Monday, May 20, 2013

Climate Change...there, I said it

The "Keeling Curve" - atmospheric CO2 in the modern era (since 1958). These data underpin one of the lines of evidence that contemporary rising CO2 concentrations are due primarily to human activities.

It seemed like spring was all about climate change, and particularly various efforts around the Olympic Peninsula aimed at preparing for projected changes. I wrapped up two different climate change projects, a large climate impact assessment for the Olympic Coast National Marine Sanctuary, and another that I was a contributor for - a community impact assessment for the Jamestown S'Klallam Tribe. I am pretty proud of this last one - not only did I get to work with some truly phenomenal partners from Adaptation International and the Jamestown Tribe, but I am also proud to have participated in this first comprehensive community assessment to take place in coastal Washington outside of Puget Sound. Another notable event was the Clallam MRC's workshop on ocean acidification, which focused on current and future "acidification" of local marine waters, driven by increasing carbon dioxide concentrations in the atmosphere.

It seems to me that media reporting on climate change has turned a corner of sorts, and I feel that I've seen far more reporting this spring on science and assessment of global climate change. This Reuters article from today on a Nature Geoscience paper is a good example. It suggests that climate models most extreme projections (i.e. on the high end of their uncertainty) regarding atmospheric warming may be too high...seems like a positive, right? But the reason - that the oceans seem to be absorbing more heat than expected, has local ramifications. Even small increases in ocean temperature may have observable impacts including shifts in the range of marine species, and reduced productivity due to increasing stratification between the warmer surface layer and the colder water below it.

The data that set off the 400 ppm media blitz - CO2 concentration measured at Mauna Loa, Hawaii

Another notable item from May - the symbolic reaching of the 400 ppm mark in atmospheric carbon dioxide concentration at the Mauna Loa CO2 observatory that generated quite a bit of media attention. Both the figure at the top of this post, as well as the one just above are atmospheric CO2 concentration data from Mauna Loa. While there is certainly still debate regarding what this threshold means and how we, as a society, should view it, I find it compelling to think about the context: CO2 levels have not been this high certainly since Homo sapiens has been around (see figure below), and pre-date many of our fore-bearers as well. The last time that atmospheric CO2 concentrations appear to have exceeded 400 ppm was during the Pliocene > 2 million years ago.

These data, from the Scripps Institute of Oceanography and posted to, suggest that the current level of atmospheric CO2 is anamalous over the 800,000 year record available by analyzing gases trapped in ice.

In light of this context, it seems worthwhile to at the very least bring the very best science to bear on the problem of projecting future climate, and use that information to plan for those changes. The OCNMS Sanctuary Advisory Committee discussed that very problem at their meeting on Friday, and I see leaders all over the Olympic Peninsula and in Washington State doing the same. I focus on the coastal implications of climate change - and there are many. One of the areas that I am interested in at the moment is the ways in which climate change, primarily through sea level rise and changes in storm pattens and wave climate, may compromise the ability of shorelines to act as effective barriers between communities and the ocean. To that end I've proposed a small shoreline monitoring program for the North Olympic Peninsula, to complement shoreline change data collected in SW Washington and Oregon. I put together the poster below on the program - check it out and let me know what you think...

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