|Ocean Acidification: Social and Economic Effects|
The ocean provides about half of the Earth's productivity and humankind takes direct advantage of this through our fisheries and shellfisheries. The wide range of goods and services provided by marine environments are essential for the maintenance of social and economic well being all over the globe. They provide food and jobs for millions of people as well as protecting our coastlines. The benefits can be seen locally, regionally and globally and support many individuals and businesses. In many developing countries people's livelihood depends on the protection and sustainability of these environments. Multi-million pound fisheries and aquaculture industries employ hundreds of thousands of people. The current rate of ocean acidification is destroying these delicate marine environments, having a direct economic impact all over the world.
Many planktonic marine organisms are able to fix carbon dioxide through photosynthesis and transfer a proportion of it to the deep sea. This biological pump and its buffering effect have been found to remove 3 GtC/yr of anthropogenic carbon dioxide from the atmosphere. A reduction in ocean productivity and the biological pump would have substantial environmental and economical impacts. The economic cost of replacing these natural processes of carbon dioxide absorption with industrial processes is in the order of $90-600 billion/yr.
Mounting evidence indicates that ocean acidification may reduce the availability of biologically important nutrients such as nitrogen, phosphates, silica and iron, many of which are used by primary producers. This will in turn alter food chains that are dependent on these primary producers. Similarly, evidence shows it to impair calcification in some calcifying organisms due to a decrease in the saturation states of the common carbonate minerals, aragonite and calcite. This includes commercially valuable mollusks, crustaceans and echinoderms. Molluscs alone accounted for $748 million (19%) of US domestic ex-vessel revenues in 2007. Further, most other commercially harvested species, such as finfish, prey on these shellfish, echinoderms, crustaceans or their predators.
Since 2005, there has been progressive decline in the $111 million/annum oyster industry in the US Pacific North-west region as year-after-year oyster larvae have failed to survive. They suspect that the corrosive acidified waters from the deep Pacific Ocean are rising up and are now being pumped into seaside hatcheries. It is thought that the water may be corrosive enough to kill oyster larvae. This will also affect the pearl industry as pearls can be cultured artificially in oysters as well as created naturally by shellfish through the secretion of aragonite. Currently, the global pearl farming industry is worth $1.5 - $3 billion per year industry, however, reduction in aragonite saturation due to ocean acidification may impact the rate of production and quality of both natural and cultured pearls and therefore the future pearl market.
The global economic value of coral reefs has been valued at $30 billion. They are incredibly important all over the world as they provide sheltered habitats for commercial fish stocks, recreation and tourism opportunities and act as a natural barrier for coastlines. The damage to these reefs due to the current rate of ocean acidification has recently been estimated to cause a substantial economic loss of 0.18% of global GDP in 2100. It is estimated that some tropical coral reefs will experience such a large decline in calcification rates with decreasing calcium carbonate saturation that erosion will be greater than reef accretion in the next few decades. The coastal protective function of reefs was valued at US$ 9.0 billion per year. A decline in this function will result in the loss of low-lying land habitat and infra structure unless there is a large investment in shore protection. Globally, tourism to coral reefs is estimated to provide US$ 9.6 billion in annual net benefits and a multiple of this amount in tourism spending. Coral reef biodiversity also has a high research and conservation value, as well as a non-use value, estimated together at US$ 5.5 billion annually. Loss of coral reefs and their diversity would impact global tourism to these areas. The slow growing, cold- water corals, which favour deep carbon dioxide rich waters, are thought to be even more vulnerable to ocean acidification than tropical coral reefs. As the aragonite saturation horizon rises, these corals become undersaturated and attacked by corrosive waters. The economic impact from the predicted loss of 70% of these corals by 2100 is thought to be huge as they provide shelter and food for a large number of commercially important species, including Queen Scallop, Atlantic Cod, Saithe and Pollack. The decrease and possible extinction of these species would result in a large economic decline in fisheries all over the world, including the UK.
At present, the socio-economic impacts of ocean acidification are difficult to predict. The suggested effects on marine organisms are not conclusive; some organisms may evolve to adapt faster than others and survival rates may also depends on the nutrient availability. However, scientists are confident that ocean acidification will lead to degradation of many marine resources, resulting in a reduction in fish harvest and protein provision, and loss of revenue and jobs. These economic losses are likely to be concentrated in developing regions, which already have less economic resilience for enduring losses of fishing revenues.