Over at Watt’s Up With That?, they ran the data from a NASA study done on an ice core from Greenland, among others. The post is here.
Included of course are some stellar graphs and this conclusion:
In fact for the entire Holocene — the period over which, by some odd coincidence, humanity developed agriculture and civilization — the temperature has been higher than now, and the trend over the past 4000 years is a marked decline. From this perspective, it’s the LIA that was unusual, and the current warming trend simply represents a return to the mean. If it lasts.
In other words, over a 12,000 year period, the ice core from Greenland produced evidence that in the near past, it had been warmer in Greenland than any time in the early 20th century.
With all this talk about reproducing results, I decided to download the data from NASA, which you can find here, and see if I can recreate the findings in Greenland, posted at Watt’s Up With That? As a side note, it proved more difficult than I imagined. My Excel (actually NeoOffice, based on OpenOffice) skills are rusty and it took most of the evening to learn how to import the data from the the NASA text file into a workable data set in a spreadsheet.
First, here’s the required citation required by NASA and their explanation of the study and data:
NAME OF DATA SET: GISP2 Ice Core Temperature and Accumulation Data LAST UPDATE: 3/2004 (Original Receipt by WDC Paleo) CONTRIBUTOR: Richard Alley, Pennsylvania State University. IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2004-013 SUGGESTED DATA CITATION: Alley, R.B.. 2004. GISP2 Ice Core Temperature and Accumulation Data. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series #2004-013. NOAA/NGDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Alley, R.B. 2000. The Younger Dryas cold interval as viewed from central Greenland. Quaternary Science Reviews 19:213-226. ADDITIONAL REFERENCE: Cuffey, K.M., and G.D. Clow. 1997. Temperature, accumulation, and ice sheet elevation in central Greenland through the last deglacial transition. Journal of Geophysical Research 102:26383-26396. GEOGRAPHIC REGION: Greenland PERIOD OF RECORD: 49 KYrBP – present DESCRIPTION: Temperature interpretation based on stable isotope analysis, and ice accumulation data, from the GISP2 ice core, central Greenland. Data are smoothed from original measurements published by Cuffey and Clow (1997), as presented in Figure 1 of Alley (2000). ABSTRACT: Greenland ice-core records provide an exceptionally clear picture of many aspects of abrupt climate changes, and particularly of those associated with the Younger Dryas event, as reviewed here. Well-preserved annual layers can be counted confidently, with only 1% errors for the age of the end of the Younger Dryas 11,500 years before present. Ice-flow corrections allow reconstruction of snow accumulation rates over tens of thousands of years with little additional uncertainty. Glaciochemical and particulate data record atmospheric-loading changes with little uncertainty introduced by changes in snow accumulation. Confident paleothermometry is provided by site-specific calibrations using ice-isotopic ratios, borehole temperatures, and gas-isotopic ratios. Near-simultaneous changes in ice-core paleoclimatic indicators of local, regional, and more-widespread climate conditions demonstrate that much of the Earth experienced abrupt climate changes synchronous with Greenland within thirty years or less. Post-Younger Dryas changes have not duplicated the size, extent and rapidity of these paleoclimatic changes.
Some things to be aware of…. The data set provided covers a period of 49,000 years, roughly 47,000 BC until 1913. Second, the authors seem to be pretty sure that the ice core samples are extremely robust indicators of temperature over time.
Without further ado, let’s look at what the NASA numbers say. The first chart plots the temperatures from 47,000 BC until 1913 (note the Greenland temps are below zero Celsius):
Click to enlarge
It has been a long time since grade school and I had to look it up, but last ice age ended some 12,000 years ago (see this article). According to NASA, according to Watt’s Up with That? and now according to my math, Greenland’s ice record is showing that temperatures have been “warm” for over 12,000 years! No cars, no factories, and precious few humans existed during most of this warming cycle. Wonder how Al Gore explains this?
Let’s take a closer look at the data:
click to enlarge
So a closer look at the graph reveals that the famous “Medieval Warming period” was in fact warmer than the early 20th century.
Okay, one more step backwards in time:
click to enlarge
Now, imagine that, Greenland’s ice core shows that it was almost 2 degrees warmer during the rise of the Roman Empire than it was during the zenith of the British Empire.
What have we learned? That NASA’s data and Watt’s Up With That’s? work on it can be replicated.
Second, the long term climate data points to something the short term graphs from the IPCC fail to catch and that is that the earth warmed and has maintained a fairly stable climate since the last ice age, as evidenced by the Greenland ice core.
One problem that the AGW crowd may point to, is the lack of data post 1913. But that is missing the greater point. The global warming camp claims that our warming is “unprecedented”, yet the true long term record shows that historically recent temperatures in Greenland are well below high points in year in the graph’s year zero (which would be either 1BC or 1 AD*) and 1000. It would take almost 1.5º C increase in temperature in the here and now to equal high temperature shown for the somewhere around 75BC..
Yet the famous “hockey stick” graph claims only a .6ºC increase in temperature during the last quarter of the 20th century.
For the sake of argument, let’s say the IPCC and CRU are right, and global temperatures have increased .6ºC since 1913. Just for illustrative purposes only, what would that look like graphed onto the Greenland ice core data (and yes I know, it isn’t scientific, but it does suggest the tenuous conclusions of the AGW data is highly unlikely):
click to enlarge
If global temperatures have increased by the IPCC’s .6ºC, today’s temperatures are still less than those recorded by the Greenland ice core in 1000 AD. If global temperatures have increased by 1ºC, they still would not exceed the temperatures mankind saw in the year 0!
The point? Even if the global warming crowd is right, and the earth warmed from 1980 to 2000, historically, that would be well within the long term climatic record.
In other words, the AGW crowd lacks a true historical perspective.
What they do possess is an ideological bent that requires them to take modern temperatures out of historical context to further their goal of the de-industrialization of the first world through greater international government and less personal freedom. Maybe we should call it Green communism.
*Update: As a reader noted, there is no year zero, just 1BC and 1AD. I should have made it clearer that I was referring to the way that Excel handled the data. Basically, the way the data was presented, it subtracted X years from 2010. Some of the data was fractional and thus Excel rounded to the closest date.
And, consider it was 2am when I finished running the data, I wasn’t in the mood to adjust the graph. But kudos for the catch and it points to the fact that true peer review isn’t always favorable!
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Take a look at the actualy GISP2 ice core data over the past 150 years: slight decrease in temperatures of .6C.
Next take a look at the temperature record (both sea and land) for the entire world: Increase of about 1.2C
Rational thinking would say that Greenland is a very poor proxy for what the rest of the world is doing. Quit cherry-picking data that just supports your own point of view and start looking at the system as a whole. The climate of the world is more than 1 data set.
The problem is, the CRU, et al, do cherry pick their data. For instance, surface temperature in Antarctica is based on ONE station on the continent’s northern most peninsula. The ice cores have the benefit of telling a consistent tale over time, while land temperatures for instance have to deal with stations to drop out, move, or are poorly placed.
And, one more thing, isn’t the main argument from the AGW crowd that the Arctic is melting?
Yet when points out that the crown jewel of the Gore and company’s argument is wrong, then that particular data is cherry picked?
That isn’t consistent thinking there Zach.