Plastics in Ocean: Formation of Garbage Patch and a way to mitigate it.

Levey (2015) mentions, "90% of sea bird sallow plastic"; which is reinforced by Wilcox et al. (2015) recent article, suggesting that threat of plastic to sea bird is increasing and spreading. Plastic wastes is major source of land and sea pollution. No wonder, plastic has revolutionized the global economy, however, increase in its use are responsible for environmental degradation, especially in ocean (Gregory, 2009). In this post, I will review three papers, which insight the composition of beach litter, formation of garbage patch and making international mechanism on sea pollution work better.

Kordella et al. (2013) studied the litter collected from volunteer clearer from 60 beaches along Greece in 2006 and a year later. The collection location consist of island, gulf (open and semi-open), lake etc. The litter is categorized broadly into metal, plastic, building material etc. Sources were classified broadly into land based (recreational and other); and marine based (navigation and fishery). R-factor and hierarchical cluster analysis method were used to analyse the data. Around 110 thousand items were observed. Among which plastic constituted 43% a dominant source of sea garbage. The analysis showed, plastic having dominant composition, affects beach regardless of its origin and location. The study suggest supply of solid waste facilities would help reduce these waste enter into ocean.

What happens to the plastic when it enters the ocean? Sebille, (2015) describe that the plastic travels far away by winds and eddies and finally settles down in garbage patch. The main forcing mechanism is spiral winds at specific location of ocean. Westerly and Easterly circulation are responsible for Ekman Transport, pushing the plastic into spiral movement in centre of gyres. Modelling of plastic movement suggest that plastic travel ends around subtropical gyres, forming garbage patch. The study doesn't support the argument of garbage island.

Source: Sebille, 2015

Schroed, Matthew(2010)  discusses about the mounting waste in the pacific ocean in between Hawaii and San Francisco located in North Pacific Sub-tropical Gyers and named Eastern Garbage Patch. Wind blowing in the gyres bring the garbage and dump it in the patch. Estimates suggest 90% of garbage is of plastic bag(Moor, 2003). This huge amount of plastic accumulate. Some part of it is broken down as plastic granule which spread along ocean and is eaten by sea animals like Whale, or birds. Fish nets entangles marine animals like Seal  and tortoise. Different international treaties are in place. The article discusses about the weak enforcement of these global and regional treaties related to pollution on ocean like UN Convention of the Law of Seas (UNCLOS). Author present Barcelona convention, which has both binding provision and voluntary provision with monitoring and enforcement mechanism, as effective enough protocol to reduce entrance of garbage to ocean. Author suggest for the replication of the convention based protocol for managing pollution in Ocean. The study also suggest three strategy (domestic management, monitoring of pollutant and dispute resolution mechanism). The take-away lessons from the study is, failure of the international treaties is also a cause of expanding garbage patch in ocean, convention-protocol are effective than UNCLOS modality, as they can target specific area of pollution and adoption of unilateral pollution control measures by countries will increase the effectiveness. 

Given marine life is important regulator of atmospheric GHG and global ecosystem services, formation of garbage patch is an critical concern. Global engagement as suggested by the article and rigorous study on effect of plastic in GHG circulation could strengthen the global #actonclimate. This could help falsify the news by Independent "almost every seabird will have eaten plastic by 2050 because of ocean pollution"