Try again. Ok, not as detailed as now. But there was pretty good global coverage for much of the last century and the one before.
The last century and the one before? Considering some of the problems that have recently been brought to light about temperature measuring stations there is some question about how good of coverage we have in the US today. We didn't have consistent temperature measuring world wide in the 19th century. As for the 20th, well it got much better but taking to account urban heat island affects, and movement of, or use of different types of sensors to get the data isn't simple. Complex adjustments can be made, but the complexity of the adjustments doesn't insure their accuracy.
Those adjustments are small.
Look to
ncdc.noaa.gov
for adjustments
specifically see
ncdc.noaa.gov
which shows that a trend would be created just from adjustments even if the raw data didn't change.
Or to get straight to the point
The US Historical Climate Network (USHCN) reports about a 0.6C temperature increase in the lower 48 states since about 1940. There are two steps to reporting these historic temperature numbers. First, actual measurements are taken. Second, adjustments are made after the fact by scientists to the data. Would you like to guess how much of the 0.6C temperature rise is from actual measured temperature increases and how much is due to adjustments of various levels of arbitrariness? Here it is, for the period from 1940 to present in the US:
Actual Measured Temperature Increase: 0.1C
Adjustments and Fudge Factors: 0.5C
Total Reported Warming: 0.6C
Yes, that is correct. Nearly all the reported warming in the USHCN data base, which is used for nearly all global warming studies and models, is from human-added fudge factors, guesstimates, and corrections.
I know what you are thinking - this is some weird skeptic's urban legend. Well, actually it comes right from the NOAA web page which describes how they maintain the USHCN data set. Below is the key chart from that site showing the sum of all the plug factors and corrections they add to the raw USHCN measurements:...
coyoteblog.com
I notice the problem in the blog post in that it talks about degrees C, while displaying charts of degrees F. But the numbers are correct and changing the text in the argument from C to F, would give you the same point. .1F measured increase, .5F adjustment factors.
And yes 1940 was a warmer than average year but its not as if the points being compared are a local unusually high year and a year that dips way down below other local temperatures.
To ignore that requires you take as a hypothesis that CO2 doesn't radiate in the infrared.
I'm not ignoring that CO2 has gone up. But you don't have to deny that CO2 is a greenhouse gas to question whether the temperature is going up. In any case I don't really question that the temperature has gone up, as I say the best available data seems to indicate that it has. But "its probably gone up" isn't the same as "it has gone up", let alone "it has gone up by X", and it certainly isn't the same as saying "it will go up multiples of X over the next century".
You have somewhat questionable data, showing the temperature has gone up. I say somewhat questionable, because it is, but its good enough to believe there has been some increase in temperature. In fact for the sake of argument, I'm going to, for a moment, suspend any doubt and assume, yes there is a current upward trend in temperature (its not difficult to do so, as the doubt is far from enormous). So if its a fact that temperatures have gone up, that still doesn't mean we know exactly how much, but lets assume they have gone up the .5 F since 1900 as shown by ncdc.noaa.gov
So for the moment stipulate .5 degrees F over a century as "established fact" even though it really isn't.
You also have the fact that CO2 is a greenhouse gas. That is firmly established fact.
Its a long stretch to take those two facts, and say something like "global temperatures will go up X degrees over the next century, and X is high enough to cause severe problems". Its even a longer stretch to take those two facts (or really one fact and one best guess) and say that "we should implement policies X, Y, and Z to fight global warming", or even "we should make a large effort to fight global warming even if it is very difficult and expensive", or "making a strong effort to reduce world wide CO2 emissions will overall be beneficial for humanity". |
