How can anyone truly believe that scientist can determine a "Global Temperature"?

Scientists use tools to measure everything. Weight, size, temperature, and any number of other variables. Every tool used to measure stuff, but one, has a standard that can be used to calibrate these tools at the time of use to provide accurate measurements. The one variable that doesn't have a universal standard is temperature. Thermometers are the most inaccurate measuring device that science uses. There are to many variables that affect temperature, and thus the tools we use to measure it. Even the most expensive thermometers have a huge accuracy variance(by scientific standards).

Now as Dana has pointed out there are thousands of temperature stations throughout the world that monitor temperature. What he did not mention though, is that over 80% of the stations in the U.S. alone do not meet N.O.A.'s criteria for location to achieve accurate readings. They are placed areas that are guaranteed to give bogus results. Some of these places include one mounted 10' from two commercial air conditioning condensers. This area happens to be located in an area that is enclosed on three sides by buildings with large roof overhangs that these condensers are under. Another one is mounted on a pole that is surrounded by asphalt. These are the rule, not the exception.

One other variable that the A.G.W. thugs like to minimize is the effect of water vapor in the atmosphere. They have to minimize it. Water vapor concentrations are higher than all other green house gasses combined, and the effects of water vapor are to complex to fully understand. If they(scientists) can not understand the full effects of water vapor, how can they predict the effects of one of the most minor of green house gasses.......Carbon Dioxide?

Well first of its not just man made and i really wouldnt call it global warming (even though it is called global warming) but its mostly just a climate change i would say. But things that we are doing are causing parts of it the waste, green house gases, and the products we use/buy. Alot of that is effecting it but thats not the only reason in my opinion I think this is how the world is suppose to do in a way but im not quite sure.

It is not shown as an absolute temperature.

The work has been on-going since 1893 under the auspices of the World Meteorological Organization who have collected temperature time series from a large number of stations.

http://www.wmo.int/pages/index_en.html

You will see from the graphs such as the one at http://www.epa.gov/climatechange/science/recenttc_...

that temperature changes are always expressed as the variation from a base time period such as 1901-2000. Therefore there is a graph for every station showing that variation. These can be analysed statistically by such measures as mean and standard deviation and the range are plotted on the graphs.

Honest scientist admit that they don't know everything. Climate science is in its infancy and is extremely complex. They make computer models, but they don't stand up to real world measurements. It is impossible to provide earth temperatures without numerous assumptions. Too often, the assumptions are not provided. They will say the world is .5 degrees warmer than a century ago. You are quite right to be skeptical of such claims. They are at best educated guesses and too often they are not that educated IMO.

"Yes it is very complicated" the instruments we have to measure climate change are very limited.Satellites can only interpret data from heat.and light,but can not read upper level atmosphere strata. Ground base stations they are limited also to lower atmosphere testing.As to date there are no instruments to measure accurately the upper levels of our atmosphere.It's basically hypothetical and based more on models then actual scientific fact.

AND 70% of the Earth is covered by water----- with not many weather stations---

And we already have the testimony of several world class Statisticians that the calculations are ^&*^&^&^!

AND many of the surface stations are improperly located or have been encroached by development.

So------ how about we wait another 10-15 years for the satellite data to mature a little more

And just exactly WHERE is the thermostat --- and what EXACTLY is the OPTIMUM Earth temperature?

Today here is what we know: Blacktop (roads and parking lots) and buildings heat cities; Air pollution causes lung (and other) diseases, deforestation causing more destruction (duststorms, hurricanes/cyclones all increasing deforestation) and destroys the ozone layer while heating earth surface; fires cause mud slides, deforestation and pollution-more heating surface temperatures; CFC's destroy the ozone layer raising skin cancer rates and killing off endanger species and increased surface temperatures; lighting produces ozone near the surface and raises air pollution levels-more heating; the suns increased magnetic field are causing increases in earthquakes (more destruction), volcanoes (wow, great distruction), sun spots and leading to more heating. Cars, airplanes, ships and most electricity production causes pollution, warmer temperatures and destruction. But most of this is in our control outside of the sun (Volcanoes, sun spots and earthquakes are part of the sun magnetic strength): We need to fix our part! That is why I founded CoolingEarth.org an geoengineering web sight.The USA Mayor's are on the right track, we can have control and economic growth. The fed gov is way out of step-even Congress. We also need a pollution surcharge to balance the field and advance new technologies. Where we are with global warming has never happened before. CO2 has never lead to temperature change, but temperature change has led to increases in CO2. The models are having to be made with little evidence!

It's not that complicated. There are thousands of temperature measurement stations all around the globe. Some are in urban areas, others in rural areas, others measure the air temperature over the oceans. Here is a list of stations used by NASA:

http://data.giss.nasa.gov/gistemp/station_data/sta...

Taken together, these stations give an accurate measurement of the global temperature. Here is a plot of average global temperature each year (black points), the 5-year average (red line), and the margin of error (green bars)

http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lr...

As you can see, the warming trend is well outside the margin of error.

If you want to check the accuracy, you can compare that NASA graph to this Hadley Centre graph:

http://www.cru.uea.ac.uk/cru/data/temperature/nhsh...

If you don't trust the land stations, you can compare their measurements to atmopsheric warming measured by satellites:

http://globalwarmingart.com/wiki/Image:Satellite_T...

Really global warming is a well-measured phenomenon.

http://www.climatecrisis.net/

I suggest you visit this site and also watch the movie AN INCONVENIENT TRUTH.

It will explain to you how they can tell. They can get the information in the polar ice caps. It will explain it watch the movie.

And if you do not want to do that then well, I am afraid you will never understand.

Oh, I get it. Since we can't know everything, therefore we can't know anything.

Get a life. Or better yet, get a degree.