One of the biggest flaws in most of the major “hard” geo-engineering schemes is that they don’t stop carbon dioxide emissions from rising. Injecting vast amounts of aerosols into the atmosphere or launching millions of tiny sun shields might theoretically reduce planetary warming a tad, but it doesn’t stop ocean acidification (see “Geo-engineering remains a bad idea“).
Yet, as Australia’s ARC Centre of Excellence for Coral Reef Studies warned in 2007:
When CO2 levels in the atmosphere reach about 500 parts per million, you put calcification out of business in the oceans.
We’re at more than 385 ppm now, rising more than 2 ppm a year (see “World carbon dioxide levels jump 2.3 ppm in 2008 to highest in 650,000 “” if not 20 million “” years“). Worse,
It isn’t just the coral reefs which are affected “” a large part of the plankton in the Southern Ocean, the coccolithophorids, are also affected. These drive ocean productivity and are the base of the food web which supports krill, whales, tuna and our fisheries. They also play a vital role in removing carbon dioxide from the atmosphere, which could break down.
In short, too much acidification, and the ocean may turn from a major carbon sink to a carbon source!
So it was a bombshell when Energy Daily (subs. req’d) reported yesterday:
Opening a new front in the U.S. global warming debate, the Environmental Protection Agency Tuesday quietly launched a regulatory proceeding that ultimately could lead to a Clean Water Act mandate to restrict carbon dioxide emissions to protect the nation’s coastal waters from acidification.
In a “notice of data availability”(NODA) released Tuesday and published in the Federal Register Wednesday, EPA announced it is soliciting the latest scientific information on a host of issues related to the environmental impacts of carbon dioxide (CO2) deposition in ocean waters….
In its Tuesday notice, EPA said it will use the data to inform its deliberations on whether to tighten its water quality criterion for marine pH””the standard unit of measurement for defining the relative acidity or causticity of water. States use EPA Clean Water Act criteria to develop water quality regulations and controls to prevent pollution from harming public health and the environment.
Although EPA took pains to say it is “only requesting information and data relevant to addressing ocean acidification under the Clean Water Act,” it acknowledged that it will use the information “to fill data gaps to inform EPA’s next steps and determine whether changes in existing criteria are warranted.”
An agency decision to tighten the marine pH criterion almost certainly would lead to constraints on carbon emissions, under EPA’s Clean Water Act authority, to reduce the volume of carbon deposited in the oceans.
EPA’s action was prompted by a 2007 petition by the Center for Biological Diversity, an energetic San Francisco-based environmental group that over the past six years racked up an impressive string of victories in legal battles with the Bush administration on climate change and other environmental issues.
In its petition to EPA, the center noted that the Clean Water Act, like other federal environmental laws, requires EPA to update its water quality criteria periodically to reflect the latest scientific research. The petition called EPA’s current marine pH criteria “outdated and inadequate” given advances in scientific understanding of ocean acidification.
EPA initially took no action on the petition, but following a threat of litigation from the center in November, the agency relented, leading to Tuesday’s notice.
Most news coverage on climate change science has focused on the increasing concentrations of greenhouse gases in the atmosphere, which have caused global average temperatures to rise and are blamed for an alarming loss of Arctic summer sea ice, rapid melting of alpine and Antarctic glaciers, and other impacts.
But many scientists fear that the chemical changes caused by the natural uptake of CO2 by the world’s oceans could devastate marine ecosystems and sharply reduce fish populations, an outcome with alarming implications for global food supplies.
“Ocean acidification is likely the greatest threat to the health of our oceans and is occurring at a frightening rate,” said Miyoko Sakashita, a Center for Biological Diversity staff attorney. “The federal government has finally acknowledged that ocean acidification is a threat. Now it must take the next step and fully implement the Clean Water Act to protect our nation’s water from the other CO2 problem.”
According to research detailed in the center’s petition, the world’s oceans have taken up about half of the CO2 that humans have produced since the Industrial Revolution, dropping average ocean pH by 0.11 units, which translates to a 30 percent increase in acidity.
Under business-as-usual emission scenarios, by the end of the century the ocean pH will plunge another 0.4 units, an increase in acidity that scientists say would cause enormous, irreparable damage.
CO2 absorbed by seawater reacts to form carbonic acid, and ensuing chemical processes reduce the volume of ocean carbonate, which marine animals use to build and maintain their protective shells and skeletons.
“These changes present potential risks across a broad spectrum of marine ecosystems,” EPA said in its notice. “Impacts to shellfish and other calcifying organisms that represent the base of the food web may have implications for larger organisms that depend on shellfish and other calcifying organisms for prey.”
EPA said ocean acidification “is forecast to reduce calcification rates in corals and may affect economically important shellfish species including oysters, scallops, mussels, clams, sea urchins, crabs and lobsters.”
In addition, EPA said a recent field study on marine plankton””the tiny organisms that form the bottom of the marine food chain and play an important role in the natural carbon cycle””described reduce plankton shell weight over time “consistent with reduction calcification today induced by ocean acidification.”
EPA’s current marine pH criteria, established in 1976, allows variation of 0.2 pH units from normal conditions, but the agency notice cited research that demonstrated adverse impacts on marine organisms of pH changes of less than 0.2 units.
The Center for Biological Diversity petition called for EPA to establish new marine pH criteria that would allow no variance from normal conditions.
“Petitioner requests a new criterion that allows no measurable criterion of pH because new scientific information has shown that harm to aquatic life can occur at levels below the current EPA criterion, which allows 0.2 pH change,” the center said. “At a minimum, the revised change of allowable pH values should be much narrower because it is now well-accepted that devastating impacts occur at pH values that are within the current acceptable range.”
The bottom line is clear.
We can’t allow human emissions of CO2 to acidify the oceans enough to hurt calcification and destroy major marine ecosystems. That alone could create a carbon cycle feedback sufficient to undermine national and international efforts to reduce net CO2 emissions build up in the atmosphere. This is it doubly worrisome because some scientific research today suggests the ocean sink has already started to saturate (see “More on soaring carbon concentrations” and “The ocean is absorbing less carbon dioxide“).
“Hard” Geo-engineering — those large-scale planetary engineering schemes that don’t involve sucking CO2 out of the air aka “emergency interventions to cool the atmosphere should less drastic measures fail” as NYT‘s Revkin puts it — remains a hypothetical techno-fix that can’t replace strong greenhouse gas reduction efforts. At worst, it is a purely false hope that might do more harm than good deployed at a large scale, and at best it might be a small, temporary bandaid that could accompany efforts to stabilize below 450 ppm, but only if it could be demonstrated to minimize amplifying carbon cycle feedbacks.
- Semi-exclusive: Science Adviser Holdren stands by his long-standing critique of geoengineering
- Geo-Engineering is NOT the Answer
- Geoengineering, adaptation and mitigation, Part 2: White roofs are the trillion-dollar solution
- Memo to DARPA, Pentagon: Stay out of geoengineering “” aka climate manipulation!
- So much for geoengineering, Part 1: Avoiding the Frankenplanet