Melting Yukon ices reveal 5,000-year-old archaeological treasures
macleans.ca
macleans.ca
It's a bit strange to think of in this way, but the Inuit are almost as new to North America as Europeans are. Vikings built tentative (and quickly abandoned) settlements on the East coast of Canada when the Inuit were establishing themselves in the West and had yet to spread across the North. The Vikings actually encountered the Dorset before they disappeared, and later the Thule as they replaced the Dorset. As such, those of us descended from Vikings are almost as intimately related to the Dorset as the Inuit!
Archaeology is a discipline that, ultimately, tries to tell the story about those who came before us, no matter our relation to them. First Nations groups really have no more right to protest these digs than we, here in Canada, have to protest digs in Italy. It is only our vast ignorance about the pre-history of the Americas that forces us to entertain their court claims. The artifacts uncovered by melting ice must be found within a very short period of time before the stories they can tell are lost for all time. While it is important to involve First Nations, just as any other Canadians, their interference, to the point of entirely preventing searches some years and thereby causing the loss of a part of our heritage, must not be permitted. The history of humanity belongs to us all.
http://www.cgg.org/index.cfm/fuseaction/Library.sr/CT/BQA/k/...
http://www.missiontoamerica.org/genesis/six-thousand-years.h...
(I don't believe the earth is 6k years old in case you're wondering.)
There are groups that will argue that dating methods assume that we know initial conditions and assume that certain parameters are constants when they may just be drifting more slowly that we can notice over the 100 years or so that we've been able to measure them.
On the other hand, one of my fraternity brothers got religious his senior year, moved into a kosher living space, finished his Physics degree from MIT, and then went to a yeshiva in Israel. Last I heard, he was a rabbi in the Boston suburbs. I think he believed the Universe is billions of years old, but he did tell me that there are some rabbis that will tell you that when God created the first trees that first week, if you drilled into trees, you would find hundreds of rings as if they had been hundreds of years old, and likewise for isotope distributions in rocks, etc. This is much harder to argue against because it makes not falsifiable claims, but fortunately, it's also much less dangerous... it doesn't deny science's ability to forecast the future or contradict our best understanding of how the world currently works.
If so, what was the climate when those artifacts were left there and how long was that area habitable? And what caused the climate to change from habitable to frozen?
We already know that we are currently in an ice age that goes through cycles of glacial periods (such as the colloquially named "last ice age") where a lot of North America, Europe and Siberia are covered in ice sheets; and warmer interglacial periods, such as this one, where the poles are covered by ice sheets (and also Greenland and various glaciers, and at high altitudes).
Outside of ice ages (which is more common for Earth, when considering its whole history), the poles aren't covered by ice sheets.
> And, perhaps we are acting as catalysts to climate change with our greenhouse gas emissions?
Perhaps. And if so, whether that is for the better or for the worse in the grand scheme of things is yet to be seen; geologists say that we are "due" for another glacial period, based on previous glacial and interglacial periods. But human emission of CO2 could keep things from spiraling towards a cool down, which might delay the next glacial period for a long time. Or perhaps glacial periods are mostly caused by cosmological forces, which are out of our control; there doesn't seem to be any clear answers.
Pretty sure this has been modelled, but it's still being debated.
http://science.nasa.gov/science-news/science-at-nasa/2004/05...
http://en.wikipedia.org/wiki/Thermohaline_circulation#Effect...
Honestly though, while we have a lot of good wine, we also have a lot of swill.
Rising temperatures in WA will raise all the ships. Everyone's wine should improve.
Do you have a need for financial technology castaways in helping build Silicon Vineyard? :-)
Are you trying to imply that climate has a single variable driver and because climate change happened before the industrial revolution, that current climate change can't be hugely impacted by human activities? This would be a conclusion from a false premise (that climate is driven by a single variable).
Denying climate change in the face of conclusive data probably wouldn't have any legs to stand on. What is causing it is harder to prove/deny, though.
Yes, there are many people who deny the existance of any climate change, not just anthropomorphic climate change.
There are a couple here on HN - searching for arctic ice will possibly turn up a few posts.
Your last sentence ignores he reality of belief: homeopathy is nonsense yet people are convinced it works and they apy mone for it. Alien probing; biblical literalism; 911 truthers; Obama is not American; the Queen of England is a lizard; there are many weird stupid beliefs that have little to do with truth or evidence.
What that reinforces in me is that regardless of cause, climate change happens, or conversely even when human carbon footprint on the planet was nearly zero, the planet was warmer than it is today. And that suggests to me that human impact is irrelevant to the challenge of surviving in a changing climate.
Sadly that puts me in the 'climate control denier' category, that is the group of people who believe that humans cannot control what the climate does (good or bad).
That said, I'm all in favor of balancing our energy economy, I'd much rather be spending ergs much more efficiently than we do today. The more efficient our energy use the more flexibly we can react to changes in climate and we are able to create a higher standard of comfort for more people.
How are you able to reach that conclusion? Clearly, the climate on Earth has changed a lot, most of it without our help, and on a magnitude much greater than we have supposedly been able to for the last couple of hundred years.
But that doesn't mean that climate change can't be influenced by human activities. It doesn't mean that releasing a lot of CO2 into the atmosphere can't affect the climate of the planet to a large degree.
We can speculate on those things, we can track down times in the geologic record where Yellowstone erupted and put dust high up in the atmosphere, we can look at iridium layers in the rocks and try to understand when large asteroids hit the planet and wrought havoc. And perhaps the biggest thing that is missing from the model is how the planet 'resets' itself. We have had warm periods and cold periods and fluxed in between them, but the model doesn't tell us how, the data tells us this happened, but the current model applied to ice cores from a million years ago gives a different answer than the data seems to indicate was true.
What all of that adds up to is that "its complicated" and we're inside a system for which we don't have a deep understanding of the variables and we have a scientific infrastructure which is actively discouraging the asking of certain questions or testing various hypothesis which are politically uncomfortable. That makes me think we aren't doing as much as we can to understand the actual system, and our lack of understanding leads to an inability to predict what it will do, or how it will respond to what we do or don't do. We are no more free to ask heretical questions about how climate works than Galileo was free to investigate whether or not the Earth was the center of the universe.
As we cannot summon the will to do the research we need to do in order to accurately answer the question of how the system works, I do not believe we will reach a point where we might understand what would be needed to move that system to a pre-determined point from some other known point.
This criticism is somewhat akin to trying to challenge the theory of relativity because our orbital models can't tell us exactly how the planets got arranged how they did. The reason they can't isn't because the models are broken; it's because there are many plausible hypotheses that could give rise to the outcome we see, and representing various possible combinations of historical parameters. And we can't necessarily know which set of parameters without the aid of a time machine.
Similarly for the climate models. They can't tell us exactly how every historical change in the climate happened because there are many climate forcings that simply aren't recorded very well (or at all) in the historical record. So we can use the models to come up with various plausible scenarios, but we'd need a time machine to figure out which one is the correct one.
To take another analogy, this criticism's akin to when creationists complain of the relative fuzziness of our knowledge of the history of life in the precambrian to argue that evolution cannot account for the major taxonomic divisions in the tree of life. Again, the truth is that the model is fine, what's inadequate is our knowledge of the historical conditions we would need to feed into that model.
The distinction between those two sorts of knowledge gap may seem pedantic and hair-splitty, but an understanding of the nature and implications of that difference is one of the boundaries that separates science from pseudoscience.
They can't explain the past behavior of the Earth's climate, and they can't predict the future behavior. They're not even directionally correct, given the fact that global temperatures, albeit amongst the highest they've been on record, haven't increased since the late 1990s[1]. Given the incredible increase in CO2 over the past 16 years, the models would have predicted much higher temperatures, but it's simply not agreeing with their own data.
1. http://www.politifact.com/rhode-island/statements/2013/aug/2...
The correlation between the recorded satellite data and the previous 9 years of IPCC predicted data shows that the models are, if anything, conservative.
There's more up to date data in the IPCC 2014 report [2] as far as I know.
EDIT: Please note that IPCC web resources are terrible for searching. They have linked powerpoint documents and PDFs, but it's very hard to just search the data from their front end. Does anyone know of a nice HTML version of all of the IPCC resources?
>The problem is that the models have all been wrong.
All models are wrong, but some are useful. Climate models have demonstrated skill at modelling important parts of the climate system.
>They can't explain the past behavior of the Earth's climate, and they can't predict the future behavior. They're not even directionally correct, given the fact that global temperatures, albeit amongst the highest they've been on record, haven't increased since the late 1990s[1]. Given the incredible increase in CO2 over the past 16 years, the models would have predicted much higher temperatures, but it's simply not agreeing with their own data.
That is just factually incorrect. There are individual model runs that do match the observed surface temperature since the 90s. The recorded temperatures are still within the expected range of most model projections. Even Hansen's crude 1988 model is surprisingly close to what has happened[1], although that is probably in part down to luck.
The most important thing to know here is that climate models are projections, not predictions. That means they aim to model what happens given a certain set of circumstances. They don't aim to predict what the actual circumstances will be. Those circumstances include things like volcanic activity, which you can appreciate is not something that is easy to predict decades in advance. Also internal variability like ENSO, PDO, NOA , and NAO will play a large part in determining the short term (decadal timescale) surface temperature. As far as I understand most models just model ENSO stochastically, so for any given model run it's going to be down to random chance whether the ENSO state in the model run matches what happened in reality. Over longer periods of time and over many models runs the result is a range of likely climate (for various different emissions scenarios). The aim of climate models is to give an upper and lower bound to what the system will probably do for a given emissions scenario, not to provide a single forecast for the exact state of the climate in x years.
Consider writing a model of a die roll. If you know the die is fair you will be able to write a simple model that gives close results over a large number of throws, but it will have basically zero ability to predict a small number of throws. You could also adjust your model considering real data if it turns out that the die is weighted based on your observations. This isn't a direct analogy to a climate model, but it's a demonstration that models can be useful without the ability to predict the short term state of the system.
Having said all that, there are some areas where the models do pretty badly. Arctic sea ice is one, but in that case the problem has been a big underestimation of the actual rate of melting.
Finally, I'm not sure you read that link you posted because it discuses why 'no warming in 16 years' is a cherry picked figure[2]. It's a bit of a statistics game as well. If your null hypothesis is that the trend has continued unchanged then the data don't give any reason to think that the trend has changed[3]. Of course it's important to remember that surface temperature is only showing a small part of the total energy in the climate system, and our surface temperature record has gaps (it misses out most of the poles). Short term variability in the trend is to be expected; you can also cherry pick time periods when the short term trend was much greater, for example 1992-2006 [4].
[1] http://tamino.wordpress.com/2014/03/21/hansens-1988-predicti... this also shows some of the techniques that have probably been used to trick you into thinking models have been wildly wrong, which is handy if you want to know what to look for in the future
[2] http://tamino.wordpress.com/2014/02/09/cherry-p/ some relevant stats on cherry picking
[3] http://tamino.wordpress.com/2013/02/12/2012-updates-to-trend... for a look at how recent years fit into the longer term trend. It uses 2000 as the cutoff - somebody redid it using 1998 but I can't seem to find that now, the story wasn't much different though
Let me is simplify things. Is there a model based on CO2 that explains the variations in global surface temperature of the last 1200-5000 years, as mentioned in the OP's article? That should be easier to project given that we are not talking about a period of 20 years, correct? I genuinely don't know, which is why I'm asking and I would like to learn more. Is there a model that projects the various ice ages and subsequent warmings over a longer period of time, including the medieval warming period, which you claim should be easier?
And a question for you: what evidence would you personally require in order to no longer in the greenhouse gas theory? I know what I need to see in order to start to believe in the greenhouse gas theory: I need to understand how CO2 is responsible for the variability of the Earth's climate pre-industrial revolution. If CO2 wasn't responsible for the Earth's climate change pre-industrial revolution, then what was it and could that same thing be responsible what for we see today?
What I've seen from people who believe this theory is that they will believe it no matter what. For example, if climate gets warmer, that's because of CO2. If the climate gets colder, that's because of CO2. If the climate goes wild, like during the time of hurricane Katrina, that's because of CO2. If it gets calmer, like it did after Katrina, that's because of CO2. I can't think of a single climate outcome that will disprove the theory, since all outcomes appear to prove it.
In my experience, a theory that can't be prove wrong despite different outcomes isn't a theory, it's a religious statement, which is not science. I believe that believers in the theory have moved over into the religious territory, which makes it about as fruitful as talking to a creationist.
Classic crank tactic: Demand outcomes far beyond anything that's claimed by working scientists, let alone what's necessary to validate the hypothesis in question. Then declare victory for yourself when it turns out that everyone's got better things to do than spend time knocking down straw men.
Demonstrating which end of the Dunning-Kruger spectrum you're at isn't necessarily a great way to win a scientific debate.
"Aside from the direct effect of ultraviolet radiation on organisms, increased surface UV leads to increased tropospheric ozone, as noted above. Paradoxically, at ground-level increased ozone is generally recognized to be a health risk, as ozone is toxic due to its strong oxidant properties."
How you can come to that conclusion, given that the dung dropped then, possibly in the snow, has remained frozen since then, and is now melting. I.e., it's been colder ever since then than it is now.
[1] http://septentrio.uit.no/index.php/rangifer/article/viewFile...
[1] http://alcesjournal.org/index.php/alces/article/viewFile/117...
It's not really that amazing if you consider the known external climate forcings like Milankovitch cycles. Also, you are extrapolating global climate from the local climate at a single location. Local change does not necessarily correlate with global changes. In this case the data we have indicates that the 'Mid-Holocene Warm Period' was only warmer in the Northern Hemisphere, and only during summer.
>What that reinforces in me is that regardless of cause, climate change happens
You are missing an important factor which is the rate of change. Faster changes have much greater potential to disrupt economies and ecosystems. To put that into some perspective: http://tamino.files.wordpress.com/2013/03/shakun_marcott_had...
>conversely even when human carbon footprint on the planet was nearly zero, the planet was warmer than it is today. And that suggests to me that human impact is irrelevant to the challenge of surviving in a changing climate.
Come on now, I don't believe you are really this ignorant. The problem with climate change isn't conditions today, which are not that much different to the past and don't yet pose many significant challenges to human activity. The problem is that continued emissions is going to result in global temperature probably at least several degrees warmer within 100 years (which means much bigger changes than that in some places), and that kind of change over such a short period of time will pose a lot of serious problems to humans (and the biosphere in general).
First, many glaciers are still in retreat from the last major ice age. There is a kind of momentum to glacier retreat and glacier advance, and that momentum plays out over centuries.
Second, in some cases there are other factors at play. For example, soot from coal/hydrocarbon combustion settling on glaciers and ice sheets reduces albedo and increases melt rates.
Third, and most importantly, glacial advance/retreat is not just a global phenomen but also a local one. Just as weather is not climate so too individual glacial change is not climate. One glacier retreating does not prove the climate is getting warmer any more than one glacier advancing (of which there are many) would prove the climate was getting colder.
So you can't point to one example and say "ahah! incontrevertible PROOF!" any more than you can tell an anecdote in support of some medical theory and assume that you've proven anything either.
"Unlike glaciers that move, slowly grinding down any artifacts trapped in them, the Yukon ice patches tend to remain stable. Or at least they did, until gradual warming over the past several decades began to shrink them and reveal treasures."
One was denying climate was changing. That was the narrative in large up until not too long ago. A lot of it was sponsored by conservative think tanks, propaganda etc. I remember in late 1990s and early 2000s. There was a lot how climate is not changing and it is all a liberal propaganda.
Well then eventually after the temperatures kept rising and ice melting the narrative has shifted to "it is changing, ok, but it is not because of anything humans did". That is where the controversy is now.
I am not involved enough to debate the last one one way or another intelligently, just making an observation of the two level of the argument.
http://www.politifact.com/rhode-island/statements/2013/aug/2...