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Receding glacier causes Canadian river to vanish in four days

theguardian.com

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Re: Receding glacier causes Canadian river to vanish in four days

#91

Post by acover »

mnarayan01 wrote: post #70
acover wrote: post #53

Earlier quoted context omitted.

Do you agree to the statement "so it's 99.5% that we correctly reject the hypothesis it occurred without warming over the industrial era"?

I think you're mainly correct. The main issue is that there's an implied "given that the model from http://www.nature.com/ngeo/journal/v10/n2/full/ngeo2863.html is 'perfect' (at least for this case)". Since it seems unlikely that the model is perfect , the numbers they give are almost certainly inflated.

Nope. I'm totally wrong.

Re: Receding glacier causes Canadian river to vanish in four days

#92

Post by acover »

archgoon wrote: post #82
archgoon wrote: post #79

Earlier quoted context omitted.

Can you clarify why it is incorrect to reverse that into the statement "We estimate that there is a 99.5 percent chance that the observed retreat did not happen in the absence of a climate trend."? I confess to a fair amount of confusion at this point :) I'm sure there is something subtle (or perhaps obvious, and my brain is failing) that I'm missing. What is the properly worded complement?

This seems similar, but not identical, to the statement: If there is not a climate trend, we would expect this to happen with a .05 chance. If they meant the latter, my confusion is resolved.

This is the blind leading the blind.

Fundamental truth: bayes theorem.

P(evidence | null hypothesis) = P(null hypothesis | evidence) * P (evidence) / P (null hypothesis)

The P-value test determines:

P(evidence | null hypothesis) = 0.5%

= there is a 0.5% chance of the observed evidence given the null hypothesis

The statement "We estimate that there is a 99.5 percent chance that the observed retreat did not happen in the absence of a climate trend."

translates to P(!null hypothesis | evidence) = 99.5%

By Bayes theorem:

P(!null hypothesis | evidence) = P(evidence | !null hypothesis) * P (!null hypothesis) / P (evidence)

We know almost none of these terms. The answer is not as simple as 99.5.

Re: Receding glacier causes Canadian river to vanish in four days

#93

Post by archgoon »

acover wrote: post #92
archgoon wrote: post #82

Earlier quoted context omitted.

This seems similar, but not identical, to the statement: If there is not a climate trend, we would expect this to happen with a .05 chance. If they meant the latter, my confusion is resolved.

This is the blind leading the blind. Fundamental truth: bayes theorem. P(evidence | null hypothesis) = P(null hypothesis | evidence) * P (evidence) / P (null hypothesis) The P-value test determines: P(evidence | null hypothesis) = 0.5% = there is a 0.5% chance of the observed evidence given the null hypothesis The statement "We estimate that there is a 99.5 percent chance that the observed retreat did not happen in t…

Oh I thought we were having an interesting discussion about the linguistic mapping between probability and regular English. Sorry for wasting your time. :(

Re: Receding glacier causes Canadian river to vanish in four days

#94

Post by [deleted] »

archgoon wrote: post #93
acover wrote: post #92

Earlier quoted context omitted.

This is the blind leading the blind. Fundamental truth: bayes theorem. P(evidence | null hypothesis) = P(null hypothesis | evidence) * P (evidence) / P (null hypothesis) The P-value test determines: P(evidence | null hypothesis) = 0.5% = there is a 0.5% chance of the observed evidence given the null hypothesis The statement "We estimate that there is a 99.5 percent chance that the observed retreat did not happen in t…

Oh I thought we were having an interesting discussion about the linguistic mapping between probability and regular English. Sorry for wasting your time. :(

[deleted]

Re: Receding glacier causes Canadian river to vanish in four days

#95

Post by titojankowski »

discreteevent wrote: post #66
titojankowski wrote: post #63

Earlier quoted context omitted.

Thanks! I hadnt heard of Paulownia before. 3-10x more sequestration than the average tree: http://paulowniabg.info/?page_id=56 One challenge with plant-based sequestration is that the carbon is released when the tree dies/decomposes. I wonder how planting more trees will balance out at the decade-century scale.

Cut them down when mature and use them as building material.

Wow cool, at first I said "but the CO2 gets released when the building burns down", so I looked into it. Apparently wood has a ton of benefits, basically it doesn't release much of the CO2 if it just sits there (http://www.awc.org/pdf/education/gb/ReThinkMag-GB500A-Evalua...). And it takes far less energy to grow a tree than the respective amount of concrete/other building materials (http://www.treehugger.com/green-architecture/new-study-confi...). So wood->building materials is a great option. Right on!

Re: Receding glacier causes Canadian river to vanish in four days

#96

Post by titojankowski »

thinkcontext wrote: post #83
titojankowski wrote: post #61

Earlier quoted context omitted.

Thanks, I watched the whole video. A great success of natural capitalism. I wonder how drone surveys, satellite mapping, and synthetic biology could extend this 35 sq-km success to 3,500 sq-km and beyond, augmenting people's needs and efforts. As said in the video, let's "properly understand the miracles performed by trees" to make this more profitable and spread everywhere. I also agree with the farmer who said "wha…

Perhaps its not exactly the best example of capitalism given that it was centrally planned. Glad you found it interesting. In the text accompanying the video they link to more videos in the series from Ethiopia and Rwanda, with similar projects to rehabilitate the land.

Food is key. This inspired me to re-read the 4 pages on Food in "Sustainable Energy without the hot air": https://www.withouthotair.com/c13/page_76.shtml

(ps I just put this great book up on github. The author passed away, would love ideas to re-release the CC content.

Specifically, merging the short Food chapter into a nicely formatted single medium-type article would be a good step for readability: https://github.com/titojankowski/sustainable_energy_without_...)

Re: Receding glacier causes Canadian river to vanish in four days

#97

Post by sctb »

kensai wrote: post #49
inetknght wrote: post #9

I'm thinking you're commenting on the wrong article ;) Did you mean -> https://news.ycombinator.com/item?id=14131759

Guys, I seriously do not know wtf happened. I never opened this "Receding glacier" thread. I was commenting on the Intel thread and my comment somehow ended up here. I got aware of it because of all these negative points which came quite unexpected. Could it have been a glitch in the database?

I'm not sure what might've happened, but the web request logs show that comment being submitted to this thread. We've restored your karma and moved your comment to the right thread.

Re: Receding glacier causes Canadian river to vanish in four days

#100

Post by titojankowski »

titojankowski wrote: post #96
thinkcontext wrote: post #83

Earlier quoted context omitted.

Perhaps its not exactly the best example of capitalism given that it was centrally planned. Glad you found it interesting. In the text accompanying the video they link to more videos in the series from Ethiopia and Rwanda, with similar projects to rehabilitate the land.

Food is key. This inspired me to re-read the 4 pages on Food in "Sustainable Energy without the hot air": https://www.withouthotair.com/c13/page_76.shtml (ps I just put this great book up on github. The author passed away, would love ideas to re-release the CC content. Specifically, merging the short Food chapter into a nicely formatted single medium-type article would be a good step for readability: https://github.c…

Ok it took an hour but I reformatted the "food" chapter on my blog as an experiment in readability.

http://titojankowski.com/sustainable-energy-without-hot-air-...

Thoughts?

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