Research Interest (updated on July 25, 2024)

I am broadly interested in climate change economics. More specifically, my research mostly focuses on materials and resource efficiency, sustainable development, input substitution, and convergence topics. The majority of my studies are based on some empirical investigations and I generally apply various panel data econometric techniques to country- and industry-level datasets in my works. My future research agenda will be directed toward three important topics: the emerging role of material demand and material efficiency strategies as a mitigation policy, the identification of discrepancies between production-based and consumption-based emissions for international climate change regime and national climate policy-making, and the growing concerns about the environmental impact of income inequality. In this statement, I summarize the contributions of my past and current research and state my future research plans.

Before completing my doctoral research, I have been awarded a scholarship to participate in the Advanced Studies Program organized by the Kiel Institute for the World Economy in Germany. During my stay in Kiel, I wrote a research paper on strategies to mitigate CO2 emissions through the input substitution channel at the industry level in Germany. This is the first study to investigate the degree of substitution in Germany for a wide range of industries by incorporating the slow response of substitution adjustment. This research paper supervised by Dr. Eckhardt Bode has been published in the Environmental Science and Pollution Research in 2020. Besides, during the writing-up process of my Ph.D. dissertation, I have written three research papers on convergence in CO2 emissions. While the paper published in Energy Economics mainly examines whether CO2 emissions converge among industrial countries by replicating the findings of an influential paper in the existing literature, the other one performs a similar empirical analysis by considering differences in production- and consumption-based emissions. My paper in Energy Efficiency investigates the existence of stochastic conditional convergence in energy consumption at the sectoral level from a developing country perspective with a special emphasis on Turkey.

After defending my Ph.D. thesis, I have intensively focused on climate change economics topics in my research activities. In a very short time, I have published several solo- and co-authored peer-reviewed articles in reputable journals indexed in the WOS core collection, such as Resources Policy, Resources Conservation & Recycling, Journal of Environmental Management, Research in Transportation Economics, and Sustainable Production and Consumption. In my recent articles, I largely focus on three crucial topics: the technology-environment nexus, the environmental effect of income inequality, and the critical role of materials in mitigating emissions. 

Regarding the impact of technology on the environment, I have so far published two solo-authored papers. In both articles, I mainly explore the effect of information and communication technologies (ICTs) on the environment using some panel data cointegration techniques and estimators. The paper published in the Research in Transportation Economics investigates the relationship between environmental technologies and CO2 emissions from the transport sector for the EU15 members for the first time, whereas the article in the Journal of Environmental Management analyses the ICT-environment nexus for a large sample of countries classified endogenously based on transitional behavior of per capita CO2 emissions. As to the environment-inequality nexus topic, I have written a book chapter on the inequality-environment nexus in an interdisciplinary book published by Springer and edited by three scholars from Harvard University and Tulane University. In this book chapter, I discuss the theoretical mechanisms explaining the channels running from income distribution to environmental quality and conduct an empirical investigation for a panel of 120 countries using the system generalized method of moments. 

The topic that I have been intensively working on recently is the emerging role of material use in greenhouse gas emission mitigation. Regarding this topic, I have published three important articles. My paper in Sustainable Production and Consumption investigates the degree of substitution between inputs at the industry level, with a particular focus on substitution/complementarity possibilities between energy and materials. In this paper, I argue that climate mitigation policies should be designed based on these industries’ specific needs and peculiarities by highlighting the importance of materials and material efficiency policies. My other study published in Resources Policy compares the widely-used domestic material consumption (DMC) indicator with material footprint (MF) to investigate how the EU countries' performances evolve over the period in terms of material use indicators. In this study, I also identify the main driving forces of DMC and MF with the Logarithmic Mean Divisia Index (LMDI) method to discuss the implications for effective policy-making in the EU. My paper in Resources Conservation & Recycling reveals that material productivity might have a greater potential for further reductions in emissions once policies are directly targeted for efficient use of material, which can enable the EU to achieve to become carbon-neutral by 2050. In addition to these three articles, my article entitled “Industrial Decarbonization: The Role of Material Efficiency Strategies” discusses the critical role of material efficiency in the industrial sector from the mitigation policy perspective and explores material efficiency strategies. My forthcoming book chapter in Springer reviews the role of critical raw materials (CRMs) in green energy transition and discusses the main risks and challenges associated with CRMs that could affect the transition to clean energy. We also discuss key strategies to tackle the supply risk by mainly focusing on the circularity aspects of strategies, and identify investment needs, and possible financial and economic policies to address this critical issue.

After getting my Ph.D. degree, I have intensively focused on climate change economics topics in my research activities, as indicated earlier. However, I have also studied some other topics, although not very intensively. I have studied production functions, income convergence, and elasticity of substitution in my doctoral dissertation. I published two articles from my dissertation. In the paper published in the Journal of Economic Studies, I examine whether the elasticity of substitution (ES) varies between developed and developing countries based on the growth regressions from the Solow model under the constant elasticity of substitution production function. My paper in the Journal of Economic and Administrative Sciences, on the other hand, investigates income convergence using different convergence concepts and methodologies. The results clearly show that heavily relying on one of the convergence techniques might lead researchers to obtain misleading results regarding the existence of convergence. Besides, in my recently published article in Social Indicators Research, I investigate the regional distribution of total public expenditures and its nine different sub-categories to reveal regional disparities in Turkey. My article published in Applied Economic Letters investigates the regional disparity of financial inclusion and its determinants in Turkey from 2004 to 2020.

As stated earlier, I intend to pursue the following research directions: the critical role of materials for a sustainable future, discrepancies between production-based and consumption-based emissions, and the environmental impact of income inequality. 

(i) The critical role of materials for a sustainable future

As many countries set out net-zero emission targets after the Glasgow Climate Meeting (COP26), green energy transition become more viable. There is no doubt that setting net-zero carbon emission targets will eventually enforce policymakers to develop more ambitious and innovative policies to implement. However, such an ambitious energy transition will require an enormous amount of materials. Therefore, some studies recently highlight the importance of materials and emphasize that relying exclusively on the energy sector and direct emissions on its own might fail the fight against deeper GHG reductions, if not supplemented with policies directly targeting material use and its embodied emissions associated with it. For example, according to the International Resource Panel (IRP) data, growth in material use has been significantly higher than energy use at the global scale. As the report reveals, while material extraction has increased by 3.4 times between 1970 and 2017, fossil energy extraction has increased by 2.5 times for the same period. As a result, material use per capita increased from 7.4 tonnes in 1970 to 12.2 tonnes in 2017. Such excessive use of material production consequently led to an increase in emissions by 120% between 1995 and 2015, raising its share to 25% in global total GHG emissions. It is worth noting that while material use in the current situation makes up almost 50% of the carbon footprint of many heavy industries and major material-using value chains, the embodied emissions caused by the intermediate input are projected to further increase in the future if not dealt with seriously. Therefore, more attention should be given to material efficiency in production as a significant part of energy consumption and its associated emissions, which are closely linked to the extraction, processing, transportation, and use of material. However, improvements in material efficiency have so far lacked behind labor and energy efficiency as the international community and individual countries overlooked the importance of material use and its mitigation potential as an effective way of reducing GHG emissions. Some scholars thus argue that the potential for material efficiency is considerably larger than the energy efficiency achievements and simply reducing demand for materials will consequently result in a reduction in energy that is embodied in material use.

In this regard, considering the issues introduced above, I plan to focus on the following topics in my future research agenda: 

(ii) Production- and consumption-based emissions

From the climate policy perspective, both national carbon emissions reduction targets and international climate change regimes heavily rely on production-based emissions (PBE). However, only focusing on PBE may not significantly help us broaden our knowledge. We, therefore, pay special attention to the critical role of an alternative way of emissions accounting that is based on consumption. Unlike PBE, consumption-based emissions (CBE) are calculated based on domestic final consumption and include imports. Needless to say, global CO2 emissions will remain the same regardless of the accounting method (PBE or CBE), meaning that the geographical distribution of CO2 emissions (for example, due to the outsourcing of the production of some carbon-intensive products in the advanced economies to emerging or less-developed countries) does not affect the total amount of CO2 emissions in the atmosphere. Yet, it might, for example, critically affect the political economy of negotiating multilateral agreements on climate change. Therefore, the difference between these two emissions accounting systems is essential and might lead us to capture some important outcomes and inferences regarding many different crucial topics, such as pollution heaven, carbon leakage, or embodied emissions in trade.

In this regard, I plan to focus on the following topics in my future research agenda:

(iii) The environmental effect of income inequality

Income inequality and climate change are two major threats faced by humankind in the twenty-first century. They undoubtedly play a key role in shaping our ecosystem and future. Therefore, both of them have gained significant attention from researchers and policymakers worldwide during the last decades. Recent model projections and data also confirm their importance. For example, according to the Intergovernmental Panel on Climate Change (IPCC, 2018), global warming due to human activities might cause further changes in the climate system if global net anthropogenic carbon emissions have not been reduced by about 45% from 2010 levels by 2030. Similarly, absolute income disparities continue to increase. As shown in the United Nations (2020) report, the per capita income gap between high and low-income countries increased from 27,600$ to 42,800$ between 1990 and 2018. Therefore, reducing inequality within and among countries, which is integral to achieving the Sustainable Development Goals (SDGs), still remains a distant goal by 2030.

The simultaneous worsening of both income distribution and environmental outcomes raises the following question: Does there exist a relationship between these two indicators? Or, more specifically, does income inequality have significant implications for climate change?  The answer to this question is regarded as highly important in the existing literature from the economic and environmental policy perspectives. It is because the balance of power between the poor and the rich is considered to have a substantial potential to determine the level of environmental degradation. The importance of this issue is also strongly supported by recent data. According to the Oxfam (2020) report, while the richest 10% is responsible for 46% of total emissions growth, it is 49% and 6% for the middle 40% and the poorest 50%, respectively.

In this regard, I intend to study these topics in the future: