Catch up on stories from the past week (and beyond) at the Slashdot story archive

 



Forgot your password?
typodupeerror

Comment: Nuclear: your granddad's power of the future (Score 0) 551

by sam_vilain (#46163543) Attached to: Should Nuclear and Renewable Energy Supporters Stop Fighting?

Nuclear power has a larger carbon footprint than you might think: from the concrete used to build the stations, to the energy used in the mining, extraction and refining processes to produce the fuel. It can take more than 6 years to mitigate the energy used in building of the facility, let alone the actual construction costs.

On account of the fact that every utility scale fission reactor design is really nuclear steam power, every watt of power it produces requires two watts of heat dissipation using water. Of course this means the plants have to shut down if it's too hot, and that source of fresh water you were drawing on is not as cool as it was when the plant was built (eg, due to climate change).

It's also super expensive, because risks must be mitigated; some have pointed out this has led to a negative learning curve of nuclear power.

Much as it is kind of cool that people are using nuclear physics to make power, it really is very dated technology. Phasing it out in favor of cheaper, safer alternatives is a much better idea: with the advent of flow batteries, liquid metal batteries, you don't need to have peaking power plants paired with the renewables. You just need more renewables.

Comment: speaking of the West Antarctic Ice Sheet's groundi (Score 1) 132

by sam_vilain (#45460473) Attached to: Tremors Mean Antarctic Volcanism May Be Heating Up
It's a good point, and I'm sure in areas where the sheet is no longer grounded the force applied to the bedrock is more a function of the depth than how much ice remains above. Want to see some science of that, too? How about a sedimentary core project from the very sheet in question? They found that the sheet responds to immense warming by disintegrating, which it did not do during the last few interglacials. On the longer scale (eg, since India collided with Asia), it has done it several times.

Comment: Prepare not to be surprised (Score 5, Informative) 132

by sam_vilain (#45450827) Attached to: Tremors Mean Antarctic Volcanism May Be Heating Up

There's a great book covering some of the science on this topic; reviewed here on NewScientist; very much worth the read. Actually what happens is that the crust "rebounds" in two phases. You can use the first phase to weigh the ice sheet as they are doing in Greenland. Then, the athenosphere (the molten layer, 15-150km deep which the crust/lithosphere sits atop) slowly slops in there and supplies extra heat and magma; generally quite a slow process, with some rebound from the last ice age still occurring.

Upshot: it's certainly possible that the events are related.

Comment: Right of asylum cannot be assumed (Score 4, Informative) 650

by sam_vilain (#44386249) Attached to: US Lawmakers Want Sanctions On Any Country Taking In Snowden
From a quick check on the Wikipedia page on it:

Protected grounds include race, nationality, religion, political opinions and membership and/or participation in any particular social group or social activities.

While I can't claim to be intimately fimiliar with the relevant international law: the UN CRSR (1951) probably applies. It specifically doesn't apply to "War Criminals", but I'm not sure what else.

Business Insider have a somewhat cynical take on Snowden's asylum claim which I think is worth reading.

Comment: Presumably one of the was Real Time Blacklisting (Score 2) 281

by sam_vilain (#42753599) Attached to: FTC Gets 744 New Ideas On How To Hang Up On Robocallers

If there was a widely publicized shortcode you could text with a number to say has been spam calling you then people could do that, and set up an ENUM–style directory which has the RBL info for use by phone companies.

Also phone companies could text people with information about this shortcode the first time every month that a previously unknown number makes a call or sends a message (until they say STOP of course ;-))

Might work for mobile spam, at least.

Comment: Re:Can someone remind me why this is sinister? (Score 1) 297

by sam_vilain (#42541335) Attached to: Texas State Rep. Files 2 Bills To Ban RFID In Schools

RFID offers a better way of tracking students while they're on campus, which in turn increases the number of seat hours while holding down the costs of keeping detailed attendance records.

If anything, this strikes me as a benefit. All the teacher then has to do is a head count, I guess. Assuming that children and teachers don't conspire to arrange for a perfect attendance, discrepancies should catch either side gaming the measurement.

But stick it on a kid and suddenly everyone goes full retard. As if.

Besides, it's nothing that can't be solved with a suitable application of Faraday cages ;-)

Comment: Let me google that for you (Score 3, Interesting) 156

by sam_vilain (#42394955) Attached to: Insurance Industry Looking Hard At Climate Change

Oh look, I found an interesting discussion about that very post from John Christy of UAH, posted on notorious denier Roger Pielke Jr's blog. The great thing about blogs as compared to scientific journals is that you get to choose your "pal review"! Who will notice if you mis–represent the original data, and use a flawed dataset?

One comment really nails it, and I can't link to it individually, so I'll just include it here:

The first thing I noticed when looking at Christy’s graph was that Hansen’s scenario B had been replotted to make it appear that it tracks scenario A very closely. It doesn’t, it never has. The graph on Real Climate uses the original data http://www.realclimate.org/images/Hansen

The next thing that was obvious was that the RSS and UAH temperature graph shows very little warming. I thought this issue was supposed to have been rectified after Spencer and Christy corrected the errors relating to orbital drift (meaning the temps were taken at progressively later times each day).

After making the corrections (version 5.2) the data now correlates with other global temperature records such as those of NASA and the CRU (remember when the skeptics always relied on the RSS / UAH temperature records, until it came to light that it was wrong).
Detail - http://www.sciencemag.org/cgi/content/fu
Summary - http://www.ssmi.com/msu/msu_data_descrip
UAH Data - http://vortex.nsstc.uah.edu/data/msu/t2l
RSS Data - http://vortex.nsstc.uah.edu/data/msu/t2l
Comparison Data - http://www.cru.uea.ac.uk/cru/data/temper
Hansen’s Data - http://pubs.giss.nasa.gov/docs/1988/1988

It appears that Christy has chosen to use the old data in his comparison. In effect, what he’s done is to exaggerate the warming predicted in Hansen’s Scenario B (the one Hansen always said was most likely) and then downplay the true amount of warming that has occurred.

When the real data are used it becomes apparent how accurate Hansen’s scenario B projections have actually been – not exact but pretty close. Considering Jim’s 1988 projections were based on single inputs then this is quite impressive.

Comment: They also need premiums to exceed payouts (Score 2) 156

by sam_vilain (#42391675) Attached to: Insurance Industry Looking Hard At Climate Change

You know, that whole solvency thing is pretty important. I think you're thinking of the gun industry.

Also, Sandy's storm surge, plus the Spring Tide, and the 1 foot of mean SLR since 1900, added up to that 2-3 metres. And also bear in mind: ice sheets are all melting far faster than expected; and also because of ocean currents and other effects, that "mean Sea Level Rise" can very dramatically depending on where you are. In a capitalist society, high flood insurance premiums are the appropriate signal to discourage people to either a) not build in low–lying areas or b) finally give a damn about Global Warming.

Heh, our /. userids differ by 11111 :-)

Comment: as a non–scientist, I presume (Score 3, Informative) 156

by sam_vilain (#42391609) Attached to: Insurance Industry Looking Hard At Climate Change

This is how you do science: you repeat the method to test the hypothesis. The article hints at what these adjustments entail:

"These included the volcanic eruption of Mt. Pinatubo in 1991, which spewed sunlight-blocking particles into the atmosphere, as well as the collapse of industry in the Soviet Union or the economic growth of China, ..."

This is similar to Hansen's 1987 (iirc) papers, which were based on a random prediction of a volcanic eruption in a particular year but it turned out to guess the year wrong. Predicting such events, which have a short term effect on the climate, is a guessing game. The numbers were pretty close, but if you repeat the method and replace the projections of CO2 emissions and aerosol emissions from volcanic and other sources, then they end up spot on.

These days, with more computing power available to run more detailed models more times, they do many model runs with a the random natural factors, and end up with a spectrum of results. This allows confidence intervals to be achieved. Hansen, in 1987, didn't have the resources for that; just like Sverre Arrhenius certainly couldn't do that when he estimated a 2C climate sensitivity from his manual model runs in ~1897.

One of the chief duties of the mathematician in acting as an advisor... is to discourage... from expecting too much from mathematics. -- N. Wiener

Working...