Has Global Warming Stopped? -Alternative Fuel Vehicles!

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Has Global Warming Stopped? I%26#039;ve been seeing a lot of people making the claim that global warming has %26quot;stalled%26quot; or stopped over the past few years (some say it stopped just last year). But I haven%26#039;t seen any data yet.

So where is it? Which data shows a negative or absent trend over the past few years (be it ten, eight, five, or whatevs)? Is it GISS? HadCRU? NCDC? RSS? And also, perhaps more importantly, what level of significance can we assign to this trend?

Also, is there a physical basis for believing that this trend (if it is statistically significant) marks the end of 20th century warming?

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7 months ago

Hm, Francis, your articles are all fine and well, but they aren%26#039;t what I%26#039;m looking for. I%26#039;m wanting to know a. whether the trend for the time period in your articles is positive, negative, or absent, and b. whether that trend, whatever it may be, is statistically significant.

Looking at the actual data for the past ten year (since 1998), the trend is quite clearly upward:

http://tamino.files.wordpress.com/2007/0...

Of course, that trend would fail statistical significance tests, so it doesn%26#039;t actually tell us anything. It%26#039;s most likely just a trend in the noise, not the signal.

7 months ago

Francis, no, I%26#039;m not telling you to look at any particular period. I%26#039;m asking which period skeptics are referring to when making the claim that warming has stopped, what the trend for this period is (the slope of the line of best fit to the data), and whether this trend is statistically significant.

Oh, and, if there is a cooling trend (or no trend), what the physical basis is for believing that it marks the end of 20th century warming. I thought I made that clear in the original details, but I guess not.

I also never said your articles were flawed. If you%26#039;ll notice I simply gave you the trend for the period discussed in your articles (which was positive), and noted that the trend for such a short period was statistically insignificant. That is, the fact that the trend was upward didn%26#039;t necessarily mean the planet had warmed during that period.

7 months ago

Frances (many apologies for misspelling your name), I%26#039;m not trying to argue anything here. I%26#039;m asking the skeptics to clarify what they%26#039;re talking about for me. I%26#039;m giving you guys the opportunity to change my mind.

Also, argue that a trend for a nine year period is statistically insignificant because it *fails statistical significance tests.* That means the trend most likely occured by chance, and doesn%26#039;t mean anything. I don%26#039;t know when Ken said that long term trends could be identified in less than 12 months of data, but I would disagree with him if he has.

Here%26#039;s an excellent article discussing uncertainty and noise in climate data, if you%26#039;re interested:

http://www.realclimate.org/index.php/arc...

Examining the data over that period and a statistical best fit line also reveals that the warming has clearly not stopped:

http://tamino.files.wordpress.com/2007/0...
http://tamino.files.wordpress.com/2007/0...

Although as you note, a 10-year trend is not much of a trend. That%26#039;s why scientists graph the 5-year running mean over long periods of time.

Any argument that global warming has stopped because 1998 was an abnormally warm El Nino year is based on analyzing noise while ignoring the clear warming signal

http://answers.yahoo.com/question/index;...

and is thus an amateurish argument. However, that%26#039;s the best the deniers can do, because the data supports the AGW theory.

http://answers.yahoo.com/question/index;...

The only other possible explanation for such a rapid warming is that the Sun is responsible, and no scientific study has ever arrived at this conclusion.

http://answers.yahoo.com/question/index;...

So in the absence of genuinely sound scientific arguments, the deniers are forced to resort to amateurish claims and outright lies. And idiocy. The 5 year average is 2002-2007. How does that include 1998?! The only reason the average isn%26#039;t up more is because 1998 brought up the previous averages!!

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