09/19/2013 03:26 pm ET | Updated Nov 19, 2013

Climate Science's Stark Ocean Truths

Next Friday (Sept. 27), the Intergovernmental Panel on Climate Change (IPCC) will issue the finalized summary of its latest assessment of climate change science, observed and projected. One of its main conclusions will be that the ocean is acting as a major defense against temperature rise in the atmosphere -- but is paying a considerable price in terms of its own health. A week later, the International Programme on the State of the Ocean (IPSO), an independent, interdisciplinary group of scientists, will enumerate some of the consequences in detail, including impacts on many of the iconic marine species that Americans, and all of us in Costa Rica, care about.

The IPCC can say a lot about the ocean this time around because of scientific advances, not least the 3,000-strong flotilla of Argo floats now patrolling the globe that are programmed to record and send back basic information on parameters such as ocean temperature, salinity and alkalinity. Before Argo deployment began in 2000, there was no methodical tool for monitoring ocean conditions across the world. Now, thanks largely to the program's successes -- for which American institutions such as Woods Hole and Scripps must take huge credit -- this IPCC report is able to tell us that fully 93 percent of the extra heat that greenhouse gases are trapping in the Earth system is being stored in the ocean. The share for the atmosphere, where we've tended to concentrate our attention, is just 1 percent. This explains the "slowdown" in atmospheric temperatures that climate deniers interpret as "global warming has stopped." A tiny increase in heat absorption by the ocean means a significant drop in the rate of atmospheric warming. But equally a tiny decrease would mean atmospheric temperatures soaring again.

In addition to heat, the ocean is soaking up our carbon dioxide emissions. About a quarter of the CO2 emitted today by factories, power stations and automobiles will end up in the ocean, cheek by jowl with sharks, whales and turtles.

The IPCC will also detail impacts of this heat and CO2 storage. Increasing acidity (a consequence of CO2 absorption), changes in salinity, changes in currents, and a decrease in oxygen concentrations are among the profound transformations that will be outlined in dry scientific prose.

For what this protection of life on land is costing the ocean, we open the IPSO file. Research assessed inside will show that species from coral and krill at one end of the scale to polar bears and tuna at the other are already feeling the impacts of a "deadly trio" -- warming, acidification and de-oxygenation of seawater.

Together with Trevor Manuel, the very influential Minister of Planning and former Finance Minister of South Africa, and David Miliband, newly arrived on U.S. shores as CEO of the International Rescue Committee and former UK Foreign Secretary, we launched earlier this year the Global Ocean Commission -- a new initiative aiming to plot a path to ocean sustainability in the interests of nature, sound business and future generations. In our deliberations so far we have debated all kinds of issues, from marine reserves and fishing subsidies to security on the high seas. But clearly, neither we, nor any other body aiming to secure ocean health in the long-term, can ignore the present and future impacts of greenhouse gas emissions.

There are two major takeaways from the IPCC and IPSO assessments. One is that all the marine protection measures that can be taken (and that have been taken under both Republican and Democrat administrations) are absolutely valuable. Curbing land-based pollution, restoring depleted fish stocks, barring invasive species, opening marine reserves -- all of these improve resilience to climate change, acidification and hypoxia. The current U.S. Administration and its peers around the world must redouble their efforts in these areas in the face of climate change.

The second takeaway is that in the long run, you cannot have a meaningful ocean policy without a meaningful climate change policy. As one of its final acts, the second administration of George W. Bush established marine protected areas around 195,274 square miles (505,757 square kilometers) of U.S. territory in the Pacific Ocean. It remains one of the largest single acts of marine protection by any government at any time. However, water inside the protected zones is warming and acidifying just as fast as that outside -- and this trend continues in large part due to President Bush's intransigence on climate change.

In the last two decades, we have tended to put all the factors affecting the ocean in separate silos. Over here is climate change; over there is fishing, and over there is chemical pollution. The distinctions are maintained through the structures of governments, in multilateral institutions, and even in civil society. The reality, which the IPCC and IPSO reports will demonstrate powerfully in the coming weeks, is that all of these issues are intimately related. There is, in truth, just one profound question we have to answer: Do we want a sick ocean, or a healthy one? And if our answer is "healthy", we cannot pretend that we can achieve it without urgent action on climate change.