Jennifer Marohasy

a forum for the discussion of issues concerning the natural environment

Archives for June 20, 2008

Amphibian Chytridiomycosis “Not Driven by Climate Change”

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A new study by a team of scientists specializing in zoology and animal health reported, “analyses found no evidence to support the hypothesis that climate change has been driving outbreaks of amphibian chytridiomycosis.”

The study was published in the peer-reviewed PLoS Biology, a journal of the Public Library of Science:

Riding the Wave: Reconciling the Roles of Disease and Climate Change in Amphibian Declines

Karen R. Lips1*, Jay Diffendorfer2, Joseph R. Mendelson III3, Michael W. Sears1

1 Department of Zoology, Southern Illinois University, Carbondale, Illinois, United States of America, 2 Illinois Natural History Survey, Champaign, Illinois, United States of America, 3 Zoo Atlanta, Atlanta, Georgia, United States of America

We review the evidence for the role of climate change in triggering disease outbreaks of chytridiomycosis, an emerging infectious disease of amphibians. Both climatic anomalies and disease-related extirpations are recent phenomena, and effects of both are especially noticeable at high elevations in tropical areas, making it difficult to determine whether they are operating separately or synergistically. We compiled reports of amphibian declines from Lower Central America and Andean South America to create maps and statistical models to test our hypothesis of spatiotemporal spread of the pathogen Batrachochytrium dendrobatidis (Bd), and to update the elevational patterns of decline in frogs belonging to the genus Atelopus. We evaluated claims of climate change influencing the spread of Bd by including error into estimates of the relationship between air temperature and last year observed. Available data support the hypothesis of multiple introductions of this invasive pathogen into South America and subsequent spread along the primary Andean cordilleras. Additional analyses found no evidence to support the hypothesis that climate change has been driving outbreaks of amphibian chytridiomycosis, as has been posited in the climate-linked epidemic hypothesis. Future studies should increase retrospective surveys of museum specimens from throughout the Andes and should study the landscape genetics of Bd to map fine-scale patterns of geographic spread to identify transmission routes and processes.

Author Summary

Once introduced, diseases may spread quickly through new areas, infecting naive host populations, such as has been documented in Ebola virus in African primates or rabies in North American mammals. What drives the spread of the pathogenic fungus Batrachochytrium dendrobatidis (Bd), which causes chytridiomycosis, is of particular concern because it has contributed to the global decline of amphibians. We modeled the spatiotemporal pattern of the loss of upland amphibian populations in Central and South America as a proxy for the arrival of Bd and found that amphibian declines in Central and South America are best explained by Bd spreading through upland populations; we identified four separate introductions of Bd into South America. Climate change seriously threatens biodiversity and influences endemic host–pathogen systems, but we found no evidence that climate change has been driving outbreaks of chytridiomycosis, as has been posited in the climate-linked epidemic hypothesis. Our findings further strengthen the spreading-pathogen hypothesis proposed for Central America, and identify new evidence for similar patterns of decline in South American amphibians. Our results will inform management and research efforts related to Bd and other invasive species, as effective conservation actions depend on correctly identifying essential threats to biodiversity, and possible synergistic interactions.

Food Crisis Consequence of Bad Government Policy

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The current global food “crisis” is not so much a consequence of natural resource constraints as it is a consequence of poor food policy decisions by government. That’s the headline in an article by Mick Keogh, Executive Director of the Australian Farm Institute, published on Monday by On Line Opinion.

I tend to agree with Mick.

The bottom line is that governments in Europe and North America, as Mick explains, have very actively discouraged agricultural production over recent decades by converting arable land into conservation areas. According to Mick, the USA has 16 million hectares of crop land (almost two thirds of Australia’s total crop area) in Conservation Reserve.

In Australia, the bans on tree clearing, but in particular the purchase of water allocation from irrigators in the Murray Darling Basin, is going to significantly impact on our potential to produce food in the longer term. Indeed while the Murray Darling Basin has historically received only 6 percent of Australia’s annual rainfall, it has produced 40 percent of Australia’s food. This is where we have concentrated the national investment in water infrastructure.

Mick suggests that the imminent introduction of greenhouse emission mitigation policies in Australia and New Zealand also has the potential to adversely impact global agricultural capacity by converting agricultural land to permanent carbon sink forests.

I thought this had already occurred to some existent in Australia, with the bans on broad scale tree clearing in our rangelands? But Mick is perhaps referring to new Blue Gum and pine plantations. Does anyone have any figures on areas likely to be converted from agriculture to this type of forestry?

Mick also mentions the lack of investment in agricultural research and development, government policies mandating the use of food crops for fuel production and policies that restrict trade.

EU Rule Put Half a Million Homes in the Dark

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Oh! the joy of living under the Soviet EU and policies driven by global warming alarmism:

The unexpected shutdown of two power stations on Tuesday, May 29, led to the worst disruption to the UK’s power network in more than 20 years, prompting new concerns over the stability of Britain’s ageing power grid.

However, industry sources say that a key factor was the European Union’s Large Combustion Plant Directive (LCPD), which sets strict limits on the number of hours that some of Britain’s largest and most heavily polluting coal and oil-fired power stations can operate before they have to close in 2015. The time is measured in “stack hours” — the length of time that chimney stacks, rather than individual generation units, are in use.

The Times: EU rule kept half a million homes in the dark

Climate Science Round Up from This Week’s Science and Nature Journals

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Science Journal:

A Greener Greenland:

Natural Variability of Greenland Climate, Vegetation, and Ice Volume During the Past Million Years

Anne de Vernal* and Claude Hillaire-Marcel

The response of the Greenland ice sheet to global warming is a source of concern notably because of its potential contribution to changes in the sea level. We demonstrated the natural vulnerability of the ice sheet by using pollen records from marine sediment off southwest Greenland that indicate important changes of the vegetation in Greenland over the past million years. The vegetation that developed over southern Greenland during the last interglacial period is consistent with model experiments, suggesting a reduced volume of the Greenland ice sheet. Abundant spruce pollen indicates that boreal coniferous forest developed some 400,000 years ago during the “warm” interval of marine isotope stage 11, providing a time frame for the development and decline of boreal ecosystems over a nearly ice-free Greenland.

Sprucing Up Greenland

Eric J. Steig and Alexander P. Wolfe

Pollen data suggest that the Greenland ice sheet was much smaller during previous warm periods.

Changes in Altitude

Elevation Changes in Antarctica Mainly Determined by Accumulation Variability

Michiel M. Helsen et al

Antarctic Ice Sheet elevation changes, which are used to estimate changes in the mass of the interior regions, are caused by variations in the depth of the firn layer. We quantified the effects of temperature and accumulation variability on firn layer thickness by simulating the 1980–2004 Antarctic firn depth variability. For most of Antarctica, the magnitudes of firn depth changes were comparable to those of observed ice sheet elevation changes. The current satellite observational period (15 years) is too short to neglect these fluctuations in firn depth when computing recent ice sheet mass changes. The amount of surface lowering in the Amundsen Sea Embayment revealed by satellite radar altimetry (1995–2003) was increased by including firn depth fluctuations, while a large area of the East Antarctic Ice Sheet slowly grew as a result of increased accumulation.

A Matter of Firn

Kurt M. Cuffey

Estimating ice sheet mass changes from elevation surveys requires adjustments for snow density variations at the ice sheet surface.

Nature journal:

Improved estimates of upper-ocean warming and multi-decadal sea-level rise

Catia M. Domingues et al

Changes in the climate system’s energy budget are predominantly revealed in ocean temperatures and the associated thermal expansion contribution to sea-level rise. Climate models, however, do not reproduce the large decadal variability in globally averaged ocean heat content inferred from the sparse observational database even when volcanic and other variable climate forcings are included. The sum of the observed contributions has also not adequately explained the overall multi-decadal rise. Here we report improved estimates of near-global ocean heat content and thermal expansion for the upper 300 m and 700 m of the ocean for 1950–2003, using statistical techniques that allow for sparse data coverage and applying recent corrections to reduce systematic biases in the most common ocean temperature observations. Our ocean warming and thermal expansion trends for 1961–2003 are about 50 per cent larger than earlier estimates but about 40 per cent smaller for 1993–2003, which is consistent with the recognition that previously estimated rates for the 1990s had a positive bias as a result of instrumental errors. On average, the decadal variability of the climate models with volcanic forcing now agrees approximately with the observations, but the modelled multi-decadal trends are smaller than observed. We add our observational estimate of upper-ocean thermal expansion to other contributions to sea-level rise and find that the sum of contributions from 1961 to 2003 is about 1.5 (+/-0.4) mm yr-1, in good agreement with our updated estimate of near-global mean sea-level rise (using techniques established in earlier studies) of 1.6 (+/-0.2) mm yr-1.

Leseur’s Frog

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Lesueuri1.jpg

Leseur’s Frogs (Litoria lesueuri) emerge after dark from their diurnal concealment amongst leaf-litter on the dark-brown forest floor, where they elude the predatory appetites of a formidable avian oversight.

Like all members of the genus, Leseur’s have large finger and toe pads and horizontal pupils, however, males out-number females, perhaps as many as fifty-to-one. Adult Females, such as the one pictured, are three to four times the mass of males and much less gregarious and stream-bound (I get the impression that the greater mass of the female provides more liberty from running water).

It has been a tough year for wildlife sightings generally with the longest, coldest patch I have known since starting my nocturnal forays, fifteen years ago. The last couple of nights have been good for the primitive northern leaf-tailed and chameleon geckos, as well as the spectacular moth Lyssa Macleayi.

AP Duped by Spoof Global Warming Study?

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CBS News have published an Associated Press (AP) story entitled: ‘Today’s Quakes Deadlier Than In Past,’ Study: Seismic Activity 5 Times More Energetic Than 20 Years Ago Because Of Global Warming:

(AP) New research compiled by Australian scientist Dr. Tom Chalko shows that global seismic activity on Earth is now five times more energetic than it was just 20 years ago

The research proves that destructive ability of earthquakes on Earth increases alarmingly fast and that this trend is set to continue, unless the problem of “global warming” is comprehensively and urgently addressed……

What a pity an earlier study by Chalko seems to have gone unnoticed: ‘Can Earth explode as a result of Global Warming?’

NU Journal of Discovery is an unknown journal, with only a handful of publications, all of them by Chalko, who happens to be on the journal editorial board. NU (or Nature University) isn’t a real university.

Here are a few more things Chalko has been involved in:

Aliens! http://thiaoouba.com/faq.htm

Auras: http://thiaoouba.com/seeau.htm

Astral Travel? http://thiaoouba.com/astr.htm

He even sells “bioresonant” shirts:
http://bioresonant.com/dress.html?PHPSESSID=1a7fd4e1219326e73544904d8d1ac67d

Now they are groovy! I might even get one myself.

Global warming causing earthquakes and exploding planet earth. What next?

Hat tip to MM and JP.

UPDATE: The CBS News article has now been pulled – the link is dead.