Well, as the guy who submitted the article, I thought the title I chose was fairly innocuous since ice ages != global warming. It's just the sad fact that when you bring up climate change of any kind people who are not climate scientists immediately start going off about global warming. It's one of those cases where everyone is an expert and few people bother to listen to what those of us who actually study this field are saying. It was a big issue in my graduate program as we constantly have to deal with people on both sides taking what we say out of context to support their political agendas.
While this study does have implications for climate change, the types of changes that this study talks about are over geologic time and have a very minimal impact on what is happening right now other than to set a baseline. I'd also point out that this idea is not new, it has been around for a very long time. The trouble has been two-fold: determining when previous ice ages (other than the most recent) have been is one piece of the puzzle, and the other is determining when orogenic events have occurred in the past. Neither of these is easy, so what it nice about this study is it offers more evidence to support what is actually a fairly old idea.
Two points. One: no one ever said humans are the sole cause. That said, it's clear we are part of what's going on. Two: the implication of the full article is that CO2 has a very large effect on climate. In turn, this implies that the rapid increase in CO2 due to humans may have a very large impact on our climate in a very short time.
And in a sense you have hit the nail on the head. Global warming is very much a political/economic issue and much less a science issue. Even if science can say what will happen, the simple fact is we can't easily reverse what we have already done, which could have consequences for a few centuries.
Now I'll pose a different question to you... what is the cost of doing nothing vs. taking what actions we can to mitigate the risk? The simple fact is we're rolling the dice and there will be winners and there will be losers, and we don't know which will be which. Even if only the least severe scenarios prove to be true, rising sea levels alone present us with an economic burden that far outweighs the costs of doing something now. So we don't understand everything well enough to know the exact outcome; but do we really want to roll those dice? I know I'm not a gambling man.
Also from Wikipedia, the explanation to your confusion:
An ice age is a period of long-term downturn in the temperature of Earth's climate, resulting in an expansion of the continental ice sheets, polar ice sheets and mountain glaciers ("glaciation"). Glaciologically, ice age is often used to mean a period of ice sheets in the northern and southern hemispheres; by this definition we are still in an ice age (because the Greenland and Antarctic ice sheets still exist). More colloquially, when speaking of the last few million years, ice age is used to refer to colder periods with extensive ice sheets over the North American and Eurasian continents: in this sense, the last ice age ended about 10,000 years ago. This article will use the term ice age in the former, glaciological, sense; and use the term glacial periods for colder periods during ice ages and interglacial for the warmer periods.
See my above comment. Ice age refers to the climate being cool on average over the past few million years. This is certainly punctuated by warm inter-glacial periods, but it is (or at least was) still an ice age.
If you look over geologic time scales, yes, we are in an ice age. People confuse ice age with glacial and inter-glacial periods. The trend for the last 40 million years has been sharp warming to temperatures similar to what we have experienced for roughly the last 10,000 years, followed by a slow decline over the next 100,000 or so years until you reach a minimum, then a sharp spike, etc. What is special about our current interglacial period is it has gone on for 10,000 years and it's suddenly getting warmer. There is some indication our current interglacial period has been somewhat long-lived even before we started pumping fossil fuels into the atmosphere, but the recent warming is more strongly correlated with the industrialization of our species. The typical interglacial temperature maximum for our ice age seems to have been in the ballpark of a few hundred to maybe a couple thousand years, a number we've far exceeded.
This study actually contradicts nothing. This idea had been around for sometime, this is just the latest study to offer for evidence in support. What has become clear to climate scientists (and was impressed upon me during my graduate studies in that field) is that climate is a very complicated, non-linear, multivariate system. The Milankovich cycles were one proposed theory for ice ages, linking natural cycles in Earth's orbit to ice ages, but it quickly became clear that wasn't the entire story. One of the questions scientists struggled with for a long time is "How do you start an ice age?" For long periods in Earth's history there have been intermittent ice ages, but they seemed to have no periodicity or pattern. Milankovich cycles definitely control whether the climate is glacial or inter-glacial during a long term ice age, but if the climate is already in a "warm" state they lack the oomph to trigger an ice age. This research provides one clue to the answer. Other proposed solutions have to do with the arrangement of the land masses on Earth's surface, and ultimately they are all probable factors.
Regarding green house gases, one of the things this study does is reinforce the link between CO2 and climate state. Weathering is one way of removing a lot of CO2 from the atmosphere over long periods of time, and is part of the reason why Earth isn't more like Venus. Geologic forces removed a huge fraction of Earth's primordial CO2 from the atmosphere, more than we could ever hope to release by burning all of the fossil fuels on the planet.
You're mostly correct, but a few things. Read the book "Stellar Interiors" by Hansen & Kawaler; it's a standard graduate text on the lifecycles of stars. I actually took a few classes on the topic from the Kawaler of that trio.
And most stars either (A) stop short of even that and become a red dwarf, or (B) blow themselves up within seconds when they start fusing helium, because that's a very unstable reaction, whose rate increases with temperature, and temperature increases with fusion rate.
For one, it's a white dwarf, not a red dwarf. Red dwarf stars are just very small stars actively burning hydrogen. Two, stars don't "blow themselves up" the instant they start fusing helium to something heavier. The red giant phase is when some stars do go through a period of instability which can result in novas (not supernovas), which is essentially the star sloughing off a small part of it's outer layers.
The way this all happens in reality is there are 3 possibilities: 1. the star is so small it never starts burning helium, and becomes a white dwarf, 2. the star does burn helium, but can't burn C and O, and stops as a white dwarf, 3. the star has sufficient mass to start fusing C and O and things get interesting. The class of stars that can begin to fuse C and O are essentially now on a runaway train, because each reaction proceeds progressively faster in the core of the star up until iron begins to be created.
But at any rate, even if you had a star massive enough, you wouldn't get many nuclei past iron, or you wouldn't get them out of the star. By the moment a star got massive and hot enough to start fusing iron into something heavier, it would just rapidly lose heat in that reaction. It just can't explode that way, so at most you'd get a black hole in the end of it all.
Yes, as soon as a star begins to fuse iron in its core, energy is actually removed from the core of the star, causing it to lose all of the thermal energy that had supported it against the force of gravity. So in some sense the creation of heavier elements is what actually causes the star to explode.
Within a very very short period of time the core of the star is in gravitational free-fall and collapses in on itself, releasing a tremendous amount of gravitational energy in the process. The core collapses and rebounds, sending shockwaves through the entire star and it "blows up" as a supernova, producing a tremendous amount of neutrinos and gamma radiation. You are correct in saying these elements don't get out of the star, they go into forming the either a neutron star or a black hole that's left of the core. The creation of heavier elements is from the gigantic shockwave propagating out of the star.
Actually, no. Typical albedo values for snow are between 0.6 and 0.9. Ocean has an albedo of ~0.1. While yes, water seems very reflective in our experience, for most of the spectrum it's not. Your typical desert however has an albedo of 0.2-0.4. Net effect, covering more of the land surface with water has the opposite effect you think it does, at least to lowest order.
You just failed to notice that her cheeks look surprisingly breast-like, especially when you compare the 7th orthonormal basis vector of the wavelet transform of her face to the transform of your poorly-drawn boobs.
The simple fact is the internet has revolutionized the speed at which new information is disseminated. While there are surely many many internet "resources" of questionable value, there are also many legitimate internet resources that prove to be invaluable to many fields of study. In some fields this has reached a point where yes, you might get a perfectly legitimate education in that field, but your education would actually be sub-par in comparison to someone with unfettered access to the internet. This is true in fields even outside my original example of digital media/art (it just seemed the most likely to be hampered by such censorship). As a previous poster mentioned, arxiv.org has proven to be extremely valuable in physics.
As someone who has actually done research in materials science, the information available on arxiv.org really was critical to the quality of my education. Does this mean I learned nothing from books? No. I had plenty of occasions to spend time digging around the library looking up papers written before I was born. What it enabled was access to the very latest research information that was out there, allowing me to more intelligently conduct my own experiments taking advantage of information so new it hadn't even been published in books yet. It's the difference between knowing what's happening now from the internet vs. what gets published a year from now after the review process. In science being a year behind can mean the difference between being the author of groundbreaking research or just the guy who independently verified what someone else has already done.
As far as bandwidth goes, my graduate research was in atmospheric science, for which lack of an internet connection would have made my research impossible. At times my work involved moving huge amounts of data, so if my university had decided to limit my access because of bandwidth issues my hands would have been tied. Again, I still would have had a nice education in the fundamentals from books, but in such a rapidly evolving field I would have been behind the times on how to use the latest tools of the trade. This in my mind would be a serious detriment to the quality of my education. So yes, sometimes it really is necessary to "leave" the university to learn. At least if you want to stay current.
You seem to be conflating two issues. No one argues that "learning" becomes impossible without the internet, the real issue is one of content. It's a question of what you're learning. While some areas of research and learning are perfectly suited to learning from books, others clearly are not. Universities are not static entities, they try to stay current and relevant. This means areas of study have appeared that no one imagined even a half century ago, and sometimes unfiltered access to the outside world is critical. Imagine trying to study digital media/art if your university blocks you from going to websites which host such content.
From the article:
He says waiters here don't hover. Instead, "there's an understanding that for every hour or so you're here, you'll buy something."
Who eats that much at work?
Better yet, a scandal involving Bill Gates? This is at least plausible, and you know some poor talking head in the media will utter it should it ever come to pass.
Of course it has a shelf life. Over time bacteria could potentially grow in your bottled water. Bottling methods aren't 100% sterile, nor do they maintain their seal until the end of the universe. Hence you assign everything meant for human consumption a shelf life based on some extremely conservative estimate of how long the product is likely to remain uncontaminated under "normal" storage conditions.
Common usage doesn't make it less ridiculous. As to the 30-year figure, the trend of affixing -gate to every Washington scandal doesn't seem to have gained traction until the late 80s, over a decade after the scandal from whence it originated.
There's only one scandal that ends in gate, Watergate. Call it for what it is and stop propagating this ridiculous use of -gate as a suffix to indicate a government scandal.
Slashdot Mirror
Well, as the guy who submitted the article, I thought the title I chose was fairly innocuous since ice ages != global warming. It's just the sad fact that when you bring up climate change of any kind people who are not climate scientists immediately start going off about global warming. It's one of those cases where everyone is an expert and few people bother to listen to what those of us who actually study this field are saying. It was a big issue in my graduate program as we constantly have to deal with people on both sides taking what we say out of context to support their political agendas.
While this study does have implications for climate change, the types of changes that this study talks about are over geologic time and have a very minimal impact on what is happening right now other than to set a baseline. I'd also point out that this idea is not new, it has been around for a very long time. The trouble has been two-fold: determining when previous ice ages (other than the most recent) have been is one piece of the puzzle, and the other is determining when orogenic events have occurred in the past. Neither of these is easy, so what it nice about this study is it offers more evidence to support what is actually a fairly old idea.
Two points. One: no one ever said humans are the sole cause. That said, it's clear we are part of what's going on. Two: the implication of the full article is that CO2 has a very large effect on climate. In turn, this implies that the rapid increase in CO2 due to humans may have a very large impact on our climate in a very short time.
And in a sense you have hit the nail on the head. Global warming is very much a political/economic issue and much less a science issue. Even if science can say what will happen, the simple fact is we can't easily reverse what we have already done, which could have consequences for a few centuries.
Now I'll pose a different question to you... what is the cost of doing nothing vs. taking what actions we can to mitigate the risk? The simple fact is we're rolling the dice and there will be winners and there will be losers, and we don't know which will be which. Even if only the least severe scenarios prove to be true, rising sea levels alone present us with an economic burden that far outweighs the costs of doing something now. So we don't understand everything well enough to know the exact outcome; but do we really want to roll those dice? I know I'm not a gambling man.
See my above comment. Ice age refers to the climate being cool on average over the past few million years. This is certainly punctuated by warm inter-glacial periods, but it is (or at least was) still an ice age.
If you look over geologic time scales, yes, we are in an ice age. People confuse ice age with glacial and inter-glacial periods. The trend for the last 40 million years has been sharp warming to temperatures similar to what we have experienced for roughly the last 10,000 years, followed by a slow decline over the next 100,000 or so years until you reach a minimum, then a sharp spike, etc. What is special about our current interglacial period is it has gone on for 10,000 years and it's suddenly getting warmer. There is some indication our current interglacial period has been somewhat long-lived even before we started pumping fossil fuels into the atmosphere, but the recent warming is more strongly correlated with the industrialization of our species. The typical interglacial temperature maximum for our ice age seems to have been in the ballpark of a few hundred to maybe a couple thousand years, a number we've far exceeded.
This study actually contradicts nothing. This idea had been around for sometime, this is just the latest study to offer for evidence in support. What has become clear to climate scientists (and was impressed upon me during my graduate studies in that field) is that climate is a very complicated, non-linear, multivariate system. The Milankovich cycles were one proposed theory for ice ages, linking natural cycles in Earth's orbit to ice ages, but it quickly became clear that wasn't the entire story. One of the questions scientists struggled with for a long time is "How do you start an ice age?" For long periods in Earth's history there have been intermittent ice ages, but they seemed to have no periodicity or pattern. Milankovich cycles definitely control whether the climate is glacial or inter-glacial during a long term ice age, but if the climate is already in a "warm" state they lack the oomph to trigger an ice age. This research provides one clue to the answer. Other proposed solutions have to do with the arrangement of the land masses on Earth's surface, and ultimately they are all probable factors.
Regarding green house gases, one of the things this study does is reinforce the link between CO2 and climate state. Weathering is one way of removing a lot of CO2 from the atmosphere over long periods of time, and is part of the reason why Earth isn't more like Venus. Geologic forces removed a huge fraction of Earth's primordial CO2 from the atmosphere, more than we could ever hope to release by burning all of the fossil fuels on the planet.
You're mostly correct, but a few things. Read the book "Stellar Interiors" by Hansen & Kawaler; it's a standard graduate text on the lifecycles of stars. I actually took a few classes on the topic from the Kawaler of that trio.
For one, it's a white dwarf, not a red dwarf. Red dwarf stars are just very small stars actively burning hydrogen. Two, stars don't "blow themselves up" the instant they start fusing helium to something heavier. The red giant phase is when some stars do go through a period of instability which can result in novas (not supernovas), which is essentially the star sloughing off a small part of it's outer layers.
The way this all happens in reality is there are 3 possibilities: 1. the star is so small it never starts burning helium, and becomes a white dwarf, 2. the star does burn helium, but can't burn C and O, and stops as a white dwarf, 3. the star has sufficient mass to start fusing C and O and things get interesting. The class of stars that can begin to fuse C and O are essentially now on a runaway train, because each reaction proceeds progressively faster in the core of the star up until iron begins to be created.
Yes, as soon as a star begins to fuse iron in its core, energy is actually removed from the core of the star, causing it to lose all of the thermal energy that had supported it against the force of gravity. So in some sense the creation of heavier elements is what actually causes the star to explode.
Within a very very short period of time the core of the star is in gravitational free-fall and collapses in on itself, releasing a tremendous amount of gravitational energy in the process. The core collapses and rebounds, sending shockwaves through the entire star and it "blows up" as a supernova, producing a tremendous amount of neutrinos and gamma radiation. You are correct in saying these elements don't get out of the star, they go into forming the either a neutron star or a black hole that's left of the core. The creation of heavier elements is from the gigantic shockwave propagating out of the star.
Oh, that's called stalking? I thought it was just how you let someone know you liked them. Guess /. was a bad place to learn my dating skills.
Actually, no. Typical albedo values for snow are between 0.6 and 0.9. Ocean has an albedo of ~0.1. While yes, water seems very reflective in our experience, for most of the spectrum it's not. Your typical desert however has an albedo of 0.2-0.4. Net effect, covering more of the land surface with water has the opposite effect you think it does, at least to lowest order.
You just failed to notice that her cheeks look surprisingly breast-like, especially when you compare the 7th orthonormal basis vector of the wavelet transform of her face to the transform of your poorly-drawn boobs.
The simple fact is the internet has revolutionized the speed at which new information is disseminated. While there are surely many many internet "resources" of questionable value, there are also many legitimate internet resources that prove to be invaluable to many fields of study. In some fields this has reached a point where yes, you might get a perfectly legitimate education in that field, but your education would actually be sub-par in comparison to someone with unfettered access to the internet. This is true in fields even outside my original example of digital media/art (it just seemed the most likely to be hampered by such censorship). As a previous poster mentioned, arxiv.org has proven to be extremely valuable in physics.
As someone who has actually done research in materials science, the information available on arxiv.org really was critical to the quality of my education. Does this mean I learned nothing from books? No. I had plenty of occasions to spend time digging around the library looking up papers written before I was born. What it enabled was access to the very latest research information that was out there, allowing me to more intelligently conduct my own experiments taking advantage of information so new it hadn't even been published in books yet. It's the difference between knowing what's happening now from the internet vs. what gets published a year from now after the review process. In science being a year behind can mean the difference between being the author of groundbreaking research or just the guy who independently verified what someone else has already done.
As far as bandwidth goes, my graduate research was in atmospheric science, for which lack of an internet connection would have made my research impossible. At times my work involved moving huge amounts of data, so if my university had decided to limit my access because of bandwidth issues my hands would have been tied. Again, I still would have had a nice education in the fundamentals from books, but in such a rapidly evolving field I would have been behind the times on how to use the latest tools of the trade. This in my mind would be a serious detriment to the quality of my education. So yes, sometimes it really is necessary to "leave" the university to learn. At least if you want to stay current.
You seem to be conflating two issues. No one argues that "learning" becomes impossible without the internet, the real issue is one of content. It's a question of what you're learning. While some areas of research and learning are perfectly suited to learning from books, others clearly are not. Universities are not static entities, they try to stay current and relevant. This means areas of study have appeared that no one imagined even a half century ago, and sometimes unfiltered access to the outside world is critical. Imagine trying to study digital media/art if your university blocks you from going to websites which host such content.
From the article: He says waiters here don't hover. Instead, "there's an understanding that for every hour or so you're here, you'll buy something."
Who eats that much at work?
Better yet, a scandal involving Bill Gates? This is at least plausible, and you know some poor talking head in the media will utter it should it ever come to pass.
Of course it has a shelf life. Over time bacteria could potentially grow in your bottled water. Bottling methods aren't 100% sterile, nor do they maintain their seal until the end of the universe. Hence you assign everything meant for human consumption a shelf life based on some extremely conservative estimate of how long the product is likely to remain uncontaminated under "normal" storage conditions.
Common usage doesn't make it less ridiculous. As to the 30-year figure, the trend of affixing -gate to every Washington scandal doesn't seem to have gained traction until the late 80s, over a decade after the scandal from whence it originated.
There's only one scandal that ends in gate, Watergate. Call it for what it is and stop propagating this ridiculous use of -gate as a suffix to indicate a government scandal.
see: Martha Stewart