضر در پي پاسخ به سؤالات زير است : - متغيرهاي رشد جمعيتي، نرخ شهرنشيني و مصرف انرژي تا چه حد تبيين کننده افزايش آلودگي هوا در ايـران هستند؟ کدام عامل نقش مهم تري دارد؟ - آيا ميزان نقش آفريني اين عوامل در طي سال هاي مختلف تغيير پيدا کرده است ؟ ٢- منطقه مورد مطالعه محدوده جغرافيايي مورد مطالعه در اين پژوهش ، کشور ايران است و اين تحقيق به مطالعه سهم عوامل مختلف تاثيرگذار بر انتشار دي اکسيد کربن در کشور بين سالهاي ١٣٧٦ تا ١٣٩٥ ميپردازد.