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Carbon Emissions 'Will Defer Ice Age'
Sven-Erik writes "Due to subtle variations in the Earth's orbit, researchers have calculated that the next Ice Age is due within 1,500 years. However, a new study suggests greenhouse gas emissions mean it will not happen that soon (abstract). 'Dr Skinner's group ... calculates that the atmospheric concentration of CO2 would have to fall below about 240 parts per million (ppm) before the glaciation could begin. The current level is around 390ppm. Other research groups have shown that even if emissions were shut off instantly, concentrations would remain elevated for at least 1,000 years, with enough heat stored in the oceans potentially to cause significant melting of polar ice and sea level rise.'"
Larry Niven, Jerry Pournelle and Michael Flynn.
Fallen Angels
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
Its good, as it turns to be? Or do we want an ice age?
Neither melting ice caps nor a new ice age sound particularly appealing.
This is good news, since many of us live in areas which would be covered with glaciers.
Wonder how many hypocrites who previously excoriate all climatologists who caution about global warming as corrupt and biased instantly trumpeting that these brilliant, honest, decent climatologists have to be right because the end result is one that they want.
And people said global warming deniers didn't care about future generations. They were trying to help them all along!
The only thing necessary for evil to triumph is for it to be pitted against a slightly greater evil
It's hard to get funding for an experiment that takes two identical planets and changes the global CO2 concentration on one.
Climatology is an observational science like geology or astronomy. Models can be checked. It's not just curve fitting to the temperature record: climatologists figure they're on the right track when their models predict phenomena like El Nino.
The experiment is currently running. Check back in 2k years or so for the results.
Violence is like duct tape. If it doesn't solve the problem, you didn't use enough.
Except... that isn't quite how it works.
Global warming means that we're changing a massively complex system. And like all massively complex system, when you tweak the parameters beyond a certain point, the system as a whole can itself wind up altering other parameters drastically as it seeks a new stable state.
Or, to put it simply, global warming could potentially lead to a sudden and drastic cooling:
http://science.nasa.gov/science-news/science-at-nasa/2004/05mar_arctic/
Check your premises.
Good book, IMHO.
For those interested, "Fallen Angels" is available at Jim Baen's Free Library to read online, or download. (linked below)
"Fallen Angels"
*Discaimer*
I'm just an enthusiastic fanboy, not affiliated with Baen Books in any way other than being a happy customer.*
Down With Slashdot BETA!!! I've been around the corner and seen the oliphant; you can only abuse me from your perspecti
That's a tad different. During the last ice age we didn't have the ability to ship food thousands of miles and make user of the land that was now useful for agriculture. Also, we didn't have insulation and heating technology like we do today.
An ice age isn't the greatest thing ever, but life has a much better chance of coping with it effectively than the rather extreme changes in climate that we're setting off.
Anything we do, "could potentially" do something, or nothing, or upset part of Mother Nature that proves unexpectedly fragile. Unless Mankind goes away, we will continue to influence the environment forever. I suggest doing Nothing as the only possible prudent course of action.
Let's roll the dice so we don't have to be inconvenienced by sorting our garbage and driving cars with smaller engines.
My UID is prime. Hah!
I buy that CO2 could prevent or delay the onset of an ice age. What I don't by is the suggestion that an ice age is due to start 1500 years from now. Looking more carefully, I see that the value of CO2 level required to prevent an ice age 1500 years from now is below the pre-industrial level. In other words they've predicted an ice age that would, under no conceivable circumstance, occur and then said, look, it won't occur because of CO2. Yes, but then again our lakes aren't frozen in the summer now because of CO2. Maybe we should send out a press release.
Support SETI@home
Remember the Greening Earth Society?
http://www.sourcewatch.org/index.php?title=Greening_Earth_Society
In the late 1990s I remember they were out there with an interesting take that not only was the greenhouse effect real, but that we should promote it because it would "make Greenland green again" and otherwise unlock many areas of tundra and for conventional agriculture and human expansion.
One thing's for certain: whether coastal cities are under 20 feet of water or up to their asses in ice 2000 years from now, there will still be politicians pointing at each other over whose fault it is.
- For every action, there is an equal and opposite criticism.
"House fires keep you warm in the wintertime!"
For your security, this post has been encrypted with ROT-13, twice.
The Earth certainly has. But humans have a pretty narrow temperature band in which they can live. Humans sweat based temperature regulation would not have functioned over most of the Earth when the dinosaurs ruled.
But really, this isn't about the Earth's survival. It's about Humans. You're right - we haven't been around that long. And it seems that our refusal to acknowledge that we're soiling our niche will ensure that we aren't around for all that long, either.
Check your premises.
The earth is just a computer. You need two. See Slartibartfast.
When the foot seeks the place of the head, the line is crossed. Know your place. Keep your place. Be a shoe.
Wouldn't glaciation pretty much end life as we know it on the planet? You can't grow anything on an ice sheet.
Given the choice of planet wide starvation and freezing VS moving to high ground and breeding heat tolerant crops,
Given the choice between the extinction of some less mobile less heat tolerant species VS the extinction of all species,
I pretty much know what I'd be in favor of and it dosen't involve freezing to death
Indeed. As is hominid evolution. Just because we are basing theories off of observed and currently happening phenomena does not mean that the science need be any weaker than working with phenomena for which active processes have largely ceased. Besides, geology is a ludicrously bad example. Just how many times do you get to observe Archean rocks form? That climatology is researching active processes is a benefit, not a negative. Helluva lot more difficult to test specifics of ancient geology or Big Bang cosmology when said events happened billions of years ago, and not, say, right fucking now.
There's this bizarre belief being stated by some of the skeptics on this particular article that somehow knowing the end of a process, but not the beginning, is in some way superior to knowing the beginning, but not the end.
The world's burning. Moped Jesus spotted on I50. Details at 11.
People tend not to be so worried about what happens in 1500 years or so.
But, they'll get into bitter dustups over what will happen in 50.
No, the other 49.95 percent is the nuclear winter the fight for habitable territory would cause.
"Think about how stupid the average person is. Now, realise that half of them are dumber than that." - George Carlin
Astronomy and geology are certainly not "observational sciences" in the sense you use that phrase. Experiments are not only possible in astronomy and geology, they are performed routinely. I don't know much about geology, but there are a lot of notable experiments in astronomy, from ancient times to yesterday. For example, the determination of the circumference of Earth by Eratosthenes, the discovery of the planets beyond Uranus, the observation of neutron stars, the background cosmic radiation, the discovery of extrasolar planets, and many, many others.
Actually, there is no such a thing as "observational" science -- ability to define your theory so that it can be tested against an experiment is what distinguishes a science.
Actually, the process with climatology was subtly different, something like
1. Someone got a PhD in science
2. They began collecting data and observe what's happening
3. They published some papers and gathered about 10 more people, who had gone thru 1 and 2
4. They published more papers
5. They collected more data, and convinced their government that even more data is necessary
6. They got more equipment, more data, came up with some ways to put these data together
7. Then they refined their hypothesis, got more funding and more students
8. Then they got publicity by semi-literate journalists, and it all went political. Unfortunately, unlike the people who play politics, the people who did the research were not prepared for the tricks on the political side.
9. Even unfortunatelier, nobody else was prepared to understand or argue sensibly the "tricks" on the research side
10. Ever since, it has been one giant downhill race in lies, accusations and misunderstandings, to the detriment of science
11. When it should have been a harmonious transition to getting more understanding of the topic, and gradually and smoothly planning and executing whatever action would be necessary.
And so it goes.
No, I'm here. What did you want to know? Getting off the Earth? That's easy:
* Orbital velocity is root (R(e) * g), where R(e) is the radius of the Earth (6378000 meters), and g is the surface gravity (9.80665 m/s^2). That works out to 7908 m/s
* Kinetic Energy is 0.5 * m * v^2. Thus kinetic energy to reach orbit is 31.27 MJ/kg.
* One kiloWatt-hour (kWh) is the common unit of electric energy. 1000 W * 3600 seconds = 3.6 MJ.
* Therefore it takes 31.27 / 3.6 = 8.7 kWh/kg to get something into orbit.
* Multiply by your local electric rate. Where I an now, that works out to $1/kg, about what potatoes cost at the local market.
So getting off the Earth is cheap, if you use energy efficiently. You haven't been, though. You have been using about the least efficient method available: chemical rockets. The best rocket fuels only have a bit under half the energy needed to get to orbit (15 MJ/kg), and the engines are around 2/3 efficient, which leaves you at around 10 MJ/kg. So the fuel can't even get itself to orbit, much less anything else, like cargo. You end up using a lot of fuel to lift a smaller amount of fuel part way, then use that to push an even smaller amount a bit further, and finally that last bit pushes a very small cargo to orbit. For those who understand math, that is an exponential ratio of fuel to cargo, where the exponent is the ratio of mission velocity / rocket exhaust velocity. For chemical rockets, that works out to 2-3, depending on which fuel. So you use e (2.718...) raised to 2-3 power as much fuel as cargo that gets to orbit.
The answer is quite obvious: use something else. Something that has better efficiency, so you are not slaughtered by the exponential. There are a number of choices. Which one you use depends on a number of "mission requirements": What are you launching, how often, how much up front development money you can spend, how much risk do you want to take, etc.
OK, that takes care of getting out of *this* gravity well. What next?
(1) Don't go right down another one. The Moon and Mars can wait till you build up some infrastructure. Use near Earth asteroids first, followed by other asteroids, including the ones orbiting Mars, as a source of building materials. You can use efficient electric thrusters as long as you are not diving down a gravity well.
(2) Don't send humans first. Humans have all kinds of picky needs about temperature, pressure, food, radiation, etc. Robots, remote controlled, and automated equipment (which I will call just "robots" for brevity) are not as sensitive. Send robots first, have them build stuff up. Once you have enough stuff in place and can support the humans, then they can come.
I think the gold standard should be it's utility. Try googling, you will find dozens of forward predictions similar to these...
1. The phenomena known as "Polar amplification" was predicted before it was observed.
2. The phenomena known as "Stratospheric cooling" was predicted before it was observed.
5. Accurately predicted the climatic impact of the Mt Pinatobo eruption.
These sort of tests don't even start to list the basic predictive skill a climate model needs to be considered useful, such as the ocean currents, air pressure patterns, the roaring forties, monsoons, ENSO, the formation of tropical cyclones in the right geographical locations in the right season, the morning clouds in the Amazon burnt of by the sun, sea ice extent, all these things and much more must be accurately hind-cast before you can even start to ask "what if" questions.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
The real history:
It started in 1824 when Fourier predicted the IR absorption properties of CO2 while inventing spectroscopy. Tyndall confirmed the prediction in the 1850's and finally in 1896 Arrhenius started looking into the effects of industrial CO2 emissions on the climate (not sure if any of them had a phd). The idea was dismissed for about 50yrs due to the argument that water's broad IR absorption spectrum obscured and therefore cancelled CO2's narrower IR absorption spectrum. It wasn't until spectrometers with better resolution (invented to research missiles) came about in the 50's that it overcame that last serious objection, (turned out that the frequency peaks are interleaved not overlapped). In 1958 the NAS warned the US government that our emission's were changing our climate and the political bun fight started in earnest.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.