Thursday, May 1, 2014

A Changing World with the Changing Climate, Part III: The Oceans

            In my previous two blog posts, I have looked at how climate change has been affecting the atmosphere and the biosphere. This concluding blog post is going analyze arguably the most important sphere: the hydrosphere. In terms of the hydrosphere, I will focus on mainly the ocean as the “rain” part of the hydrosphere was analyzed with the atmosphere analysis. The ocean is the home to over one million species, and the ocean is so large that there may be another million species out there to be discovered. Therefore, the ocean has to maintain a relatively constant chemistry or the species will have to adapt or suffer. Also, the melting ice caps are making sea levels rise and that can put many coastal cities in danger of flooding or submersion.
            With concentrations of carbon dioxide continuing to increase in the atmosphere, the ocean is absorbing that carbon dioxide out of the atmosphere at a similar consistent rate, as well. The Intergovernmental Panel on Climate Change (IPCC) reports that the increased carbon dioxide absorption is changing the chemistry of the sea water.
Fluctuation of pH in the oceans 

 The oceans absorb more than 90% of the increased energy in our atmosphere; the oceans cannot take this strong radical shift without some drastic changes within itself. The carbon dioxide molecules will break apart the water molecules, and the chemistry will shift from carbonic acid to bicarbonate to carbon trioxide. Once the carbon trioxide state is reached, two hydrogen atoms are left isolated, and that will make the ocean more acidic. Unfortunately, we can protect species from over-fishing and local pollution, but we cannot protect them from the ocean changing with the atmosphere. In fact, 30-50% of coral types will not be able to cope with the rising carbon dioxide levels as they will not be able to repair themselves. Also, some fish will lose their sense of smell and behave recklessly in the presence of predators. Therefore, if we want to lower the possibility of these situations from happening, we have to be proactive in reducing our carbon dioxide emissions in hopes for a change.
            The other growing concern with the oceans is the rising sea levels. Over 1 billion people currently live in cities and coastal areas that are at risk of sea level rise and coastal flooding.
Possible changes in coast lines with melting ice caps

Globally, the sea levels have already risen 8-10 inches since 1880; planners are preparing for a 24-inch rise by 2060. If this situation were to happen and we were to take no action, the two foot rise would cause at least $1.6 trillion dollars worth of property damage just due to coastal flooding. This two foot rise may also put some islands completely under water such as Kiribati. Therefore, we need to make smart decisions on how to mitigate these sea level rises.  It is easy to offer the solution to just evacuate people from an area and move them somewhere safer, but moving over 400,000 people from the city of Miami will be quite the chore.
`           The good news is the ocean may provide us more time to try to adapt to these rising sea levels and climate change. Yair Rosenthal of Rutgers and Braddock Linsley of Columbia University conducted a 10,000 year study of temperature changes in the Pacific Ocean, and they noticed that the temperatures at depths of 500-1000 meters were about two degrees Celsius cooler than what they were about 10,000-8,000 years ago. Therefore, we still have not seen the oceans at their warmest and there is still time to mitigate. However, Rosenthal and Linsley noticed one unfavorable trend; the recent warming period is faster than any warmer period observed during the Holocene (period since the last ice age). The other drawback of their study was they did not identify the sea levels when the oceans were at their warmest temperature.
            Therefore, we may indeed have time to make mitigation a smooth transition. However, the urgency for mitigation needs to start today because time may not necessarily be on our side. Mitigation examples include building stronger dams, placing houses on stilts, and evacuations (this should be used only if there are no other options). Hopefully, we will figure out a way to control our emissions and adapt successfully to the climate change that is occurring right now.