Global Mean Temperature

Is there a global mean temperature upon which claims of AGW are based?

What is that temperature at present?

What was it 20 years ago?

And Here it is,,he Media blames it on Global Warming


Well,, Wasnt my prediction was right when after the winter the news media was going blame global warming when summer comes? Am i wrong folks?

I am guessing that warmers don't want to answer for fear of exposing the fact that the disparity that exists between various "databases" on what the global mean is is multiple times larger than the amount of warming being claimed for the past 100 years.

This gives the sources:
https://en.wikipedia.org/wiki/File:Instrumental_Temperature_Record.svg

What about this?


So who was responsible for Global Warming in 1000BC? Cars,Air Condtioners werent invented back then

Ox, you are missing the point. It isn't what happened over the last millennia. It is well known that there were many swings in temperatures. The OP asked what is happening over the last two decades. That is the nature of the graph I posted.

Im not missing the point..Liberals claim man is the reason for global warming. Man is not to blame. Its the Sun. The Sun is getting hotter like Mars is also having global warming. If Mars is getting warmer then how can it be mans fault? were not even on Mars yet.

You are still missing the point. I only showed a graph. Where did I say anything about blaming man?

You didnt but these damn liberals will do anything to twist the truth around. Like Al Gore for example

Any idea what the margin of error is for that graph?

The graph is the average of several hundred points points throughout the world. The averaging of many points increases the accuracy by the square root of the number of measurements. This is an excerpt of the abstract of the research.

Now that's interesting. In your posts above, you were all over steveox for supposedly missing the point of the original post. I ask very specific questions.....do you have any idea of what the margin of error is for that graph? You apparently missed the point of the very specific question asked in the original post and my very specific follow up question. First, your graph didn't provide an answer to the original question, you provided a graph of temperature anomolies which is not the global mean temperature and secondly, there were two possible answers to my question: 1) Yes I do, it is X degrees or 2) No I don't.

So again, do you have any idea what the margin of error is for that graph which, by the way, didn't answer any of the questions in the original post.

I'm sorry I misread what you wanted. From the graph and references, I thought you could figure it out from there. The error for each red point is about +/- .2 degrees C. For the 5 year moving average on the blue curve, the error would be about +/-.05.

To answer your OP, the surface temperature over a ten year average is 14.51 deg C for the 2000's. The ten year average for the 1980's is 14.18 deg C. (Goddard Institute for Space Studies) Errors for the later two measurements are about +/- .1 deg C. That translates to 58.12 deg F now and 57.52 in the 1980's. I know you asked for the temperature for the "present", but nobody could possibly know that.

A further note that has nothing to do with your OP is that surface temperature is not always a good measure for some analyses of global problems. In the long run, the air temperature in your refrigerator is less important than the temperature of the stuff inside. I don't know of any study of that includes the thermal capacity of the earth mantel, the heat of fusion of ice, thermal gradients in the ocean, etc.

Oops, the errors I gave above are from the HadCRUT data set and are only one aspect of the error. The NASA data set is clearer, and the errors are +/- .5 C annually. (See http://data.giss.nasa.gov/gistemp/graphs_v3/)

I figured this out long ago. I asked the question in an effort to help you and others figure it out as well.

+/- .1 degrees C. Now that is interesting also. You are apparently a fount of interestingness. I can only guess that 14.5 degrees is your personal favorite and that is why you used it, but if you look around the world at the various agencies, it seems that not everyone agrees. For example:

• On German public TV in 2009, Hans Schellnhuber stated that the global mean was 15.3 degrees.
• Stefan Rahmstorf states that it is 15.5 degrees.
• The IPCC 2007 4AR says 14.5 degrees.

Just a bit of research yields claims from 14 degrees to nearly 16 degrees. You state confidently that it is 14.5 with a margin of error of .1 degree when with little effort, one can find a two degree variance depending on which data base one cares to look at and I won't even go into the rampant data tampering.

The point is that while you may believe that the global mean is this or that for this period of time or that period of time and the margin of error is a tenth of a degree, you are kidding yourself because the fact is that we don't really know what the global mean is within a whole degree. Contrast that with claims of warming of tenths of a degree per decade and a thinking person can't help but see some real problems with claims of warming or cooling.

The anomoly chart you provided is no better. The baseline for calculating anomolies is the global mean and the spread there is, again, two degrees or so. It is laughable to me for a group of people to be claiming fractions of a degree of change per decade or century when there is a two degree spread depending on which set of data one cares to start with.

How does one claim fractions of degrees of change with a straight face and a clear conscience when the margin of error is orders of magnituded greater than the claimed change?

I'm not surprised that the assessment of the current global temperature has a one degree spread. It depends on sparse sampling (i.e. A few hundred temperature points around the world) and a various types of modeling.

Here is a little story that shows how to assess something like global warming. My swimming pool seemed to be leaking, so I made a float apparatus to measure the water level of the pool. It was hard to measure because of slow undulations, so I took several readings each day and averaged. On a graph of the daily level, the leak seemed to be about 2 mm a day, and looked similar to the GW graphs – a noisy but definite trend. I then wondered about evaporation and filled a non-leaking pan and measured it for evaporation. That correction turned out to be .5 mm a day.

I had absolutely no idea what the absolute depth of the pool was. It wasn't important in determining that there was a leak. The important factor was consistency in the way the daily levels were measured, and the evaporation correction I made after the fact. (Data tampering??!).

In the same way, the important thing in measuring changing temperature of the planet is consistency of the measurement concept. And yes, science makes corrections and improves accuracy as newer models come about.

Your focus on the absolute measurement of temperature at some particular point of time is quite misguided in the same way that an accurate measure of the absolute depth of my pool was not a factor.

And you don't believe there is a difference between the evaporative rate of a swimming pool and that of a pan?

And there is where your problem began. In order to accurately determine whether or not you have a leak, you first need to know how much water you have. Further, you altered your data based on the evaporative rate from a pan vs a body of water that was many orders of magnitude larger. You have no idea what effect your data tampering had on the actual amount of water you were or were not losing to a leak. Perhaps you made a decision to act based on what you believed, but that decision wasn't based on anything like hard data.

The decision to call in a repairman or not is a relatively small financial decision and while it wouldn't be entirely rational to make it based on flawed methodolgy, the decision only affects you; but the financial decisions being made based on the terribly flawed hypothesis, methodology, and modelling of climate change are very large and stand to alter the world's economies.

So now I know. For a very long time I have wondered how someone could look at obvious examples of an effort to lower the temperature of the past in order to make the present appear warmer; now I know. You apparently believe they are making the data base more accurate. I have to tell you guy, that is one of the most delusional statements anyone has ever made to me regarding the whole climate change issue.

The fact is that we don't know enough about the climate to even begin to have a clue as to what sort of adjustments might need to be made and the fact that more and more data collection stations are being taken off line around the world thus giving us an even poorer picture of what the climate is actually doing does nothing more than further blur what we believe we know.

But knowing the absolute amount of water in your pool was an important factor if you actually wanted to know what was happening. In the end, you made your decision based on an opinion that wasn't founded on anything like fact but just a suspicion, and although you probably won't admit it, your financial situation was a major factor in guiding that suspicion. Regardless, whatever you did in the end, it wasn't based on anything like actual science and the same holds true for decisions being made today based on the assessments of the field of climate science.

The actual spread is more like 2 degrees but aside from that, what does the fact that you can confidently tell me the global mean temperature within a tenth of a degree and tell me that the margin of error is 5 tenths of a degree when you acknowledge that the spread for the basis of your anomoly chart is at least a full degree say about your critical thinking skills?

When someone tells me that they are accurate to a tenth of a degree and their margin of error is half a degree, and the spread for the basis of the temperature that they gave me is 4 times larger than that, I have to wonder whether they have been completely duped or whether they are trying to dupe me.

So which is it?