Natural Resources Defense Council


So what is ocean acidification and why is it one of the most important issues regarding climate change?

Lisa Suatoni is a senior scientist in the oceans program at the Natural Resources Defense Council. She works on a variety of topics including fisheries, marine-ecosystem based management, climate change impacts on marine ecosystems, and ocean acidification, and appeared in the documentary, Acid Test. She's taken some time to answer our questions and give us the details we need to grasp just how important ocean acidification is to life on earth.

The Most Important Things to Know About Ocean Acidification

What's the most important thing for a person to know about how ocean acidification affects them? In other words, for someone who lives in the middle of the USA, far from any coast lines, what do they need to know about ocean acidification today?

You don't need to live near the ocean to be affected by it - from the air we breath, to the food we eat - Americans from all parts of the country rely on the sea.

Ocean acidification will affect us first, and most visibly, through the loss of important commercial fish stocks (primarily shellfish but quite possibly finfish). This will not only hurt valuable fishing industries in our country but also diminish an important and healthy food source.

Coral reefs will feel the consequences as well - impacting tourists who want to snorkel them, and the tourism industries that rely on them alike. Tropical areas that depend on healthy coral reefs for food, shore-line protection, and lucrative tourism industries will be profoundly impacted by the loss of coral reefs - an outcome that is expected within 40-60 years.

And when the loss of coral reefs is coupled with sea level rise, it could become nothing less than a national security issue for the United States as it will contribute to displacement of coastal populations and to world-hunger as a result of suffering fisheries.

Lastly, the oceans supply numerous services which are less visible, but nonetheless of vital importance. The oceans regulate earth's climate, supply us with most of our oxygen, and moderate global warming. As we rapidly change the chemistry of the sea we are altering the oceans' ability to perform these functions.

Ocean acidification could be viewed as a final warning sign that we are perilously close to destabilizing the earth's vital systems. We know from global warming that changes to the composition of the atmosphere from the burning of fossil fuels have been significant. Yet, the oceans are an even bigger system - 500 times by weight - compared to the atmosphere. Measurable changes to ocean chemistry signal a massive upset to our planet. The First Signs Ocean Acidification is Changing Our Marine Systems A statistic in Acid Test was that we've seen a 30% increase in ocean acidification since industrial revolution and levels will double again by end of century. What are the impacts we'll see first? Is it the softening of sea shells, and if so, what is the next major problem that will arise? Evidence is accumulating from around the world that acidification may already be having chronic impacts on a range of ocean life. For example, coral in the Great Barrier Reef in Australia show a 14% decline since 1990; body weights of a species of plankton in Antarctica are 30-35% lower now than historic times. In other words, the visible rise in acidity over the past two hundred years may already be causing a sort of 'osteoporoses' in species scattered around the globe. By the time atmospheric CO2 reaches 560-ppm (a level which could happen by mid-century), all coral reefs are expected to cease growing and start dissolving. However, before that happens, many researchers believe that the combined stresses of warming and acidification will cause wide-spread extinction among tropical coral reefs. Such losses would have profound social impacts in affected nations. You noted that acidification is affecting the most vital areas for production of life - where cold water comes up to surface. What does it mean to have acidification changing these areas most? Acute impacts from ocean acidification will occur first in the poles, and regions where water wells up to the surface from the deep. Polar waters are projected to become corrosive to some shelled organisms within decades and water that is corrosive to sea shells is already being observed seasonally off the west coast of the United States. This is expected to cause local extinctions of sensitive species. It is not clear how these losses will impact the larger marine food web. However, disappearance of species - particularly at the base of the food web - can cause disturbances all the way up the food-chain threatening fish, birds, and mammals. Impacts to important commercial fisheries are anticipated. Ocean Acidification, Coral Reefs and Marine Protected Areas What does it mean if corals disappear? The documentary notes that 25% of species live on coral reefs. Will losing all that life accelerate acidification? The loss of corals will not accelerate acidification, but it will accelerate the extinction of other species. Coral reefs provide the foundation for one of the most biologically diverse ecosystems in the world. Loss of the reef structure would cause extinctions of organisms that inhabit the reefs, making these ecosystems less rich, less resilient, and less beneficial to humans. It should also be noted that these reefs provide food, protection, and livelihoods for hundreds of millions of people in the world. Their extinction will have profound socio-economic impacts as well. On the subject of marine protected areas - how are we doing compared to what we need to be doing? Are we drastically under par for setting aside protected areas? Marine protected areas alleviate pressures from local threats - such as fishing and oil drilling - and therefore enable the recovery of marine ecosystems. Intact, healthy ecosystems are more resilient and more able to withstand the dual stresses of ocean acidification and global warming. Seeing the Impacts of Ocean Acidification Within Our Lifetime You say ocean acidification is a problem we're going to see in the next two decades. If you were to point people to particular resources to show them this fact, where would you point them? We're forever altering the food we eat, our landscapes, our climate, and parts of our economy. Humans (as a race) will persist - but in a less rich, diverse, resilient, and productive world. Both ocean acidification and global warming are expected to disrupt food production and the availability of fresh water in many parts of the world. This, very likely, will lead to social unrest. Acute impacts from ocean acidification have not yet occurred - but they are imminent (20-50 years). The first conspicuous casualty will likely be coral reefs. Coral reefs have slowly but consistently been disappearing around the world for hundreds of years. More recently, there have been drastic declines. For example greater than 90% of species of elkhorn and staghorn corals have disappeared from sites across the Caribbean. The IUCN classify 90% of coral species as threatened or near threatened. Corals face a multitude of threats including overfishing, coastal pollution, global warming and ocean acidification. Therefore it is difficult to point the finger at any one. The effect of ocean acidification is unique, however. It is simple chemistry, and it will literally dissolve the corals.