Abstract:
In the age of the Anthropocene, the Ocean have typically been viewed as a sink for our pollution. Pollution is varied, ranging from human-made plastics and pharmaceutical compounds, to human-altered abiotic factors, such as sediment and nutrient runoff. As the global population, wealth and resource consumption continues to grow, so too does the amount of pollution we produce. This presents us with a grand challenge which requires interdisciplinary knowledge to solve. While there is sufficient data on the human health, social economic, and environmental risks of marine pollution, a significant lag exists when implementing strategies to address this issue. We gathered 17 experts from the fields of social sciences, marine science, visual arts, logistics and traditional and first nations knowledge holders to present two futures; the Business-as-usual, based on current trends and observations of growing marine pollution, and a More Sustainable Future, which imagines what our Ocean could look like if we implemented current knowledge and technologies. We identified priority actions that governments, industry and consumers can implement at pollution sources, vectors and sinks, over the next decade to reduce marine pollution and steer us towards the More Sustainable Future.
Keywords: future scenario, Sustainable Development Goals (SDGs), pollution, ocean decade, 2030, sustainable solutions
Introduction
The Ocean has historically been a sink for pollution, leaving modern society with significant ocean pollution legacy issues to manage (Elliott and Elliott 2013; O’Shea et al. 2018). People continue to pollute the Ocean at increasing rates creating further damage to marine ecosystems. This results in detrimental impacts on livelihoods, food security, marine navigation, wildlife and well-being, among others (Krushelnytska 2018; Lebreton and Andrady 2019; Nichols 2014; Seitzinger et al. 2002). As pollution presents a multitude of stressors for ocean life, it cannot be explored in isolation (Khan et al., 2018). Thus, global coordinated efforts are essential to manage the current and future state of the Ocean and to minimise further damage from pollution (Krushelnytska 2018; Macleod et al. 2016; O’Brien et al. 2019; Williams et al. 2015). Efforts are also needed to tackle key questions, such as how do pollutants function in different environments, and interact with each other?
Pollution can be broadly defined as any natural or human-derived substance or energy that is introduced into the environment by humans and that can have a detrimental effect on living organisms and natural environments (UNEP 1982). Pollutants, including light and sound in addition to the more commonly recognised forms, can enter the marine environment from a multitude of sources and transport mechanisms (Carroll et al. 2017; Depledge et al. 2010; Longcore and Rich 2004; Williams et al. 2015). These may include long range atmospheric movement (Amunsen et al. 1992) and transport from inland waterways (Lebreton et al. 2017).
Current pollutant concentrations in the marine environment are expected to continue increasing with global population growth and product production. For example, global plastic production increased by 13 million tonnes in a single year (PlasticsEurope 2018), with rising oceanic plastic linked to such trends (Wilcox et al. 2020). Pharmaceutical pollution is predicted to increase with population growth, resulting in a greater range of chemicals entering the Ocean through stormwater drains and rivers (Bernhardt et al. 2017; Rzymski et al. 2017). Additionally, each year new chemical compounds are produced whose impacts on the marine environment are untested (Landrigan et al. 2018).
Marine pollution harms organisms throughout the food-web in diverse ways. Trace amounts of heavy metals and persistent organic pollutants (POPs) in organisms have the capacity to cause physiological harm (Capaldo et al. 2018; Hoffman et al. 2011; Salamat et al. 2014) and alter behaviours (Brodin et al. 2014; Mattsson et al. 2017). Artificial lights along coasts at night can disrupt organism navigation, predation and vertical migration (Depledge et al. 2010). Pharmaceutical pollutants, such as contraceptive drugs, have induced reproductive failure and sex changes in a range of fish species (Lange et al. 2011; Nash et al. 2004). Furthermore, some pollutants also have the capacity to bioaccumulate, which means they may become more concentrated in higher trophic marine species (Bustamante et al. 1998; Eagles-Smith et al. 2009).
Pollution also poses a huge economic risk. Typically, the majority of consequences from pollution disproportionately impact poorer nations who have less resources to manage and remediate these impacts (Alario and Freudenburg 2010; Beaumont et al. 2019; Golden et al. 2016; Landrigan et al. 2018). Marine pollution can negatively impact coastal tourism (Jang et al. 2014), waterfront real estate (Ofiara and Seneca 2006), shipping (Moore 2018) and fisheries (Hong et al. 2017; Uhrin 2016). Contamination of seafood poses a perceived risk to human health, but also incurs a significant financial cost for producers and communities (Ofiara and Seneca 2006; White et al. 2000). Additionally, current remediation strategies for most pollutants in marine and coastal ecosystems are costly, time consuming and may not prove viable in global contexts (Ryan and Jewitt 1996; Smith et al. 1997; Uhrin 2016).
Reducing marine pollution is a global challenge that needs to be addressed for the health of the Ocean and the communities and industries it supports. The United Nations proposed and adopted 17 Sustainable Development Goals (SDGs) designed to guide future developments and intended to be achieved by 2030. It has flagged the reduction of marine pollution as a key issue underpinning the achievement of SDG 14, Life Under Water, with target 14.1 defined as “prevent and significantly reduce marine pollution of all kinds, in particular from land-based activities, including marine debris and nutrient pollution” by 2025 (United Nations General Assembly 2015). In the UN Decade of Ocean Science (2021-2030), one of the six ocean outcomes relate specifically to the reduction and identification of marine pollution (A Clean Ocean; UN DOS SD). The task of reducing marine pollution is daunting - the Ocean is so vast that cleaning it seems almost impossible. However, effective management of pollution at its source is an effective way to reduce it and protect the Ocean (DeGeorges et al. 2010; Rochman 2016; Simmonds et al. 2014; Zhu et al. 2008). Strategies, implemented locally, nationally and globally, to prevent, or considerably reduce pollution inputs in combination with removing pollutants from the marine environment (Sherman and van Sebille 2016) will allow healthy ocean life and processes to continue into the future.
To help explain how we can most effectively address pollution sources and clean the Ocean, we depict two different future seas scenarios by 2030. The first is a business-as-usual scenario, where we continue to adhere to current management and global trends. The second is a technically achievable, more sustainable future that is congruent with the SDGs, and where we actively take actions and adopt sustainable solutions. We then explore pollution in three ‘zones’ of action; at the source(s), along the way, and at sink, in the context of river or estuarine systems, as water-transported pollution is commonly associated with urban centres alongside river systems (Alongi and McKinnon 2005; Lebreton et al. 2017; Lohmann et al. 2012; Seitzinger and Mayorga 2016).