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Re: our early discussion on the reality, possible lack thereof, of the phenomenon called “global warming” and its postulated causes.

It is helpful, to occasionally refer to the beginning of a discussion, to bring it back to the original track. In that spirit, please allow me to repost a few items from previous posts below (my previous post in italicized red and quoted site excerpts in blue):

From post # 8: Author’s [referring to the original article beginning this thread] implied proposed logic chain:

Premise: The earth’s climate is becoming warmer than it should from natural processes.
Premise: This warming is the result of human activity.
Conclusion: Changing human activity will stop global warming.

This syllogism is invalid as well as unsound from a number of perspectives. First, the major premise contains an unproven assumption that the current postulated warming is not part of a natural statistical variation. Second, the minor premise is unproven and, hence, the conclusion is potentially false. Third, the conclusion is not inevitable as, even if the second premise were true, it may be too late to reverse any trend or, perhaps, a natural mechanism will mitigate the situation such as a increase in plant life (like algae) to absorb and convert CO2 or other green house gases.

In post #39 to DBrow you cited the Vostok ice core drillings as a part of your post. For the sake of discussion, let us assume that the inferences and the graph from this source you provided are accurate and representative of global temperatures for the time frame represented. Temperatures, in previous cycles shown on this graph have been equal to, or greater than, the currently recorded temperatures. Given that the previous cycles were many thousands of years before the industrial age, there is no way that any of them could be due to any anthropogenic influence. Therefore, the only logical conclusion that can be inferred from this information is that the current temperatures may be driven by the same natural mechanisms that drove previous temperatures of equal or greater magnitude.

There are no data (accurate and precise measures in contrast to estimates, extrapolations and assumptions) of phenomena such as solar activity, volcanic activity, inorganic and/or organic sources of atmospheric gases, etc., that can be used to statistically explain previous long term change cycles observed in the ice core drillings. In fact, there are no (detailed, comprehensive and confirmed by multiple scientific sources) data that can be described as accurate and precise in statistical terms for possible “drivers of change” of global climate phenomena prior to the 1940’s. Consequently, the argument put forward that “today’s” temperatures are “global warming” due to anthropogenic influences cannot be statistically substantiated. In fact, a strong statistical case can be established (with acceptable alpha and beta risk) that “today’s” temperatures are well within the (plus or minus) 3-sigma limits of a normally varying, natural process.

No counter-argument you have presented nor source you have referenced (and I have reviewed them all in addition to independent research on my own) has successfully contradicted the above arguments. Therefore, my assertion concerning the author’s lack of indisputable facts and logical support for his thesis stands unrefuted.

In the interest of space on this thread and time, I will not repeat the rest of my posts. Rather, I invite you to present data (accurate and precise measures in contrast to estimates, extrapolations and assumptions) to support your opposition to my statements. Opinions of some in the “climate science community’s” are just that: “opinions.” I might point out in this topic area that the opinions agree on only one thing: there is insufficient information to reach indisputable conclusions.

Below are a series of excerpted, direct quotes with some key phrases emphasized from just few of the sites which you have referenced in previous discussion:

The Maunder Minimum coincided with the middle — and coldest part — of the so-called Little Ice Age, during which Europe and North America, and perhaps much of the rest of the world, were subjected to bitterly cold winters. Whether there is a causal connection between low sunspot activity and cold winters is the subject of ongoing debate. [emphasis added] Some scientists believe that solar variation drives climate change more than carbon dioxide does.

Recently published research suggests that the Sun's rotation slowed in the deep Maunder minimum (1666–1700).[1] …The mechanism behind the Sun's expansion and contraction is still unclear [emphasis added] …

For much of the underdeveloped world there is a dearth of early historical digital climate data. The well known plots of global temperature trends from the 1850 to the present should really be thought of as basically just representing the U.S. and Europe prior to 1900, perhaps even up to 1930 or 1940, depending on the gridding algorithm used. Therefore, without early data from Africa, South America, and other developing regions, our knowledge of global climate trends is severely limited. [emphasis added]

Even if all these processes were fully understood conceptually, which isn't the case [emphasis added] …

Temperatures, in previous cycles shown on this graph have been equal to, or greater than, the currently recorded temperatures. Given that the previous cycles were many thousands of years before the industrial age, there is no way that any of them could be due to any anthropogenic influence. Therefore, the only logical conclusion that can be inferred from this information is that the current temperatures may be driven by the same natural mechanisms that drove previous temperatures of equal or greater magnitude.

Faulty reasoning. The forcing mechanisms of previous cycles are known -- and one of the primary mechanisms is increased atmospheric CO2. In the context of the current climate system, the increase in CO2 from 280 ppm to 360 ppm would be expected to cause a warming trend. There are currently no other forcings operating sufficiently to cause such an increase. Bottom line: No natural mechanism can be identified that is sufficient to cause the currently observed warming. The only forcing that is sufficient is anthropogenic greenhouse gases.

There are no data (accurate and precise measures in contrast to estimates, extrapolations and assumptions) of phenomena such as solar activity, volcanic activity, inorganic and/or organic sources of atmospheric gases, etc., that can be used to statistically explain previous long term change cycles observed in the ice core drillings.

Paleoclimatologists use the data that is available to determine the forcings operating in past climate states. If you have a problem with how that is done, your argument is not with me, because all I can do is describe how such research is conducted.

In fact, there are no (detailed, comprehensive and confirmed by multiple scientific sources) data that can be described as accurate and precise in statistical terms for possible “drivers of change” of global climate phenomena prior to the 1940’s.

This is incorrect. The GHCN has sufficient quality-controlled data to examine 20th century trends. If you're going to argue about data quality, it's a non-starter, because the analysis of current trends and future changes is not critically connected to the 20th century record.

Consequently, the argument put forward that “today’s” temperatures are “global warming” due to anthropogenic influences cannot be statistically substantiated.

This statement is also probably incorrect. For one thing, the trend of main concern is the warming since the 1970s -- and there is sufficient global data of high quality to determine that trend is happening. Because there are no other apparent forcings of note operating during this period other than greenhouse gas forcing (and that's largely anthropogenic in nature), the attribution of the current warming trend to anthropogenic GHG forcing is well-supported.

In fact, a strong statistical case can be established (with acceptable alpha and beta risk) that “today’s” temperatures are well within the (plus or minus) 3-sigma limits of a normally varying, natural process.

Specious argument. The past range of values is not the primary way in which the current "diagnosic" of anthropogenic GHG forcing is made.