Sharks and global warming?
I just received an interesting question from a member of the Save the Sharks cause on facebook. I’m curious what you all think of the question, and of my response. Please excuse her grammar, she is not a native English speaker.
“I have a question, does finning (or decline in number of Sharks) affects Global Warming?…
(E-mail continues)
Most of my friends are more interested in global warming, so i was wondering if the decline affects Global Warming in any way? If there is any, i believe approaching them from an issue they are more interested in would be more effective.“
My initial reaction was confusion- it seemed to me that there was no possible way that sharks could have anything to do with global warming. But this member made a good point- people care about global warming, and if the loss of shark populations was tied to global warming, more people might care. I began to think of ways to connect the two.
Here’s what I was able to come up with.
1) The loss of predators can result in a trophic cascade, destabilizing the whole food chain. The base of oceanic food chains is phytoplankton, which, through photosynthesis, absorb CO2 and take it out of the atmosphere. Fewer of these phytoplankton means less Co2 taken out of the atmosphere, and since Co2 is a greenhouse gas, this could affect global climate change.
2) The shark fin industry itself is a huge greenhouse gas emitter. The large factory ships cruising the oceans are polluters, and the simple act of shipping luxury items (in this case shark fins) halfway around the world generates plenty of Co2.
Both of these ideas have their problems, though. We really don’t understand food web dynamics remotely well enough to be able to predict if #1 will happen. Though we know that the loss of sharks can result in short trophic cascades that destabilize short lengths of the food chain, many oceanic food chains have 10 or even 15 links between the top predator and the phytoplankton. A scenario like this one (#1) is probably pretty unlikely.
The other scenario (#2) is actually happening, but is a stretch. Shipping shark fins across the globe doesn’t generate any more Co2 than shipping anything else. It seems like a silly reason to get upset at the shark finning industry.
I became frustrated, but then realized that the problem isn’t my inability to link sharks to global warming. The problem is that the general public seems to erroneously believe that global warming is the only threat to the environment.
This problem isn’t just with the public. On last year’s Earth Day, I attended a debate between the science and environment advisors of then-candidates Hillary Clinton and Barack Obama. After the first 90% of the debate dealt with climate change, I couldn’t take it anymore. I asked if they had a plan for dealing with the loss of sharks, and both seemed dumbstruck at the notion of dealing with a problem other than global warming.
To his credit, Obama’s advisor Jason Grumet came up to me after the debate and gave me his e-mail address. I sent him some information about shark conservation that he read and promised to pass along. Though I haven’t heard from him since this summer, the selection of Dr. Lubchenko as the head of NOAA reassures me that at least some in the administration understand the plight of sharks.
The threats sharks face and the impacts this will have on the ocean are important, more than important enough for people to care even if it has nothing to do with global warming.
I suppose the short answer to this member’s question is: “No, sharks have nothing to do with global warming, but that doesn’t mean they don’t matter”.
~WhySharksMatter
David is a graduate student in South Carolina studying shark conservation. He is the author of the upcoming book “Why Sharks Matter: Using New Environmentalism to Show The Economic And Ecological Importance of Sharks, The Threats They Face, and How You Can Help”. His time is divided between educating the public about sharks, spending days at a time at sea playing with sharks, and eating horribly unhealthy foods. Follow him on Twitter @WhySharksMatter.
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Maybe people need more shark fin ice cubes in their drinks? http://kaylinq.blogspot.com/2009/02/sharks-in-your-drinks.html
Yes, its awesome.
Kevin! Those things are based in the UK and don’t ship here! You got me all excited… what a letdown!
u know… this is a really good point. To be honest, your first connection between the two is a good idea, but I’m not entirely sure it’s on point. Loss of predators does mean that there are more fish that eat the phytoplankton, etc. yet I think that this does not affect global warming very strongly, and certainly not with a direct impact. I’d say that one of the reasons that we are losing so many sharks (specifically reef sharks) may also be concerning our loss of coral reefs – which is a much bigger threat in my opinion. (dont get me wrong – i love sharks and their conservation is something that I feel very strongly about).
You made a great point about the contribution to greenhouse gases to global warming, and that many of those gases come from the ships that are used to transport shark fins once they have been cut and packaged. I’d like to point out, perhaps redundantly, that the ships that are USED to catch the sharks also emit as much if not more gases, seeing as how many shipping routes are being updated, and many of the larger ships used to transport cargo are becoming newer and fitted with better means of filtering harmful gases, etc. Many times, the people who procure the fins are not on big fishing expeditions, and are local, low-budget fishermen who are looking to make extra cash.
In short, the existence of sharks is vital. In the troposphere, and biologically, they are a necessary part of the marine environment; as many of histories extinctions have shown, every species has a niche and the erasure of that species disrupts the entire system. No, they do not have a particular impact on global warming, but sharks are indeed important and should not be ignored.
One more thing I wanted to point out – in my opinion, based on what I have read and seen on the news, and based on the reactions of my fellow students and friends when I told them that I was doing research involving sharks – Many people do not care so much about sharks because they are afraid of them, and do not understand them. To sound cliché and a little silly, shark awareness is like aids awareness – you don’t know until you’ve learned about it and understand it.
ok, my thesis is over… hope i made sense and helped you out a bit
dave b
David I like you point simply because I believe we should be concentrating more so on things we can have a much greater effect on such as helping sharks and other species of animals that are in danger. I would love to here politicians talk a lot less about global warming (since there just the same amount of evidence saying that its natural global climate shifts and not necessarily greenhouse gasses causing the heating up of the poles) and talk about how we can conserve more tangible things in the natural world.