Confirmation Of My Post Of January 17 2006 That The Extinction Of Frogs In Costa Rica Cannot Be Explained By Global Warming

On January 17 2006 I posted

Is the Report Linking the Extinction of Frogs with Global Warming a Scientifically Balanced Conclusion?

In 2006, I concluded that the Report was not balanced.

There is a new press release from The Earth Institute of Columbia University on March 1 2010 titled

El Niño and a Pathogen Killed Costa Rican Toad, Study Finds Challenges Evidence That Global Warming Was the Cause


[h/t to Watts Up With That] which provides further support for my perspective that the 2006 Report is in error.

The 2010 news release contains the text

“Scientists broadly agree that global warming may threaten the survival of many plant and animal species; but global warming did not kill the Monteverde golden toad, an often cited example of climate-triggered extinction, says a new study. The toad vanished from Costa Rica’s Pacific coastal-mountain cloud forest in the late 1980s, the apparent victim of a pathogen outbreak that has wiped out dozens of other amphibians in the Americas. Many researchers have linked outbreaks of the deadly chytrid fungus to climate change, but the new study asserts that the weather patterns, at Monteverde at least, were not out of the ordinary.”

As I wrote in my 2006 post

“[The] claim [of global warming] being the cause of the extinctions], however, is not scientifically sound as it does not explore the relative role of other reasons for the extinctions and loss of biodiversity. This is hardly how balanced scientific work should be performed.

As Tom Stohlgren has informed me (Dr. Stohlgren is an internationally respected ecologist who studies invasive plant species), chytrid fungus (an invasive disease) is by far the number one cause of amphibian decline in the world. According the ISI Web of knowledge, Dr. Stohlgren found that there are over 90 peer-reviewed publications on the role of chytrid disease in amphibian decline.

Possible reasons for the increase for the prevalence of chytrid disease and its role in the decline in frog populations include the effect on the local weather of landscape change in the region where the frogs live. We have shown in several papers that landscape change in Costa Rica has had a major effect on the climate of this region, including the rain forest. These papers are

Nair, U.S., R.O. Lawton, R.M. Welch, and R.A. Pielke Sr., 2003: Impact of land use on Costa Rican tropical montane cloud forests: 1. Sensitivity of cumulus cloud field characteristics to lowland deforestation. J. Geophys. Res. – Atmospheres, 108, 10.1029/2001JD001135.

Lawton, R.O., U.S. Nair, R.A. Pielke Sr., and R.M. Welch, 2001: Climatic impact of tropical lowland deforestation on nearby montane cloud forests. Science, 294, 584-587.

Ray, D.K., U.S. Nair, R.O. Lawton, R.M. Welch, and R.A. Pielke Sr., 2006: Impact of land use on Costa Rican tropical montane cloud forests. Sensitivity of orographic cloud formation to deforestation in the plains. J. Geophys. Res., 111, doi:10.1029/2005JD006096.

These studies, which the authors acknowledge in the Nature paper but do not accept their conclusions, indicate that a local human intervention is a major contributor to altering the immediate environment of the frogs. Since tropical landscape continues unabated (e.g. see Table 1 in Pielke Sr., R.A., J.O. Adegoke, T.N. Chase, C.H. Marshall, T. Matsui, and D. Niyogi, 2005: A new paradigm for assessing the role of agriculture in the climate system and in climate change. Agric. Forest Meteor., Special Issue, in press. ) this certainly must be affecting the viability of frog populations…….

We need to move beyond the over simplistic view of global warming as being the dominant cause of the demise of the frogs (or other enviromental threats). The spectrum of risks to frog population (their vulnerability), including global warming, need to be presented and assessed for their relative importance. This was not done in the Nature study. Moreover, reporters need to more objectively assess whether a paper was used to advance an agenda (in this case as clearly stated by the lead author), or is actually a balanced scientific study. We certainly should be concerned about declining populations of amphiphians, but we do not serve those who are seeking to alter this decline but focusing on just one possible environmental explanation.”

The new 2010 study does indeed show that the claim in the 2006 Nature news release , which is titled “Dead frogs linked to global warming”, that the study findings require that their findings “will ram home the global-warming message [that] [w]e have to reduce concentrations of greenhouse gases very soon if we are to avoid massive losses of biodiversity” is not based on an inclusive scientific assessment of the diversity of influences on biodiversity.

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