Green Economy in a Blue World-Full Report

1. Introduction: ocean nutrient pollution presents an important opportunity for the Green Economy Most human activity is conducted in the coastal zones or within river catchments that discharge to coastal zones. The consequence of these activities, be they farming, industrial production, transport, power generation or urban development, is the inevitable release of pollutants – nutrients, solids, organic chemicals, metals, etc. – to water, land and air. Over the last fewdecades there have been considerable efforts to reverse the historical approach of dumping wastes, including nutrients, into the oceans and to reduce the associated degradation of coastal and ocean water quality and ecosystems. This drive for pollution reduction has responded to human health concerns or preservation of the environment to protect, for example, drinking water quality or the wider ecosystem. These improvementshavebeendrivenbyacombination of national or regional regulations, economic and financial instruments, and international treaties responding to wider public concerns and the need for a healthy environment. While many of the identified hazardous or persistent pollutants are controlled or in the process of being controlled (such as through the Stockholm Convention and Montreal Protocol), the issue of excess reactive nitrogen (and phosphorus) in the environment still needs to be addressed in a coherent and integrated manner. Reactive nitrogen and phosphorus are essential to all plant life, both terrestrial and marine

(including the free-living microscopic marine algae called phytoplankton), and to the animals that feed on these plant products. In most areas of the ocean, nitrogen is considered a limiting nutrient whose presence (or absence) largely determines the level of primary production (production by plankton of organic carbon via photosynthesis) and the broader level of biological activity (secondary production, fisheries biomass, etc.) in a given ocean area. Over about the last 60 years, the dependence of developed (and increasingly, many developing and/or middle-income) countries on fertilizers containing nitrogen and phosphorus to enhance agricultural productivity has led to massive increases in the production and application of fertilizers to farmed land (figure below). The often inefficient use of this fertilizer has led to substantial run-off and releases of nitrogen and phosphorus to waterways and groundwater, which, combined with comparable losses of nutrients from livestock (manure) operations, and the inadequacy of much of the world’s waste-water treatment, has resulted in substantial increases in releases of nutrients both directly to the coastal zone and via rivers receiving emissions from upstream population centres and agriculture. The massive increase in anthropogenic reactive nitrogen introduced into the environment, deriving principally from the mass production of nitrogen fertilizers, has had significant negative environmental consequences (Drinkwater, et al. 2009) (Brown, 2011). The link between industrial agriculture and reactive nitrogen pollution is well established with impacts on drinking water (Powlson, et al. 2006) (Galloway, et al. 2008)

in a Blue World

and the eutrophication of fresh water and marine ecosystems, including the proliferation of harmful algal blooms and hypoxic “dead zones” in marine ecosystems such as the Black Sea, Gulf of Mexico, Baltic Sea and elsewhere. Eutrophication occurs when excess nutrient inputs feed overgrowth of ocean plankton; dying plankton are consumed by oxygen- using bacteria which can lead to low oxygen or hypoxic conditions. This can have significant negative impacts on fisheries, food security and livelihoods, and lead to degradation of habitats which not only have important biodiversity values but, in the case for example of coral reefs, can result in the loss of natural coastal defences. The relatively recent rapid growth in the occurrence of ocean hypoxic zones has resulted from a roughly threefold increase in global loads of reactive nitrogen to the oceans compared to

Production of nitrogen fertilizer in relation to world population

Nitrogen, million tonnes

Population, million

6 000

100

World population

80

5 000

4 000

60

40

3 000

20

2 000

Total Nitrogen produced

0

1 000

1850

1900

1950

2000

Source: Dawson and Hilton, 2011

78