Environmental News

i haven't followed it, but i'm glad you mentioned it. we dostill have a few old trees here and there. i only recognize them when the fruit is on the ground.
and i almost forgot, i planted a gecko a few years back, but i don't think they're indigenous

 

you'reright, white pines are ubiquitous, and they spread rapidly.

 

The gecko knew too much. We hadda plant 'im.

 

i have had a love affair with chestnuts since we carved pipes from them in cubscouts

 

iirc, someone made an engine that could run on urine. so you could drink coffee all day, and just keep driving

 

are you saying i should pee on my tomatoes?

 

I had several Mountain Ash on my property in Connecticut, but all are now extinct due to a fungus. Now mostly Oak, Maple, Birch, Hickory, and Sycamore along with the usual evergreens.

JeffD

 

birch and hickory are good ones, i forgot.

 

cool story. bob reminds me of our bob wilson

 

with lyme disease, we don't hike in the woods anymore, stick to open paths

 

It seems that Greenland's ice sheet is a very major producer of hydropower, as the large flow of meltwater on top falls down through holes and cracks to the base on bedrock typically a kilometer below. But instead of spinning turbines to generate mechanical or electrical power, it can only be converted to frictional heat. And that heat then melts additional ice as the water flows between the ice sheets and bedrock on its way to the ocean. This seems to explain what had been an inexplicably high rate of melting from below, far greater than from the other heat sources (e.g. geothermal heat flow from earth's interior?) that had been previously considered.


"The team calculated that as much as 82 million cubic meters of meltwater was transferred to the bed of Store Glacier every day during the summer of 2014. They estimate that the power produced by the falling water during peak melt periods was comparable to the power produced by the Three Gorges Dam in China, the world’s largest hydroelectric power station. With a melt area that expands to nearly a million square kilometers in total during peak melt, the Greenland Ice Sheet produces more hydropower than the world’s ten largest hydroelectric power stations combined. [emphasis added] ...

To verify the high basal melt rates recorded by the radar system, the team integrated independent temperature measurements from sensors installed in a nearby borehole. At the base, they found the temperature of water to be as high as +0.88 degrees Celsius, which is unexpectedly warm for an ice sheet base with a melting point of -0.40 degrees.

“The borehole observations confirmed that the meltwater heats up when it hits the bed,” said Christoffersen. “The reason is that the basal drainage system is a lot less efficient than the fractures and conduits that bring the water through the ice. The reduced drainage efficiency causes frictional heating within the water itself. When we took this heat source out of our calculations, the theoretical melt rate estimates were a full two orders of magnitude out. The heat generated by the falling water is melting the ice from the bottom up, and the melt rate we are reporting is completely unprecedented.”"


From other sources, it appears that Three Gorges Dam has an installed electric capacity of 22.5 GW, average output of 12.7 GW. The ten largest hydro plants have a combined installed capacity of 110 GW, while the ten highest output dams (not all the same dams) have a combined average output 60 GW. I don't know which figure the above group meant, but either way, that is a lot of power to be just melting ice.

Greenland's ice is melting from the bottom up and far faster than previously thought - CNN
Accelerating melt rate makes Greenland Ice Sheet world’s largest ‘dam’
https://news.ucsc.edu/2022/02/melting-glaciers.html

 

A similar function should work on Antarctica. However, I'm also seeing articles claiming 'warm' sea water is also melting the bottom of ice sheets holding the glaciers back.

Bob Wilson