[Parked Out]

[Randito]

[CC]

[MtnGoat]

[thunderhead]

[drm]

Antarctica has a pretty damn big edge, mentioning the ice cap is a diversion. The question is whether the physical dynamics will feed that very cold inland ice to dump into the ocean, where it will melt. A 30,000 sq mile hole in the sea ice off the coast was recently found. Melting in Antarctica has been speeding up fast in recent years. I would like to know what your source is for thinking that it won't happen seriously till we reach 1000ppm CO2.

[drm]

As to the issue of past melting not attributed to human activity, the key question is attribution. If attributed to human emissions, and those emissions don't stop or significantly decrease, then what we have seen now is just the tip of what we will see. That is not comparable to past recent events that we know did end - because what was causing them did not continue to cause an increase in impacts.

[thunderhead]

I played with a number of global climate model datasets in grad school. Here is one of them: Figure 9 is the most relevent. The 2x CO2 scenario(just over 500ppm) has no impact on the antarctic ice cap for the next 3000 years at least. The 4x CO2 scenario(~1100ppm) does have a significant impact, though it is important to note that the time scale is still huge, with significant melting not starting even in the 4x scenario until about 500 years in the future. This is in good agreement with the other datasets. In this particular model, the 4x CO2 scenario results in Antarctica losing ~10% of its ice cap in the first 3000 years, the end of the simulation. Now obviously that would be a large sea level rise, but it also takes a LONG time, and we would really have to mess up our nuclear and battery research to reach 4x CO2. We are currently at about 1.5x CO2. http://rd.springer.com/article/10.1007/s10712-011-9131-5 And yes, thermal expansion, Greenland, and the edges of Antarctica would drive minor rates of sea level rise before the main Antarctica cap starts melting.

[Parked Out]

If you want to wade into the technical weeds of the Antarctic ice mass gain/loss issue, I recommend this post by the always-excellent Stephen McIntyre at Climate Audit: https://climateaudit.org/2015/12/02/antarctic-ice-mass-controversies/ "Conclusions While it is obviously up to specialists to try to ultimately figure out whether Antarctic ice mass was increasing in the periods 1992-2001 and 2003-2008 (per Zwally) or whether it was decreasing (as IPCC and others had previously asserted), there does not appear to be any objective basis by which, for example, Gavin Schmidt could reasonably “pin more weight” to highly negative estimates from GRACE gravity data than to Zwally’s positive estimates from laser altimetry. The size of the GIA adjustment for GRACE gravity estimates is the same order of magnitude as the estimate of ice mass loss and, in many cases, is larger. These GIA adjustments have been dramatically reduced by specialists over the past decade and have concurrently reduced estimates of ice mass loss. Many popular (warmist) discussions of Antarctic ice mass loss continue to use obsolete (overly high) estimates of ice mass loss e.g. NASA’s estimate of “134 billion tons” per year. Such estimates rely on GRACE estimates using obsolete GIA adjustments. The estimates of mass loss in IPCC AR5 were highly questionable. They were much higher (nearly double) than contemporary specialist (IMBIE) estimates. They appear to have been based on studies using GIA adjustments, already known to be obsolete. It was separately highly questionable to attribute “high confidence” (and relatively narrow confidence intervals) to these very high estimates of mass loss. Most of the Antarctic continent (especially East Antarctica) appears to be experiencing ice mass gain, with ice mass loss being localized to less than 5% of the continent: parts of the Antarctic Peninsula and west Antarctica (especially Pine Island and Thwaites glaciers). This peculiar localization requires its own explanation. Recent specialist literature has concluded that West Antarctica was up to 3 km higher in the LGM, while the height of East Antarctica has changed little and might even have increased slightly through the Holocene. West Antarctica has experienced dramatic ice mass loss through the Holocene, attenuating to the present. AR4 had pointed out the possibility that localized ice mass loss in Antarctica was continued Holocene ice mass loss. This possibility vanished in AR5 without discussion. In an inline comment to Bamber’s realclimate article, Eric Steig said that his opinion, and that of “50% of experts”, was that the connection of Antarctic glacier retreat to “anthropogenic global warming” was “weak” and that the localization of the glacier retreat to West Antarctica was “well understood” and something that he had written about “extensively”: I think the evidence that the current retreat of Antarctic glaciers is owing to anthropogenic global warming is weak. The literature is mixed on this, about 50% of experts agree with me on this. So you’ll get no argument from me there. Second, the localization in West Antarctica is well understood, and I’ve written about it extensively. Elsewhere, Steig has attributed the West Antarctic glacier retreat to erosion of the grounding line of the glaciers by relatively warm Circumpolar Water, rather than to very slight warming of air temperatures above West Antarctica. Given the continuous retreat of West Antarctic grounding lines over the Holocene, it seems implausible to attribute present grounding line erosion to a different cause than past grounding line erosion that has taken place over the Holocene. Steig’s position on this point seems entirely reasonable. However, it still seems like one of those too typical situations where the less alarming explanation is presented in specialist literature, but left unmentioned or unconfronted when retreat of West Antarctic glaciers is presented as a cause of alarm."

[drm]

Well, if your model says there will be no impact on Antarctic ice for a long time, it's already wrong. And I'm not about to trust Climate Audit over a mass of peer reviewed studies. But I'm not sure what you mean when you refer to the ice cap. Antarctic ice melting has been speeding up significantly, a lot faster than was previously thought. But I usually interpret an ice cap to be the part at the center, which in Antarctica is also at I think 7000 feet altitude. But antarctic ice is hollowing out at the edges and underneath. I recently was surprised to see that grid battery storage is going mainstream. Politico magazine had an article and one industry insider said natural gas peaker plants will be pushed out and may not get built after another decade.

[thunderhead]

Oh yes, a news article written by journalists that don't know the difference between a megawatt and a megawatt-hour. Great source. I'm sure their battery conclusions are excellent, even though they apparently don't understand such basics as how to measure battery capacity.

[thunderhead]

Now for some actual numbers. At my old company our nat gas peakers were about 15 dollars per megawatt-hour more expensive than our average(baseload) generation, all inclusive. At a current cost of 150 dollars per kilowatt-hour raw, lets say double that for installation and maintenance, a battery pack would have to last for ~20,000 charge cycles to compete with a natural gas peaker financially. Now thats about 10 times as long the reasonable lifespan for a good lithium ion battery now, I believe, thus making the battery pack 10 times more expensive than the natural gas peaker for semi-frequent use. As use gets rarer, on the lower end of the probability curve, batteries look relatively less bad, but that's a tiny fraction of energy generation. The bottom line: Except for your very rare "turn-on-everything!" desperation hours at the afternoon peak of the years worst heat wave, natural gas is so cheap and gas turbines so awesome that batteries are not going to compete with natural gas peakers on their own financial merits in the next decade. No chance.

[Doppelganger]

[thunderhead]

[drm]