CO2 emissions could violate US ocean quality criteria within decades

8th October 2007

 

A commentary by an international team of 25 leading scientists, including Dr Carol Turley from PML, has stated that human-induced CO2 will alter ocean chemistry to the point where it will violate U.S. Environmental Protection Agency (EPA) Quality Criteria for Water by mid-century, if emissions are not dramatically curtailed now.

 

The commentary, which was published in the Geophysical Research Letters (GRL), also says that CO2 generated “changes in ocean chemistry, within the ranges predicted for the next decades and centuries, present significant risks to marine biota” and that “adverse impacts on food webs and key biogeochemical process” would result.

 

It is widely recognised that the current rapid increases in atmospheric CO2 have actually reduced the pH of the oceans, as natural chemistry-balancing processes (the carbonate buffering system) struggle to keep pace with the influx of absorbed atmospheric CO2. The U.S. Environmental Protection Agency [1976] Quality Criteria for Water state: “For open ocean waters, where the depth is substantially greater than the euphotic zone*, the pH should not be changed more than 0.2 units outside the range of naturally occurring variation...”

 

Dr Carol Turley, from PML and co-author of this paper, commented: “The GRL paper states that the increased acidity of the oceans, that will occur as surface oceans take up the increasing CO2 from the atmosphere because of burning fossil fuels, will violate US Environmental Protection Agency quality criteria in approximately 50 years, if our CO2 emissions continue at the same rate.

 

Dr Turley continues: “This is the 1st time that atmospheric CO2 emissions have been recognised to violate EPA water quality criteria and these changes in ocean chemistry are of great concern as this may adversely affect marine organisms, ecosystems and key biogeochemical processes.”

 

Further information

*Euphotic zone
The euphotic zone goes to a depth of about 650 feet (200 meters), where light can still reach and photosynthesis can occur.