I thought I'd read once that water vapor is a very potent "green house" gas - but it rarely ever gets mentioned.
It is a potent greenhuse gas, but it plays a secondary role (non-causative), because its concentration in the atmosphere is a function of temperature (warm air holds more moisture). This means it acts as a very powerful "positive feedback" - warm the atmosphere through some means (e.g. CO2), that increases the water vapor content, which causes more warming, which raises water vapor levels, etc.
Don't think of water vapor as a dial we can control - rather, it's the gain stage in the amplifier.
I cringed when I learned how weather stations report "average" temperature. It is usually just the mid-point of the day's min and max temperature! For example: http://www.climate.weatheroffice.ec.gc.ca/climate_ normals/climate_info_e.html#1 Since the min/max temp is strongly influenced - by several degrees in just a few hours - by cloud cover (solar heating by day and cooling by the open sky at night), the error on this "statistic" can be very significant when compared to a more meaningful average (average of 24 measurements from each hour).
Interesting point. Be careful though; the effect of CO2 increase is to reduce the cooling into deep space, kind of like if there were clouds overhead. So CO2 level changes will tend to increase the night-time and mid-winter lows more than the average temperatures. That doesn't mean it isn't a real effect - just that it has a non-trivial effect.
It is certainly important to be careful how you average together large data sets, and people are careful when they do that. One other point to remember is that the observed increase in temperature is also seen in things like ice-cores, tree rings, lake sediments and coral layers; these all reflect some form of 'average temperature' for that region, and have the added advantage that they are uniform data sets - so systematic errors should be common to all measurements and not act to obscure warming trends.
Im assuming by carbon you are talking about CO2. CO2 != particulates.
I know. I meant the carbon locked up in CO2 - but one typically uses "carbon" in this context because CO2 also contains oxygen, and so there is a difference between saying a given mass of carbon and a given mass of carbon dioxide has been released. Important, becauase its easier to relate the carbon to the fossil fuel source mass, which is what is usually done.
Particluates were thrown in by the OP as a red herring. Volcanoes are a small source of greenhouse gases, but can be a significant source of particulates; enough to cause noticeable cooling for a year or two. (think nuclear winter).
Of course, as we clean up human sources of particulates, volcanoes become more noticeable. In any case, the OP was just plain wrong with his claim that volcanoes dwarf human impact.
Interesting, but a couple of things. First, do they list the "raw numbers" in a non-graphical format (preferably a table)? I usually like to make my own graphs with these things. Lets me get a better comparison.
Dunno. Ask 'em. Let me know what they say.
Second, I notice that temperature falls before CO2 decreases. However, under the CO2=higher temperatures, shouldn't the CO2 fall first?
It's hard to tell that from the plot, in my opinion. The scale is very compressed, and there are uncertainties in the dating. You could also imagine various feedback mechanisms that would cause something like that. In any case, a correlation does not imply a causation. You could have a feedback loop, or a common third cause. But there is other evidence for why CO2 will cause warming (IR absorption properties and the greenhouse effect).
Third, the graph shows that CO2 levels started rising a bit over 10,000 years ago.
They did, and that is associated with the end of the most recent Ice Age. Note that the data does not include recent increases, which stand out like a spike. The current CO2 level is 370 ppm and occurs in the last 100 years. Put that into the plot and grok it...
In the absence of human sources, CO2 is released by volcanoes (at a much slower rate than human release rates, mind you); it is removed by chemical reactions with rocks. Ice ages cover large amounts of rock, reducing the weathering and thus causing a net increase in CO2 - with associated warming, which removes the ice.
You get a "limit-cycle" oscillation. The problem is that we are kicking this system pretty hard - way, way out of the regime it has been in for the last 0.5 Myr. It's not clear what will happen, but the models indicate it will be pretty exciting.
The fireworks on this topic seems to have subsided, so I can sit back and give a longer-term view, or at least my more-or-less well-formed opinion as a PhD scientist in a very closely related field (planetary science). Climate change is going to really, really suck. There is little chance we'll do anything about it - and Kyoto is not the final answer. Neither is denial. Kyoto is CRUCIAL because it buys us time. Time to solve our energy problems. Time to develop nuclear fusion, which is the only way we'll ever manage to become a long-term sustainable civilization. It's either that or an ever more dismal, Hobbesian scramble for the last remaining fossil fuels. What is so frustrating is that the cost of doing the right thing is not actually a cost at all - the U.S. could change the rules of the game entirely by embracing efficiency. Detroit could re-capture the lead in cars if they just thought far enough past their own damned noses to embrace hybrids... U.S. industry could embrace the idea of innovation and efficiency as a competitive tool, and this would help keep jobs here. China will always beat the US in cost; the only way to stay competitive is by staying ahead in knowledge and efficiency. But of course US policymakers don't care (they get their wealth from - potentially foreign - stocks rather than work, so they don't have to keep US industry competitive.) and US workers are too brainwashed by the likes of Fox News to see their own best interests.
It's so frustrating. Like watching a trainwreck in slow motion.
Boiling a pot of watter has been repeated. I have not seen anyone show me that in that past CO2 levels have gone up and temperature went up with it.
Check out: this link. Scroll down to the plot of CO2 vs temperature and then tell me there isn't a correlation. Now recall that CO2 levels are at 370 ppm and rising... Before you run off an put the cart before the horse (that warming causes CO2), know that we have good, sound physical reasons to expect CO2 rises to cause warming, but few reasons to expect the converse.
Besides, wouldn't the sun be a better analogy for the burner as opposed to CO2? Especially seeing as how solar output has gone up?
If you care to take an analogy too far, then adding CO2 to the atmosphere is like putting a lid on the pot. As for your comment about solar output - that is very unclear, and even the ones who published that said it can't explain all of the observed warming. Not to mention that its a result that doesn't have a lot of back-up, whereas CO2 increases, the observed warming, and the effect of CO2 increases on radiative transport are all things that have been studied by hundreds of researchers.
The argument that it's all Man and the fixation of greenhouse gases and the refusal to look at anything else but Man and greenhouse gases.
That's simply not true; there is a lot of research going on on the impact of other potential sources of global climate change. Some by people intent on proving it isn't caused by CO2, even...
It's not that no-one has looked, its that most of the evidence points to anthropogenic CO2.
O2 does not mean warming. [...] urban heat-island effect
That claim has been accounted for for at least 15 years; the effect also doesn't appear in things like ice-core and coral records. The heat-island effect doesn't explain the apparent warming. Period.
Check out
this link for an interesting discussion on ice-cores and temperature records. Also, if you scroll down you'll notice that there is a pretty obvious correlation between CO2 and temperature.
Now for all this CO2 in the air, why is the ice mass of Antarctica growing?
The claim is not that temperatures have to increase everywhere; just on the average.
In fact, the increased precipitation is expected from the modeling (warmer temps=>more evaporatio=>more snow=>more ice); but it won't be enough to reduce the net warming.
The World is getting warmer, but just because CO2 is increasing at the same time doesn't mean CO2 is causing it.
Really officer, there is dead body at my feet, and I have a smoking gun in my hands, but it wasn't me. I fired my gun at the other guy. That guy over there on the grassy knoll. Sure you did...
Look - we know that CO2 released into the atmosphere would cause warming in the absence of any negative feedbacks. We know CO2 is being released by us into the atmosphere. We see warming. We've managed to quantify most of the possible negative feedbacks and se that they are small. What is a reasonable conclusion?
When you don't know everything, you know nothing, but you can guess at a great deal.
Do you really want to discuss the philosophy of knowledge, or are you just being cute? It's more than "guesses". Much is based on experiment, observation, and other, directly verified, laws of physics.
We don't "know" everything about gravity (e.g. what happens at very small or very large distances, how it's quantized, etc), but I can tell you that if you jump out of a window, the world will be a better place. Some "guesswork" is more reliable than other guesswork, and I'd put the science of climatology at a level high enough to warrant action.
Sure, there is always room for surprises; any good scientist will admit this. But then any politician will twist that uncertainty into an excuse for inaction - which it most definitely is NOT.
The debate over the "hockey puck" shows that there is disagreement over basic foundational data (which only represents a very short time period as far as the Earth is concerned) so drawing conclusions especially to the point of X degrees more and we all die is misleading at best and scientifically dishonest at worst.
There will always be someone who disagrees with a scientific theory, no matter how strongly the evidence supports it. There are people who argue - I kid you not - that the Sun is made up of iron, or that the Big Band theory is wrong. No scientific theory will ever be supported by everyone...
I will confidently draw the conclusion that if the mean temperature of the Earth increased by 100C we'd all die. If it increased by 20C civilization would end. If it increase by 10 deg we'd be in seriously deep sh*t. Even a 2 degree rise will be problematic.
That being said - the tone fo the article was a bit too definite; it gave the impression of an on/off system, or a critical point of no return. I doubt that is the case - I suspect we have already passed the point where there will be some damage, but I don't know for certain.
but don't make the mistake of thinking that just because we admit uncertainty that there is no reason to act based on the knowledge that we do have. We should begin to act, and continually refine our action as we learn more.
All this being said, I have essentially no hope. Civilizations have collapsed many times in the past, usually due to self-inflicted environmental damage. I don't think humanity is capable of keeping itself from self-destruction.
Large volcanos like Mt.St. Helens barf more particulates and greenhouse gas into the atmosphere in a single eruption than all the human activity since 1900.
No, that's wrong. Volcanoes on average put in 100-200 million tons of carbon into the atmosphere. Humans dump about 6 BILLION tons each year. Here is a reference. here is another
Care to speculate on the climate changes caused by the tsunami? Wide spread destruction of ocean plant life and coastal habitats will obviously affect O2 generation and CO2 processing. Did you know that the North Pole moved and that the day got shorter thanks to the earth quake that triggered the tsunami?
The Tsunami could conceivably have a short-term effect on something; but I think you can do some fairly simple back-of-the-envelope calculations to bound the maximum CO2 release (calculate the total area affected and compare it to the total sea surface, or coastal area). As for the change in the length of the day, it was about a micro-second. That's pretty small; enough to be negligible in this context.
Are you deliberately trying to confuse the issue, or are you just confused? You need to work on order-of-magnitude estimation, I think.
We do Computational Fluid Dynamics modelling here at my work and the computer models always have to be checked against physical experiments to validate their results. Additionally, due to the limitations of computers (something that is constantly improving) the detail of the models has changed over time.
Do you think climate change researchers don't test their models against real data whenever possible?
Of course they do. You can accuse an entire field of science of misconduct if you like, but I've read papers and know people in that field, and I think they are more credible than you are. In any case, they quantify their uncertainties - they give a range of predicted warming; it's just that that range doesn't include 0 in the 1-sigma range.
As for the hockey stick you can read about it here.
Thanks. The German guy basically said that the averaging procedure smoothed out the variations too much, making the recent rise stand out less. But it didn't make the rise go away; it's still there as much as ever. He also ignored other data sets such as ice-cores that give variability information over much longer timecsales. The MIT claim was just vacuous; he made assumptions about people taking running averages which aren't true.
we don't KNOW that our actions are causing the changes.
Well, Sherlock, we have some pretty good evidence for it. As I keep having to repeat: we know we are releasing CO2, we know that CO2 is staying in the atmosphere, and we know that CO2 absorbs IR radiation. We also know a bunch of other facts about the physics of radiative transfer, thermodynamics, fluuid flow etc etc. We know that when we combine those facts in a computer model that that model shows warming (on average). Finally, we know that it is getting warmer (on average).
Don't confuse not knowing everything with knowing nothing.
if you don't agree with me, you must be bad routine.
Well, I see you using deliberately disingenous arguments to defend a position that would allow you to continue polluting, even in the face of evidence that such pollution causes long-term risks for the survival of others (and yourself).
Is that "bad"? Are you actually an environmentalist? Perhaps, but I'd be willing to wager my left nut that you aren't.
This of course ignores the whole fact that no one agrees that we've actually "turned the burner on" as far as Earth is concerned.
We have. It's indisputable that we are releasing CO2 into the atmosphere, and that CO2 levels are rising. It's also beyond dispute that CO2 absorbs IR radiation, and that such absorption will act to warm the surface. That means to me that "we've turned on the burner". People argue about negative feedback that might counteract the warming effect - but that's not the "burner".
Further we don't know what would happen if we "turned the burner off"
We know withing some range of uncertainty; and the odds are that it would be less disruptive than keeping the burner on. We have recent historical data to indiucate what the world does at lower CO2 levels, and it's probably ok.
The other article about Global Dimming also would suggest that there are other changes we aren't accounting for.
I remember studying the effects of aerosols 5 years ago in my radiative transfer class; the effect you mention is a second-order effect that will amplify current warming trends.
It's a complex system that is "described" using things like chaos theory.
"Chaos theory" is one of those words that should never be used in a scientific/political context because it means different things to different people. You seem to think it means "can't be predicted and so isn't real". In a scientific context it has a more definite meaning; and my example does include that - fluid flow during boiling is "chaotic" and unpredictable. The effect of radiative forcing on climate is somewhat less so.
statistical analysis against the old "hockey stick" temperature data suggests that the seed data is flawed and will always create a hockey stick shaped graph no matter what data is fed in to it.
That's an underhanded piece of crap for an argument. Care to provide a reference for that claim? Care to defend it? I take issue with you blithely dismissing many thousands of temperature measurements from dozens of researchers based on some bogus "statistical argument" that you won't even elaborate.
p.s. Why was my original comment modded "flamebait"? It wasn't inflammatory. Overrated I could accept, but "flamebait" is just wrong.
It doesn't mean any of them will occur. The fact of the matter is, all the computer models in the World and wildassed guesses mean that we know very little about how the planet
Don't confuse knowing very little with knowing nothing at all. Take a pot of water and put it on the stove. Turn on the burner. You know that the water will get warm and eventually boil. Scientists could make some measurements and tell you pretty much exactly when it will boil, and how quickly it will boil dry. But no computer program in the world can accurately tell you exactly what the pattern of bubbles will be during the boiling. So what? It just means that there are some things we can't model/predict, like boiling or weather, and there are some we can, like climate and thermodynamics.
We do know that our actions are causing changes, and we know that further actions will cause further changes - within a range of uncertainty.
This won't change just because you want to continue to pollute.
I am getting so tired of this junk science. The world has been coming to an end for my entire 40+ years on this planet. Nothing has happened yet. Ain't going to happen either.
Maybe the world has been coming to an end, just slower than your average Hollywoood movie would have you think it will. Climate change really has happened, and you can talk to plenty of old people living in places like Alaska and they will usually tell you that it used to be colder. There is ample evidence for glacier retreat and ice thinning (the letter from e.g U.S. Navy polar research).
Now, some reports have been overly dramatized - and some people retro-actively exaggerate the reports so they can say that its was all hype. In truth, there is always a range of opinion on something as important as climate change, and you can pretty much alway find someone who says something youi find useful, if you look hard enough.
All that notwithstanding, the large majority of the worlds' climate scientists have over the last 15-20 years consistently been saying that we are causing climate change. There is so much evidence that only someone who wanted to believe otherwise would be in serious doubt.
You make an obvious logical fallacy: the fact that something hasn't happened doesn't prove that it won't happen.
No, climate change will happen over the next 20-100 years. It might be "slow" compared to an asteroid impact, but it will nonetheless happen and it will have an impact on our environment.
How much it interfers with civilization is still somewhat up for debate...
There is another example of this sort of thing that I find infomative; when I was a kid I learned about the dangers of over-population, and how diseases were a common consequence. As a kid I thought that there would be a large pandemic that would sweep through the teeming masses and kill millions of people. Of course, I was right - it's just that that pandemic happened slower than I expected (AIDS infects and will kill >20% of some poulations in Africa. That's pretty Malthusian if you ask me).
Why has it better getting progressively colder over the past 20 years in places like Russia and China?
It hasn't. In fact, there are many cities in northern Russia that have a new problem: apartment buildings collapse because the permafrost their foundations sit on has melted.
That sounds like warming to me.
When someone says people of group a have an advantage/disadvantage in x relative to people of group b, that person is eigther right or wrong. That person is also eigther biggoted or not.
It's not that black-and-white. In most cases, two large goups will each have a distribution of ability in a given area; a "gaussian" or "bell curve". That bell curve has two important numbers: the mean value, and the variance or "width" of the distribution. It is often the case that the means differ by less than the variance; in such a case it becomes hard (statistically insignificant) to use group identity as a proxy for ability - instead you have to just measure that ability directly. (Example: Women are on average weaker than men. But not all women are weaker than all men, so if you are, say, selecting firefighters, you should give everyone the same test - not just select the men.)
However, all this pre-supposes that there is a single (or small number) of measurable traits associated with the ability you care about.
It is not at all obvious that there is a single trait associated with being successful in math and science (to talk about Summers' comment specifically). Even if there are a few important traits, it is even less obvious that men would be superior to women in all of them.
So, I will agree that it might be useful to understand if there are traits that make people more or less suited for science careers; i.e. it might be a question worthy of scientific inquiry.
But you have to be careful not to ask the question in a manner that pre-supposes the answer; gender may not be the largest factor, but if its the only one you look for... In addition, it has often been the case that the only people who research such questions do so because they have a pre-determined agenda that they want to support; this is probably also the case here.
Unbiased scholarly inquiry was not what Summers was doing - he was trying to come up with an excuse why Harvard should not be criticised for its sexist promotion record. He also blatantly ignored much evidence contrary to his claim (including stuff presented at that very meeting). Finally, he is the president of Harvard and as such has certain responsibilities, which includes trying to encourage diversity at his University.
Again, if Summers had asked the very same question, but about black people rather than women, what would you think? Especially if you knew that a) he had a record of personally intervening to stop promotions of the kinds of people in question, and b) since he started as President, the number of tenured people of that kind had dropped and was now significantly under-representative.
What happens if your swap religeous belief for political ideology? They're both equally mutable.
Tell you what - I'll support a tenure-quota for Republicans, the day the first self-proclaimed atheist is elected President of the U.S.
It's the age-old question confronting those who hold tolerance as an important value: how tolerant should you be of those who are intolerant? Should universities promote bigotry and sexism in the name of inclusiveness?
Getting back to the original topic: what if you replaced "women" in Summers question with "black people"? Would you condemn him as being racist?
Racists and sexists have no business being... er, well, in business.
However, turn it over to politics, and people can be as discriminatory as they want. Don't fool yourself, that's still discrimination.
I disagree. The difference is that you can change your politics; you (usually) can't change your gender or skin color. The former is a matter of creating a "level playing field", the latter is a matter of preferring good judgement.
I'm not arguing that sexism and racism don't still exist in academia - obviously they do. Including in the president of Harvard.
However, I am saying that there is a difference between sexism and what you might call "political correctness"; some political views are offensive to others, and can rightly count against you. Note how we don't usually encourage or accept people who advocate slavery these days.
That being said, what your political views are is pretty much irrelevant to your ability to do a mathematical/engineering job, and so shouldn't be an issue in hiring there. But it might be a matter of concern in a college professor of social science. Then again, I happen to think that having a diversity in opinion is actually valuable.
I don't pretend to understand whether it's a cultural matter or a genetic one, but there are a variety of biological reasons for women to be less capable of maintaining abilities in math and logic (which are devoid of emotion). Women have a lot of games that their bodies, for better or worse, play on them that men do not suffer or experience.
Swear off sex and masturbation for three weeks, then tell me that men don't have "drives" that interfer with clear thinking.
And I bet none of them were conservatives; so much for diversity...
Yes, because having a political opinion is as much an inborn, immutable trait as is the color of your skin or the number of Y chromosomes you have. Sure.
The reason that nearly no women probably went for the jobs in the first place is because of this guy.
You've obviously never been in a position to apply seriously for an academic position at an elite university. Who the president is and what his views on your gender are does not top things like the prestige and resources of the place. And besides, when applying, you know that they can't be too overtly recist/sexist or there will be trouble. No, those positions have literally hundreds of applicants of both genders; most of whom are fully qualified for the job. 4/32 is pretty obviously problematic.
It seems to me that when discussing this topic people need to start by taking a deep breath, holding it, then slowly exhale while saying out loud: "Suspend your emotional reactions and just think objectively about this."
Now, once we've all been reminded to stop thinking with our hind-brains, let's try and see if we can agree on some preliminary conclusions...
1) There are women who perform outstandingly well in areas of math and science. In my experience I've known women who are as amazing prodigies in things like physics as any men I've met. I'm a scientist in a field of physics, and I've met my fair share of geniuses, Nobel prize winners, child prodigies, idiot savants, and just plain freaks. Of both genders.
2) There are fewer women than men in general in the mathematical/physical sciences.
3) There are definite societal pressures against women doing well in math and science, starting from an early age and continuing all the way into tenure-level academic selection. This includes of course the pressure to raise children, but also includes social pressure in high school and college.
4) There are obvious (and wonderful) physical differences between men and women.
It is possible that there are similar psychological gender differences, but in all truth, there is no hard scientific evidence for this, and some evidence against it.
5) In the past, many people have used strikingly similar arguments to defend blatantly racist claims. The obvious examples are things like claimed IQ differences between "white", "black" and "yellow" races; or claims about differences in "sexual restraint", or other equally repugnant things. I think most reasonable people see such claims as the bigotry it is, and there is ample societal evidence to disprove such claims.
Based on my personal experience, and on discussions with friends and colleagues, I think that the explanaition for why there are fewer women in the matheatical sciences has more to do with inherent societal biases and the way that the job market works than any inherent gender differences. It is blindingly obvious to anyone in physics these days that the system was set up in a day and age when a professor was expected to have a wife at home who would take care of everything, including raising children. It is almost impossible for a dual-career couple to balance having a family with having successful careers at an elite institution. Something has to give, and that is often the wifes career (although among my friends it is oddly enough more often the other way around. Statistical anomaly, or recent trend?)
So, I think a) Summers is betraying his own mind-set, which is gender-biased. b) he's missing the larger issue, which is a career ladder that demands total sacrifice of everything including family life.
You don't understand the mindset of the European public, so stop giving stupid advice.
And what do you know of that? Do you presume to know what countries I've lived in? In any case, it's not just the European mindset that matters. This was a 3 billion dollar mission. Who paid for most of that? Who built the launch vehicle? Who built the spacecraft that flew for 7 years to get to Saturn? Who did the deep space nav? Who supplied the downlink? If you'd only been listening to the press conferences today you might come away with the impression that NASA was just an interested bystander. But then that opens up a whole other can of worms. International collaboration is nice and all - but why do Europeans have to be such dicks when it comes to sharing credit? (Read the "Hubble Wars" for an entertaining story along the same lines).
From a PR point of view, this is a complete non-issue.
This just proves my point - you don't care. Maybe that's why the U.S. outspends Europe 5:1 in space science, and in most other science too, for that matter.
It took over seven years for this ground-breaking mission to reach its destination. The probe spent over two weeks tumbling towards Titan's atmosphere. It spends two hours parachuting down to the moon's surface and another 90 mins "talking" to Cassini. Cassini then has to send back the (potentially corrupt) data and it has to get relayed to the ESA guys. Then they have to set all their data reduciton/processing routines at work, none of which will have been properly field tested due to the unpredictable nature of the telemetry.
And back on Earth sits Mr Bender, feet up on his desk, coffe in his hand, bitching because the ESA guys won't put out a pretty picture in under five minutes.
If they had that much time, maybe they could have spent some of it preparing those scripts. Your argument about how difficult and unpredictable science is would carry more weight if it wasn't already pretty standard practice for JPL to have data put on the web within minutes of the downlink.
I'm just saying this: landing on a virtually unknown world is a great opportunity to excite the public about space science. An excited public is more willing to spend the gigabuck(euros?) needed to do science. People won't give sh*t if the image comes out in Science six months from now. ESA is wasting a hug opportunity because they're too stupid to learn from NASA.
You may be a scientist on paper, but you are not a scientist at heart.
Gee, thanks. So being a scientist at heart means keeping your data carefully hidden from everyone else because you're afraid that someone will publish first, or somehting? Or is it just a matter of acquiring the proper amount of arrogance, and looking down on the unwashed masses too stupid to deserve to look at your pretty pictures, but not too stupid to have to support your science?
Slashdot Mirror
Hehe. Personally, I prefer the "bogosort" algorithm: 1) randomly permute the set. 2) see if it is sorted. 3) Iterate until it is.
N-factorial, with no guaranteed endpoint. It's worthy of Microsoft...
It is a potent greenhuse gas, but it plays a secondary role (non-causative), because its concentration in the atmosphere is a function of temperature (warm air holds more moisture). This means it acts as a very powerful "positive feedback" - warm the atmosphere through some means (e.g. CO2), that increases the water vapor content, which causes more warming, which raises water vapor levels, etc.
Don't think of water vapor as a dial we can control - rather, it's the gain stage in the amplifier.
Interesting point. Be careful though; the effect of CO2 increase is to reduce the cooling into deep space, kind of like if there were clouds overhead. So CO2 level changes will tend to increase the night-time and mid-winter lows more than the average temperatures. That doesn't mean it isn't a real effect - just that it has a non-trivial effect.
It is certainly important to be careful how you average together large data sets, and people are careful when they do that. One other point to remember is that the observed increase in temperature is also seen in things like ice-cores, tree rings, lake sediments and coral layers; these all reflect some form of 'average temperature' for that region, and have the added advantage that they are uniform data sets - so systematic errors should be common to all measurements and not act to obscure warming trends.
I know. I meant the carbon locked up in CO2 - but one typically uses "carbon" in this context because CO2 also contains oxygen, and so there is a difference between saying a given mass of carbon and a given mass of carbon dioxide has been released. Important, becauase its easier to relate the carbon to the fossil fuel source mass, which is what is usually done.
Particluates were thrown in by the OP as a red herring. Volcanoes are a small source of greenhouse gases, but can be a significant source of particulates; enough to cause noticeable cooling for a year or two. (think nuclear winter). Of course, as we clean up human sources of particulates, volcanoes become more noticeable. In any case, the OP was just plain wrong with his claim that volcanoes dwarf human impact.
Dunno. Ask 'em. Let me know what they say.
Second, I notice that temperature falls before CO2 decreases. However, under the CO2=higher temperatures, shouldn't the CO2 fall first?
It's hard to tell that from the plot, in my opinion. The scale is very compressed, and there are uncertainties in the dating. You could also imagine various feedback mechanisms that would cause something like that. In any case, a correlation does not imply a causation. You could have a feedback loop, or a common third cause. But there is other evidence for why CO2 will cause warming (IR absorption properties and the greenhouse effect).
Third, the graph shows that CO2 levels started rising a bit over 10,000 years ago.
They did, and that is associated with the end of the most recent Ice Age. Note that the data does not include recent increases, which stand out like a spike. The current CO2 level is 370 ppm and occurs in the last 100 years. Put that into the plot and grok it...
In the absence of human sources, CO2 is released by volcanoes (at a much slower rate than human release rates, mind you); it is removed by chemical reactions with rocks. Ice ages cover large amounts of rock, reducing the weathering and thus causing a net increase in CO2 - with associated warming, which removes the ice. You get a "limit-cycle" oscillation. The problem is that we are kicking this system pretty hard - way, way out of the regime it has been in for the last 0.5 Myr. It's not clear what will happen, but the models indicate it will be pretty exciting.
The fireworks on this topic seems to have subsided, so I can sit back and give a longer-term view, or at least my more-or-less well-formed opinion as a PhD scientist in a very closely related field (planetary science). Climate change is going to really, really suck. There is little chance we'll do anything about it - and Kyoto is not the final answer. Neither is denial. Kyoto is CRUCIAL because it buys us time. Time to solve our energy problems. Time to develop nuclear fusion, which is the only way we'll ever manage to become a long-term sustainable civilization. It's either that or an ever more dismal, Hobbesian scramble for the last remaining fossil fuels. What is so frustrating is that the cost of doing the right thing is not actually a cost at all - the U.S. could change the rules of the game entirely by embracing efficiency. Detroit could re-capture the lead in cars if they just thought far enough past their own damned noses to embrace hybrids... U.S. industry could embrace the idea of innovation and efficiency as a competitive tool, and this would help keep jobs here. China will always beat the US in cost; the only way to stay competitive is by staying ahead in knowledge and efficiency. But of course US policymakers don't care (they get their wealth from - potentially foreign - stocks rather than work, so they don't have to keep US industry competitive.) and US workers are too brainwashed by the likes of Fox News to see their own best interests.
It's so frustrating. Like watching a trainwreck in slow motion.
Check out: this link. Scroll down to the plot of CO2 vs temperature and then tell me there isn't a correlation. Now recall that CO2 levels are at 370 ppm and rising... Before you run off an put the cart before the horse (that warming causes CO2), know that we have good, sound physical reasons to expect CO2 rises to cause warming, but few reasons to expect the converse.
Besides, wouldn't the sun be a better analogy for the burner as opposed to CO2? Especially seeing as how solar output has gone up?
If you care to take an analogy too far, then adding CO2 to the atmosphere is like putting a lid on the pot. As for your comment about solar output - that is very unclear, and even the ones who published that said it can't explain all of the observed warming. Not to mention that its a result that doesn't have a lot of back-up, whereas CO2 increases, the observed warming, and the effect of CO2 increases on radiative transport are all things that have been studied by hundreds of researchers.
That's simply not true; there is a lot of research going on on the impact of other potential sources of global climate change. Some by people intent on proving it isn't caused by CO2, even... It's not that no-one has looked, its that most of the evidence points to anthropogenic CO2.
O2 does not mean warming. [...] urban heat-island effect
That claim has been accounted for for at least 15 years; the effect also doesn't appear in things like ice-core and coral records. The heat-island effect doesn't explain the apparent warming. Period. Check out this link for an interesting discussion on ice-cores and temperature records. Also, if you scroll down you'll notice that there is a pretty obvious correlation between CO2 and temperature.
Now for all this CO2 in the air, why is the ice mass of Antarctica growing?
The claim is not that temperatures have to increase everywhere; just on the average. In fact, the increased precipitation is expected from the modeling (warmer temps=>more evaporatio=>more snow=>more ice); but it won't be enough to reduce the net warming.
The World is getting warmer, but just because CO2 is increasing at the same time doesn't mean CO2 is causing it.
Really officer, there is dead body at my feet, and I have a smoking gun in my hands, but it wasn't me. I fired my gun at the other guy. That guy over there on the grassy knoll. Sure you did...
Look - we know that CO2 released into the atmosphere would cause warming in the absence of any negative feedbacks. We know CO2 is being released by us into the atmosphere. We see warming. We've managed to quantify most of the possible negative feedbacks and se that they are small. What is a reasonable conclusion?
Do you really want to discuss the philosophy of knowledge, or are you just being cute? It's more than "guesses". Much is based on experiment, observation, and other, directly verified, laws of physics.
We don't "know" everything about gravity (e.g. what happens at very small or very large distances, how it's quantized, etc), but I can tell you that if you jump out of a window, the world will be a better place. Some "guesswork" is more reliable than other guesswork, and I'd put the science of climatology at a level high enough to warrant action.
Sure, there is always room for surprises; any good scientist will admit this. But then any politician will twist that uncertainty into an excuse for inaction - which it most definitely is NOT.
There will always be someone who disagrees with a scientific theory, no matter how strongly the evidence supports it. There are people who argue - I kid you not - that the Sun is made up of iron, or that the Big Band theory is wrong. No scientific theory will ever be supported by everyone...
I will confidently draw the conclusion that if the mean temperature of the Earth increased by 100C we'd all die. If it increased by 20C civilization would end. If it increase by 10 deg we'd be in seriously deep sh*t. Even a 2 degree rise will be problematic.
That being said - the tone fo the article was a bit too definite; it gave the impression of an on/off system, or a critical point of no return. I doubt that is the case - I suspect we have already passed the point where there will be some damage, but I don't know for certain.
but don't make the mistake of thinking that just because we admit uncertainty that there is no reason to act based on the knowledge that we do have. We should begin to act, and continually refine our action as we learn more.
All this being said, I have essentially no hope. Civilizations have collapsed many times in the past, usually due to self-inflicted environmental damage. I don't think humanity is capable of keeping itself from self-destruction.
No, that's wrong. Volcanoes on average put in 100-200 million tons of carbon into the atmosphere. Humans dump about 6 BILLION tons each year. Here is a reference. here is another
The Tsunami could conceivably have a short-term effect on something; but I think you can do some fairly simple back-of-the-envelope calculations to bound the maximum CO2 release (calculate the total area affected and compare it to the total sea surface, or coastal area). As for the change in the length of the day, it was about a micro-second. That's pretty small; enough to be negligible in this context.
Are you deliberately trying to confuse the issue, or are you just confused? You need to work on order-of-magnitude estimation, I think.
We do Computational Fluid Dynamics modelling here at my work and the computer models always have to be checked against physical experiments to validate their results. Additionally, due to the limitations of computers (something that is constantly improving) the detail of the models has changed over time.
Do you think climate change researchers don't test their models against real data whenever possible? Of course they do. You can accuse an entire field of science of misconduct if you like, but I've read papers and know people in that field, and I think they are more credible than you are. In any case, they quantify their uncertainties - they give a range of predicted warming; it's just that that range doesn't include 0 in the 1-sigma range.
As for the hockey stick you can read about it here.
Thanks. The German guy basically said that the averaging procedure smoothed out the variations too much, making the recent rise stand out less. But it didn't make the rise go away; it's still there as much as ever. He also ignored other data sets such as ice-cores that give variability information over much longer timecsales. The MIT claim was just vacuous; he made assumptions about people taking running averages which aren't true.
Well, Sherlock, we have some pretty good evidence for it. As I keep having to repeat: we know we are releasing CO2, we know that CO2 is staying in the atmosphere, and we know that CO2 absorbs IR radiation. We also know a bunch of other facts about the physics of radiative transfer, thermodynamics, fluuid flow etc etc. We know that when we combine those facts in a computer model that that model shows warming (on average). Finally, we know that it is getting warmer (on average).
Don't confuse not knowing everything with knowing nothing.
if you don't agree with me, you must be bad routine.
Well, I see you using deliberately disingenous arguments to defend a position that would allow you to continue polluting, even in the face of evidence that such pollution causes long-term risks for the survival of others (and yourself). Is that "bad"? Are you actually an environmentalist? Perhaps, but I'd be willing to wager my left nut that you aren't.
We have. It's indisputable that we are releasing CO2 into the atmosphere, and that CO2 levels are rising. It's also beyond dispute that CO2 absorbs IR radiation, and that such absorption will act to warm the surface. That means to me that "we've turned on the burner". People argue about negative feedback that might counteract the warming effect - but that's not the "burner".
Further we don't know what would happen if we "turned the burner off"
We know withing some range of uncertainty; and the odds are that it would be less disruptive than keeping the burner on. We have recent historical data to indiucate what the world does at lower CO2 levels, and it's probably ok.
The other article about Global Dimming also would suggest that there are other changes we aren't accounting for.
I remember studying the effects of aerosols 5 years ago in my radiative transfer class; the effect you mention is a second-order effect that will amplify current warming trends.
It's a complex system that is "described" using things like chaos theory.
"Chaos theory" is one of those words that should never be used in a scientific/political context because it means different things to different people. You seem to think it means "can't be predicted and so isn't real". In a scientific context it has a more definite meaning; and my example does include that - fluid flow during boiling is "chaotic" and unpredictable. The effect of radiative forcing on climate is somewhat less so.
statistical analysis against the old "hockey stick" temperature data suggests that the seed data is flawed and will always create a hockey stick shaped graph no matter what data is fed in to it.
That's an underhanded piece of crap for an argument. Care to provide a reference for that claim? Care to defend it? I take issue with you blithely dismissing many thousands of temperature measurements from dozens of researchers based on some bogus "statistical argument" that you won't even elaborate.
p.s. Why was my original comment modded "flamebait"? It wasn't inflammatory. Overrated I could accept, but "flamebait" is just wrong.
I think it's fairly safe to assume that a Texan isn't going to adopting anything French anytime soon. (Louisiana maybe).
Don't confuse knowing very little with knowing nothing at all. Take a pot of water and put it on the stove. Turn on the burner. You know that the water will get warm and eventually boil. Scientists could make some measurements and tell you pretty much exactly when it will boil, and how quickly it will boil dry. But no computer program in the world can accurately tell you exactly what the pattern of bubbles will be during the boiling. So what? It just means that there are some things we can't model/predict, like boiling or weather, and there are some we can, like climate and thermodynamics.
We do know that our actions are causing changes, and we know that further actions will cause further changes - within a range of uncertainty. This won't change just because you want to continue to pollute.
Maybe the world has been coming to an end, just slower than your average Hollywoood movie would have you think it will. Climate change really has happened, and you can talk to plenty of old people living in places like Alaska and they will usually tell you that it used to be colder. There is ample evidence for glacier retreat and ice thinning (the letter from e.g U.S. Navy polar research).
Now, some reports have been overly dramatized - and some people retro-actively exaggerate the reports so they can say that its was all hype. In truth, there is always a range of opinion on something as important as climate change, and you can pretty much alway find someone who says something youi find useful, if you look hard enough.
All that notwithstanding, the large majority of the worlds' climate scientists have over the last 15-20 years consistently been saying that we are causing climate change. There is so much evidence that only someone who wanted to believe otherwise would be in serious doubt.
You make an obvious logical fallacy: the fact that something hasn't happened doesn't prove that it won't happen.
No, climate change will happen over the next 20-100 years. It might be "slow" compared to an asteroid impact, but it will nonetheless happen and it will have an impact on our environment. How much it interfers with civilization is still somewhat up for debate...
There is another example of this sort of thing that I find infomative; when I was a kid I learned about the dangers of over-population, and how diseases were a common consequence. As a kid I thought that there would be a large pandemic that would sweep through the teeming masses and kill millions of people. Of course, I was right - it's just that that pandemic happened slower than I expected (AIDS infects and will kill >20% of some poulations in Africa. That's pretty Malthusian if you ask me).
Why has it better getting progressively colder over the past 20 years in places like Russia and China?
It hasn't. In fact, there are many cities in northern Russia that have a new problem: apartment buildings collapse because the permafrost their foundations sit on has melted. That sounds like warming to me.
It's not that black-and-white. In most cases, two large goups will each have a distribution of ability in a given area; a "gaussian" or "bell curve". That bell curve has two important numbers: the mean value, and the variance or "width" of the distribution. It is often the case that the means differ by less than the variance; in such a case it becomes hard (statistically insignificant) to use group identity as a proxy for ability - instead you have to just measure that ability directly. (Example: Women are on average weaker than men. But not all women are weaker than all men, so if you are, say, selecting firefighters, you should give everyone the same test - not just select the men.)
However, all this pre-supposes that there is a single (or small number) of measurable traits associated with the ability you care about. It is not at all obvious that there is a single trait associated with being successful in math and science (to talk about Summers' comment specifically). Even if there are a few important traits, it is even less obvious that men would be superior to women in all of them.
So, I will agree that it might be useful to understand if there are traits that make people more or less suited for science careers; i.e. it might be a question worthy of scientific inquiry. But you have to be careful not to ask the question in a manner that pre-supposes the answer; gender may not be the largest factor, but if its the only one you look for... In addition, it has often been the case that the only people who research such questions do so because they have a pre-determined agenda that they want to support; this is probably also the case here.
Unbiased scholarly inquiry was not what Summers was doing - he was trying to come up with an excuse why Harvard should not be criticised for its sexist promotion record. He also blatantly ignored much evidence contrary to his claim (including stuff presented at that very meeting). Finally, he is the president of Harvard and as such has certain responsibilities, which includes trying to encourage diversity at his University.
Again, if Summers had asked the very same question, but about black people rather than women, what would you think? Especially if you knew that a) he had a record of personally intervening to stop promotions of the kinds of people in question, and b) since he started as President, the number of tenured people of that kind had dropped and was now significantly under-representative.
Tell you what - I'll support a tenure-quota for Republicans, the day the first self-proclaimed atheist is elected President of the U.S.
It's the age-old question confronting those who hold tolerance as an important value: how tolerant should you be of those who are intolerant? Should universities promote bigotry and sexism in the name of inclusiveness?
Getting back to the original topic: what if you replaced "women" in Summers question with "black people"? Would you condemn him as being racist?
I disagree. The difference is that you can change your politics; you (usually) can't change your gender or skin color. The former is a matter of creating a "level playing field", the latter is a matter of preferring good judgement.
I'm not arguing that sexism and racism don't still exist in academia - obviously they do. Including in the president of Harvard. However, I am saying that there is a difference between sexism and what you might call "political correctness"; some political views are offensive to others, and can rightly count against you. Note how we don't usually encourage or accept people who advocate slavery these days.
That being said, what your political views are is pretty much irrelevant to your ability to do a mathematical/engineering job, and so shouldn't be an issue in hiring there. But it might be a matter of concern in a college professor of social science. Then again, I happen to think that having a diversity in opinion is actually valuable.
Swear off sex and masturbation for three weeks, then tell me that men don't have "drives" that interfer with clear thinking.
Dumbass.
Yes, because having a political opinion is as much an inborn, immutable trait as is the color of your skin or the number of Y chromosomes you have. Sure.
The reason that nearly no women probably went for the jobs in the first place is because of this guy.
You've obviously never been in a position to apply seriously for an academic position at an elite university. Who the president is and what his views on your gender are does not top things like the prestige and resources of the place. And besides, when applying, you know that they can't be too overtly recist/sexist or there will be trouble. No, those positions have literally hundreds of applicants of both genders; most of whom are fully qualified for the job. 4/32 is pretty obviously problematic.
Now, once we've all been reminded to stop thinking with our hind-brains, let's try and see if we can agree on some preliminary conclusions...
1) There are women who perform outstandingly well in areas of math and science. In my experience I've known women who are as amazing prodigies in things like physics as any men I've met. I'm a scientist in a field of physics, and I've met my fair share of geniuses, Nobel prize winners, child prodigies, idiot savants, and just plain freaks. Of both genders.
2) There are fewer women than men in general in the mathematical/physical sciences.
3) There are definite societal pressures against women doing well in math and science, starting from an early age and continuing all the way into tenure-level academic selection. This includes of course the pressure to raise children, but also includes social pressure in high school and college.
4) There are obvious (and wonderful) physical differences between men and women. It is possible that there are similar psychological gender differences, but in all truth, there is no hard scientific evidence for this, and some evidence against it.
5) In the past, many people have used strikingly similar arguments to defend blatantly racist claims. The obvious examples are things like claimed IQ differences between "white", "black" and "yellow" races; or claims about differences in "sexual restraint", or other equally repugnant things. I think most reasonable people see such claims as the bigotry it is, and there is ample societal evidence to disprove such claims.
Based on my personal experience, and on discussions with friends and colleagues, I think that the explanaition for why there are fewer women in the matheatical sciences has more to do with inherent societal biases and the way that the job market works than any inherent gender differences. It is blindingly obvious to anyone in physics these days that the system was set up in a day and age when a professor was expected to have a wife at home who would take care of everything, including raising children. It is almost impossible for a dual-career couple to balance having a family with having successful careers at an elite institution. Something has to give, and that is often the wifes career (although among my friends it is oddly enough more often the other way around. Statistical anomaly, or recent trend?)
So, I think a) Summers is betraying his own mind-set, which is gender-biased. b) he's missing the larger issue, which is a career ladder that demands total sacrifice of everything including family life.
Maybe I already did, dumbass. Or where do you think science funding comes from?
And what do you know of that? Do you presume to know what countries I've lived in? In any case, it's not just the European mindset that matters. This was a 3 billion dollar mission. Who paid for most of that? Who built the launch vehicle? Who built the spacecraft that flew for 7 years to get to Saturn? Who did the deep space nav? Who supplied the downlink? If you'd only been listening to the press conferences today you might come away with the impression that NASA was just an interested bystander. But then that opens up a whole other can of worms. International collaboration is nice and all - but why do Europeans have to be such dicks when it comes to sharing credit? (Read the "Hubble Wars" for an entertaining story along the same lines).
From a PR point of view, this is a complete non-issue.
This just proves my point - you don't care. Maybe that's why the U.S. outspends Europe 5:1 in space science, and in most other science too, for that matter.
If they had that much time, maybe they could have spent some of it preparing those scripts. Your argument about how difficult and unpredictable science is would carry more weight if it wasn't already pretty standard practice for JPL to have data put on the web within minutes of the downlink.
I'm just saying this: landing on a virtually unknown world is a great opportunity to excite the public about space science. An excited public is more willing to spend the gigabuck(euros?) needed to do science. People won't give sh*t if the image comes out in Science six months from now. ESA is wasting a hug opportunity because they're too stupid to learn from NASA.
You may be a scientist on paper, but you are not a scientist at heart.
Gee, thanks. So being a scientist at heart means keeping your data carefully hidden from everyone else because you're afraid that someone will publish first, or somehting? Or is it just a matter of acquiring the proper amount of arrogance, and looking down on the unwashed masses too stupid to deserve to look at your pretty pictures, but not too stupid to have to support your science?