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Messages - Bernard

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I thought I had already asked, but can't find the subject now. Maybe I only intended to do it?
This is an international scientific forum, which makes two sufficient reasons to forbid local units such as miles, gallons, Fahrenheit etc.
Is it possible to use only units from the International System of Units in all posts in this Forum?

Note that SI will go through a major revision on 20 May 2019  :)
https://www.bipm.org/en/CGPM/db/26/1/

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Antarctica / Re: Thwaites Glacier Discussion
« on: February 09, 2019, 05:09:40 PM »
how to make people aware that understanding what's going on behind those difficult-to-grasp images and data has a critical impact on their future?

You don't. If people don't ask independently they will not listen most likely anyway. So spear your breath i say.

When people ask you, you have already won. In this case, encourage them to stay curious.

Wisdom indeed. But now that Thwaites news are flowing in mainstream media, maybe time has come to be a bit more proactive. ;)

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Antarctica / Re: Thwaites Glacier Discussion
« on: February 09, 2019, 12:09:35 PM »
I've been following this thread for a while, but it's often very hard in this complex zone to figure out scale of things, and what is what, default explicit scale and orientation of pictures. Would it be difficult to have some reference map, with scale and orientation, on which background the different pictures posted here could be localized? Or are things so mobile there that the very notion of such a map is impossible?

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Science / Re: 2019 Mauna Loa CO2 levels
« on: February 01, 2019, 06:01:48 PM »
A hopeful, uplifting paragraph should follow the one above. Something to inspire the vegan cyclists  growing kale in their kitchen window that have voted Green since James Hansen addressed Congress in 1988, but nothing hopeful or inspiring comes to mind. :-\
Terry

La lutte elle-même vers les sommets suffit à remplir un coeur d'homme. Il faut imaginer Sisyphe heureux.
Albert Camus, Le Mythe de Sisyphe, 1942

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Science / Re: Underground temperatures trends
« on: January 17, 2019, 07:32:42 PM »
Default serious papers about it, I tried a napkin computation of the Underground Heat Content growth under the conservative hypothesis of 1K growth in surface temperature over the past century.

According to different papers previously quoted, the diffusion of the mean ground temperature on such a time scale would reach depths around 100 m. So I try below to asses the energy needed to heat up by 1K the first 100 m of bedrock all over continents.

I take mean values for granite or similar rocks :

heat capacity ~ 25 J/mol/K
molar mass ~ 60 g/mol
density ~ 2.5 g/cm3

Continents being about 1.4x108 km² gather to a depth of 100 m a volume of 1.4x107 km3, a mass of 3.5x1022 g, around 6x1020 mol.

To heat this up 1K, you need to transfer 1.5x1022 J, or 15 zettajoules.

This is one order of magnitude (less than 5%) smaller than the ~400 zettajoules added to Ocean Heat Content since 1940, according to https://www.carbonbrief.org/state-of-the-climate-new-record-ocean-heat-content-and-growing-a-el-nino

But not small enough to ignore it in any accurate assessment of global warming.

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Consequences / Re: Ocean Temps
« on: January 20, 2018, 02:56:23 PM »
By the time I thought about it I was in the pub.

Ha! Happy to see my own computation was correct  ;)

Meanwhile, I made another impressive one over my coffee. Given that the fusion enthalpy of ice is 333.55 J/g, 2.3E+23 J is potentially able to melt (at 0°C) 6.9E+14 tons of ice, representing about 7.7E+14 m3, or 770,000 km3 of ice. This represents a layer of about 360m thick if spread over Greenland. Or a significant 3% of the total volume of ice in Antarctica.

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Consequences / Re: Ocean Temps
« on: January 20, 2018, 12:38:22 PM »
PS: To get a better idea of the energy acquired by the oceans in recent years:-

ENERGY ACQUIRED BY OCEANS SINCE ABOUT 1985 in Joules            
Depth 0 to 700 metres   1.5E+23 = 41,667,000,000 Gigawatt hours   
Depth 0 to 2000 metres   2.3E+23 = 63,889,000,000 Gigawatt hours

Eon Musk's mega battery's capacity in S. Australia is 100 Megawatt hours.

Also to compare with the Total Primary Energy Supply, a measure of worldwide human production/consumption of energy, all sources added. For 2013, according to WP, it was 1.575E+17 Wh, or 1.575E+8 GWh.
The above figure represent, for each year, more than 10 times the TPES (correct me if I am wrong).
https://en.wikipedia.org/wiki/World_energy_consumption

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