"First Person": Examining Climate-Related Changes in the Arctic with an Eye Towards What is Yet to Come

Eric post

Eric Post in the field.

A conversation with Eric Post about climate change in the Arctic and how some effects are so subtle as to be, for now, "like a thief in the night."

10/29/2009

This is one of a projected series of articles, exclusive to this site, to highlight discoveries made possible, in whole or in part, through IPY funding. Support for this research came from National
Science Foundation grants
0817967,
0713994, and 0732168.

 

Eric Post, an associate professor of biology at Pennsylvania State University, is the lead author of  a paper published by more than 20 researchers in the journal Science in July of 2009 that discusses climate-related changes observed in the Arctic during the IPY.

One overall idea of the synthesis, the authors say, is to establish a baseline for comparison during the next Polar Year. The paper describes the current state of Arctic ecology: the authors note, for example, that as the Arctic has warmed, vegetation growth has peaked earlier, while the caribou who depend on the forage for food continue to give birth at the same time of year, creating a serious mismatch of resources.

But the synthesis also emphasizes aspects of ecological research that should be the focus of future studies. In the following question-and-answer session, Post discussses the paper's findings as well as the implications for the Arctic and future research.

Can you explain the nature of this paper in relation to scientific studies of Arctic climate change? In other words, this seems to be not so much a paper about a single event, but a recap of observed changes and an effort set out an agenda of what needs to be done to understand the potential effects of climate change in the Arctic. Correct?

The paper is an attempt to synthesize the current state of knowledge about ecological responses to climate change in the Arctic and establish research priorities for the near future.

Does this synthesis indicate, as some news accounts would have it, that we are seeing "the end of the Arctic" as most of us think of it? Is it as simple as that? Or more complex? Is there any consensus?

Well, it is, in fact, pretty complex. The Arctic isn't just defined by geography, for example, it's also defined by iconic landscape features such as treeless tundra, ice sheets, and permafrost, all of which are in flux; and unique collections of species, some of which have begun to decline. At what point do you say that a system has changed enough from the baseline features that used to make it unique that it's no longer the same system? I think the Arctic is already moving away from that baseline.

Can you explain the role of IPY in this work and in the discussion of the Arctic climate change generally, as described in the paper?

In preparing our synthesis paper, we realized how little single-source information was available from previous IPYs or [International] Geophysical Years on ecological systems or the state of science then. We felt it was imperative to establish, as we called it in the paper, a “waymarker” of what we know about the Arctic today and what we would like to know by the time the next IPY comes around.

Was there a “Eureka!” moment in producing this work in which something that had not been previously clear became so?

For me, that moment came when I began to realize the breadth and depth of changes occurring across the Arctic. As a scientist, it’s difficult not to develop “tunnel vision” as you get to know your own study system in greater and greater detail.

Is it fair to do say that one, perhaps clumsy, way to sum up this finding is “When it comes to the effects of climate change in the Arctic, in many ways we don’t even know what we don’t know”?

That’s precisely what became apparent to me and many of the co-authors on this paper as, like I said, the scope of ecological changes across the Arctic took shape as the paper developed. I believe Darwin is attributed with a statement along the lines of “Looking back, I realize that finding the answers to the questions was not as difficult as coming up with the questions in the first place”. This is probably a common phenomenon to many scientific disciplines.

Would it be unfair to draw an inference from your paper that studying the conditions and ecological relationships in the Arctic during this period of rapid warming is like attempting to hit a very rapidly moving target? And if so, what is the value of doing that?

 Well, I’d say that sometimes it feels more like you’re constantly trying to catch up. Some aspects, like the start of the plant growing season, are changing rapidly. The value in returning every year to the Arctic to see how much things have changed-–or in some cases to see whether they’ve changed at all-–is that it allows us to try to figure out whether or not there are limits on the responsiveness of different elements of the biological community.

Following along those lines, it seems to me that while large numbers of people around the world are now aware that the extent of Arctic sea ice has been shrinking dramatically in recent years, far fewer would be aware of the example of the imbalance between vegetation peak and caribou calving. Could you explain that relationship and why such understanding such interactions are important to Arctic climate-change research?

This is a prime example of what you could refer to as a “thief in the night” component of climate change.

Not all responses to climate change are direct or immediate. In this case, caribou aren’t being affected directly by rising temperatures.

Instead, the peak availability of high-quality, newly emergent plants that they’re depending upon to provide them with the nutrition they need to raise their calves is coming earlier and earlier with warming. That might sound like it could be beneficial, but the problem for caribou is that they don’t know that peak is coming earlier and earlier on their calving grounds. Caribou time their annual migration to those calving grounds based on changes in the number of daylight hours in a 24-hour period. When the days get longer in spring, a hormonal trigger tells caribou it’s time to migrate. And of course, the timing of that trigger won’t change no matter how much warmer it gets.

So caribou at my study site are arriving later and later relative to the start of the growing season at their destination.

It’s as if you left your office for lunch at the same time every day, but the restaurant you were headed to began opening and closing earlier and earlier every day, until eventually you arrived after it was closed. Interactions such as these are not immediately apparent, but can reveal the importance of indirect consequences of climate change that you may not see coming, like a thief in the night.

You note the effects of a warming of 1.8 degrees Fahrenheit over the past 150 years, which has already caused dramatic changes in the Arctic. How does this reconcile with the widely held notion that climate change, climate warming, is a fairly recent and immediate problem?

Well, most of that warming has occurred over the past two decades, but in an ecological and evolutionary context 150 years is quite recent.

What was the genesis of this study? What brought this seemingly disparate group of roughly 25 researchers together to produce this one paper?

The study grew out of a conference that in turn grew out of a hallway conversation I had with colleagues at Aarhus University in Denmark.

I was there on sabbatical during the IPY, and was planning the organization of a workshop on efforts to model animal responses to climate change, when it occurred to me and my colleagues how exciting it would be to bring together the world’s experts on Arctic ecology for a sweeping conference on ecological responses in general to Arctic climate change.

Having found ourselves well into the IPY with what seemed like a good idea on our hands, we began extending invitations, searching for available conference venues and accommodations, and scrambling for funds to support the initiative.

The conference was held in May 2008 with an explicit goal of producing an IPY synthesis paper for a top journal.

Who supported this work and why? 

My own work was supported both by NSF and National Geographic. Support for the conference that led to this paper came from NSF, the Danish Polar Center, and Aarhus University in Denmark.

I think all of these organizations were excited about supporting a multi-national effort to synthesize results of research programs across the Arctic because such efforts really exemplified the goals of the IPY.

And, as always, what question did I fail to ask you, if any, that is important to understanding this work?

None that I can think of.