By Lindley Mease and Larry Crowder
Will our children look back on the 2015 UN Climate Change talks in Paris this December as the sea change that saved our global ocean, or as a failed attempt to protect the resource that sustains billions of lives and livelihoods?
Leaders from more than 190 nations plan to negotiate a legally binding agreement to cut global fossil fuel emissions to at least 60% below 2010 levels by 2060. While this may sound ambitious, the proposed emissions reduction is not enough to prevent dramatic ocean changes projected over the next century, including rising sea levels, more intense storms, and ocean acidification. These changes will directly affect billions of people worldwide, particularly coastal communities at high risk for flooding and populations that are dependent on seafood for livelihoods and protein.
Past climate talks gave short shrift to ocean issues, but recent science has drawn a bolder line: any effective climate treaty must achieve aggressive CO2 emissions reduction targets, with clear accountability mechanisms, to stave off ocean impacts. Oceans, and the communities that depend on their services, have the most to lose from these negotiations than anything or anyone else.
It’s difficult to grasp the dramatic implications of a changing ocean from day-to-day, or even decade-to-decade. That’s why motivating action on a global scale is so challenging. However, those who study, use, or extract from the seemingly boundless ocean—like shellfish businesses, coral reef scientists and coastal city planners—are on the front lines, calling for action, and we should be listening.
There’s a lot at stake, particularly because the oceans have been doing much of the planet’s heavy lifting on stabilizing our global climate. As fossil fuel emissions increase, the ocean absorbs proportionately larger and larger amounts of CO2, lowering pH and resulting in a more acidic ocean. On average our ocean has absorbed about 30% of our carbon emissions, but this capacity to absorb our CO2 is slowing down as oceans warm, resulting in the acceleration of climate change.
Ocean acidification harms ocean organisms throughout the marine food web, from shellfish like abalone and oysters to phytoplankton that support marine life and generate the oxygen we breathe. Ask the folks in Massachusetts who work in sea scallop fisheries, Louisiana oyster farmers, or Washington’s shellfish businesses—they’ll all describe the losses they’ve already suffered from increasing acidification.
While the ocean has done us the favor of absorbing 93% of Earth’s additional heat since the 1970s, the result has been warmer waters that increase sea level rise and have ripple effects throughout ocean habitats. Although an increase in 7 inches over the last century may not sound like a game-changing number, the trend is exponential and will dramatically alter coastlines. In concert with predicted mounting storm frequency and intensity, rising seas will flood many coastal areas and force climate refugees to leave low-lying island states as well as impact U.S. cities like New York, Boston and Miami. Warming ocean waters will also heavily impact global fisheries that supply 15% of the animal protein for 3 billion people worldwide.
Californians have seen warm-water species—including bluefin tuna, whale sharks, and even green sea turtles—moving farther north. We are also witnessing the largest harmful algal bloom ever documented on our coast. The toxic algae have shut down fisheries, including the lucrative Dungeness crab fishery, indefinitely. With the onset of El Niño, these issues may become worse as heavy rains wash excess nutrients into the ocean, leading to more algal blooms. These unusually warm waters in 2014 and 2015 may provide a glimpse of what the "new normal" may be for our coastal ocean.
The commitments that countries have made, or are likely to make, to reduce greenhouse gas emissions will not keep our global temperature from increasing at least 2°C—the often cited threshold at which we should expect to see dramatic ecological change. That’s bad news for the ocean, because a recent scientific review emphasized that even a 2°C temperature increase will substantially alter the marine resources and services we depend on for our survival. We need to do better.
To truly have a chance at reducing climate change impacts, the UN Convention on Climate Change must create emission reduction targets for CO2 specifically—we can reduce other greenhouse gases all we want, but only reductions in CO2 will make a dent in slowing ocean acidification. Funding and carbon target schemes should take geographic differences into consideration to ensure equitable action based on historical CO2 contributions, ability to take action, and vulnerability to impacts (e.g., island nations and Arctic tribes). And these accountability structures must be rooted in a collective commitment to emissions reductions, not individual ones, as a recent policy review in Nature posits.
These considerations are urgent because our options for adaptation become fewer and more costly as our global ocean continues to undergo ever more stress. The more successful UN negotiators are in crafting an agreement that holds countries accountable to stringent CO2 emissions reductions, the more opportunity regional and local decision-makers will have to protect critical ocean resources on local scales. And let’s not forget that the ocean itself has a decreasing capacity to absorb our CO2 the more we spew emissions, amplifying climate change in the coming decades.
Climate change has already had a significant impact on the global ocean, yet the UN climate talks have largely ignored ocean-specific considerations thus far. To achieve any durable and equitable agreements, this must change—for the health of the ocean and our own survival. The question, again, is whether COP21 will be remembered as a lost opportunity, or one where agreements were brokered, responsibilities were accepted and nations cooperated to address the problems of one of our greatest resources—the planet’s blue heart.
Lindley Mease is a senior research analyst at the Center for Ocean Solutions, at Stanford Woods Institute for the Environment
Larry Crowder, director of the Center for Ocean Solutions, is a senior fellow at the Stanford Woods Institute for the Environment and Edward Ricketts Provostial Professor of Biology, Marine Conservation at Hopkins Marine Station