Pliocene Perils and Global Warming Scare Tactics

April 9, 2014 4:37 pm5 comments

Renowned climate scientist Dr. Maureen Raymo claims in this video that global warming will “almost certainly lead to the collapse of ecosystems” (1:41) and that “historically…  the climate [science] community has always underestimated the rate of change in the climate system” (3:19). I deeply respect Dr. Raymo for her excellent paleoclimate work and I think the rest of the video is fine, but I disagree with these two statements.

I’m not aware of clear evidence supporting the “certain collapse of ecosystems” claim. I think scientists should be careful in their public statements with regard to certaintly of projections, particularly concerning ecosystem changes which are not well understood. What is more, today’s editorial in the New York Times argues that scare tactics don’t work in communicating climate change.

The rate of global surface temperature change for the past 15 years has certainty not been underestimated. It could be argued that it has been overestimated.

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Pliocene Perils

Source: National Science Foundation, Zina Deretsky, republished by Michael Quirke under fair use.

 

THE FORUM'S COMMENT THREAD

  • I agree with Maureen Raymo on the ecosystem collapse statement. She is not saying all ecosystems will collapse, but implying some will collapse. This statement can be well argued based on the examination of many time series of ecosystem change. In the Pliocene data such as that in the fantastic series of paper from the Lake El’gygytgyn volume in Climate of the Past, especially note the comments on the vegetation complex in the Arctic by Lozhkin and Anderson . We also have many ecosystem collapses at the beginning of the Holocene that have been well documented. Toth et al (2012) indicate a collapse of reef growth for 2500 in the East Pacific.Gerlach (2010) points out the particular sensitivity of ecosystems that are isolated, “islands”, in this case an actual island the Seychelles and ongoing ecosystem change due to current climate. I have observed the loss of glaciers in particular watersheds during the last 20 years (Pelto, 2010), and cannot imagine how the complete loss in a watershed fed by many glaciers will not be highly altered-collapse with the complete loss of glacier runoff. Hence we have seen ecosystem collpase due to climate change in different settings and time scales, how could we not expect more with current climate change?

  • I agree with Andres that the video is great and that we need to be very careful with our language. In isolation, the statement “almost certainly lead to the collapse of ecosystems,” does sound somewhat severe, but when I listened to the video in full, I felt that Dr. Raymo was conveying a message along the lines of “some ecosystems will collapse, some won’t, some will recover quickly, some won’t”, which is a fairly reasonable statement.

  • Moderator’s note: See Dr. Raymo’s reply in the Public Comment Thread below. Respectfully, MQ

  • Mauri: I appreciate your comments. I’m not an expert in ecosystems, so I admit that I may have been wrong. But I had a quick look at two of the references you provide to support your argument, but I don’t think they do.

    The Lozhkin and Anderson paper is about past warm periods in Siberia, during which tundra vegetation was replaced by forests. (Correct me if I’m saying something wrong.) This makes a lot of sense and I don’t question that vegetation shifts will occur. The paper itself does not talk about ecosystem collapse though. But I guess if tundra is replaced by forest it can be called collapse of the tundra ecosystem. Very similar transitions happened between ice ages and the warm periods like the current Holocene. I think much of Europe had a tundra / steppe like vegetation during the ice age, which turned into forest afterwards. So, it is clear that such ecosystem transitions occur naturally. Whether or not it is a bad thing is another question. But if one ecosystem (e.g. tundra) is replaced by another (e.g. forest) it is not only a collapse of the one that is vanishing, but also the emergence of the other. So, in mentioning only the collapse it leaves out that something else is replacing it. It sounds to me very negatively and scary. But what it really is is trees growing instead of shrubs.

    The abstract of the Toth paper says: “Global climate change is probably driving eastern Pacific reefs toward another regional collapse.”

    It does not say that it will certainly collapse.

    • Maureen: thanks for the clarification. I’m well aware that sometimes climate scientists underestimate changes. One example you don’t mention is the recent sea ice decline in the Arctic, which most models underestimated. I wasn’t aware of the issues you mention. Can you provide references?

      I just don’t think that it is generally true that climate scientists always underestimate changes. I also know examples where dramatic predictions have been made that later have been corrected. E.g. Cox et al’s Amazon dieback http://link.springer.com/article/10.1007%2Fs00704-004-0049-4
      which has subsequently been found to be very unlikely.

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PUBLIC COMMENT THREAD

  • http://glacierchange.wordpress.com/ Mauri Pelto

    I agree with Maureen Raymo on the ecosystem collapse statement. She is not saying all ecosystems will collapse, but implying some will collapse. This statement can be well argued based on the examination of many time series of ecosystem change. In the Pliocene data such as that in the fantastic series of paper from the Lake El’gygytgyn volume in Climate of the Past, especially note the comments on the vegetation complex in the Arctic by Lozhkin and Anderson . We also have many ecosystem collapses at the beginning of the Holocene that have been well documented. Toth et al (2012) indicate a collapse of reef growth for 2500 in the East Pacific.Gerlach (2010) points out the particular sensitivity of ecosystems that are isolated, “islands”, in this case an actual island the Seychelles and ongoing ecosystem change due to current climate. I have observed the loss of glaciers in particular watersheds during the last 20 years (Pelto, 2010), and cannot imagine how the complete loss in a watershed fed by many glaciers will not be highly altered-collapse with the complete loss of glacier runoff. Hence we have seen ecosystem collpase due to climate change in different settings and time scales, how could we not expect more with current climate change?

  • http://web.mit.edu/physics/people/academic/robinson_sean.html Sean Robinson

    I agree with Andres that the video is great and that we need to be very careful with our language. In isolation, the statement “almost certainly lead to the collapse of ecosystems,” does sound somewhat severe, but when I listened to the video in full, I felt that Dr. Raymo was conveying a message along the lines of “some ecosystems will collapse, some won’t, some will recover quickly, some won’t”, which is a fairly reasonable statement.

  • http://ClimateChangeNationalForum.org Michael Quirke

    Moderator’s note: See Dr. Raymo’s reply in the Public Comment Thread below. Respectfully, MQ

  • http://ceoas.oregonstate.edu/profile/schmittner/ Andreas Schmittner

    Mauri: I appreciate your comments. I’m not an expert in ecosystems, so I admit that I may have been wrong. But I had a quick look at two of the references you provide to support your argument, but I don’t think they do.

    The Lozhkin and Anderson paper is about past warm periods in Siberia, during which tundra vegetation was replaced by forests. (Correct me if I’m saying something wrong.) This makes a lot of sense and I don’t question that vegetation shifts will occur. The paper itself does not talk about ecosystem collapse though. But I guess if tundra is replaced by forest it can be called collapse of the tundra ecosystem. Very similar transitions happened between ice ages and the warm periods like the current Holocene. I think much of Europe had a tundra / steppe like vegetation during the ice age, which turned into forest afterwards. So, it is clear that such ecosystem transitions occur naturally. Whether or not it is a bad thing is another question. But if one ecosystem (e.g. tundra) is replaced by another (e.g. forest) it is not only a collapse of the one that is vanishing, but also the emergence of the other. So, in mentioning only the collapse it leaves out that something else is replacing it. It sounds to me very negatively and scary. But what it really is is trees growing instead of shrubs.

    The abstract of the Toth paper says: “Global climate change is probably driving eastern Pacific reefs toward another regional collapse.”

    It does not say that it will certainly collapse.

    • http://ceoas.oregonstate.edu/profile/schmittner/ Andreas Schmittner

      Maureen: thanks for the clarification. I’m well aware that sometimes climate scientists underestimate changes. One example you don’t mention is the recent sea ice decline in the Arctic, which most models underestimated. I wasn’t aware of the issues you mention. Can you provide references?

      I just don’t think that it is generally true that climate scientists always underestimate changes. I also know examples where dramatic predictions have been made that later have been corrected. E.g. Cox et al’s Amazon dieback http://link.springer.com/article/10.1007%2Fs00704-004-0049-4
      which has subsequently been found to be very unlikely.