Peroxide

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Member Since: February 17, 2007
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Comments to Peroxide

siftbot says...

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bcglorf says...

And the straightforward observation from my point below is that if the reconstructions from the last 2k years show that similar climate change and extremes have occurred naturally then maybe it isn't time to panic just yet.

bcglorf says...

It's not even that I am 'doubting' the proxy measures. I am directly observing that the proxy measures DO NOT register the last 100 years as particularly unusual or abnormal. In fact, the more accurate and improved the proxy reconstructions have become, the more normal the last 100 years appears in those reconstructions.

The proxy reconstructions are as much 0.6 degrees cooler than instrumental records at the exact same point in time. I am objecting to a laymen like in the video coming along and saying the instrumental record's warmth is unprecedented over the last 2k years. Sure the proxy records don't show temperatures as high as the instrumental record in the last 2k years. The proxy records don't even show temperatures as high as the instrumental record in the last 10. The proxy records fail to recreate the temperatures observed in the instrumental record.

Is that making sense or clear what I am talking to?


In reply to this comment by Peroxide:
hmmm, I was aware that we only have thermometric readings of temperature for the last 100-150+ years. So basically you are doubting the ability of tree rings, pollen identification in sediments, and other methods of temperature reconstruction.

If I may reiterate my point, which I made rudely in the video post, I would say that you might be interested to know that if you go back further than 2k years, as in, more than 10k, there are temperature changes that were even greater than 1 degree, however, homo-sapiens was not around to endure them. Irregardless of previous temperature deviation, science tells us that our "freeing-up" of carbon dioxide, and creation of methane, are the culprits of the current temperature increase.

How does our ability to measure the last 2k years change that? or change the fact that we are heading for a 6 degree increase (which would not be uniform, for instance the poles have already warmed more than by 0.8 degrees, while the tropics may have warmed by less than 0.8 degrees)?

I fail to see that you have any point outside of that our estimations going back past 150+ years may be slightly off.

"It is obviously true that past climate change was caused by natural forcings. However, to argue that this means we can’t cause climate change is like arguing that humans can’t start bushfires because in the past they’ve happened naturally. Greenhouse gas increases have caused climate change many times in Earth’s history, and we are now adding greenhouse gases to the atmosphere at a increasingly rapid rate." -s.s.


bcglorf says...

You are exactly right, the red line is directly measured temperature, and it shows that we are indeed breaking records. The trick is it only shows that we have hit the record for the last 100 years for which we actually have a measured record. The temperature over the last 2k years is not directly measured, but derived from proxies like tree rings. Those temperature reconstructions never hit the heights of the measured record. The speaker in the video then declares that current temperature is then a record over 2k years. The trick is to look closer. When we state that the reconstruction of the last 2k years never hits the current measured records it doesn't only mean it never hit them before today, it means that even where the measured temperature hits the record today, the reconstruction STILL doesn't come close to hitting the measured record. Seems very strong evidence that the reconstruction might have missed a record like today that happened over the last 2k years, as clearly they missed THIS ONE.


In reply to this comment by Peroxide:
I can't understand how you are interpreting Mann's graph, you do realize the red line at the end is not a projection, but in fact current measurements...

So how are you coming to the conclusion that we are not (already, if not soon) breaking records?

In reply to this comment by bcglorf:
>> ^alcom:

By your own admission, the composite readings are now at record highs. Nowhere in my previous post did I mention that these measurements were exactly equal to the 0.8 instrumental record. I only said that they followed the same directional trend. Read it and weep, a 2000 year-old record is a 2000 year-old record.
To argue that 'Mann's statement that the EIV construction is the most accurate,' is to willfully ignore all the other data sources. You completely miss the point that instrumental data is by far the most accurate. Proxy reconstructions are relied on in the absence of instrumental data.
The lack of widespread instrumental climate records before the mid 19th century, however, necessitates the use of natural climate archives or “proxy” data such as tree-rings, corals, and ice cores and historical documentary records to reconstruct climate in past centuries.
The curve of this warming trend is gradually accellerating accourding to all data sources, even if you ignore the two instrumental lines. And what a coincidence that it matches the timeline of the industrial revolution. Ignore science at your own peril!
>> ^bcglorf:
What graph are you reading?
CPS Land with uncertainties: Peaked at 0.05 in 600, but yes a new peak in the lat 1990's at 0.15(not 0.8), recent temp is the internal record by only 0.1.
Mann and Jones 2003: current peak at 0.15(not 0.8), but current is the record by 0.25.
Esper et. Al 2002: peaks once in 990 and again in 1990 at negative 0.05, not positive 0.8 nor is current warming a record.
CPS land+ocn with uncertainties: peaks at 0.2 (not 0.8) and only starts at 1500 not sure how much the record would've been set by if it included the year 600 where land alone hit 0.05.
Briffa et al. : Series begins in 1400, but again peaks at 0.15 (not 0.8). Can't tell from the graph how much of a record but by Briffa et al's original 2001 paper it's by 0.2
Crowly and Lowery (2000): peaks at 0.15(not 0.8), granted it current warming sets the record within the series, by 0.25 higher than 1100.
Jones et al. (1999): peaks at 0.05(not 0.8), current is record by 0.1
Oerlemans (2005) and both borehole sample go back less than 500 years. The boreholes who a smooth curve throughout, with warming starting 500, not 100 years ago. They all peak at 0.2 or lower, again not 0.8.

If I repeat my main point, I think it is reinforced by each of the series above. Instrumental measured warming is completely anomalous compared to the proxy reconstructions. The instrumental record peaks fully 0.6 degrees higher than any of the proxy series. How can anyone look at that and NOT object to the declaration that the last 2k years as shown by proxies proves temperatures have been far cooler and more stable than the last 100 years as shown on the instrumental record. If you instead compare like to like, and compare the last 100 years as projected by each proxy and not the instrumental record, you clearly see that the last 100 years is anything but a radical anomaly.
If you accept Mann's statement that the EIV construction is the most accurate, it can be easily said that the last 100 years, as appears in proxy reconstructions, isn't much of an anomaly at all.

>> ^alcom:
Ah, now I see your point, bcglorf. Of the various methodologies, the 2 instrumental record sets of the last 100 years are the only ones that show the extreme spike of temperature. The composite reconstructions have not yet shown data that is above previously held records in the last 2 millennia, with the exception of the following:
CPS Land with uncertainties
Mann and Jones (2003)
Esperg et al. (2002)
CPS land+ocn with uncertainties
Briffa et al. (2005)
Crowely and Lowery (2000)
Jones et al. (1999)
Oerlemans (2005)
Mann et al. Optimal Borehole (2003)
Huang et al. Borehole (2000)
If you closely follow these lines, you will see that each plot above has indeed set 2000 year-old records in the last 25 years within their own recorded plots, even if not as pronounced as the instrumental record highlighted by the red line. I'm not sure why the EIV lines stop at 1850, but I'm also not a climatologist. The instrumental record has more or less agreed with the EIV record since its existence, including an extending cooling trend midway through this century. The sharp divergence is not fully understood perhaps, but I still think it foolish to ignore the provable, measurable and pronounced upward trend in all calculated measurements.
>> ^bcglorf:
>> ^alcom:
After a cursory reading of Mann's Proxy-based reconstructions of hemispheric and global surface temperature variations over the past two millennia, I can't see how climate change deniers can both read about his methodology AND at the same time gripe about a bias towards measurements that support his argument while ignoring conflicting measurements through other means.
These measurements AGREE. The regression measurement data seems to have a wider variance as you go backwards, but they all trend in the same directions both up and down over the last 2000 years. (I'm looking at the graph here: http://www.pnas.org/content/105/36/13252/F3.expansion.html ) converge and climb at the same incredible rate at the end (the last 25 years or so.) Show me ANY scientific data that reports a measurement of +.8°C over such a short period of time.
As for the polynomial curve objection, the variation in measurements over such a limited data set my not yet reveal the true nature of the curve. And Earth's feedback mechanisms may already be at work to counteract the difference in atmospheric composition. For example, trees will grow faster and more quickly in slightly warmer temperatures with elevated CO2 levels, and naturally counteract the effects of fossil fuel burning by simply converting more of it into O2. There are undoubtedly many, many more factors at play. I'm suggesting perhaps that apparent "straight line" graphing is currently the fastest rate of increase possible based on the feedback systems that are at work.
The point is that it is a losing battle, according to the current trend. At some point, these feedback systems will fail (eg., there will come a point when it is so hot in a region that no type of tree will continue to grow and absorb CO2) and worst still, there are things like the methane in permafrost that will exacerbate the problem further. This isn't like a religious doomsday scenario, the alarm bells are not coming from a loony prophet but from real, measurable evidence that so many people continue to ignore. I'd rather be wrong and relieved that there is no climate crisis and clean energy initiatives end up being a waste of time and money than wrong that there IS in fact cause to make serious changes. The doubt that has driven so much misinformation will at some point be exposed for the stupidity that it truly is.

Look closer at the graph in http://www.pnas.org/content/105/36/13252/F3.expansion.html for me. It is the graph I was talking about. NONE of the reconstructions from proxy sources spike up to 0.8 at the end. The all taper off short of 0.2, the bold red(instrumental) line makes them very hard to see precisely. The closest curve to the red that can be seen is the grey one, which is in fact the other instrumental record they include, and even it stops below 0.6. What is more, the green EIV reconstruction peaks past 0.2 twice over the last 2k years. It also spikes much more quickly around 900 and 1300. Most noteworthy of all is if you read further up in Mann's report, because the big reason for re-releasing this version of his paper is to evaluate the EIV method because statisticians recommended as far more appropriate. Mann notes in his results as well stating that of all the methods, 'we place the greatest confidence in the EIV reconstructions'.
My key point is glaringly obvious when looking at Mann's data, even on the graph. The instrumental record of the last 100 years spikes in an unprecedented fashion. The proxy reconstruction of that same time frame does not. Two different methodologies yielding 2 different results. The speaker in this video points at that and declares it's because of human emissions 100 years ago, but we must look at the fact the methodology changed at that exact point too. The EIV reconstruction was the latest attempt to bridge the gap between the proxy and instrumental records, and although it more closely matches the instrumental, it still doesn't spike 0.8 degrees over the last 100 years, and more interestingly it also shows much greater variation over the last 2k years. Enough variation in fact that if you look at just the green EIV line, the last 100 years isn't particularly note worthy or anomalous.





The speaker in the video makes a very big deal though about the current 0.8 of the instrumental record, and similarly a very big deal about it being unprecedented in the last 10k years, which you have to admit has been plainly proven as apples to oranges.

Yes, most current proxies show a 2k year old record, except the EIV which is the most recent and deemed most accurate record. If you can accept comparing reconstructions using the same proxy data but different analysis, the EIV proxy reconstruction shows that current temperatures are not record breaking at all.

If you want to say that "the curve of this warming trend is gradually accellerating accourding to all data sources" I'd say you need also observe warming trends in the reconstructions over the last 2k years. Again, the rate of change over the last century is not unprecedented in the proxy records over the last 2k years. You can again plainly see that similarly or more severe warming and/or cooling within the last 2k years in the proxy reconstructions.


MrFisk says...

Not at all, more people should downvote. But just because global warming is real, it's by no means uncontroversial. And we can agree it's eco, right?
In reply to this comment by Peroxide:
sorry for the downvote, you probably don't care, but I would argue that the controversy tag being applied to this issue was at most appropriate up until about 2005.

In reply to this comment by MrFisk:
*nochannel
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