What to do when facts are few

What to do when facts are few

March 29, 2017

Using expert opinion to assess socio-economic effects of ocean acidification on cold-water corals.

Ocean acidification is known as “the other CO2 problem”. Global warming due to CO2 and other greenhouse gases having been released to the atmosphere is a well-known phenomenon.

That the oceans take up CO2 and thereby become more acidic has received less attention. Consequently, even less is known about how ocean acidification may affect ecosystems and hence humans, than for global warming.

Despite the limited amount of knowledge, management decisions to try to secure human well-being must be made. Since assessments of economic costs and benefits are an important part of decision making today, we consider the opportunities and limitations of such a framework in trying to deal with uncertain environmental changes.

Case: Cold water corals

We use cold water corals in Norwegian waters as a case-study since their values are relatively well studied and their calcium carbonate skeletons, making up the reef structures, are expected to be negatively affected by acidification.

We identified five types of information needed to evaluate the impact of ocean acidification on the benefits cold water corals provide to society. These are
(1) the current distribution
(2) ecosystem services
(3) associated values of the corals
(4) the physical impacts
(5) ecosystem service impacts of acidification

The status of knowledge was evaluated for each type of information. In addition to a literature review, we used expert opinion to assess status of knowledge and compensate for limited published scientific knowledge.  

Knowledge gaps

Despite this, it was concluded that the knowledge gaps are too large to assess if and how ocean acidification on Norwegian cold water corals affect human well-being. The gaps were particularly large for points 4 and 5.

However, the experts were confident that dead coral structures will be negatively affected at the levels of acidification expected from the so-called “Higher” emissions scenario for CO2 (“RCP6”; 800 ppm atmospheric CO2 by year 2100).

For management, the experts had high confidence that adaptation through construction of artificial reefs, reduced fishing pressure or marine protected areas could be possible. The experts had low confidence in geoengineering measures to reduce CO2 levels in the atmosphere.

We conclude by pointing out the most urgent areas for future research to be able to do a reasonable social and economic assessment of the effects of ocean acidification on cold water corals.  With uncertainties inevitable, a precautionary attitude should nevertheless always be present.


Social and Economic Assessment of Ocean Acidification - the case of cold water coral