'Why do we need to march for climate change?'

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As evident above, there is no negative temperature trend from 1998 to 2014 in any of the 3 combined records.

I've also taken the liberty - just like you - of cherry-picking another year where the temperature deviates highly from the trend... this time it is 1978, where the temperature fell drastically below the trend since 1880. And just as easily as you, I can produce a result which deviates widely from the long-term trend. In this case, global warming is now happening 2-3 faster than we thought!

It looks like all three are showing a slight negative trend.

I wish 1978 was relevant, but we have to use the most recent trend shift.

No. If there was, there would be a *minus* in front of the trend coefficient.

Why?

Longer datasets provide more reliable estimates, as the error margins above demonstrate. Why *deliberately* use less reliable data when you want to make claims about the temperature trend?

There is a minus in front of the latter coefficient.

Because the most recent shift is relevant now (a trend is by definition the current direction).

The data is not less reliable. It is just more relevant. The trend prior to the shift in 1998 was not the same as the current trend.

There is a minus in front of the latter coefficient.

Because the most recent shift is relevant now (a trend is by definition the current direction).

The data is not less reliable. It is just more relevant. The trend prior to the shift in 1998 was not the same as the current trend.

No cyclical activity on a geological time scale, though.

How could we know how much atmospheric CO2 there was before humans existed ?

One should remember that we've been having record, or near record, global high-temperature months for quite a long time. We're in the midst of global warming, alas.

...you're reading the margin of error and thinking the minus in the +/- is there by itself. The actual increase or decrease comes just after the year range, and it has no minus; it's positive every time.

So maybe if the temperature went up today, it proves global warming, by your logic.

How could we know how much atmospheric CO2 there was before humans existed ?

Isotope geochemists have developed time series of variations in the 14C and 13C concentrations of atmospheric CO2. One of the methods used is to measure the 13C/12C in tree rings, and use this to infer those same ratios in atmospheric CO2. This works because during photosynthesis, trees take up carbon from the atmosphere and lay this carbon down as plant organic material in the form of rings, providing a snapshot of the atmospheric composition of that time. If the ratio of 13C/12C in atmospheric CO2 goes up or down, so does the 13C/12C of the tree rings. This isn?t to say that the tree rings have the same isotopic composition as the atmosphere ? as noted above, plants have a preference for the lighter isotopes, but as long as that preference doesn?t change much, the tree-ring changes wiil track the atmospheric changes.

Sequences of annual tree rings going back thousands of years have now been analyzed for their 13C/12C ratios. Because the age of each ring is precisely known** we can make a graph of the atmospheric 13C/12C ratio vs. time. What is found is at no time in the last 10,000 years are the 13C/12C ratios in the atmosphere as low as they are today. Furthermore, the 13C/12C ratios begin to decline dramatically just as the CO2 starts to increase ? around 1850 AD. This is exactly what we expect if the increased CO2 is in fact due to fossil fuel burning. Furthermore, we can trace the absorption of CO2 into the ocean by measuring the 13C/12C ratio of surface ocean waters. While the data are not as complete as the tree ring data (we have only been making these measurements for a few decades) we observe what is expected: the surface ocean 13C/12C is decreasing. Measurements of 13C/12C on corals and sponges ? whose carbonate shells reflect the ocean chemistry just as tree rings record the atmospheric chemistry ? show that this decline began about the same time as in the atmosphere; that is, when human CO2 production began to accelerate in earnest.***

In September 2014, according to NOAA data, 1, 413 cities in the US hit the lowest high temperature ever recorded.

If the statistically illiterate could also follow that principle, that would be great. Though at least they're showing that Messrs Dunning and Kruger were correct.

Thanks for the explanation and wikipage! Thanks ThetaIn3D!

However, given that it seems you agree with Humanaut's historical data of atmospheric CO2 data. Are the charts accurate ? Because they seem to show atmospheric CO2 and global temperature are independent ?

I found the chart on this article of "The Thinker" ...
http://www.americanthinker.com/2008/11/ ... it_on.html

The margin of error is bigger than the positive signal? Satellite data is more reliable. It shows a cooling trend.

Not at all, but 16 years will give you an indication. It's definitely getting colder.

Horrible. It's only going to get worse.