Re-examining the environmental kuznets curve hypothesis in the economic community of West African states: A panel quantile regression approach Ahmed Malumfashi Halliru a, b , Nanthakumar Loganathan a , Asan Ali Golam Hassan c , Abbas Mardani d, e, ** , Hesam Kamyab f, * a Azman Hashim International Business School, Universiti Teknologi Malaysia, 81310, Johor Bahru, Johor, Malaysia b Department of Economics, Umaru Musa Yar’adua University, Katsina, Katsina State, Nigeria c Azman Hashim International Business School, Universiti Teknologi Malaysia, 54100, Kuala Lumpur, Malaysia d Informetrics Research Group, Ton Duc Thang University, Ho Chi Minh City, Viet Nam e Faculty of Business Administration, Ton Duc Thang University, Ho Chi Minh City, Viet Nam f Engineering Department, Razak Faculty of Technology and Informatics, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100, Kuala Lumpur, Malaysia article info Article history: Received 26 January 2020 Received in revised form 23 August 2020 Accepted 14 September 2020 Available online 19 September 2020 Handling Editor: Prof. Jiri Jaromir Kleme s Keywords: CO 2 emissions Economic growth Human capital EKC hypothesis ECOWAS abstract This study investigates the validity of the Environmental Kuznets Curve (EKC) hypothesis for six West African countries over 1970e2017 while using human capital and biocapacity as additional determinants of carbon emissions. It uses the panel quantile regression method that provides robust results in case the classical econometric assumptions fail. The empirical results revealed that a U-shaped relationship be- tween economic growth and Carbon dioxide (CO 2 ) emissions holds in the low, middle and high- emissions countries as opposed to the inverted U-shaped EKC hypothesis. Trade openness reduces environmental performance in low-emission countries. Financial development has mixed impacts on CO 2 emissions across the quantiles. While financial development enhances environmental quality in the low-emissions countries, it exerts a detrimental impact in the middle and high-emissions countries. Human capital has significantly positive effects on the lower, middle and upper quantiles. The obtained results highlight the need for raising environmental awareness and promoting green R&D. In addition, relevant incentives are required to redirect private credits towards green projects and renewable energy development. © 2020 Elsevier Ltd. All rights reserved. 1. Introduction The increasing global warming and changes to climatic condi- tions are results of rising energy consumption in industry sector, high economic growth, consequently has led to environmental variation around the globe (Waqih et al., 2019). As part of the response to this challenge, the international community is aimed at limiting the average global temperature to 2  C above the pre- industrial temperature. To this end, the United Nations adopted the ‘2030 Agenda for Sustainable Development’ and the ‘Paris Climate Change Agreement’ in 2015. Yet, the Intergovernmental Panel on Climate Change predicted that global temperature could even rise to 5.8  C by 2100 and this, according to Pao and Chen (2019), points to the fact that the task of mitigating climate change is enormous, and it is imperative to formulate policies to combat climate change in a way to prevent its devastating effects on humanity and environment. Katircioglu et al. (2020) asserted that a large body of research endeavored to analyse the determinants of environmental degra- dation to aid better understanding and formulation of sound environmental policies to mitigate climate change. Evidence indi- cate that rising economic activities is a major driving force that significantly alters environment condition. West African sub-region * Corresponding author. ** Corresponding author. Informetrics Research Group, Ton Duc Thang University, Ho Chi Minh City, Viet Nam. E-mail addresses: halliruam77@gmail.com (A.M. Halliru), n4nantha@yahoo.com (N. Loganathan), asanali@utm.my (A.A. Golam Hassan), abbas.mardani@tdtu.edu.vn (A. Mardani), hesam_kamyab@yahoo.com (H. Kamyab). Contents lists available at ScienceDirect Journal of Cleaner Production journal homepage: www.elsevier.com/locate/jclepro https://doi.org/10.1016/j.jclepro.2020.124247 0959-6526/© 2020 Elsevier Ltd. All rights reserved. Journal of Cleaner Production 276 (2020) 124247