Thursday, December 21, 2017


Having tired of polar bears, WUWT is busy denying that other arctic creatures have responded to climate change by invading the warming tundra -- and causing more :
Arctic Restoration — Go Beavers!
Guest Essay by Kip Hansen 
"Oh those busy, busy beavers — aren’t they great? There’s the little guy in the corner of the photo, he and his pals built that dam that slowed the stream and produced a large shallow beaver pond. The American beaver is a keystone species on the North American continent…

This lovely active creature has been accused — in the NY Times Science /Climate section by Kendra “Gloom is My Beat” Pierre-Louis [seriously, that’s her real Twitter handle] — in an article with the anti-Darwinian title of “Beavers Emerge as Agents of Arctic Destruction”.

This is a marvelous piece of CAGW propaganda based on the AGU Poster presented by Ben Jones, Ken Tape and others at the recent 2017 AGU meeting in New Orleans... 

Bottom Line:
I’m with Ben Goldfarb. The re-introduction of beavers into the landscapes of the far north do not represent destruction — on the contrary, they represent a restoration."

It's odd  Watts should  delegate boreal biology to Hansen,  who lives in the Virgin Islands, when  the very short bibliography of another polar bear circuit regular,  Tim Ball, includes works in some of the most relevant journals on the subject :

As Cold As I Ever Knew It. 
History & Science Society  of  Manitoba Transactions                          
An Early Enrgy Crisis:
The Importance of  Woodcutting  at Churchill in the Early Years of the Fur Trade  
                              Horizon Canada,                 1985  
"Timber"            The Beaver                         1987  
Here's a more lucid account of what the AGU meeting paper says: 

Hordes of Beavers Are Invading Alaska’s Tundra

Research shown at last week’s American Geophysical Union meeting revealed that everyone’s favorite rodent has been using sticks to build dams on the Alaska’s treeless tundra. The colonization is reshaping the geography of the north Even if moose or other species benefit, there’s another unintended consequence of the beaver invasion. The dams they build impound water, which can contribute to thawing the icy layer of permafrost that covers much of northern Alaska. When the dams fail and the ponds drain and cause small floods downstream, that further melts out permafrost.
That is distinctly bad news from a climate change perspective because permafrost releases carbon dioxide and methane as it thaws. Both greenhouse gases further turn up the planetary heat, cause more permafrost to melt, and create a terrible feedback loop of ever-worsening climate change."

Interesting as the AGU poster on which Kahn reports in Earther may be, the beaver's black mischief in the great white north isn't the only way in which the industrious creatures compete with H. sapiens in the climate forcing game: Tundra thawing but adds to the climatic impact of beavers living south of the tree line.
There  each adult constructs a hectare or so of ponds,  whose dark water typically reflects only half  as much solar energy as the surrounding landscape.
As pond surfaces are only 7% reflective , habitat darkening by beaver communities has the opposite effect of human efforts to cool cities by using white roofs to offset the impact of heat absorbing dark asphalt.
Published reseach by the Lawrence Berkeley National Laboratory includes calculations comparing climate forcing from dark urban surfaces to that arising from human CO2 emission . It estimates that replacing sixteen square meters of black asphalt roofing or paving of ~7% reflectivity with  a surface  that reflects 40% of solar energy  is equivalent to cutting CO2 emission by a tonne over the   20 year lifetime of the new surface
Reversing that calculation for the case of a beaver building and maintaining a 10,000 square meter ( 1 hectare) pond over its similar lifetime one arrives at the disconcerting conclusion that, if the pond  is only 10% lower than its surroundings, the radiative impact of its reduced ‘albedo’ on global climate will equal adding 156 tonnes of CO2 to the air. In other words, the beaver’s habitat presents a carbon footprint   roughly on a par with a Range Rover or other hefty SUV.

The Peabody Museum of Comparative Zoology says the total area covered  by  Castor faber  ponds may excced a hundred thousand km2 : the voracious varmints may have darkened more area than human "cool cities" initiatives have brightened to date.  While polar bear  table manners may be deplorable-- they ate a Peabody graduate student on  Labrador's Ungava peninsula some years ago,  at least they have a respectably  high albedo.