Socioeconomic drivers of marine debris in North America

Highlights

• The paper examines socioeconomic footprints on marine debris in the United States.

• We find empirical evidence for the “Environmental Kuznets Curve” hypothesis.

• Population growth along coastlines contributes to greater debris accumulation.

• Social capital and education play significant role in curbing debris pollution.

Abstract

Economic development, coastal population growth, and expansion of tourism-related activities along coastlines have been the leading causes of marine debris pollution worldwide. While the problem of marine debris pollution has been increasingly recognized, there has been limited research on its socioeconomic drivers, primarily due to a paucity of consistent data on debris. The research described here utilizes newly available data from the U.S. National Oceanic and Atmospheric Association (NOAA) on marine debris along eight coastal states of North America to examine the relationship of such debris pollution with socioeconomic variables including population, age, education, and tourism, as well as the mitigating effect of social capital on debris pollution. The results indicate that marine debris increases with income; however, at higher income levels the amount of pollution starts to decline, supporting the “Environmental Kuznets” hypothesis. We also find that population growth along coastlines contributes to greater debris accumulation. Our results further highlight the significant roles social capital and education play in curbing debris pollution. Understanding the socioeconomic drivers of marine debris is an important first step in informing abatement policy and allocation of resources by public agencies to address the marine pollution problem.

Introduction

Rapid industrial growth and human settlements in coastal areas have contributed to an elevated exploitation of valuable coastal resources and the marine environment (Kennish, 1996). The world's bodies of water are used as dumping grounds for waste from air, land, and water-based sources, exacerbating the marine pollution problem (Chung, 1986; Crain et al., 2008; Kennish, 1996). Marine pollution, in turn, adversely impacts not only marine species and the economic sectors dependent on them (Derraik, 2002), but also the provision of a wide range of ecosystem services that directly and indirectly contribute to human well-being (Beaumont et al., 2019; Grizzetti et al., 2016) and could have concerning wildlife and human health implications (United Nations Environment Programme [UNEP] 2011). From a policy and coastal planning perspective, it is thus important to understand how coastal development contributes to marine pollution and the potential ways to mitigate unintended consequences of human settlements in coastal areas.

This paper examines socioeconomic footprints on the marine environment in terms of debris pollution. Marine debris is defined as materials ranging from rubber, paper, plastic, polystyrene, glass, metal, wood, ceramics, and fishing gear and lines (Sheavly, 2010). Debris enters the water from multiple sources, some of which are land-based, such as litter, industrial discharge, and poor waste management, as well as ocean-based sources, primarily commercial and recreational fishing vessels (Ribic et al., 2010). In several regions across the globe, land-based sources, rich in hard plastic materials, are considered the most prominent in terms of amount of debris entering the system (Eastman et al., 2013; Slavin et al., 2012). In the United States, while there is regional variation in amounts of debris accumulation and the overall trend, and because fishing activities are relatively stabilized, it has been suggested that the Mid-Atlantic region exhibits a heavy and upward trend in land-based source debris (Ribic et al., 2010). On the Pacific West Coast, Hawaii has the largest amount of debris, while Southern California exhibits the highest amount of debris accumulation from land-based sources (Ribic et al., 2012). Marine debris is regarded as one of the most ubiquitous and highly understudied problems plaguing the world's oceans today (Hofer, 2008; Laist, 1997; Sheavly and Register, 2007). The total number of estimated marine debris particles is approximately 9.6 million, with the highest concentration recorded in the North Atlantic and North Pacific Oceans (Lebreton et al., 2012). The majority of studies focusing on modelling marine debris have been conducted at small spatial scales, often along small stretches of ocean basins, estuaries, islands, and beaches (Becherucci et al., 2017; Mansui et al., 2015; Pichel et al., 2012; Zhou et al., 2011). The lack of comprehensive study has been due to the paucity of consistent data on marine debris. We contribute to this line of research by utilizing newly available data on marine debris from the National Oceanic Atmospheric Association (NOAA) to focus on understanding the socioeconomic drivers of debris pollution along the U.S. coastlines.

An important contribution of this research is to show empirical evidence for the Environmental Kuznets Curve (EKC) hypothesis. The EKC states that at the early stage of economic development, environmental pollution grows rapidly, because people are more concerned about jobs and economic growth and they lack resources for abatement (Stern, 2004). However, the relationship shifts with the rise of income. This happens because people start to more highly value a clean environment; leading pollution industries become cleaner; and there is a strong public policy push for pollution regulation and abatement (Dasgupta et al., 2002; Lambin and Meyfroidt, 2010). Past EKC studies have focused on measuring environmental degradation in terms of air quality (Panayotou, 1997; Selden and Song, 1994; Stern and Common, 2001) and water quality (Torras and Boyce, 1998). However, to the best of our knowledge, no prior study has examined or provided empirical evidence for this hypothesis in the context of marine debris pollution.

Another important contribution is investigation of the mitigating effect of civic engagement, a proxy for social capital, on marine debris pollution. Social capital could promote behaviors that result in effective realization of a society's goals (Coleman, 1988), thus playing a vital role in combating the marine debris problem.

The results of this research indicate a statistically significant non-linear relationship between income and the level of marine debris pollution, thereby lending support to the EKC hypothesis. Furthermore, significant effects of population growth are found to lead to proliferation of marine debris pollution. Our results also suggest empirical evidence that social capital offsets the effects of these contributing factors on marine debris pollution.

Marine debris pollution is regarded as a purely anthropogenic form of pollution, making the phenomenon a direct reflection of the attitudes and perceptions of people toward the marine environment. These attitudes are shaped by varying individual attributes, including (among other things) educational attainment, socioeconomic and demographic status, and awareness. Understanding socioeconomic footprints on the marine environment, realized in terms of debris accumulation, is an important first step in policy making related to its abatement and allocation of resources by public agencies to curb it.