In general, there has been little to no work done on what would be an optimum average temp for the planet. Some have worked on this, like Richard Tol. Of course, the answer is "it depends". "Optimum" depends on where you live and what sector of the economy you work in.
It's somewhat misleading, though, because the economic benefits/damages do not depend on just temperature, but on rate of change of temperature. Change in either direction, and especially relatively rapid change, incurs losses simply because economies and civilizations are adapted to a particular range. The real question is whether the overall temperature change has benefits that outweigh the losses due to the rate of change, and it's one whose answer is less favorable to climate change than the question you're asking.
There's already doubts about the accuracy of our current measurements. There are inaccuracies in any data set. The question is the extent to which they actually influence any conclusions. Some points:
1. The SurfaceStations folk rely on suggestion and implication, not on actual measurement: to what extent does an A/C 10 feet away actually influence temperature measurements? They don't say. They haven't shown that there are actual problems with the recorded temperatures. 2. They then retreat to a generic argument of "Well, something could be wrong with the temperature record, therefore we should just disregard it as unreliable". 3. Siting problems are generally worse in urban areas, which they have so far focused mostly on. They have only found a relatively small fraction of "potential" siting problems among the stations surveyed; the overall fraction and influence of "potential" problems should be even lower once they look at the rural stations. 4. There are already plenty of statistical procedures in place to detect and correct (if possible) or discard (if not possible) anomalous temperatures, such as jump discontinuity detection, renorming urbanized sites against local rural sites, etc. 5. Two independent satellite records agree with the surface temperature record during the late 20th century/21st century period of warming. So too do other less direct measures, within their respective errors, such as borehole temperatures, temperature reconstructions from glacier melt rates, species redistribution patterns, etc.
The SurfaceStations effort is worthwhile in documenting some of this site evidence, but the idea that the surface temperature record is untrustworthy due to site location, or that they are going to overturn the rate of warming, is absurd, given all the other evidence as well as the statistical analysis procedures already in place. Even McIntyre admits that the warming is real; he just wants it to be better quantified.
If more CO2 leads to higher temperatures; Venus could serve as pretty solid evidence In fact, it is. You can calculate Venus's maximum possible equilibrium temperature from its distance from the Sun and its reflectivity, and its actual temperature far exceeds that value.
For that matter, the Earth's actual temperature also exceeds its maximum possible temperature according to such energy balance considerations, and that too is because of the greenhouse effect, which adds about 30 degrees C to the global mean temperature.
But Mars can throw a wrench into the whole theory Mars is much further from the Sun than is Venus, and more importantly, has almost no atmosphere to speak of. It doesn't matter if it's pure CO2 if there just isn't much of it in the first place. The greenhouse effect depends on the amount of CO2, not just the fraction.
Earth's atmosphere contains the following gasses (by volume): nitrogen: 78%, oxygen: 20.95%, argon: 0.93% and finally - carbon dioxide: 0.038% - wow, that's a pretty high concentration - I think we're all going to die. We're not going to die, but that amount of CO2 does contribute to the greenhouse effect. 0.038% looks like a small number, but it's meaningless out of context. You can ingest a small amount of cyanide and still die. You have to multiply the amount of CO2 by its potency as a greenhouse gas.
And again, it's not the relative concentration that matters, but the actual amount. You could dilute the atmosphere with as much non-greenhouse gas as you want, making the GHG concentration arbitrarily small, but the greenhouse effect will be the same since you have the same actual amount of GHGs. (Not exactly true because eventually the atmosphere will turn opaque to visible light, but you get the idea.)
Note, too, that the direct greenhouse warming of CO2 so far only amounts to about a 0.1% increase in the planet's temperature. While that's not big as far as the planet's temperature is concerned, it's important as far as we are concerned. A 10% increase in the planet's temperature would wipe out most life on Earth. We may see an eventual increase of 1 or 2% or more.
No, the AGW theory is based entirely on the tenuous idea that increased CO2 increases temperatures. Tenuous my ass. It's been established for over 100 years and even the skeptics don't argue against the existence of the greenhouse effect; they only argue that the feedback effects which amplify CO2 warming aren't as strong as the mainstream claims, and therefore CO2 is responsible for less of the warming than is thought. (More than half of the warming in climate models is not attributable directly to the greenhouse effect of CO2, but to other warming factors which are caused by the initial CO2 warming.)
(At it is challenging, to say the least, to explain the ice core data while holding to that idea.) Of course it isn't, but I'm sure you're going to wave around the CO2 lag as if it disproves the greenhouse effect.
It's always possible to find a handful of contrarians in any field, no matter how settled; their mere presence doesn't say much. The vast preponderance of evidence supports the idea that global temperatures have increased. Even among the skeptics, the debate has largely moved on: McIntyre himself admits that he doesn't think the global warming trend is going to go away, just that it's not as precisely quantified as is claimed. Of your references, I only find the first one to have credible evidence against the surface temperature record, and if you want to argue against that, you're going to have to argue why identical errors have been made in the satellite temperature record, borehole temperatures, glacial melt records, species migration patterns, etc. all of which support the warming trend.
As with most of that site's content, you're only telling part of the story.
1) Global plant biomass up 6% since the 1970s due to more CO2, and longer growing seasons. A big win on dozens of fronts, but two bear particular mention:
Plant biomass can go up as a whole, but the effect of CO2 fertilization is strongly limited by water and nutrient availability, which in many regions will go down. Longer growing seasons do not occur everywhere, but only in places that don't get too hot or too dry.
3) Increased crop yields, contributing to making the famines that used to regularly afflict India, China, etc. a thing of the past.
Increased crop yields have far more to do with agricultural practices than CO2 fertilization or climate change. Furthermore, even when crop yield goes up, nutritional content often goes down: the planets are bigger but not as good for you.
4) Decreased mortality. Deaths increase from a one degree drop in temperature at around four times the rate of a one degree rise in temperature.
That contradicts other studies I've read, but now I have to do some hunting for them.
5) Extra calamari! Squids get bigger and grow faster in warmer oceans.
6) Fewer typhoons/hurricanes/etc., due to increase in wind shear making them less likely to form.
The studies I've read indicate that hurricane numbers stay constant or increase, not decrease, and that hurricane strength may increase.
7) Better beer! There's no water more pure than that from melting ice caps.
Strangely enough, the positive vastly outweighs the negative. Really? Then why do leading economists like Nordhaus find net economic damage from warming? Even Tol, who's in the "small warming is good" camp agrees that we need to mitigate our emissions to avoid large warming.
Your one sided story neglects all the other negative impacts of climate change (sea level rise, drought, flooding, heat waves, abrupt threshold responses in the climate system), etc., and also neglects the difference between the climate change which has occurred so far, and the much larger change which is predicted to occur in the future.
I'm sorry, I haven't followed that debate very closely, and your excerpt doesn't make it very clear to me.
You can see the IPCC report for the latest sea level estimates. Note that a number of scientists have claimed those numbers are too conservative, because they explicitly chose not to estimate the possible contribution of nonlinear ice sheet responses, for which there is recent evidence. Hansen is still on the side of very large potential sea level rise over the next century, on the basis of those nonlinear responses and paleoclimate evidence of large sea level changes. He is on the more extreme end of the spectrum in that regard, but mainstream climatologists agree that potential ice sheet responses are worrisome and could dramatically change the current estimates.
The raw and adjusted data are available, and the detailed algorithm for performing adjustments is published. However, McIntyre has been unable to exactly reproduce the adjusted data from the raw data using the published adjustment algorithm (he can get close, but not exactly), and he says that GISS refused to give him the algorithm's source code.
It's at a minimum interesting that there were reports in the 1920s of widespread arctic ice melting, It wouldn't be surprising if there were, since there was warming in the 1920s. What is your point?
followed in the 1970s by a "Global Cooling" scare. Which was mostly media driven hype (here). Of course, there was some cooling from 1940 to 1970, but again, what is your point? Neither that nor the above contradict the reality of the global warming trend.
This recent revision of which was the warmest year in US history casts even more doubt. "The warmest year in US history" is utterly irrelevant to any warming trend and the two top years were statistically tied both before and after the revision.
Looking further back into history, there has been historical warming in Greenland that exceeds the current trend, well before human produced greenhouse gasses could have been a factor. Yes, we know that climate change has occurred in the past, and there have been large, rapid changes in Greenland temperatures associated with, for instance, the shutdown/restart of the North Atlantic thermohaline circulation. However, that doesn't change the evidence that the current warming is not largely due to such natural events.
Further, they are modeling inherently chaotic systems which we have trouble forecasting only a week into the future. Hubris, anyone? Give me a break. Yes, it's impossible to forecast the weather more than a couple weeks in the future, due to chaos. But you can forecast the climate, which is a temporal and spatial average of all possible weather events, out much farther. The ability of climate models to do this has been demonstrated in hindcasting and out-of-sample validation experiments.
I too agree that there *is* global warming. But the numbers on what actually causes it are avoided like the plague. Wow, you haven't read any papers on climate change detection and attribution, have you?
Why? Because while global warming itself might be an issue, the effect that human activity has on it is less than 5% of the total CO2 emissions. Human emissions are smaller than natural emissions, but that's not the point. Natural emissions are almost exactly balanced by natural sinks which remove CO2 from the atmosphere; over centennial time scales this leaves the atmospheric CO2 level constant to within 10 ppm. Human emissions, while comparatively small, have overwhelmed the natural sinks' ability to remove the excess CO2: they can only take up about half of human emissions, leaving the other half to accumulate in the atmosphere year after year. Since pre-industrial times, CO2 levels have gone up by 100 ppm (~35%), much larger than the natural variability (excepting long term geological scale events like ice age cycles). Almost all of that CO2 is directly attributable to human emissions, through (a) estimates of human industrial activity, (b) measurements of natural sources, and (c) isotopic fingerprinting of the types of CO2 put in the air (fossil fuels are isotopically distinct from, say, CO2 emitted by respiration).
And the dreadful horrible CO2 emissions we ought to establish a tax on breathing for is not a big part of that 5%. We should be more worried about methane for example, but there isn't much money to be made on taxing cow farts. It's cow belches that are the problem, and even those, while not negligible, don't approach the total greenhouse effect of human-emitted CO2.
Mars is getting warmer too. Mars's south pole has been getting warmer in recent years. That has nothing to do with the climate on Earth: the only link between the two planets is the Sun, and changes solar output are inadequate to explain the warming on either the Earth or Mars, as they generally disagree in timing, rate, and magnitude. The Martian warming is likely attributable to albedo changes due to patterns of dust storm activity.
There are two sides to every story and one should do their own research. Why haven't you done yours?
I curious about a particular aspect of global warming: is the temperature increase constant? In other words, do nighttime temperatures rise the same amount as daytime and do winter temperatures rise as much as summer temperatures? According to the IPCC report (section 3.2.2.1, 3.2.2.7, diurnal temperature range), daytime and nighttime temperatures appear to have increased by the same amount in the warming since the 1970s. Warming appears to be slightly greater in winter than summer (FAQ 3.1).
The fact that they trumpeted the first findings and quietly released the second makes one wonder about the real reason for releasing them in the first place. Actually, Hansen is on record back in 1998 as stating that 1934 was the warmest year. Since then, 1998 and 1934 have ping-ponged back and forth in the NASA data as "warmest year" as various minor adjustments have been made, and NASA hasn't made much of it. As far as I can tell, it was NOAA, not NASA, which played up 1998 (or 2005, or whatever the record of the moment is) as the "warmest year".
If Global Warming has increased the earths tempature from.3-.6 C then a.15C IS a big deal. You're comparing apples to oranges (global temperature to U.S. temperatures). 0.15 C in the U.S. is not a big deal to the global picture, since the affect on global temperatures is about 50 times smaller.
It actually isn't that big of a deal to U.S. temperatures, either (here is a before-after graph of the change), although it is noticeable. It's really only a big deal for trends in specific regions of the U.S.
The bigger story I see in TFA's graphs is: we're looking at an increase of less than 1 degree C per century. What's the fuss? The "fuss" is:
1. The climate change so far is relatively small, but has already had noticeable impacts on ecosystems. 2. The amount of change is attributable largely (but not wholly) to human activity. 3. The amount of change is projected to accelerate in the future, based both on increases in human activity, the long atmospheric residence time of CO2, and the long term response being delayed by ocean heat uptake. 4. The damages (economic, ecological, and otherwise) are estimated to increase faster than linearly as a function of the climate change. 5. The damages are also rate-dependent, and the rate is projected to increase as in (3).
The guy who found the error - Steve something or other, predicts that the change brings the surface mesasurements down to the point where Global warming will top out at a TOTAL of 1-2 degrees above where it is now.
That "prediction" only holds if he made the same prediction before the surface measurements were changed: the change in surface measurements makes essentially no difference at all to the global warming trend (here).
The change in the U.S. temperature trend was on the order of 10%. The change in global temperature should be about two orders of magnitude smaller than that, as the U.S. only comprises 2% of the surface area of the Earth. Thus, a back of the envelope estimate suggests that the global warming trend will be altered by a few parts in 1000. There was actually a statement by NASA GISS to that effect quoted somewhere on Climate Audit, but it's been down so I can't access it.
The ground state of the vacuum is still thermodynamically at zero temperature when in an inertial frame, for the reasons I stated. Virtual particles do not contribute to temperature; only real particles do.
Virtual particles don't contribute to actual heating unless you're in a non-inertial reference frame where they become real (usually Unruh radiation, unless you're near an event horizon, then it's Hawking). Even then, you need a lot of acceleration for any measurable effect, which is why Unruh radiation has never been observed.
But the number of galaxies is not infinite. The universe itself has a finite ammount of mass and energy inside it, and that is used to make up a finite number of galaxies. This is unknown, and in the now-standard inflationary cosmology, is commonly believed to be false: an infinite universe is more compatible with inflation, and is certainly compatible with observations to date.
You are assuming certain things to come up with that probability. Yes, but it's pretty ridiculous to assume otherwise: that "the largest galaxy" is going to get finite probability mass out of an infinite collection of galaxies.
Unlikely? sure, but that's not the point. Yeah, it kind of is the point: it is not mathematically impossible, but still absurd, to believe that we have actually run across the largest galaxy out of an infinitude of galaxies.
You're thinking of the Saggitarius dwarf galaxy, which subtends 10 degrees. That's the largest in apparent size (other than the Milky Way, of course) because it's so close, but it's not the largest in actual size.
Not much mass is centered in central black holes, compared to the galaxy they're in. Our galaxy is around 100 billion solar masses, and the central black hole is only a few million solar masses — that's like 1/1000 of a percent of the total mass. Some supermassive black holes in quasars can be billions of solar masses, but that's not the sort of galaxy we're talking about here.
Colliding black holes can radiate a lot of their mass-energy as gravitational waves, though; something like 30-40% in the best case. My point is just that in colliding galaxies, there isn't much relativistic gravitation going on; in fact, the stars themselves generally don't approach each other that closely.
Slashdot Mirror
It's somewhat misleading, though, because the economic benefits/damages do not depend on just temperature, but on rate of change of temperature. Change in either direction, and especially relatively rapid change, incurs losses simply because economies and civilizations are adapted to a particular range. The real question is whether the overall temperature change has benefits that outweigh the losses due to the rate of change, and it's one whose answer is less favorable to climate change than the question you're asking.
1. The SurfaceStations folk rely on suggestion and implication, not on actual measurement: to what extent does an A/C 10 feet away actually influence temperature measurements? They don't say. They haven't shown that there are actual problems with the recorded temperatures.
2. They then retreat to a generic argument of "Well, something could be wrong with the temperature record, therefore we should just disregard it as unreliable".
3. Siting problems are generally worse in urban areas, which they have so far focused mostly on. They have only found a relatively small fraction of "potential" siting problems among the stations surveyed; the overall fraction and influence of "potential" problems should be even lower once they look at the rural stations.
4. There are already plenty of statistical procedures in place to detect and correct (if possible) or discard (if not possible) anomalous temperatures, such as jump discontinuity detection, renorming urbanized sites against local rural sites, etc.
5. Two independent satellite records agree with the surface temperature record during the late 20th century/21st century period of warming. So too do other less direct measures, within their respective errors, such as borehole temperatures, temperature reconstructions from glacier melt rates, species redistribution patterns, etc.
The SurfaceStations effort is worthwhile in documenting some of this site evidence, but the idea that the surface temperature record is untrustworthy due to site location, or that they are going to overturn the rate of warming, is absurd, given all the other evidence as well as the statistical analysis procedures already in place. Even McIntyre admits that the warming is real; he just wants it to be better quantified.
For that matter, the Earth's actual temperature also exceeds its maximum possible temperature according to such energy balance considerations, and that too is because of the greenhouse effect, which adds about 30 degrees C to the global mean temperature. But Mars can throw a wrench into the whole theory Mars is much further from the Sun than is Venus, and more importantly, has almost no atmosphere to speak of. It doesn't matter if it's pure CO2 if there just isn't much of it in the first place. The greenhouse effect depends on the amount of CO2, not just the fraction. Earth's atmosphere contains the following gasses (by volume): nitrogen: 78%, oxygen: 20.95%, argon: 0.93% and finally - carbon dioxide: 0.038% - wow, that's a pretty high concentration - I think we're all going to die. We're not going to die, but that amount of CO2 does contribute to the greenhouse effect. 0.038% looks like a small number, but it's meaningless out of context. You can ingest a small amount of cyanide and still die. You have to multiply the amount of CO2 by its potency as a greenhouse gas.
And again, it's not the relative concentration that matters, but the actual amount. You could dilute the atmosphere with as much non-greenhouse gas as you want, making the GHG concentration arbitrarily small, but the greenhouse effect will be the same since you have the same actual amount of GHGs. (Not exactly true because eventually the atmosphere will turn opaque to visible light, but you get the idea.)
Note, too, that the direct greenhouse warming of CO2 so far only amounts to about a 0.1% increase in the planet's temperature. While that's not big as far as the planet's temperature is concerned, it's important as far as we are concerned. A 10% increase in the planet's temperature would wipe out most life on Earth. We may see an eventual increase of 1 or 2% or more.
It's always possible to find a handful of contrarians in any field, no matter how settled; their mere presence doesn't say much. The vast preponderance of evidence supports the idea that global temperatures have increased. Even among the skeptics, the debate has largely moved on: McIntyre himself admits that he doesn't think the global warming trend is going to go away, just that it's not as precisely quantified as is claimed. Of your references, I only find the first one to have credible evidence against the surface temperature record, and if you want to argue against that, you're going to have to argue why identical errors have been made in the satellite temperature record, borehole temperatures, glacial melt records, species migration patterns, etc. all of which support the warming trend.
1) Global plant biomass up 6% since the 1970s due to more CO2, and longer growing seasons. A big win on dozens of fronts, but two bear particular mention:
Plant biomass can go up as a whole, but the effect of CO2 fertilization is strongly limited by water and nutrient availability, which in many regions will go down. Longer growing seasons do not occur everywhere, but only in places that don't get too hot or too dry.
3) Increased crop yields, contributing to making the famines that used to regularly afflict India, China, etc. a thing of the past.
Increased crop yields have far more to do with agricultural practices than CO2 fertilization or climate change. Furthermore, even when crop yield goes up, nutritional content often goes down: the planets are bigger but not as good for you.
4) Decreased mortality. Deaths increase from a one degree drop in temperature at around four times the rate of a one degree rise in temperature.
That contradicts other studies I've read, but now I have to do some hunting for them.
5) Extra calamari! Squids get bigger and grow faster in warmer oceans.
Ocean acidification, ecosystem stress, forced migration
6) Fewer typhoons/hurricanes/etc., due to increase in wind shear making them less likely to form.
The studies I've read indicate that hurricane numbers stay constant or increase, not decrease, and that hurricane strength may increase.
7) Better beer! There's no water more pure than that from melting ice caps. Strangely enough, the positive vastly outweighs the negative. Really? Then why do leading economists like Nordhaus find net economic damage from warming? Even Tol, who's in the "small warming is good" camp agrees that we need to mitigate our emissions to avoid large warming.
Your one sided story neglects all the other negative impacts of climate change (sea level rise, drought, flooding, heat waves, abrupt threshold responses in the climate system), etc., and also neglects the difference between the climate change which has occurred so far, and the much larger change which is predicted to occur in the future.
I'm sorry, I haven't followed that debate very closely, and your excerpt doesn't make it very clear to me.
You can see the IPCC report for the latest sea level estimates. Note that a number of scientists have claimed those numbers are too conservative, because they explicitly chose not to estimate the possible contribution of nonlinear ice sheet responses, for which there is recent evidence. Hansen is still on the side of very large potential sea level rise over the next century, on the basis of those nonlinear responses and paleoclimate evidence of large sea level changes. He is on the more extreme end of the spectrum in that regard, but mainstream climatologists agree that potential ice sheet responses are worrisome and could dramatically change the current estimates.
The raw and adjusted data are available, and the detailed algorithm for performing adjustments is published. However, McIntyre has been unable to exactly reproduce the adjusted data from the raw data using the published adjustment algorithm (he can get close, but not exactly), and he says that GISS refused to give him the algorithm's source code.
It actually isn't that big of a deal to U.S. temperatures, either (here is a before-after graph of the change), although it is noticeable. It's really only a big deal for trends in specific regions of the U.S.
What's the fuss? The "fuss" is:
1. The climate change so far is relatively small, but has already had noticeable impacts on ecosystems.
2. The amount of change is attributable largely (but not wholly) to human activity.
3. The amount of change is projected to accelerate in the future, based both on increases in human activity, the long atmospheric residence time of CO2, and the long term response being delayed by ocean heat uptake.
4. The damages (economic, ecological, and otherwise) are estimated to increase faster than linearly as a function of the climate change.
5. The damages are also rate-dependent, and the rate is projected to increase as in (3).
The guy who found the error - Steve something or other, predicts that the change brings the surface mesasurements down to the point where Global warming will top out at a TOTAL of 1-2 degrees above where it is now.
That "prediction" only holds if he made the same prediction before the surface measurements were changed: the change in surface measurements makes essentially no difference at all to the global warming trend (here).
The change in the U.S. temperature trend was on the order of 10%. The change in global temperature should be about two orders of magnitude smaller than that, as the U.S. only comprises 2% of the surface area of the Earth. Thus, a back of the envelope estimate suggests that the global warming trend will be altered by a few parts in 1000. There was actually a statement by NASA GISS to that effect quoted somewhere on Climate Audit, but it's been down so I can't access it.
Global warming is not "toast".
The ground state of the vacuum is still thermodynamically at zero temperature when in an inertial frame, for the reasons I stated. Virtual particles do not contribute to temperature; only real particles do.
Virtual particles don't contribute to actual heating unless you're in a non-inertial reference frame where they become real (usually Unruh radiation, unless you're near an event horizon, then it's Hawking). Even then, you need a lot of acceleration for any measurable effect, which is why Unruh radiation has never been observed.
Bah, never mind, I just realized that I was looking at comment ID, not user ID ... no wonder it was a "coincidence".
You beat me to the post by less than a minute, and beat me to registering on Slashdot by only 10 users. Get out of my head, Godai-kun!
Hmm, that's interesting. I'm going to have to read that in more detail. Thanks!
You're thinking of the Saggitarius dwarf galaxy, which subtends 10 degrees. That's the largest in apparent size (other than the Milky Way, of course) because it's so close, but it's not the largest in actual size.
Not much mass is centered in central black holes, compared to the galaxy they're in. Our galaxy is around 100 billion solar masses, and the central black hole is only a few million solar masses — that's like 1/1000 of a percent of the total mass. Some supermassive black holes in quasars can be billions of solar masses, but that's not the sort of galaxy we're talking about here.
Colliding black holes can radiate a lot of their mass-energy as gravitational waves, though; something like 30-40% in the best case. My point is just that in colliding galaxies, there isn't much relativistic gravitation going on; in fact, the stars themselves generally don't approach each other that closely.