holyoutlaw: (me meh)

Some Trees Use Less Water Amid Rising Carbon Dioxide, Paper Says
[New York Times, might be behind pay wall]

After collating data from 21 different sites, gathered over 20 years, there is an indication that some trees are using less water to achieve a given amount of growth, because there is more carbon dioxide in the atmosphere. As one of the persons quoted in the article says, this is the first word, not the last, on this issue.

The article refers to a couple things that I’ve come across recently (not explicitly, but they caught my eye).

First, the “invisible present” and long-term ecological research. This data was gathered over 20 years, and some people are saying that that’s not long enough to verify the trend. This shows why we need long-term research, and why it needs to be funded.

Second, assisted migration. The article refers to trees at the edge of their ranges struggling, but trees (it doesn’t say if they’re the same trees or different species) in the middle of their range doing well. I consider assisted migration an open question, even though I go back and forth on it. Assisted migration will be of limited help, and mostly for large, charismatic species that are more or less on the human scale (ie, visible to the naked eye). But there probably are trees that could be moved, either into new areas entirely or into refugia.

Mirrored from Nature Intrudes. Please comment over there.

holyoutlaw: (me meh)

Science is good at measuring short term events, ranging from a day or so for bacterial growth down to femtoseconds for some physical processes. Science is also good at extrapolating very long term events from observations, such as geologic process shown in rocks or cosmological events in the microwave background.

However, there is a middle ground that is difficult to study, events that take anywhere from several years to a few decades. They’re within the span of a human lifetime, but gradual enough to appear static. This is what Magnuson (1990) calls “the invisible present.” This is the scale of most ecological processes, and why researchers sometimes have to gather data for decades before being able to make an informed hypothesis.

Most scientific research is centered on the “falsifiable hypothesis.” That is, a scientist has a question they want to explore, and tries to construct the experiment in such a way as to disprove their original question. This can work for relatively short term processes of three to five years or less (which, by remarkable coincidence, is about the length of the grant cycle).

I think the scale of “the invisible present” makes climate change such a difficult process to grapple with socially. The evidence has been accumulating for decades and is incontrovertible now. But the change has been so gradual that it’s only noticeable in long-term records, such as the 170+ years of ice-coverage data for Lake Mendota (WI) or the bloom records kept by Thoreau at Walden Pond compared to bloom dates of the same plants today.

When I was young the perceived risks to nuclear war or pollution were immediate. I heard the sirens every week, we did the duck’n'cover exercises under the desk, there were headlines about Mutually Assured Destruction. You could see the sky turn brown with smog and the rivers foam with phosphates. We’ve since cleaned up those problems (even though some were “cleaned up” by exporting the pollution to China).

But because the change caused by climate change has been so gradual, and below the threshold for direct human perception so far, we haven’t begun to make the deep cultural changes needed to make to deal with it.

Reference
Magnuson, John J. “Long-Term Ecological Research and the Invisible Present.” BioScience, Vol. 40, No. 7 (Jul. – Aug. 1990), pp. 495-501.

Mirrored from Nature Intrudes. Please comment over there.

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