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Bering Sea Benthic Studies

Hi Emily and Team!

Maggie brought up an interesting topic in her last post about the view of climate change by the researchers.  I've attended a lot of presentations recently from the scientific community and they all say that scientists agree that climate change is happening and that humans are the main reason for the change.  Would your team agree?

So, here are my questions that relate to this topic:

Have you or the team seen any changes to the Bering Sea ecosystem to date? 

If so, what are some of the changes you are seeing? 

How does a researcher determine if the change is in response to "climate change" versus something else? 

How do researchers determine if changes are human induced versus a natural trend?

Thanks!
Janet

Fri, 04/11/2008 - 09:45

Emily S. Davenport

Hi Janet-
To answer your questions, I asked around the ship and two researchers, Nancy Kachel and David Shull, gave me a few interesting answers. Here is a summary of what they told me:
Climate change is over a long term period- there is a difference between weather (short term) and climate (long term). In general, there has been a noticeable change in climate over time (spring starts earlier, fall ends later) but this is something that has to be studied for many years (not just 3 like we are doing up in the Bering Sea) in order to record this trend. This is something that can take 20, 30, 40 years to see the real effects of climate change on an ecosystem. One of the longest data sets relevant to the Bering Sea is satellite data on sea ice extent. This dataset indicates that ice melts earlier today than it used to and that the maximal extent of ice coverage has decreased during the last few decades. There is a shorter dataset from temperature sensors maintained on buoys moored in the southern Bering Sea. This approximately 15-year dataset shows that the Bering Sea has been getting steadily warmer during this time period. However, 15 years is a short time period relative to climate change (100 yrs).
CO2 ice records are showing the highest concentrations of CO2 ever, something called the "hockey stick phenomenon", and these concentrations coincide with a time right around the industrial revolution, which is a time when human impacts on our earth increased significantly, and things like fossil fuel burning and deforestation (by humans) became more prevalent.
Natural weather patterns have a significant effect on the weather of a region too- such as La Nina. Right now we are in the second year of La Nina, which is impacting the Bering Sea- we are seeing a larger ice extent (although the ice is thinner) and cold temperatures. This doesn't mean that the overall trend in the Bering Sea is heading towards colder weather, this just means that this year is a cold year in comparison to last year. The overall trend is still towards a warmer climate. There are observations that animals in the Bering Sea, such as fish, crabs and gray whales, have shifted their geographic distributions northward, consistent with a warming climate.
Again, the scientists on board Healy cannot emphasize enough that detecting the effects of climate change requires long-term datasets, and the more the merrier.