rg767 wrote:And so, if you already believe in the greenhouse effect (which you have to, because it is clearly in existence), and given that the amount of energy arriving in the atmosphere is so massive, then a miniscule change in carbon dioxide (a known greenhouse gas) concentration changing the energy balance is not all that hard to imagine.
So your belief is that with a system in equilibrium (not that it ever actually is) between the solar radiation and the greenhouse effect, then a small change to the composition of the gases can make a significant change to the temperature, but a small change to the internal generation of heat cannot?
If we assume that "normally" the temperature of the earth is stable (it never is, as can be seen by the historical temperature data), then the situation is clearly that the solar radiation hiting the earth is fairly much balanced by that which is being radiated back into space. This is a basic requirement, as energy cannot be created or destroyed, so if the energy radiated away is not the same as that arriving from the sun then the temperature of the planet will increase or decrease.
The AGW theory is that the addition of CO2 to the atmosphere has decreased the amount of energy being radiated back in to space, and that additional trapped energy has caused the atmosphere to warm.
It is, however, logical to think that given a constant amount of "insulation" (greenhouse gases) then producing additional heat inside that insulation will increase the temperature until a new equilibrium is created. In your house, if you add insulation but retain the same heating your house will get warmer. However if you keep the same insulation but increase your heating the same will happen - the temperature will increase.
You seem to be suggesting that on a planetary level ths would not happen, but instead the heat created locally would somehow bypass the "insulation".
By the way, the amount of energy received from the sun is not relevant to the concept - we have already established that by simple laws of physics the earth must be radiating as much energy as it receives otherwise it would be in a constant state of heating or cooling.
Why then should it be the case that adding "insulation" will shift the equilibrium, but adding heat (inside the insulation) will not? Clearly there is enough energy to make a difference, based simply on mathematics.
In fact the very concept of the greenhouse effect would surely suggest that locally produced heat is more "dangerous" than solar radiation. If, as is the suggested basis of the greenhouse effect, gas molecules in the atmosphere absorb particular IR wavelengths and then randomly re-radiate the energy, then logically that process would happen in both directions such that solar radiation in those wavelengths would be equally effected. An increasing amount of those gases might well cause some of the incoming energy to be radiated back to space more quickly. Obviously as the wavelengths in question are a very tiny band, incoming radiation will be less impacted, as the theory goes that as the solar energy hits the earth it heats the ground, which then radiates it in the IR wavelengths, some of which wavelengths are the ones we are talking about. Hence, in theory, a greater proportion of the outgoing energy is in "greenhouse" wavelengths than was in the incoming radiation (thus, to put in simply, it comes in and gets trapped). However the overall amount of energy being radiated away from the earth is still the same as that which is arriving, except for alledged AGW impacts. Note then that the heat we are generating from burning the fossil fuels will all be in those same IR wavelengths, and will therefore be impacted by the greenhouse gases and trapped in the atmosphere to exactly the same extent as any incoming solar radiation.
The amount of energy required to heat the atmosphere is the same no matter where it came from. So if the atmosphere has heated by 0.1C it has absorbed X joules of energy to do it. The AGW theory is that this amount has come from trapped solar radiation. However, if our burning of fossil fuels has produced a similar amount of energy, what has happened to it? That energy cannot have simply vanished, it has either passed through the atmosphere and out to space, or has been trapped in the atmosphere and caused it to warm.
rg767 wrote:And on models: I really don't agree with the way that you represent the climate models: there is nowhere that anyone would say that carbon dioxide concentration equals a reduction in rainfall. That would be biased. It just doesn't work like that.
No, like I said, I was simplifying. All models work based on known data. However some models use all known data and all known "rules" and some use the data to extrapolate a rule. How many items of data are included are not relevant to the design, other than to make a bigger and more complex program.
So, for example, an engineering model of a length of steel might include its strength, cross sectional area and weight. From this model we can see how long that length of steel can extend (self supporting) before its own weight creates enough force to bend it. This is a simple model, but based entirely on known data. We can make the model more complicated by adding temperature, and the variation of strength (and length due to thermal expansion) based on temperature. The next step would be to add "design", such that instead of a single piece of heavy steel we could use multiple triangulated pieces of sectional steel, however we are still using known, measured, data.
The other sort of model uses extrapolated relationships. For this model we still use known data, but the relationships are not proven.
If we take our modelling back to the simplist point we end up with a graph. A graph is a graphical representation of data, to model a "relationship". In our engineering model above, we could take length and temperature and create a graph. We could then predict the length of that piece of steel at any given temperature (within the temperature range for which we have experimental proof of the relationship), by reading it from the graph. On the other hand, we could plot a graph (as has laughingly been done in this forum before) of global temperature against number of pirates. We could then plot a best fit line through this graph, but it doesn't prove a relationship. Even the fact that if we look at our historical records and "test" the graph, it means nothing because the grpah was created from those records.
In the case of the AGW model, there is no known relationship between the data items, only a theoretical one. All the "proof" of the relationship is derived from the model. So a model created from the data is used to show a relationship based on the model confirming what it was originally told. Obviously this doesn't mean the model is inherently wrong, simply that it is not "proof".
Your specific point that the model was not told that increasing CO2 means decreasing rainfall is not strictly true. The model is created from data. So it was "told" that in 1900 the CO2 level was X, the temperature was Y, the rainfall was Z...etc. for all the required data items. It was then told that in 1901 the data for those criteria were X1, Y1 etc., and so on for all the years in question. If I entered those same numbers in to Excel and created a graph, I would not have "told" Excel that there was a relationship between rainfall and CO2, but a best fit graph will always find one. The trouble is that as with the "pirates" graph, the fact that a relationship can be found does not prove that one exists! The model uses the data to extrapolate a relationship between the data items, but will do so whether one exists or not. In this case, for the last 100 years the levels of CO2 have been rising. Any data item that exhibits a trend over that period of time will be seen to have a relationship with the level of CO2, whether or not any cause/effect relationship actually exists. So for example, the model has been told that global temperature has been increasing for that time, hence it derives a relationship between the two data items and predicts that if CO2 levels continue to rise, temperature will also rise. In fact that may or may not be true, but the statement that "the model agrees with what has happened" demonstrates only that the model has derived the relationship that it was originally given.
Of course there will be data that does not show any particular relationship, and that even with the full force of statistics brought to bear cannot be shown to have any relationship. This, of course, is where the "increasing variability" comes from. What that means is "we can't find any mathematical relationship between these data items".
rg767 wrote:I started doing calcualtions, but then I found that table below:
That table is of primary energy, it does not relate to the use of energy.
In fact, as described above, none of it is of any importance. Most "renewable" energy is already heat or near enough (wind, solar). Even burning a tree can be considered as part of the very short term energy cycle. Burning fossil fuels however is releasing energy that was stored millions of years ago. The heat released from fossil fuels is energy that is new to the short term energy cycle. It must make it's way through the atmosphere (as heat) before escaping to space. The result is that regardless of the scale of the existing equilibrium, it must have an impact. The size of the impact is based solely on the amount of energy involved. Wiki states "In 2008, total worldwide energy consumption was 474 exajoules (474×10^18
J) with 80 to 90 percent derived from the combustion of fossil fuels." Taking 85% as a fossil fuel use, that means that 85% of 474×10^18joules of heat, or a large proportion thereof, have been produced in addition to the short term cycle.
From my original equations that means we are creating enough energy from fossil fuels to heat the atmosphere by 0.08C each and every year.That energy MUST be heating the atmosphere, as it has nowhere else to go!!!