In a new study authored by Dr. John Talberth and Ernie Niemi of Natural Resource Economics, CSE reviewed the economic consequences of ocean acidification and warming – the two most prominent effects of climate change on our oceans – and estimated what increment to the existing social cost of carbon (SCC) needs to be made to account for these damages. Preliminary results suggest that proper accounting of an economic risk that could approach $20 trillion per year by 2100 would raise SCC 1.5 to 4.7 times higher than the current federal rate, to $60–$200 per metric ton CO2-e. The study has been published online by Elsevier as part of their Reference Module in Earth Systems and Environmental Sciences.
Climate change has the potential to disrupt ocean and coastal ecosystems on a scale that is difficult to grasp. There are two interrelated processes at work: ocean acidification and ocean warming (OAW). Oceans have absorbed roughly half of all anthropogenic emissions of carbon dioxide. Acidification occurs as the absorption of CO2 triggers a series of chemical reactions that increase the acidity and decrease the concentration of carbonate ions in the water. So far, absorption of CO2 has increased acidity of surface waters by about 30% and, if current trends in atmospheric CO2 continue, by 2100 these waters could be nearly 150 percent more acidic, resulting in a pH that the oceans haven’t experienced for more than 20 million years. Among the dire predictions associated with acidification include dramatic reductions in populations of some calcifying species, including oysters, clams, sea urchins, shallow water corals, deep sea corals, and calcareous plankton – the latter effect putting the entire marine food chain at risk. Some models suggest that ocean carbonate saturation levels could drop below those required to sustain coral reef accretion by 2050.
The second process is ocean warming. The mechanisms of ocean warming are complex, and include heat transfer from the atmosphere, downwelling infrared radiation, stratification, reductions in mixing, changes in ocean currents, and changes in cloud cover patterns. Already, the global average sea surface temperature (SST) has risen by over 2.0 °F since the post-industrial revolution low point in 1909. Sea level rise is one of the most conspicuous effects with potentially catastrophic consequences. Models that account for collapse of Antarctic ice sheets from processes driven by both atmospheric and ocean warming indicate sea level rise may top one meter by 2100 and put vast areas of coastal infrastructure at risk.
Obviously, all these physical effects have enormous economic consequences, yet relatively little research has been completed to date on their expected magnitude, timing, and distribution. Indeed, as late as 2012, several prominent climate researchers concluded that economic assessments of the effects of ocean acidification “are currently almost absent.” To help fill in this information gap, we combed through all published research on OAW economic consequences, updated figures where needed, and made some original calculations of our own to estimate some plausible worst-case scenarios. These scenarios appear in Table 4, below. Alarmingly, they suggest that OAW costs could near $20 trillion per year by 2100 in association with a variety of dramatic impacts, such as loss of all charismatic marine species.
John Talberth, Center for Sustainable Economy, 21 February 2017. Article.