Arctic is warmest it's been in 10,000 years

[Black Aeronaut]

I seem to recall somebody in this thread mentioning solar irradiance as a possible cause for climate change.

We now have some numbers.


Source: NASA

Is solar irradiance a possible cause for climate change? No. Solar irradiance has been dropping since the late-1950s while temperatures have been rising during the same period.

Better hope that doesn't change or else we'll REALLY be fucked.
(Edited to add the quote)

[hazard]

Better hope it changes, and fast, or we're absolutely fucked. That upwards incline of temperature is terrifying.

Also? Solar irradiance variance is about 0.07%. Temperature variance appears to be about 0.35%, or 5 times as strong (average temperature of the Earth is about 14.5 degrees Celsius, or 288 Kelvin). That's... not something you'd see under normal circumstances if irradiance was the only factor, and if it was a result of 'store and release received solar energy' with no meaningful changes in atmospheric composition you'd see a delay and a damping effect in temperature's response to solar irradiance. Something that you can actually spot in the 1880 to 1920 segment of the graph.

[classicdrogn]

I believe what BA meant was that if the irradiance trends up again as well, that'll accelerate the process even more. Which should be obvious, but then so should a lot of things that the deniers dismiss as coincidental or badly measured or deliberately manipulated data, so...

[hazard]

Ah yes, that makes sense.

And in that case he's absolutely right.

[Black Aeronaut]

You guys know how I've said before that if it goes, it'll happen slowly?

Probably nowhere nearly as slowly if good old Sol decides to turn the thermostat up. More like, "Okay, where the fuck did all this water just come from!?" fast.

(Edited to fix clumsy sentences. God, I need to sleep...)

[classicdrogn]

Here's another set of supporting data - apparently the amount of atmospheric CO2 is the highest it's been in the better part of a million years, as determined from ice cores and the history of direct measurements. How much higher? Looking a these graphs, it's nearly double the long term mean.




(aggregator site) source
academic site providing the actual graphs
second article quoted by the BGR story, and below.

The rise in CO2 is unambiguously caused by human activity, principally fossil-fuel burning. This is clear from the numbers: We know how much fossil fuel is converted into CO2 each year and emitted into the atmosphere. The CO2 doesn’t all stay there because some enters the ocean and some is taken up by photosynthesis, which ends up in land plants and various types of biomatter.

Carbon atoms are not created or destroyed in any of these processes, so the total fossil-fuel emission to date must equal the combined increases in these other reservoirs. We can document large carbon increases in all these reservoirs. In the atmosphere, it’s especially easy, because the atmosphere is quite well mixed. As it happens, about 57 percent of the emissions have remained in the air.

It’s true that atmospheric CO2 has almost certainly been higher than present in Earth’s distant past, many millions of years ago. But because fossil-fuel burning is not natural, the recent carbon increases in the atmosphere, oceans, and land biosphere cannot be natural either. And you are correct that even though the levels of CO2 in the air may not be unprecedented, the pace of rise probably is. Few if any natural processes can release fossil carbon into the atmosphere as fast as we humans are doing it now via the extraction and burning of fossil fuels.

[Labster]

OK, so 800 kyr is about the limit for ice core data. Those are pretty much the deepest parts of Antarctica, since glaciers move, we can't get anything older with short term (~2-5 year) data. Incidentally, the ice cores near Summit in Greenland only go back about 400 kyr but they generally have annual data as snow is much more regular there. Source: some of my fellow grad students who took ice cores up there.

Before that, your carbon proxies are pretty much entirely soils and rocks. Except for extreme events, your resolution shoots up to about 50 years at best, and more likely in the tens of thousands of years. We can also get temperature in all of these samples because of isotope ratios -- heavier isotopes of oxygen are more likely to evaporate in warmer weather.

So that graph doesn't tell the whole story. As a way to be somewhat less alarmist, our carbon dioxide levels are heading towards the levels we saw during the Miocene, when there were in fact primates alive. So all is not lost. We have had much higher levels before, although the Sun is more intense now. We think. Though this doesn't explain how Mars had liquid water.

[Dartz]

Maybe there's a way to keep the sun from reaching the surface...

Like raising gigatons of particulate matter or something. Either that or seeding jet fuel to promote high altitude contrail formation. Less light to the surface - less heat.

Can't really make and launch a giant interstellar sunshade, can we?

[robkelk]

Maybe there's a way to keep the sun from reaching the surface...

Like raising gigatons of particulate matter or something.

I suspect the amount needed would require something along the lines of the Yellowstone supercaldera finally blowing. It could happen, but do we really want it to?

Either that or seeding jet fuel to promote high altitude contrail formation. Less light to the surface - less heat.

Accusations of "chemtails" in 5...4...3...

Can't really make and launch a giant interstellar sunshade, can we?

Not all at once, no.

[Labster]

Wars do have a tendency to cool the Earth by blowing things up. You can see a noticeable dip in global temperature in the 1940s, but it's hard to say it wasn't just a natural local minimum either. Particulate matter pollution has the main problem that it, um, kills people. Millions so far. And you don't want your PM to land and turn into black carbon on snow, either. But yes, some of the geoengineering proposals involve injecting particulates into the stratosphere to provide a solar shade.

Launching an orbital solar shade is one approach. Spaceflight is getting a lot cheaper, to the extent that next year Chengdu is purportedly going to launch an artificial moon for night lighting. Increasing insolation with a reflector is kind of backwards, unless you can get equivalent energy savings out the other end. Either way this sort of solar shade is a good deal safer than the particulate approach, as turning it off is a simple as rotating the craft.

Either that or seeding jet fuel to promote high altitude contrail formation. Less light to the surface - less heat.

Haha nope. High clouds warm the surface, low clouds cool the surface. Contrails provide a global average +0.012 W/m² radiative forcing, with the bulk from night and winter flights. You do not want this to increase. Cloud seeding/silver iodide in general is a tricky thing, because it can theoretically work, but it's impossible to prove that it did. And if you could prove that it worked, then someone downwind could sue you for stealing their rainfall. I got the feeling from my professors that cloud seeding was all the rage for a while and then they collectively decided there was probably nothing there and moved on.

Actually aerosol and cloud physics and how it feeds back into albedo is massively complicated. Actually the wikipedia page on albedo has a really good overview.

[classicdrogn]

A solar shade made of photovoltaic panels would be pretty good, except how do you get the power down? Microwave beaming seems less than ideal if the goal is to reduce the amount of energy reaching the planet, and either way it's a stupidly huge amount of material to launch and deploy even if you can paint the cells onto mylar film or something. (Can we even do that? I know flexible solar cells are kind of a thing, but there's a lot of fiction contamination in that part of my memory.)

edit: better ones than I was remembering, but still something that would be ridiculously expensive at the scale required. In the meantime, though, I found something interesting from the angle of reducing atmospheric carbon dioxide by freezing it in carbonates:

Microbialites have been discovered in an open pit pond at an abandoned asbestos mine near Clinton Creek, Yukon, Canada.[33] These microbialites are extremely young and presumably began forming soon after the mine closed in 1978. The combination of a low sedimentation rate, high calcification rate, and low microbial growth rate appears to result in the formation of these microbialites. Microbialites at an historic mine site demonstrates that an anthropogenically constructed environment can foster microbial carbonate formation. This has implications for creating artificial environments for building modern microbialites including stromatolites.

source: Wikipedia article on stromatolites

[nocarename]

A solar shade made of photovoltaic panels would be pretty good, except how do you get the power down? Microwave beaming seems less than ideal if the goal is to reduce the amount of energy reaching the planet, and either way it's a stupidly huge amount of material to launch and deploy even if you can paint the cells onto mylar film or something. (Can we even do that? I know flexible solar cells are kind of a thing, but there's a lot of fiction contamination in that part of my memory.)

So, the thing about using microwaves to move the power down is that it hopefully displaces some of the high carbon baseline generating capacity so that even with losses to microwave heating you're still taking on less solar heating. Also, it's kind of a terrible transmission system if you're losing a lot to microwave heating, so there is a strong incentive to avoid that since you'd be throwing money or your other generic resource of choice away in the form of cooked birds or whatever. Never mind that the schemes all call for staying just under the exposure limits for microwave anyway, so if it wasn't safe then those regulations should probably be rewritten too.

And you use the mylar film sections as solar concentrators to much smaller solar arrays rated for higher exposure levels. Mirrors that are good to a 'close enough' standard are much lighter than finicky things like solar panels.

[Black Aeronaut]

Honestly, I don't see it happening unless we get orbital elevators off the ground (Hah!) - otherwise there's just no safe and efficient way of getting the energy back down to Earth. You may just have to settle for reflecting the sun's energy away, and little else for the short term.

Also, you'll have to be careful about how much you shade at once and where. Even though only a tiny fraction of the energy that the sun gives off hits the Earth, it's still a fuck-off huge amount. You can only too easily turn Death Valley into a huge open-air reefer where you can just leave whole sides of beef out and they'll keep for a week or so. And that will do horrible things to weather patterns here.

[classicdrogn]

I found a bit more on the Clinton Creek microbialites in the form of a non-paywalled academic paper about their genetics. Lots and lots of five- and ten-dollar words about what they're related to and so on, but there is some mention of using them for carbon-fixing.

Our data suggest that polar mats have the metabolic potential to make microbialites under the correct chemical conditions. Further work is needed to definitively ascertain specific microbe influence in terms of the speed of microbialite formation. In the future, this may provide an avenue for us to engineer microbial communities to store atmospheric carbon through biolithification, especially given the recent, anthropogenic origin of the Clinton Creek site. Biogenic carbonate deposits are the largest reservoirs of carbon on Earth and could provide a cost-efficient method of carbon sequestration for greenhouse gas emissions (Falkowski et al., 2000). Passive carbonation and carbon capture has been documented within the Clinton Creek mine tailings, leading to the proposition that microbially-mediated carbonate precipitation is a means to ameliorate carbon emissions from mining operations (Power et al., 2011a).

source

[Epsilon]

Arctic Sea Ice Highest New Record Low

hahahaha.

We're all going to die! 

[Matrix Dragon]

*Looks at his own government approving a stupidly huge thermal coal mine.* Fuuuuuuuuuuuuuuuuuuuuuuuuuck.

[Epsilon]

Canadian Permafrost Melting 70 Years Ahead of Schedule

Seventy years faster than predicted. It's gonna get bad, folks. And faster than you think.

[classicdrogn]

... time to look into breaking those Florida timeshare contracts, perhaps?

[Bob Schroeck]

Nah, we can always switch our home resort to Kissimmee. Or Arizona.

[Black Aeronaut]

Bob, Right after the Keys, places like Kissimee are gonna be the very next ones to disappear under the rising tides. (And why I warned Rajvik to sell his property and get out while it was still worth something.) Might I recommend San Antonio instead?

(Really, we're about 850ft above the current sea level here, and our city is quickly gaining a reputation for being among the biggest of big cities, but with the friendliest of folks - think Austin, only slightly less oddball, but every bit as friendly.)

[robkelk]

Actually, Bob, if you're looking to retire someplace that's as warm as New Jersey currently is, I might recommend north of Lake Huron in 20 years.

[classicdrogn]

I suppose Canada does have quite a lot of real estate that's going to rise in value as fast as the melting permafrost makes it subside. Maybe those cavorite deposits under Hudson Bay will finally be accessible with a warmer climate, too, and we'll get our flying cars at last?

[Bob Schroeck]

Might I recommend San Antonio instead?  

Sorry, been both there and Austin during the summer; I couldn't stand the heat+humidity.

Besides, I wasn't talking about a retirement location, just the location of our "home" timeshare resort.

[robkelk]

I suppose Canada does have quite a lot of real estate that's going to rise in value as fast as the melting permafrost makes it subside. Maybe those cavorite deposits under Hudson Bay will finally be accessible with a warmer climate, too, and we'll get our flying cars at last?

The problem there is, that as the permafrost melts, the land it's holding together drops into the sea. One story here, under "Arctic Thaw".