خلاصة:
تغییرات آب و هوایی کره زمین به عنوان نتیجه روز افزون کشورها برای دستیابی به رشد اقتصادی بالاتر در دهه های اخیر اثرات زیـادی را بـدنبال داشـته کـه نمی توان تأثیرآن بر بخش کشاورزی را نادیده گرفت. بخش کشاورزی به لحاظ نقشی که در تأمین مواد غذایی مردم دارد، یکی از اصلی ترین بخش های متاثر از تغییر اقلیم است که بـا تأثیرپـذیری از شـرایط اقلیمـی هـر منطقـه می تواند بر اقتصاد آن منطقه تأثیر بگذارد. در این میان برخی از مناطق در معرض تغییرات آب و هوایی شدیدتری قرار دارند از جمله منطقه خاور میانه و کشور ایران که از این مسئله مستثنی نیستند. لذا در این تحقیق به بررسی تأثیر تغییرات آب و هوایی بر ارزش افزوده بخش کشاورزی کشورهای منطقه منا پرداخته می شود. بدین منظور از داده های دما و بارش و ارزش افزوده بخش کشاورزی 11 کشور منطقه منا برای دوره زمانی 2001-2016 و مدل هم جمعی با رهیافت حداقل مربعات معمولی اصلاح شده (FMOLS) و حداقل مربعات معمولی پویا (DOLS) استفاده شده است. نتایج حاکی از آن است که یک رابطه بلند مدت هم جمعی میان تغییر اقلیم و ارزش افزوده بخش کشاورزی وجود دارد. در طول دوره مورد بررسی متغیر دما اثر منفی و معنادار و متغیر بارش اثر مثبت و معنادار داشته است، به نحوی که با هر یک درصد افزایش دما و بارش در بلندمدت ارزش افزوده بخش کشاورزی در مدل (FMOLS) به ترتیب به میزان 0.28-، 0.03 درصد و در مدل (DOLS) به میزان 0.09-، 0,02 درصد تغییر می یابد.
Climate change on planet earth as a result of growing economies in recent decades has had many effects that could not be ignored agricultural wise. The agriculture sector is one of the main sectors influenced by climate change because of it’s role in providing nutrition, which in turn effects the economy of region. Some regions, including the Middle East and Northern Africa (MENA), are exposed to more severe climate change. Therefore, in this research, the effects of climate change on value-added agriculture in the MENA region countries are investigated. For this purpose, we used temperature and precipitation data and value-added agriculture of 11 MENA countries during 2001-2016. This study employed Panel Data cointegration models of Fully Modified Ordinary Least Squares (FMOLS) and Dynamic Ordinary Least Squares (DOLS). The results revealed that there is a cointegrated long-term relationship between climate change and value-added agriculture. Additionally, comparing these estimated coefficients in both applied approaches shows that temperature changes had a negative and significant effect, and precipitation changes positively and significantly impacted the value-added agriculture variable. It implies that with a one percent increase in temperature and precipitation over the long run, value-added agriculture is changed in the FMOLS model at a rate of -0.28, 0.03 percent, and in the DOLS model -0.09, 0.02 percent, respectively.Climate change on planet earth as a result of growing economies in recent decades has had many effects that could not be ignored agricultural wise. The agriculture sector is one of the main sectors influenced by climate change because of it’s role in providing nutrition, which in turn effects the economy of region. Some regions, including the Middle East and Northern Africa (MENA), are exposed to more severe climate change. Therefore, in this research, the effects of climate change on value-added agriculture in the MENA region countries are investigated. For this purpose, we used temperature and precipitation data and value-added agriculture of 11 MENA countries during 2001-2016. This study employed Panel Data cointegration models of Fully Modified Ordinary Least Squares (FMOLS) and Dynamic Ordinary Least Squares (DOLS). The results revealed that there is a cointegrated long-term relationship between climate change and value-added agriculture. Additionally, comparing these estimated coefficients in both applied approaches shows that temperature changes had a negative and significant effect, and precipitation changes positively and significantly impacted the value-added agriculture variable. It implies that with a one percent increase in temperature and precipitation over the long run, value-added agriculture is changed in the FMOLS model at a rate of -0.28, 0.03 percent, and in the DOLS model -0.09, 0.02 percent, respectively.Climate change on planet earth as a result of growing economies in recent decades has had many effects that could not be ignored agricultural wise. The agriculture sector is one of the main sectors influenced by climate change because of it’s role in providing nutrition, which in turn effects the economy of region. Some regions, including the Middle East and Northern Africa (MENA), are exposed to more severe climate change. Therefore, in this research, the effects of climate change on value-added agriculture in the MENA region countries are investigated. For this purpose, we used temperature and precipitation data and value-added agriculture of 11 MENA countries during 2001-2016. This study employed Panel Data cointegration models of Fully Modified Ordinary Least Squares (FMOLS) and Dynamic Ordinary Least Squares (DOLS). The results revealed that there is a cointegrated long-term relationship between climate change and value-added agriculture. Additionally, comparing these estimated coefficients in both applied approaches shows that temperature changes had a negative and significant effect, and precipitation changes positively and significantly impacted the value-added agriculture variable. It implies that with a one percent increase in temperature and precipitation over the long run, value-added agriculture is changed in the FMOLS model at a rate of -0.28, 0.03 percent, and in the DOLS model -0.09, 0.02 percent, respectively.Climate change on planet earth as a result of growing economies in recent decades has had many effects that could not be ignored agricultural wise. The agriculture sector is one of the main sectors influenced by climate change because of it’s role in providing nutrition, which in turn effects the economy of region. Some regions, including the Middle East and Northern Africa (MENA), are exposed to more severe climate change. Therefore, in this research, the effects of climate change on value-added agriculture in the MENA region countries are investigated. For this purpose, we used temperature and precipitation data and value-added agriculture of 11 MENA countries during 2001-2016. This study employed Panel Data cointegration models of Fully Modified Ordinary Least Squares (FMOLS) and Dynamic Ordinary Least Squares (DOLS). The results revealed that there is a cointegrated long-term relationship between climate change and value-added agriculture. Additionally, comparing these estimated coefficients in both applied approaches shows that temperature changes had a negative and significant effect, and precipitation changes positively and significantly impacted the value-added agriculture variable. It implies that with a one percent increase in temperature and precipitation over the long run, value-added agriculture is changed in the FMOLS model at a rate of -0.28, 0.03 percent, and in the DOLS model -0.09, 0.02 percent, respectively.
ملخص الجهاز:
بررسي تأثير تغيير اقليم بر ارزش افزوده بخش کشاورزي کشورهاي منتخب منا 1 2 سميه ميقاني دانشجوي دکتري رشته اقتصاد، دانشگاه فردوسي مشهد 3 مهدي خداپرست مشهدي دانشيار گروه اقتصاد، دانشگاه فردوسي مشهد 4 نرگس صالح نيا استاديار گروه اقتصاد، دانشگاه فردوسي مشهد تاريخ دريافت : ١٣٩٩/١٠/٢٣ تاريخ پذيرش : ١٤٠٠/٠٣/١٠ چکيده تغييرات آب وهوايي کره زمين به عنوان نتيجه روزافزون کشورها براي دستيابي بـه رشـد اقتصـادي بـالاتر در دهه هاي اخير اثرات زيـادي را به دنبال داشـته کـه نميتوان تأثير آن بر بخش کشـاورزي را ناديـده گرفـت .
همچنين با توجه به پيش بينيهاي مدل هاي آب وهوايي اخير، انتظار ميرود حتـي در صـورت کـاهش انتشـار گازهـاي ________________________________________________________________ 1- Dynamic Ordinary Least Squares 2- Fully Modified Ordinary Least Squares 3- Intergovernmental Panel on Climate Change گلخانه اي ، دما در سطح جهاني حداقل ٢ درجه سانتيگراد بالاتر از سطوح قبل از صـنعتي شـدن تـا سال ٢٠٥٠ افزايش يابد که آثار نامطلوبي بر اکوسيستم ها، سلامت و رشد اقتصـادي خواهـد داشـت .
در سه مدل مورداستفاده در اين روش (مـدل هـاي Solow-Swan، Ramsey-Cass-Koopmans و Mankiw, Romer and Weil)، بـا فـرض يـک نـرخ پـس انـداز ثابت ، مشخص شده است که اگر تغييرات آب وهوايي بر توليد اثر منفي داشته باشد، ميزان سرمايه - گذاري نيز کاهش خواهد يافـت .
برخي از معروف ترين آزمون هاي ريشه واحد پانـل کـه جهت بررسي ايستايي متغيرها مورداستفاده قرار ميگيرد، عبارتند از: آزمـون Chu &Levin, Lin (٢٠٠٢( test، آزمون (٢٠٠٣( Shin test &Im, Pesaran ، آزمون ديکي فولر تعميم يافته ١ Fisher (١٩٩٩( و آزمون PP- فيشر؛ اما زماني که ميان واحدهاي مقطعـي همبسـتگي وجـود داشـته باشـد، نتايج اين آزمون ها با خطاي برآورد همراه است .