Carbon Dioxide and the Oceans (A post for those tired of hearing about global warming)

I am writing this blog for a friend who showed concern for the topic and asked if I could write about it. It’s an important topic, and a little less politically heated than the other problem with carbon dioxide. Please read on, I promise its good stuff.

In my first post about climate change I wanted to, simply put, explain the phenomenon, which I think I accomplished. Unfortunately, the idea of global warming has become more of a political issue than a science issue. There are many reasons for this. Two are put forth by Joseph Romm, a physicist who was an acting assistant secretary in the Department of Energy during the Clinton administration and currently edits the blog climateprogress.org. Romm sites first the faceless nature of scientists when compared to politicians, and second the tendency of the American media to adopt the view of the climate change deniers “that climate change was a political issue, not science, and therefore it has two sides.”

Whatever the reason, global warming has become a buzz word. It has the ability to evoke serious emotion, and make the closest friends bicker like sworn enemies. I believe global warming should evoke emotion because it is a serious issue, but I would like to make an argument for reducing our carbon dioxide emissions which has nothing to do with global warming. I want to step away from global warming and all the emotion surrounding it and simply talk about carbon dioxide. Now, forget what anyone has ever said to you or you’ve read or you’ve seen on TV about the global temperature rise. Just forget it.

Carbon Dioxide ratios in the atmosphere are higher now than in the last 800,000 years. Now I know what you’re asking, how the heck do they know what the carbon dioxide levels were 800,000 years ago? The answer lies in ice. Ice cores, 3.2 km and longer, are taken in Antarctica. Over millennia the ice has trapped tiny pockets of ancient air which becomes locked in the ice with the falling snow flakes.


Like tiny time capsules, bubbles trap
ancient samples of atmosphere(Amos, 2006)

Just as a side note, this is also how scientists gauge past temperatures. They look within the caught air samples for different types, or isotopes, of hydrogen atoms which are found preferentially in precipitating water (snow) when temperatures are relatively warm.

But forget all about that, I promised to not talk temperatures, I apologize.

In these ice cores studies, scientists found that for the past 800,000 years there has been a natural rhythm in the carbon dioxide levels with increases and decreases. The highest level they found in the last 799,800 years was 280 parts per million. In the last 200 years carbon dioxide levels have increased to about 380 parts per million in 2006, with an increasing rate of 2 parts per million each year.

So, we have lots of carbon dioxide….where does it all go? Well about two-thirds go into the atmosphere, but this is not about that CO2. This blog is about the other one-third, or about 500 billion tons. This CO2 has been absorbed into the seas.

When carbon dioxide enters the ocean, it reacts with sea water to form carbonic acid. The reaction is seen here:


CaCO3 (s) + CO2 (g) + 2H2O (l) -> Ca2+ (aq) + 2 HCO3- (aq)

Carbon dioxide (CO2 (g)) in gaseous form reacts with water (H2O (l)) and calcium carbonate (CaCO3 (s)) in solid form dissolved in the water. The reaction breaks the calcium bond and carbonic acid is formed (HCO3- (aq)) in aqueous form. This large increase in carbonic acid has caused the average acidity of the oceans to be increased by 30%.

The primary concern with the acidification of the ocean is the reduction of available calcium carbonate. Carbonate is a substance used by thousands of marine species to form shells and skeletons. Acidification means slower growth and weaker shells. The result is a drop in not only commercially important shellfish, but also key species in the marine food webs, including plankton the base of most marine food webs. The ripple up the food chain would affect fish, birds, and mammals.

The hardest and fastest hit by ocean acidification will be coral reefs. As ocean acidity rises, corals will begin to erode faster than they can grow, and long admired reef structures will be lost worldwide. Scientists predict that by the time atmospheric CO2 reaches 560 parts per million (a level which could be reached by mid-century), coral reefs will cease to grow and even begin to dissolve. Areas that depend on healthy coral reefs for food, shoreline protection, and tourism industries will be profoundly impacted by their loss.

The point I want to make with this blog is that even if you do not believe our planet is warming, carbon dioxide levels are huge. They are significantly larger than they have ever been in the past 800,000 years, and this large outpouring of carbon dioxide is affecting our planet, negatively. The problem in the oceans is chemistry, pure, simple, and proven. Already coral reefs are growing at a stunted rate. If we continue to refuse to do nothing, our oceans could become sterilized, and I think we can all make the connection that if everything in the ocean is dead; everything on land is not far behind.

I hate to become negative and I don’t want that to be the tone of this blog, but I wanted to make sure everyone understands there’s more to this carbon dioxide thing than global warming. So if global warming has become a political issue for you, remember there are other reasons, which are just as dire, to take the steps needed to reduce our out pouring of carbon dioxide.

Citations:

Amos, J. “Deep Ice Tells Climate Story.” Sept. 2006. BBC News. http://news.bbc.co.uk/2/hi/science/nature/5314592.stm

Doney, S. et al. “Ocean Acidification: The Other CO2 Problem.” Annual Review of Marine Science. January 2009. Vol. 1, Pages 169-192.

Reay, D. “Carbon Dioxide.” The Encyclopedia of Earth. January 2009. http://www.eoearth.org/article/Carbon_dioxide