THE EXAMINATION OF CARBON EMISSIONS UNDER THE SHADOW OF INFLATION IN MENA COUNTRIES: A PANEL DATA ANALYSIS (2000–2023)

Abstract

In accordance with recent global developments, developing countries have experienced increasing economic uncertainty, reflected in rising unemployment and inflation rates. This trend poses a significant threat, particularly regarding environmental challenges such as increasing carbon emissions. This study builds upon the framework established by Kashem and Rahman (2020) and investigates the Environmental Phillips Curve to analyze the relationship between economic variables and environmental indicators. This study employs panel data analysis covering selected MENA countries during the period from 2000 to 2023. The independent variables include GDP per capita, the squared term of GDP, foreign direct investment, trade openness, and unemployment rate, while the inflation rate is included as a control variable. The dependent variable is carbon dioxide (CO₂) emissions. A distinctive feature of this study is the explicit examination of the impact of inflation on CO₂ emissions. Through this approach, the Environmental Kuznets Curve, Pollution Haven Hypothesis, and Pollution Halo Hypothesis are revisited. The empirical findings demonstrate that inflation has a positive and statistically significant effect on environmental pollution, highlighting its critical role as a determinant of environmental degradation in the MENA region.

Keywords

• CO₂ Emissions
• Inflation
• Environmental Kuznets Curve
• Environmental Phillips

MENA ÜLKELERİNDE ENFLASYONUN GÖLGESİNDE KARBON EMİSYONLARININ İNCELENMESİ: PANEL VERİ ANALİZİ (2000–2023)

Öz

Dünyada yaşanan küresel gelişmelere paralel olarak, son dönemlerde gelişmekte olan ülkelerde ekonomik belirsizlik artmakta; buna bağlı olarak işsizlik ve enflasyon oranlarında yükseliş gözlemlenmektedir. Bu durum, çevresel sorunlar, özellikle de karbon emisyonundaki artışla birlikte önemli bir tehdit oluşturmaktadır. Ekonomik değişkenler ile çevresel göstergeler arasındaki ilişkiyi incelemek amacıyla, Kashem ve Rahman (2020) çalışmasından yola çıkılarak Çevresel Phillips Eğrisi analiz edilmektedir. 2000-2023 yılları arasında seçili MENA bölgesi ülkelerine yönelik çalışmada; kişi başına düşen GSYİH, GSYİH’nın karesi, doğrudan yabancı sermaye yatırımları, ticaret hacmi ve işsizlik oranı bağımsız değişken, enflasyon oranı kontrol değişkeni, karbon emisyonu ise bağımlı değişken olarak ele alınmıştır. Çalışmanın özgün yönü, enflasyonun CO₂ emisyonları üzerindeki etkisini ayrıca değerlendirmesidir. Bu kapsamda, Çevresel Kuznets Eğrisi, Kirlilik Sığınağı Hipotezi ve Kirlilik Halesi Hipotezi panel veri analiziyle yeniden test edilmektedir. Elde edilen bulgular, enflasyonun çevre kirliliği üzerinde pozitif yönde ve istatistiksel olarak anlamlı bir etkisi olduğunu göstermektedir.

Anahtar Kelimeler

• CO₂ Emisyonları
• Enflasyon
• Çevresel Kuznets Eğrisi
• Çevresel Phillips Eğrisi

Kaynakça

1. Artan, S., Hayaloğlu, P., & Seyhan, B. (2015). Türkiye’de çevre kirliliği, dışa açıklık ve ekonomik büyüme ilişkisi. Yönetim ve Ekonomi Araştırmaları Dergisi, 13(1), 85–104. https://doi.org/10.11611/yead.205
2. Al-Mulali, U., Solarin, S. A., & Ozturk, I. (2016). Investigating the presence of the environmental Kuznets curve (EKC) hypothesis in Kenya: An autoregressive distributed lag (ARDL) approach. Natural Hazards, 80, 1729–1747. https://doi.org/10.1007/s11069-015-2050-x
3. Adedoyin, F., Ozturk, I., Abubakar, I., Kumeka, T., Folarin, O., & Bekun, F. V. (2020). Structural breaks in CO₂ emissions: Are they caused by climate change protests or other factors? Journal of Environmental Management, 266, 110628. https://doi.org/10.1016/j.jenvman.2020.110628
4. Ahmad, W., Ullah, S., Ozturk, I., & Majeed, M. T. (2021). Enflasyon istikrarsızlığı çevre kirliliğini etkiliyor mu? Asya ekonomilerinden yeni kanıtlar. Enerji ve Çevre, 32(7), 1275–1291. https://doi.org/10.1177/0958305X20971804
5. Albayrak, M., & Telek, C. (2022). Çevresel Kuznets Eğrisi (EKH) hipotezinin Türkiye için geçerliliği. Finans Ekonomi ve Sosyal Araştırmalar Dergisi, 7(4), 719–731. https://doi.org/10.29106/fesa.1177795
6. Bhagwati, J. (1993). Trade and the environment: Does environmental diversity detract from the case for free trade? The World Economy, 16(6), 499–518.
7. Bernanke, B. S. (1983). Irreversibility, uncertainty, and cyclical investment. The Quarterly Journal of Economics, 98(1), 85–106. https://doi.org/10.2307/1885568
8. Beckerman, W. (1992). Economic growth and the environment: Whose growth? Whose environment? World Development, 20, 481–496.

9. Başar, S., & Temurlenk, M. S. (2007). Çevresel uyarlanmış Kuznets eğrisi: Türkiye üzerine bir uygulama. İktisadi ve İdari Bilimler Dergisi, 21(1), 1–12.
10. Baek, J. (2016). A new look at the FDI-income-energy-environment nexus: Dynamic panel data analysis of ASEAN. Energy Policy, 91, 22–27. https://doi.org/10.1016/j.enpol.2015.12.045
11. Balsalobre-Lorente, D., Shahbaz, M., Jabbour, C. J. C., & Driha, O. M. (2019). The role of energy innovation and corruption in carbon emissions: Evidence based on the EKC hypothesis. In A. M. González-Pernía, A. D. Macke, & G. P. Pérez (Eds.), Energy and environmental strategies in the era of globalization (pp. 271– 304). Cham: Springer.
12. Banerjee, S., & Murshed, M. (2020). Do emissions implied in net export validate the pollution haven conjecture? Analysis of G7 and BRICS countries. International Journal of Sustainable Economics, 12(3), 297–319. https://doi.org/10.1504/IJSE.2020.10033008
13. Bah, M. M., Abdulwakil, M. M., & Azam, M. (2020). Income heterogeneity and the environmental Kuznets curve hypothesis in Sub-Saharan African countries. GeoJournal, 85, 617–628. https://doi.org/10.1007/s10708- 019-09985-1
14. Boukhelkhal, A. (2022). Energy use, economic growth and CO2 emissions in Africa: Does the environmental Kuznets curve hypothesis exist? New evidence from heterogeneous panel under cross-sectional dependence. Environment, Development and Sustainability, 24(11), 13083–13110. https://doi.org/10.1007/s10668-021-01983-z
15. Çakmak, A. İ., & Tosun, B. (2017). Economic growth–income distribution relation: Investigation of Kuznets hypothesis on selected countries. Kocaeli University Journal of Social Sciences, 33, 33–44.
16. Çekiç, A. İ., & Gültekin, H. (2019). R uygulamalı panel veri analizi ve ampirik bir uygulama. Ekin Basım Yayın Dağıtım.
17. Çoban, M. N., & Özkan, O. (2022). Türkiye’de enerji tüketimi, ticari açıklık, CO₂ emisyonları ve kirlilik sığınağı hipotezi: Yeni dinamik ARDL simülasyonlarından kanıtlar. Kırklareli Üniversitesi İktisadi ve İdari Bilimler Fakültesi Dergisi, 11(2), 480–507.
18. Dong, K., Sun, R., & Hochman, G. (2017). Do natural gas and renewable energy consumption lead to less CO₂ emission? Empirical evidence from a panel of BRICS countries. Energy, 141, 1466–1478.
19. Destek, M. A. (2018). Çevresel Kuznets eğrisi hipotezinin Türkiye için incelenmesi: STIRPAT modelinden bulgular. C.Ü. İktisadi ve İdari Bilimler Dergisi, 19(2), 268–283.
20. Demirtaş, C. (2023). Does inflation instability cause environmental pollution in Turkey? Evidence from the Fourier-Wavelet causality test. Ekonomi, Politika & Finans Araştırmaları Dergisi, 8(4), 622–642.
21. Erataş, F., & Uysal, D. (2014). Çevresel Kuznets eğrisi yaklaşımının “BRICT” ülkeleri kapsamında değerlendirilmesi. İktisat Fakültesi Mecmuası, 64(1), 1–25.
22. Essandoh, O. K., Islam, M., & Kakinaka, M. (2020). Linking international trade and foreign direct investment to CO₂ emissions: Any differences between developed and developing countries? Science of the Total Environment, 712, 136437.
23. Fischer, S. (1993). The role of macroeconomic factors in growth. Journal of Monetary Economics, 32(3), 485– 512.
24. Friedman, M. (1977). Nobel lecture: Inflation and unemployment. Nobel Media. https://www.nobelprize.org/uploads/2018/06/friedman-lecture-1.pdf
25. Fahed, A. C., El-Hage-Sleiman, A. K., Farhat, T. I., & Nemer, G. M. (2012). Diet, genetics, and disease: A focus on the Middle East and North Africa region. Journal of Nutrition and Metabolism, 1–19. https://doi.org/10.1155/2012/109037 (Varsa DOI ya da link eklenebilir.)
26. Forson, J. A. (2024). Public sector corruption, FDI and sustainable development in Africa: Does the pollution halo or haven hypothesis hold in Ghana? Scientific African, 26, 1–19.
27. Grossman, G. M., & Krueger, A. B. (1991). Environmental impacts of a North American free trade agreement (NBER Working Paper No. 3914). National Bureau of Economic Research. https://www.nber.org/papers/w3914
28. Gujarati, D. N., & Porter, D. C. (2009). Basic econometrics (5th ed., pp. 192–198). McGraw-Hill Education.
29. Gunby, P., Jin, Y., & Reed, W. R. (2017). Did FDI really cause Chinese economic growth? A meta-analysis. World Development, 90, 242–255. https://doi.org/10.1016/j.worlddev.2016.10.001
30. Gyamfi, B. A., Adedoyin, F. F., Bein, M. A., & Bekun, F. V. (2021). Environmental implications of N-shaped Environmental Kuznets Curve for E7 countries. Environmental Science and Pollution Research, 28(25), 33072–33082. https://doi.org/10.1007/s11356-021-12967-x
31. Grolleau, G., & Weber, C. (2024). The effect of inflation on CO₂ emissions: An analysis over the period 1970– 2020. Ecological Economics, 217, 108029. https://doi.org/10.1016/j.ecolecon.2023.108029
32. Habib ur Rahman, H., Ghazali, A., Bhatti, G. A., & Khan, S. U. (2020). Role of economic growth, financial development, trade, energy and FDI in Environmental Kuznets Curve for Lithuania: Evidence from ARDL bounds testing approach. Engineering Economics, 31(1), 39–49. https://doi.org/10.5755/j01.ee.31.1.22087
33. Hossain, M. S., & Islam, M. M. (2020). Inflation uncertainty and economic growth in Bangladesh: Evidence from nonlinear ARDL approach. International Journal of Energy Economics and Policy, 10(2), 123–131. https://www.econjournals.com/index.php/ijefi/article/download/3234/pdf/10298
34. Hanif, I., & Gago-de-Santos, P. (2017). The importance of population control and macroeconomic stability to reducing environmental degradation: An empirical test of the environmental Kuznets curve for developing countries. Environmental Development, 23(1), 1–9.
35. Jebli, M. B., Youssef, S. B., & Ozturk, I. (2016). Testing environmental Kuznets curve hypothesis: The role of renewable and non-renewable energy consumption and trade in OECD countries. Ecological Indicators, 60, 824–831. http://dx.doi.org/10.1016/j.ecolind.2015.08.031
36. Jin, X., Xu, R., Farooq, U., Tabash, M. I., & Aljughaiman, A. A. (2024). How do inflation rate and energy alternatives influence environmental quality? A BRICS analysis. Energy Strategy Reviews, 53, 101369. https://doi.org/10.1016/j.esr.2024.101369
37. Kim, D. H., Huang, H. H., & Lin, S. C. (2011). Kuznets hypothesis in a panel of states. Contemporary Economic Policy, 29, 250–260.
38. Kalantari, S., Kazemipoor, H., Movahedi Sobhani, F., & Hadji Molana, S. M. (2022). Designing sustainable closed-loop supply chain network with considering spot-to-point inflation and carbon emission policies: A case study. Computers & Industrial Engineering, 174, 108748. https://doi.org/10.1016/j.cie.2022.108748
39. Khan, M. (2019). Does macroeconomic instability cause environmental pollution? The case of Pakistan economy. Environmental Science and Pollution Research, 26(14), 14649–14659.
40. Khan, M. A., & Ozturk, I. (2020). Examining foreign direct investment and environmental pollution linkage in Asia. Environmental Science and Pollution Research, 27(7), 7244–7255. https://doi.org/10.1007/s11356- 019-07363-7
41. Kashem, M. A., & Rahman, M. M. (2020). Environmental Phillips curve: OECD and Asian NICs perspective. Environmental Science and Pollution Research. Advance online publication. https://doi.org/10.1007/s11356-020-11107-6
42. Khan, M., & Ozturk, I. (2021). Examining the direct and indirect effects of financial development on CO₂ emissions for 88 developing countries. Journal of Environmental Management, 293, 112812, 1–13.
43. Kırıkçı, M. B. (2023). Kurumsal yapı ve doğrudan yabancı yatırımların karbon emisyonu üzerindeki etkisinin incelenmesi: E7 ülkelerinden kanıtlar. Uluslararası İktisadi ve İdari İncelemeler Dergisi, C-iasoS 2022 Özel Sayısı, 191–206. https://doi.org/10.18092/ulikidince.1234095
44. Kivyiro, P., & Arminen, H. (2014). Carbon dioxide emissions, energy consumption, economic growth, and foreign direct investment: Causality analysis for Sub-Saharan Africa. Energy, 74, 595–606. https://doi.org/10.1016/j.energy.2014.07.025
45. Klier, H., Schwens, C., Zapkau, F. B., & Dikova, D. (2017). Which resources matter how and where? A metaanalysis on firms’ foreign establishment mode choice. Journal of Management Studies, 54(3), 304–339.
46. Koca, A., & Sevinç, D. (2022). Çevresel Kuznets Eğrisi’nin BRICS-T ülkelerinde geçerliliği ve finansal gelişmişlik ve dışa açıklığın çevre kirliliği üzerindeki etkisi. İzmir İktisat Dergisi, 37(2), 318–333. https://doi.org/10.24988/ije.816882
47. Kohler, M. (2013). CO₂ emissions, energy consumption, income and foreign trade: A South African perspective. Energy Policy, 63, 1042–1050.
48. McKee, M., Keulertz, M., Habibi, N., Mulligan, M., & Woertz, E. (2017). Demographic and economic material factors in the MENA region. MENARA Working Papers, 3, 1–42.
49. Li, H., Shahbaz, M., Jiang, H., & Dong, K. (2021). Is natural gas consumption mitigating air pollution? Fresh evidence from national and regional analysis in China. Sustainable Production and Consumption, 27, 325– 336.
50. Mert, M., & Caglar, A. E. (2020). Testing pollution haven and pollution halo hypotheses for Turkey: A new perspective. Environmental Science and Pollution Research, 27, 32933–32943. doi:10.1007/s11356-020- 09469-7
51. Musarat, M. A., Alaloul, W. S., Liew, M. S., Maqsoom, A., & Qureshi, A. H. (2021). The effect of inflation rate on CO₂ emission: A framework for Malaysian construction industry. Sustainability, 13(3), 1562.
52. Musah, M., Mensah, I. A., Alfred, M., Mahmood, H., Murshed, M., Omari-Sasu, A. Y., ... Coffie, C. P. K. (2022). Reinvestigating the pollution haven hypothesis: The nexus between foreign direct investments and environmental quality in G-20 countries. Environmental Science and Pollution Research, 29, 31330– 31347. doi:10.1007/s11356-021-17508-0
53. Mahmood, H. (2023). Trade, FDI, and CO₂ emissions nexus in Latin America: The spatial analysis in testing the pollution haven and the EKC hypotheses. Environmental Science and Pollution Research, 30(6), 14439– 14454. doi:10.1007/s11356-022-23154-x
54. Mbassi, C. M., Hyoba, S. E. C., & Shahbaz, M. (2023). Does monetary policy really matter for environmental protection? The case of inflation targeting. Research in Economics, 77(3), 427–452. doi:10.1016/j.rie.2023.06.004
55. Orubu, C. O., & Omotor, D. G. (2011). Environmental quality and economic growth: Searching for environmental Kuznets curves for air and water pollutants in Africa. Energy Policy, 39(7), 4178–4188. doi:10.1016/j.enpol.2011.04.025
56. Oktavilia, S., & Firmansyah, F. (2016). The relationships of environmental degradation and trade openness in Indonesia. International Journal of Economics and Financial Issues, 6(6Special Issue), 125–129.
57. Öztürk, İ., &Acaravcı, A. (2016). Energy consumption, CO₂ emissions, economic growth and foreign trade relationship in Cyprus and Malta. Energy Sources, Part B: Economics, Planning, and Policy, 11(4), 321– 327.
58. Özmen, İ., &Balı, S. (2024). Pollution haven hypothesis: Smooth quantile evidence from BRICS. International Journal of Business and Economic Studies, 6(1), 48–58. doi:10.54821/uiecd.1434322
59. Panayotou, T. (1993). Empirical test and policy analysis of environmental degradation at different stages of economic development (Working Paper No. 238). Technology and Environment Programme, International Labour Office.
60. Pethig, R. (1976). Pollution, welfare, and environmental policy in the theory of comparative advantage. Journal of Environmental Economics and Management, 2(3), 160–169. doi:10.1016/0095-0696(76)90031-0
61. Paul, J., & Benito, G. R. (2018). A review of research on outward foreign direct investment from emerging countries including China: What do we know? How do we know? and Where should we be heading? Asia Pacific Business Review, 24(1), 90–115.
62. Paul, J., & Singh, G. (2017). The 45 years of foreign direct investment research: Approaches, advances, and analytical areas. The World Economy, 40(11), 2512–2527.
63. Pazienza, P. (2019). The impact of FDI in the OECD manufacturing sector on CO₂ emission: Evidence and policy issues. Environmental Impact Assessment Review, 77(1), 60–68. doi:10.1016/j.eiar.2019.04.002
64. Peña, E. M. S., Reyes, J. S., & Gonzalez, A. N. (2022). Assessment on the applicability of environmental Kuznets curve hypothesis on the macroeconomic factors driving carbon dioxide emissions in the Philippines. Journal of Economics, Finance and Accounting Studies, 4(1), 76–92. doi:10.32996/jefas.2022.4.1.5
65. Resmî Gazete. (1993, Nisan 21). Zararlı atıkların sınır ötesi taşınımının ve bertarafının kontrolüne ilişkin Basel Sözleşmesi’nin onaylanmasının uygun bulunduğuna dair kanun (Kanun No: 3940). Resmî Gazete, Sayı: 21534. https://www.resmigazete.gov.tr/arsiv/21534.pdf
66. Rahman, Z. U., Chongbo, W., & Ahmad, M. (2019). An (a)symmetric analysis of the pollution haven hypothesis in the context of Pakistan: A non-linear approach. Carbon Management, 10(3), 227–239. doi:10.1080/17583004.2019.1577179
67. Rakshit, B., & Neog, Y. (2022). Do macroeconomic uncertainty and financial development cause environmental degradation? Evidence from an emerging economy. International Journal of Social Economics, 49(5), 659– 678. https://doi.org/10.1108/IJSE-10-2020-0690
68. Sun, C., Zhang, F., & Xu, M. (2017). Investigation of pollution haven hypothesis for China: An ARDL approach with breakpoint unit root tests. Journal of Cleaner Production, 161, 153–163. https://doi.org/10.1016/j.jclepro.2017.05.086
69. Sarkodie, S. A., & Strezov, V. (2019). A review on environmental Kuznets curve hypothesis using bibliometric and meta-analysis. Science of the Total Environment, 649, 128–145. https://doi.org/10.1016/j.scitotenv.2018.08.276
70. Sun, H., Clottey, S. A., Geng, Y., Fang, K., & Amissah, J. C. K. (2019). Trade openness and carbon emissions: Evidence from belt and road countries. Sustainability, 11(9), 2682. https://doi.org/10.3390/su11092682
71. Suki, N. M., Sharif, A., Afshan, S., & Suki, N. M. (2020). Revisiting the environmental Kuznets curve in Malaysia: The role of globalization in sustainable environment. Journal of Cleaner Production, 264, 121669. https://doi.org/10.1016/j.jclepro.2020.121669
72. Singhania, M., & Saini, N. (2021). Demystifying pollution haven hypothesis: Role of FDI. Journal of Business Research, 123, 516–528. https://doi.org/10.1016/j.jbusres.2020.10.007
73. Shpak, N., Ohinok, S., Kulyniak, I., Sroka, W., Fedun, Y., Ginevičius, R., & Cygler, J. (2022). CO₂ emissions and macroeconomic indicators: Analysis of the most polluted regions in the world. Energies, 15(8). https://doi.org/10.3390/en15082928
74. Setyadharma, A., Oktavilia, S., Wahyuningrum, I. F. S., Nikensari, S. I., & Saputra, A. M. (2021). Does inflation reduce air pollution? Evidence from Indonesia. E3S Web of Conferences, 317, 01068. https://doi.org/10.1051/e3sconf/202131701068
75. Tatoğlu, F. Y. (2020). Panel veri ekonometrisi Stata uygulamalı, genişletilmiş beşinci baskı. Beta Basım Yayım Dağıtım A.Ş.
76. Tahir, M., Rehman, Z. U., & Javed, F. (2022). Asymmetric effects of inflation instability and GDP growth volatility on environmental quality in the USA. Human Nature Journal of Social Sciences, 3(1), 31–43.
77. Ullah, S., Apergis, N., Usman, A., & Chishti, M. Z. (2020). Asymmetric effects of inflation instability and GDP growth volatility on environmental quality in Pakistan. Environmental Science and Pollution Research, 27(24), 31892–31904. https://doi.org/10.1007/s11356-020-09310-y
78. Wang, J., & Dong, K. (2019). What drives environmental degradation? Evidence from 14 Sub-Saharan African countries. Science of the Total Environment, 656, 165–173.
79. Wang, S., Wang, H., & Sun, Q. (2020). The impact of foreign direct investment on environmental pollution in China: Corruption matters. International Journal of Environmental Research and Public Health, 17(18), 6477. https://doi.org/10.3390/ijerph17186477
80. Wan, G., Wang, C., Wang, J., & Zhang, X. (2022). The income inequality–CO₂ emissions nexus: Transmission mechanisms. Ecological Economics, 195, 107360.
81. Wencong, L., Kasimov, I., & Saydaliev, H. B. (2023). Foreign direct investment and renewable energy: Examining the environmental Kuznets curve in resource-rich transition economies. Renewable Energy, 208, 301–310. https://doi.org/10.1016/j.renene.2023.03.054
82. Wang, M., Liu, J., Rahman, S., Sun, X., & Sriboonchitta, S. (2023). The effect of China’s outward foreign direct investment on carbon intensity of Belt and Road Initiative countries: A double-edged sword. Economic Analysis and Policy, 77, 792–808. https://doi.org/10.1016/j.eap.2022.12.030
83. Yeşilorman, M., & Koç, F. (2014). Bilgi toplumunun teknolojik temelleri üzerine eleştirel bir bakış. Fırat Üniversitesi Sosyal Bilimler Dergisi, 24(1), 117–133.
84. Zarsky, L. (1999). Havens, halos and spaghetti: Untangling the evidence about foreign direct investment and the environment. Foreign Direct Investment and the Environment, 8, 47–74. URL: https://www.iatp.org/sites/default/files/Conference_on_Foreign_Direct_Investment_and_th.pdf
85. Zhang, Y. J. (2011). The impact of financial growth on carbon emissions: An empirical analysis in China. Energy Policy, 39, 2197–2203.
86. Zhang, C., & Zhou, X. (2016). Does foreign direct investment lead to lower CO₂ emissions? Evidence from a regional analysis in China. Renewable and Sustainable Energy Reviews, 58, 943–951. https://doi.org/10.1016/j.rser.2015.12.226
87. Zhu, H., Duan, L., Guo, Y., & Yu, K. (2016). The effects of FDI, economic growth and energy consumption on carbon emissions in ASEAN-5: Evidence from panel quantile regression. Economic Modelling, 58, 237– 248. https://doi.org/10.1016/j.econmod.2016.05.003
88. Zafar, M. W., Zaidi, S. A. H., Khan, N. R., Mirza, F. M., Hou, F., & Kirmani, S. A. A. (2019). The impact of natural resources, human capital, and foreign direct investment on the ecological footprint: The case of the United States. Resource Policy, 63, 101428.
89. Zoundi, Z. (2017). CO₂ emissions, renewable energy and the environmental Kuznets curve: A panel cointegration approach. Renewable and Sustainable Energy Reviews, 72, 1067–1075.