So, sometime in the 1970s, MIT and Mass General were working on an experimental treatment called Boron Neutron Capture Therapy (BNCT for short). The idea was that you could fire thermal neutrons at a person, and they would only interact with elements that had a high neutron capture cross section, such as Boron or Gadolinium.
So, if you can add boron to a compound that is taken up preferentially by cancer cells, and then aim a thin beam of neutrons at the area of the tumor, then you will (theoretically) not kill anything but those cells.
The treatment was used mainly on large, likely-to-be-fatal brain tumors (at the time, they weren't candidates for operations). Unfortunately, most of the patients died anyway, sometimes from necrotic tissue or brain voids resulting from the decayed/destroyed tumor, sometimes because the boron containing compounds were not specific enough to cancer cells.
So the US stopped research on BNCT, but Japan and some other countries have continued the research, and I think recently some US researchers are thinking of taking it back up.
And the neutron source the MIT researchers used was their nuclear reactor (recently featured on NPR's "Wait, wait don't tell me"). One could presumably also use an accelerator.
So, milder winters will be good for heating bills and deaths from excess cold in places like the northern US, Siberia, etc.
On the other hand, hotter summers will be bad anywhere that isn't prepared for it: cf France, India this year.
Melting glaciers have killed thousands in Peru. Change in precipitation patterns will cause problems for farmers (while making some land that wasn't arable before arable). Changes in sea level will cause the loss of homes for millions.
As far as wildlife is concerned: they were adapted to whatever the "baseline" climate in their region was. They can adapt/migrate to new climates, given time, but projections show that the difference between the temperature at the end of this century and today will be more than half the temperature difference between the last Ice Age and today (and I'm talking the real Ice Age, not the little one in the 1800s). That's a lot of temperature change, very fast.
To sum up: the costs and benefits of a 4 degree warming might, in the equilibrium case, come close to balancing out. But the process of warming is going to cause a heck of a lot of pain for a lot of people, until they adapt/migrate, and that is going to cost a heck of a lot to the economy. So it makes sense to put in some greenhouse gas emissions constraints that will cause some harm to the economy, hopefully at the right level such that the marginal benefit of emitting an additional ton of greenhouse gas will be equal to the damage prevented from the warming that ton would cause... (ie, halting all production: bad. Burning fossil fuels like mad: also bad. We want something in between!)
"Although we can't be certain why methane concentrations have levelled out, we think it is in response to emissions declining due to better management of the exploration and use of fossil fuels and the increasing recovery of landfill methane.
"If this global decline in methane emissions continues, global atmospheric methane concentrations will start to fall."
The stabilizing of methane concentrations is great news! However, I think that it is overly optimistic to assume they will stay stable.
First, the authors of the article admit they don't understand why concentrations have leveled off. We are not very good at determining methane emission inventories, because they aren't nearly as easy to track as carbon based fuels. Cows emit different amounts of methane if they are grass or corn fed, rice paddies are hard to monitor, there are many poorly understood natural sources like wetlands and warming tundra, etc. And the methane sink is hard to calculate, since it is a chemical reaction depending on temperature and hydroxyl radical concentrations, and we cannot directly measure OH radicals so those are very uncertain. So our estimates of emissions are uncertain by a factor of 2 or more.
So when we see a pause in concentration increase, it is possible that it is due to long term structural changes in our economies (optimistic view).
But I actually think it is due to the collapse of the Russian economy, since leaking Russian pipelines were a major source of methane, and with their disuse of course methane emissions dropped. But this is a one-time drop, I would expect other sources to continue to increase in the absence of major policy actions... (Pessimistic view)
Or it could be some other complicated interaction. So I say, good news but hold on before assuming that the good news will continue...
Most energy economists I know would scoff at this.
First, oil is only a portion of fossil fuels. And we can produce oil from coal or shale oil, and reserves of both of those are enormous.
So, no, we aren't going to run out of oil soon. It may become significantly more expensive in 50 years, when easily accessible cheap oil runs out, but then again, I wouldn't bet against the improvements of extraction and conversion technologies to keep prices low...
Yes, the most important greenhouse gas is water vapor.
The most important _anthropogenic_ greenhouse gases are (in order) CO2, CH4, N2O, then in lesser amounts HFCs, SF6, PFCs, etc. (And tropospheric O3, but we only indirectly produce that...)
Of course, the point is that increases of temperature due to the increased radiative forcing due to the increase in CO2 and CH4 will lead to more evaporation and therefore more water vapor in the air. Mmm, positive feedback loops.
Of course, it is more complicated than that, because more water vapor means more clouds. And more clouds sometimes means more cooling during the day, but more warming during the night. Depending on the altitude of the clouds. People disagree on the magnitude of this feedback (and sometimes even whether it is positive or negative).
And of course, particulate emissions can impact cloud formation. As well as having a direct climate impact through reflection/absorption (depending on whether they are sulfate based or black carbon based).
Actually, the assumption is that Sapient attempts to maximize its profit by looking for the cheapest programmers who can do the necessary job:
However, Sapient _should_ have competitors, who will undercut Sapient if their profit margin gets too large. So in the long run, customers of Sapient + other companies in the industry will effectively receive a discount.
Of course, the "free market" has its limitations: there isn't perfect information, there isn't perfect mobility of labor, there isn't "free entry", oligopolies are common, etc. etc.
So I think that in the big picture outsourcing to India is just fine if they can do a good job for less money, and in the long term this means that a) India's standard of living will go up (which is good), b) they will have to pay their programmers more (good), c) therefore, we will be more competitive again, d) they will buy more products increasing the global economy (mostly good, except for the environment)... however, in the small picture PHBs often create much more pain and suffering than is needed, and run off with much more money than they really deserve, because of market imperfections...
I believe that the "26" comes from the fact that there are certain physical constants which have (as far as we know so far) arbitrary values, and (as far as we can calculate) the existence of a universe favorable to life is very sensitive to the value of these constants (like c, the rate of decay of various forces, the mass of elementary particles, etc. etc.)
Now, there are a series of scientific respones, including the following:
1) They aren't arbitrary, we just haven't figured out the science yet.
2) The existence of life is not actually sensitive to these variables, we just can't calculate/imagine what the universe would have been like with a different constant for Heisenberg's uncertainty principle.
3) Anthropomorphic principle: There are many, many universes with different values of these constants. In order to observe the universe, we had to exist, therefore the constants must be favorable to life.
4) My favorite wacky idea: The universe "evolved" these constants. Mechanism: every black hole singularity is a new universe. These new universes have sets of constants similar to but slightly different than their parent universe. Now we have reproduction and mutation. In the long term: universes will evolve to optimize black hole production. Testable hypothesis: The observable constants will be optimized for black hole production. Coincidentally, also being relatively optimal for life.
5) Intelligent Design.
So, of the 5 possibilities above, the non-interesting ones (ie, non-provable, that give us no real insights), are 3 and 5. If those are true, then we just throw up our hands and stop thinking.
Humans account for about 7 Gigatons of Carbon emitted into the atmosphere every year - that is about 6 GtC from fossil fuels, and 1 GtC from "land use changes" (ie, deforestation etc.).
The entire planetary ecosystem absorbs about 3.5 GtC more than it emits every year. This is because the atmosphere now contains 360+ ppm CO2, where it used to have 280 ppm in preindustrial times, and therefore ecosystems and oceans are no longer in equilibrium with the atmosphere.
Atmospheric CO2 levels are increasing at a rate equal to about 3.5 GtC a year - ie, one half of the amount that we emit.
(That breaks down into the ocean having a net absorption of about 2 gigatons of carbon a year. The terrestrial ecosystem has a further absorption of about 1 gigaton)
You might hear other numbers, like "the forests take up 50+ gigatons of carbon every year!". That is "gross primary production", which is almost exactly balanced by 50+ gigatons of "decomposition + forest fires". These are the two numbers which are usually in balance... the difference is "net primary production" which is only 1 gigaton per year.
And volcanoes don't produce much CO2 at all.
Trust me - no one with any real scientific background believes that the increases in CO2 are due to anything except fossil fuel burning. There is disagreement about how much the temperature has risen, how much that temperature is due to human influence, what future temperature rise will be, what the damages that rise will cause... BUT THERE IS NO DISAGREEMENT ABOUT THE REASON FOR CO2 INCREASES IN THE ATMOSPHERE!!!
-Marcus
Similar numbers to the ones in my memory can be found here: http://earthobservatory.nasa.gov/Library/Gl obalFir e/fire_3.html
It isn't our output of waste energy. It is the increase in greenhouse gas concentration that means that the energy we receive from the sun is trapped more efficiently in the atmosphere.
And we do output CO2 on a globally significant scale.
And the forcing of that CO2 every year is larger than the sun's observed energy variations in the last century.
Its amazing how many people cite volcanoes when dismissing human influence on the climate.
Yes, a single volcano (Pinatubo for example) can cause global scale cooling by throwing particulates into the atmosphere. Then the particulates settle out, and in a year or two temperatures return to normal.
This is compared with CO2, which lasts 100+ years in the atmosphere, and during each and every one of those years is adding a little bit of extra heat to the planet. We have changed the concentration of CO2 in the atmosphere by 30%!!!
The forcing caused by that extra 80+ ppm of carbon dioxide is much larger than the observed variability of solar forcing. It is _not_ insignificant. Think about it. Please.
It is certainly a metric to take into consideration. But I will point out that most of what we produce so generously, we also consume. If I generate 1000 tons of CO2, produce a widget worth $1000, and then use that widget myself for my own pleasure, is that really better than Bob producing 10 tons of CO2 and producing no widgets whatsoever?
GNP is _not_ a perfect measure of "good for society". (A standard example being that GNP includes both the sale of cigarettes and the hospital treatment for the cancer those cigarettes cause)
Having said that, I don't actually think that the idea of using "intensity targets" (improving the CO2 to GNP ratio, not necessarily reducing CO2 emissions) (ala the Bush administration proposal) is necessarily a bad idea. Of course, the target he chose was practically business as usual, which I do object to...
So, most rational people make decisions based on "expected value". You weigh the cost of your preventative measure against the probability of your bad outcome times the value of your bad outcome. Anybody who pays for insurance does this all the time - there is a small chance of me getting into a car accident. I am willing to spend some money every year so that in the (unlikely) case where I am sued for (potentially large) damages, my insurance company will cover me. Now, I don't have infinite money, so I am not going to buy 100 million dollars worth of coverage. But it might be worth it to buy 100 thousand dollars worth of coverage.
So, we don't know how much damage climate change will cause yet. But it seems like there should be some amount (perhaps small, perhaps large) that we should be spending today to reduce emissions because there is a chance (perhaps small, perhaps large) that climate change will cause damages (perhaps small, perhaps large).
And that amount spent should be designed to be equal to the reduction in the sum of (Probability(damage)*Amount(damage)) across all possible futures.
(Of course, a policy has uncertain cost too... but how to incorporate that I leave as an exercise to the reader)
(The controversy about the Mann study might imply that we should adjust our probabilities or projected damages down - however, keep in mind that it is only one study out of 100s, and this is only one critique...)
And do you seriously think that climate change researchers have been basing all of their assumptions just on a correlation between temperature change and CO2 rise?
Start back at Tyndall in the 19th century who recognized the IR absorbing properties of CO2, and Svante Arrhenius at the turn of the century who asked whether CO2 emissions might lead to a warming earth, and you will see that the theory of global warming started long before there was any correlation to observe.
An increase of CO2 in the atmosphere will, in the absence of other factors, lead to warming. That is incontrovertible. The questions then become: how much warming? What other factors might change the climate (natural variability, aerosol cooling, etc)? What are the feedbacks involved? Can we come closer to answers to the above questions by looking at the historical record (This is where the accuracy of the Mann study becomes important)? How good are our models?
And then we might go on to ask, how much should we invest in reducing greenhouse gas emissions today, given our uncertainty in how much damage they will cause tomorrow? The answer may not be "Kyoto Protocol", but it seems rather unlikely that the answer is "do nothing"...
And, as long as we are correcting false impressions about sea level rise:
The vast majority of current observed sea level rise, and projected sea level rise over the next century, is actually based on thermal expansion of the oceans. Eg, as the oceans warm, they expand.
Some amount of current and near term projected rise is due to melting glaciers outside of Greenland and Antarctica.
The total projected rise from the above causes by 2100 is between 20 cm and 1 m.
In the longer term (multiple centuries), we may have to worry about melting of the Greenland and Antarctic ice sheets, which would cause serious sea level rise (the Ross Ice Shelf collapsing might lead to several meters of rise by itself). However, in the short term increased precipitation over the centers of those land masses is actually projected to balance out increased melting at the edges...
Hmm. Well, those of us who have taken high level economics courses realize that capitalism and the free-market do require some level of regulation to make them efficient. Whether that regulation is to ensure that property rights are respected, to create patent law so that inventors are rewarded, or to tax activities that have "negative externatalities", regulation actually goes hand in hand with the free market.
So, yes, burning oil does have externalities, whether it is local pollution in cities or global warming. And no, burning hydrogen will not materially alter the water vapor levels in the atmosphere. (Of course, there was an article in Science magazine this week about the potential impacts of H2 leakage on a large scale... but they seem to be much smaller than the impacts of CO2, mostly to do with small decreases in hydroxyl radical level which will lead to small increases in methane and other pollutant levels...)
One might also argue for a case for government intervention where there is path dependence due to technology choices... but this requires much more confidence in the ability of government to predict the future, so I tend not to emphasize this argument.
But yes, most fuel cells run off of fossil fuels. Methane -> reformer -> H2 -> fuel cell is common. FutureGen is the Bush administration $1 billion dollar coal -> H2 with CO2 sequestration experiment (so theoretically it won't contribute to global warming, though it also won't wean us from fossil fuels).
However, switching to hydrogen for our transport sector at least gives us the _option_ of generating the hydrogen by a non-fossil fuel route (ie, nuclear, solar, wind power can be used for the electrolysis of water). Biofueled or electric cars are other options, though they have their own drawbacks (biofuel can be dirty, and we don't really want to use all our agricultural land to power our cars, electric vehicles are limited by battery technology and still require the non-fossil-fuel power source problem to be solved)
I still like using NMR and hydrogen spin states in common organic molecules to do quantum computing. The number of Q-bits is equal to the number of different hydrogens on a single molecule, and you can target each hydrogen with a separate magnetic pulse to manipulate that bit.
Making a "macroscopic" object enter a quantum state is really cool, but I don't foresee it being a step directly towards quantum computing. (Though there may be spin-off learning).
Of course, one would imagine that the wavefunction of an object that large would collapse very quickly as it will be hard to prevent interaction with the environment.
Actually, what you want to do is take the best data you can find for "exogenous" variables over the last 100 years (solar cycle, volcanoes, anthropogenic emissions), and plug them into the model and compare the overall trends to reality (rather than trying to predict a "specific" hurricane, which is not what the model is designed for):
One would expect that you can match global average temperature and sea level rise pretty well since current (100 km resolution) models already do so (see IPCC report). The question is whether you can match extreme weather events. Unfortunately, I don't know if we have good enough data about hurricanes going back long enough to really see trends...
And this is a controversial area, because many climate change scientists believe that an increase in radiative forcing due to greenhouse gas emissions will lead to increased latent heat (ie, more water in gaseous state) in equatorial regions, which should increase the frequency of events like hurricanes... Which would be yet another reason to reduce GHG emissions. But others disagree.
And when it comes down to it, you are trying to validate your model either because you believe you have done a good job on the fundamental physical processes, or by matching external data, and I think we may not be confident in either of those areas yet. But it is still a useful exercise to see what our best predictions show, even if there is significant uncertainty in those predictions.
Slashdot Mirror
The operating systems for the Earth Simulator (#1 supercomputer) is described on the following page:
e ra ting.html
http://www.es.jamstec.go.jp/esc/eng/Software/op
Because it is a vector based parallel processing machine it wouldn't be able to run standard OS's...
So, sometime in the 1970s, MIT and Mass General were working on an experimental treatment called Boron Neutron Capture Therapy (BNCT for short). The idea was that you could fire thermal neutrons at a person, and they would only interact with elements that had a high neutron capture cross section, such as Boron or Gadolinium.
Neutron meets Boron, excitement ensues, cells die.
So, if you can add boron to a compound that is taken up preferentially by cancer cells, and then aim a thin beam of neutrons at the area of the tumor, then you will (theoretically) not kill anything but those cells.
The treatment was used mainly on large, likely-to-be-fatal brain tumors (at the time, they weren't candidates for operations). Unfortunately, most of the patients died anyway, sometimes from necrotic tissue or brain voids resulting from the decayed/destroyed tumor, sometimes because the boron containing compounds were not specific enough to cancer cells.
So the US stopped research on BNCT, but Japan and some other countries have continued the research, and I think recently some US researchers are thinking of taking it back up.
And the neutron source the MIT researchers used was their nuclear reactor (recently featured on NPR's "Wait, wait don't tell me"). One could presumably also use an accelerator.
-Marcus
So, milder winters will be good for heating bills and deaths from excess cold in places like the northern US, Siberia, etc.
On the other hand, hotter summers will be bad anywhere that isn't prepared for it: cf France, India this year.
Melting glaciers have killed thousands in Peru. Change in precipitation patterns will cause problems for farmers (while making some land that wasn't arable before arable). Changes in sea level will cause the loss of homes for millions.
As far as wildlife is concerned: they were adapted to whatever the "baseline" climate in their region was. They can adapt/migrate to new climates, given time, but projections show that the difference between the temperature at the end of this century and today will be more than half the temperature difference between the last Ice Age and today (and I'm talking the real Ice Age, not the little one in the 1800s). That's a lot of temperature change, very fast.
To sum up: the costs and benefits of a 4 degree warming might, in the equilibrium case, come close to balancing out. But the process of warming is going to cause a heck of a lot of pain for a lot of people, until they adapt/migrate, and that is going to cost a heck of a lot to the economy. So it makes sense to put in some greenhouse gas emissions constraints that will cause some harm to the economy, hopefully at the right level such that the marginal benefit of emitting an additional ton of greenhouse gas will be equal to the damage prevented from the warming that ton would cause... (ie, halting all production: bad. Burning fossil fuels like mad: also bad. We want something in between!)
"Although we can't be certain why methane concentrations have levelled out, we think it is in response to emissions declining due to better management of the exploration and use of fossil fuels and the increasing recovery of landfill methane.
"If this global decline in methane emissions continues, global atmospheric methane concentrations will start to fall."
The stabilizing of methane concentrations is great news! However, I think that it is overly optimistic to assume they will stay stable.
First, the authors of the article admit they don't understand why concentrations have leveled off. We are not very good at determining methane emission inventories, because they aren't nearly as easy to track as carbon based fuels. Cows emit different amounts of methane if they are grass or corn fed, rice paddies are hard to monitor, there are many poorly understood natural sources like wetlands and warming tundra, etc. And the methane sink is hard to calculate, since it is a chemical reaction depending on temperature and hydroxyl radical concentrations, and we cannot directly measure OH radicals so those are very uncertain. So our estimates of emissions are uncertain by a factor of 2 or more.
So when we see a pause in concentration increase, it is possible that it is due to long term structural changes in our economies (optimistic view).
But I actually think it is due to the collapse of the Russian economy, since leaking Russian pipelines were a major source of methane, and with their disuse of course methane emissions dropped. But this is a one-time drop, I would expect other sources to continue to increase in the absence of major policy actions... (Pessimistic view)
Or it could be some other complicated interaction. So I say, good news but hold on before assuming that the good news will continue...
Most energy economists I know would scoff at this.
First, oil is only a portion of fossil fuels. And we can produce oil from coal or shale oil, and reserves of both of those are enormous.
So, no, we aren't going to run out of oil soon. It may become significantly more expensive in 50 years, when easily accessible cheap oil runs out, but then again, I wouldn't bet against the improvements of extraction and conversion technologies to keep prices low...
-Marcus
Yes, the most important greenhouse gas is water vapor.
The most important _anthropogenic_ greenhouse gases are (in order) CO2, CH4, N2O, then in lesser amounts HFCs, SF6, PFCs, etc. (And tropospheric O3, but we only indirectly produce that...)
Of course, the point is that increases of temperature due to the increased radiative forcing due to the increase in CO2 and CH4 will lead to more evaporation and therefore more water vapor in the air. Mmm, positive feedback loops.
Of course, it is more complicated than that, because more water vapor means more clouds. And more clouds sometimes means more cooling during the day, but more warming during the night. Depending on the altitude of the clouds. People disagree on the magnitude of this feedback (and sometimes even whether it is positive or negative).
And of course, particulate emissions can impact cloud formation. As well as having a direct climate impact through reflection/absorption (depending on whether they are sulfate based or black carbon based).
Complicated enough yet?
http://www.sluggy.com/daily.php?date=030810 Clearly, they just need to make the show a musical (see above) and it will be a smashing success! -Marcus
Actually, the assumption is that Sapient attempts to maximize its profit by looking for the cheapest programmers who can do the necessary job:
However, Sapient _should_ have competitors, who will undercut Sapient if their profit margin gets too large. So in the long run, customers of Sapient + other companies in the industry will effectively receive a discount.
Of course, the "free market" has its limitations: there isn't perfect information, there isn't perfect mobility of labor, there isn't "free entry", oligopolies are common, etc. etc.
So I think that in the big picture outsourcing to India is just fine if they can do a good job for less money, and in the long term this means that a) India's standard of living will go up (which is good), b) they will have to pay their programmers more (good), c) therefore, we will be more competitive again, d) they will buy more products increasing the global economy (mostly good, except for the environment)... however, in the small picture PHBs often create much more pain and suffering than is needed, and run off with much more money than they really deserve, because of market imperfections...
-Marcus
I believe that the "26" comes from the fact that there are certain physical constants which have (as far as we know so far) arbitrary values, and (as far as we can calculate) the existence of a universe favorable to life is very sensitive to the value of these constants (like c, the rate of decay of various forces, the mass of elementary particles, etc. etc.)
Now, there are a series of scientific respones, including the following:
1) They aren't arbitrary, we just haven't figured out the science yet.
2) The existence of life is not actually sensitive to these variables, we just can't calculate/imagine what the universe would have been like with a different constant for Heisenberg's uncertainty principle.
3) Anthropomorphic principle: There are many, many universes with different values of these constants. In order to observe the universe, we had to exist, therefore the constants must be favorable to life.
4) My favorite wacky idea: The universe "evolved" these constants. Mechanism: every black hole singularity is a new universe. These new universes have sets of constants similar to but slightly different than their parent universe. Now we have reproduction and mutation. In the long term: universes will evolve to optimize black hole production. Testable hypothesis: The observable constants will be optimized for black hole production. Coincidentally, also being relatively optimal for life.
5) Intelligent Design.
So, of the 5 possibilities above, the non-interesting ones (ie, non-provable, that give us no real insights), are 3 and 5. If those are true, then we just throw up our hands and stop thinking.
-Marcus
Ok. Let's try this again:
l obalFir e/fire_3.html
Humans account for about 7 Gigatons of Carbon emitted into the atmosphere every year - that is about 6 GtC from fossil fuels, and 1 GtC from "land use changes" (ie, deforestation etc.).
The entire planetary ecosystem absorbs about 3.5 GtC more than it emits every year. This is because the atmosphere now contains 360+ ppm CO2, where it used to have 280 ppm in preindustrial times, and therefore ecosystems and oceans are no longer in equilibrium with the atmosphere.
Atmospheric CO2 levels are increasing at a rate equal to about 3.5 GtC a year - ie, one half of the amount that we emit.
(That breaks down into the ocean having a net absorption of about 2 gigatons of carbon a year. The terrestrial ecosystem has a further absorption of about 1 gigaton)
You might hear other numbers, like "the forests take up 50+ gigatons of carbon every year!". That is "gross primary production", which is almost exactly balanced by 50+ gigatons of "decomposition + forest fires". These are the two numbers which are usually in balance... the difference is "net primary production" which is only 1 gigaton per year.
And volcanoes don't produce much CO2 at all.
Trust me - no one with any real scientific background believes that the increases in CO2 are due to anything except fossil fuel burning. There is disagreement about how much the temperature has risen, how much that temperature is due to human influence, what future temperature rise will be, what the damages that rise will cause... BUT THERE IS NO DISAGREEMENT ABOUT THE REASON FOR CO2 INCREASES IN THE ATMOSPHERE!!!
-Marcus
Similar numbers to the ones in my memory can be found here:
http://earthobservatory.nasa.gov/Library/G
It isn't our output of waste energy. It is the increase in greenhouse gas concentration that means that the energy we receive from the sun is trapped more efficiently in the atmosphere.
And we do output CO2 on a globally significant scale.
And the forcing of that CO2 every year is larger than the sun's observed energy variations in the last century.
Its amazing how many people cite volcanoes when dismissing human influence on the climate.
Yes, a single volcano (Pinatubo for example) can cause global scale cooling by throwing particulates into the atmosphere. Then the particulates settle out, and in a year or two temperatures return to normal.
This is compared with CO2, which lasts 100+ years in the atmosphere, and during each and every one of those years is adding a little bit of extra heat to the planet. We have changed the concentration of CO2 in the atmosphere by 30%!!!
The forcing caused by that extra 80+ ppm of carbon dioxide is much larger than the observed variability of solar forcing. It is _not_ insignificant. Think about it. Please.
-Marcus
The "only" fair metric to use?
It is certainly a metric to take into consideration. But I will point out that most of what we produce so generously, we also consume. If I generate 1000 tons of CO2, produce a widget worth $1000, and then use that widget myself for my own pleasure, is that really better than Bob producing 10 tons of CO2 and producing no widgets whatsoever?
GNP is _not_ a perfect measure of "good for society". (A standard example being that GNP includes both the sale of cigarettes and the hospital treatment for the cancer those cigarettes cause)
Having said that, I don't actually think that the idea of using "intensity targets" (improving the CO2 to GNP ratio, not necessarily reducing CO2 emissions) (ala the Bush administration proposal) is necessarily a bad idea. Of course, the target he chose was practically business as usual, which I do object to...
So, most rational people make decisions based on "expected value". You weigh the cost of your preventative measure against the probability of your bad outcome times the value of your bad outcome. Anybody who pays for insurance does this all the time - there is a small chance of me getting into a car accident. I am willing to spend some money every year so that in the (unlikely) case where I am sued for (potentially large) damages, my insurance company will cover me. Now, I don't have infinite money, so I am not going to buy 100 million dollars worth of coverage. But it might be worth it to buy 100 thousand dollars worth of coverage.
So, we don't know how much damage climate change will cause yet. But it seems like there should be some amount (perhaps small, perhaps large) that we should be spending today to reduce emissions because there is a chance (perhaps small, perhaps large) that climate change will cause damages (perhaps small, perhaps large).
And that amount spent should be designed to be equal to the reduction in the sum of (Probability(damage)*Amount(damage)) across all possible futures.
(Of course, a policy has uncertain cost too... but how to incorporate that I leave as an exercise to the reader)
(The controversy about the Mann study might imply that we should adjust our probabilities or projected damages down - however, keep in mind that it is only one study out of 100s, and this is only one critique...)
And do you seriously think that climate change researchers have been basing all of their assumptions just on a correlation between temperature change and CO2 rise?
Start back at Tyndall in the 19th century who recognized the IR absorbing properties of CO2, and Svante Arrhenius at the turn of the century who asked whether CO2 emissions might lead to a warming earth, and you will see that the theory of global warming started long before there was any correlation to observe.
An increase of CO2 in the atmosphere will, in the absence of other factors, lead to warming. That is incontrovertible. The questions then become: how much warming? What other factors might change the climate (natural variability, aerosol cooling, etc)? What are the feedbacks involved? Can we come closer to answers to the above questions by looking at the historical record (This is where the accuracy of the Mann study becomes important)? How good are our models?
And then we might go on to ask, how much should we invest in reducing greenhouse gas emissions today, given our uncertainty in how much damage they will cause tomorrow? The answer may not be "Kyoto Protocol", but it seems rather unlikely that the answer is "do nothing"...
-Marcus
And, as long as we are correcting false impressions about sea level rise:
The vast majority of current observed sea level rise, and projected sea level rise over the next century, is actually based on thermal expansion of the oceans. Eg, as the oceans warm, they expand.
Some amount of current and near term projected rise is due to melting glaciers outside of Greenland and Antarctica.
The total projected rise from the above causes by 2100 is between 20 cm and 1 m.
In the longer term (multiple centuries), we may have to worry about melting of the Greenland and Antarctic ice sheets, which would cause serious sea level rise (the Ross Ice Shelf collapsing might lead to several meters of rise by itself). However, in the short term increased precipitation over the centers of those land masses is actually projected to balance out increased melting at the edges...
-Marcus
Hmm. Well, those of us who have taken high level economics courses realize that capitalism and the free-market do require some level of regulation to make them efficient. Whether that regulation is to ensure that property rights are respected, to create patent law so that inventors are rewarded, or to tax activities that have "negative externatalities", regulation actually goes hand in hand with the free market.
So, yes, burning oil does have externalities, whether it is local pollution in cities or global warming. And no, burning hydrogen will not materially alter the water vapor levels in the atmosphere. (Of course, there was an article in Science magazine this week about the potential impacts of H2 leakage on a large scale... but they seem to be much smaller than the impacts of CO2, mostly to do with small decreases in hydroxyl radical level which will lead to small increases in methane and other pollutant levels...)
One might also argue for a case for government intervention where there is path dependence due to technology choices... but this requires much more confidence in the ability of government to predict the future, so I tend not to emphasize this argument.
Well, coal isn't oil.
But yes, most fuel cells run off of fossil fuels. Methane -> reformer -> H2 -> fuel cell is common. FutureGen is the Bush administration $1 billion dollar coal -> H2 with CO2 sequestration experiment (so theoretically it won't contribute to global warming, though it also won't wean us from fossil fuels).
However, switching to hydrogen for our transport sector at least gives us the _option_ of generating the hydrogen by a non-fossil fuel route (ie, nuclear, solar, wind power can be used for the electrolysis of water). Biofueled or electric cars are other options, though they have their own drawbacks (biofuel can be dirty, and we don't really want to use all our agricultural land to power our cars, electric vehicles are limited by battery technology and still require the non-fossil-fuel power source problem to be solved)
-Marcus
I still like using NMR and hydrogen spin states in common organic molecules to do quantum computing. The number of Q-bits is equal to the number of different hydrogens on a single molecule, and you can target each hydrogen with a separate magnetic pulse to manipulate that bit.
Making a "macroscopic" object enter a quantum state is really cool, but I don't foresee it being a step directly towards quantum computing. (Though there may be spin-off learning).
Of course, one would imagine that the wavefunction of an object that large would collapse very quickly as it will be hard to prevent interaction with the environment.
Actually, what you want to do is take the best data you can find for "exogenous" variables over the last 100 years (solar cycle, volcanoes, anthropogenic emissions), and plug them into the model and compare the overall trends to reality (rather than trying to predict a "specific" hurricane, which is not what the model is designed for): One would expect that you can match global average temperature and sea level rise pretty well since current (100 km resolution) models already do so (see IPCC report). The question is whether you can match extreme weather events. Unfortunately, I don't know if we have good enough data about hurricanes going back long enough to really see trends... And this is a controversial area, because many climate change scientists believe that an increase in radiative forcing due to greenhouse gas emissions will lead to increased latent heat (ie, more water in gaseous state) in equatorial regions, which should increase the frequency of events like hurricanes... Which would be yet another reason to reduce GHG emissions. But others disagree. And when it comes down to it, you are trying to validate your model either because you believe you have done a good job on the fundamental physical processes, or by matching external data, and I think we may not be confident in either of those areas yet. But it is still a useful exercise to see what our best predictions show, even if there is significant uncertainty in those predictions.