Stoneforge Chronicles

By John Mauer

Global warming is in retreat at the moment, even as CO2 concentration increases. If one looks at the data, increased CO2 concentration does not cause, and has not caused, a large world-wide increase in temperature. The greenhouse effect, however real, is neither large enough nor independent of other effects to cause substantial warming.

In the last article in this series, we showed the measured increase in CO2 concentration and a physically realistic projection of future changes. Here we will look at current temperature data with respect to the CO2 data, and then review the literature that caused such alarm.

Temperature can be measured in many ways, but, for the purpose of looking at the greenhouse effect, the best measurements are of the lower troposphere. The troposphere itself is the lowest portion of Earth’s atmosphere, and is approximately 17 km thick.[1] Satellite measurements of the lower troposphere, about 2.5 km thick, would be the most sensitive to the greenhouse effect, because that is where the heat would be trapped.

A plot of the Northern Hemisphere temperature in the lower troposphere over a recent period[2] shows the temperature holding constant or decreasing, even while the CO2 concentration at the Mauna Loa site[3] (MLO) was increasing. (Mind you, the Mauna Loa site is near the top of this region. Local temperature measurements at Mauna Loa reflect the satellite measurements.)

Several characteristics of this plot deserve mention. First, the large temperature value in 1998 is not spurious, but is the result of a large El Niño effect[4], which quickly dissipated. Other than that effect, the overall temperature appears to hold constant or decrease slightly except for seasonal swings; the CO2 concentration continues to rise.

Close examination of the data shows that the temperature rose early in each year. While this was coincident with seasonally increasing CO2 early on, it dropped off while the CO2 was still rising. Note that increased temperature not only releases CO2 from the oceans but evaporates water vapor as well. And water vapor forms clouds, which reflect sunlight and cause cooling.

The important point to take from this data is not that the greenhouse effect cannot contribute to global temperature, but that it is not the dominant effect.[5]

Because this conclusion is at odds with the 2007 report by the Intergovernmental Panel on Climate Change (IPCC)[6], a look at their referenced data is in order. (Note that the IPCC report summarizes the data from other sources, occasionally very suspect sources.[7])

The main source of global warming visualization comes from a plot of the global temperature for the last 1000 years by Mann, Bradley, and Hughes.[8]

This is really two plots, a blue plot of temperatures estimated mostly from tree rings and a red plot of surface temperatures from various monitors. This plot was dubbed the “hockey stick”, and has been dissected for errors by a plethora of scientists.[9] The details of the controversy are mostly beyond the scope of a popular discussion, so we will concentrate on just two artifacts of the plot.

First, note that the growth at the end of the temperature measurements (red curve) is that same large El Niño effect shown before, although the report fails to mention that. Instead the report represents this change as man-made, without any supporting data. (Models aren’t data.)

Second, look at the blue plot of historical temperatures. These temperatures are taken largely from tree ring proxies. These become temperatures by measuring the growth rings of old trees and relating these to temperature through a process called reconstruction.

Of particular note is the period around the 1960s. Below is a plot of the tree ring data[10] against the surface measurements of temperature[11]. The base period for both curves reflects the 1961-1990 period as specified in the tree ring data.

Two things stand out instantly. First the errors in the tree ring data are large; go back and check out the gray bars in the previous graph. In science, the blue curve is actually far less meaningful than the envelope of possible error.

Second, and most importantly, the trend of the tree ring proxies for temperature is going down while the trend of the measured surface temperature does not. The tree ring data does not faithfully represent known measurements. (This discrepancy was obviously unwanted by this particular group of climate scientists; this tree ring data was dropped from the archived data set[12].)

This, and other data, calls into question the use of tree rings for historical temperature reconstruction. These reconstructions assume that trees responded linearly with temperature. But tree growth can be limited by parameters other than temperature such as water, and, at higher elevations, CO2 concentration. The growth can also be accelerated by these same things; the observed increase in CO2 can fertilize tree growth.[13] This observed growth acceleration indicates that the limiting factor is not temperature, so that tree ring data may not be measuring temperature.

So if tree ring estimates of historical temperature are suspect, what can we use? The other available proxies include ice core data and sea floor sediment from all over the globe. A plot of these various data sets by Loehle[14], normalized to a common baseline, shows a wholly different picture from the tree ring data.

Here, the shaded areas are the dates for the Medieval Warm Period and the Little Ice Age. These periods are well known historically. For instance, Greenland was first settled by the Norse in the 900s, but died out due to increasing cold and ice by the 1400s. Europe, during this time, had long season farming both further north and at higher elevations. Curiously, during the Little Ice Age, Europe recorded increased storms and reduced farming seasons with famine.

A look back at the tree ring data shows that it largely glossed over the Little Ice Age and missed the end of the Medieval Warm Period if the errors bars are ignored. The IPCC commented that the Medieval Warm Period was endemic to the North Atlantic and was not global, but it is hard to have climate be local then and global now. From radioisotope data[15], contaminants are delivered from the Northern Hemisphere to the Southern Hemisphere in about two years. Volcanic contaminates are delivered around the globe, that is, within the same hemisphere, in less time[16].

But the current temperature data and the non-tree ring data makes certain conclusions obvious.

The global temperature of the earth has seen an increase in the last century and a half. However, the increase is not exceptional when compared to historical trends. And CO2 is not the cause, man-made or not.

A note of caution is in order. CO2 concentrations are directly measured; global temperatures are not. All temperature data, while having a relatively local source, has been filtered, censored, averaged, extrapolated, and otherwise massaged to produce the curves given above. In order to be believable, the scientists in question must exhibit a high level of integrity and release accurate data and algorithms on a timely basis during peer review. The scientists who wrote, or contributed to, the IPCC report and provided the temperature curves failed in this regard. Apparently, they have even destroyed original data rather than turn it over to Freedom of Information requests. The IPCC report has been suborned by their work and their lack of scientific integrity.

In summary, global warming is not dominated by burning fossil fuels. As such, political global warming is a hoax. The proponents of global warming claim a consensus, but it is only among themselves. And they have, according to their own emails, made every attempt to control the peer-reviewed literature. This forced unanimity of view, in which contrary opinions are suppressed, can only be termed political zeal. It is certainly not scientific.

Because the current data will not support the global warming fraud, the comment that CO2 is actually causing climate change, not global warming, is now in vogue. There is no scientific basis for such a statement, but that’s for another discussion. Or, perhaps, global cooling should be the next topic, perhaps possible causes of warming, perhaps the source of the CO2.

[1] Wikipedia, Troposphere
[2] Data from NASA Satellite collected and corrected by John Christy, University of Alabama, Huntsville, Atmospheric Science Department
[3] C. D. Keeling, S. C. Piper, R. B. Bacastow, M. Wahlen, T. P. Whorf, M. Heimann, and H. A. Meijer, Exchanges of atmospheric CO2 and 13CO2 with the terrestrial biosphere and oceans from 1978 to 2000. I. Global aspects, SIO Reference Series, No. 01-06, Scripps Institution of Oceanography, San Diego, 88 pages, 2001.
[4] Trenberth, K. E.; et al. (2002). “Evolution of El Niño – Southern Oscillation and global atmospheric surface temperatures”. Journal of Geophysical Research 107 (D8): 4065
[5] Douglass, D.H., J.R. Christy, 2009: Limits on CO2 climate forcing from recent temperature data of Earth. Energy & Environment, 20, 178-189
[6] IPCC, Climate Change 2007: Synthesis Report
[7] For a short summary, Is it time to overhaul the IPCC?, Christian Science Monitor, 2/10/2010
[8] Mann, Michael E.; Bradley, Raymond S.; Hughes, Malcolm K. (1998), “Global-scale temperature patterns and climate forcing over the past six centuries”, Nature 392: 779–787
[9] Wikipedia, Hockey Stick Controversy
[10] K. R. Briffa et al., Nature 391, 678 (1998)
[11] P. Brohan, J.J. Kennedy, I. Harris, S.F.B. Tett and P.D. Jones, Uncertainty estimates in regional and global observed temperature changes: A new data set from 1850, J. G. R., Vol. 111, D12106, 24 June 2006 (HADCRUT3 data set)
[12] Data archived by the National Oceanic and Atmospheric Organization, US Dept. of Commerce, ftp://ftp.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/n_hem_temp/briffa2001jgr3.txt (no guarantees here, they can change the data at will.)
[13] Graybill, D.A. and Idso, S.B., Detecting the Aerial Fertilization Effect of the Atmospheric CO2 Enrichment in Tree Ring Chronologies, Global Biogeochemical Cycles, 7 (1993), 81-95 (There are a lot of regerences on this subject, most very technical.)
[14] Loehle, Craig, Energy & Environment, 18 No. 7+8, 2007
[15] Wikipedia, Carbon-14, check out the delay of the C14 isotope from the atmospheric nuclear tests in going from the Northern Hemisphere (Austria measurement) to the Southern Hemisphere (New Zealand measurement)
[16] Start at NASA Facts On-Line, Volcanoes and Global Cooling and NASA, Earth Science Reference Handbook