Ocean Acidification: Economic impacts

For my last post in my Ocean Acidification (OA) series, I want to focus on the socio-economic impacts of ocean acidification. While previously there has been very little research on this topic, recently there seems to have been a spurt of papers looking at this issue. It’s a very complex topic and there is much debate around how to go about assessing the economic impacts.

I’m going to start this blog by looking at a fairly straightforward paper. Narita et al.(2011) looks at the global economic impacts of OA on shellfish production. This sector accounts for 9% of the total value of global fisheries production, which equates to around $15 billion. To find the economic impact of OA, two factors are assessed; welfare costs relating to a decreased production and consumption and welfare impacts from the increased price of molluscs due to a decreased supply. It was found that if demand for molluscs increases as expected due to continued income growth and emissions trends continue to increase in a ‘business as usual’ scenario, global costs of OA on shellfish production could be in excess of $100 billion.

However, for Rodrigues etal. (2012), calculating the economic impacts of OA requires much higher levels of detail and more complex analysis. The paper comments that Narita et al.’s paper has too restricted a focus because it only deals with the impact on shellfish production and ignores other impacts of OA. It also considers the issue on a global scale, while Rodrigues et al. argue that this is contentious because there are large regional variations in the impacts of OA. When calculating the effect of OA on marine life, Narita et al. also rely on data from laboratories or microcosms, while Rodrigues et al. write that up-scaling this data is unreliable because this method ignores interactions that occur with the ecosystem, and the impacts the OA has on the trophic system. Finally, Rodrigues et al. comment that while Narita et al. assume that reduced calcification rates have a linear relationship with production levels, we are actually unsure whether OA will increase of decrease the production and economic value of molluscs.

So, Rodrigues et al. go on to define how they would implement assessing the economic impacts of OA in the Mediterranean. Firstly they would look at the direct impacts of OA on marine ecosystems, then assess the impact of this on human services and translate this into socio-economic costs. While the main sectors affected are fisheries, tourism, recreation and red coral extraction, Rodrigues et al. also argue that the value of costs associated with OA, which have no real market value must also be considered. For example, the oceans capture 25% of anthropogenic CO₂ through a process known as carbon sequestration. OA is likely to inhibit the ocean’s ability to do this, so the cost of this must be identified. There are also habitats and ecosystems that are likely to be affected by OA, but which have no specific economical use. However we must still consider the value of this ‘non use’ effect in order to fully estimate the costs of OA.

Obviously, valuing things which don’t have an economic use is incredibly challenging. However, it seems to be necessary. Narita et al.’s paper has only calculated 1.5% of the future costs of climate change, therefore it would seem that a more holistic approach is necessary to really evaluate the cost of OA overall. Calculating the economic impacts of OA is made even more difficult by the uncertainties in future predictions for scenarios of climate change and OA and how biological organisms will react to the changing ocean. 

After all these complications, you may find yourself asking what the point in calculating economic impacts is, why not just wait and see what happens? I think this blog post from The Center for Climate & Security helps to show that it is important to try and work out what the impacts of OA and climate change will be, so we can find ways to address the needs of those who are most vulnerable to it, before it is too late.