Scientists often use statistics like a drunk uses a lamp-post, more for support than illumination.
The hardest tumble a [scientist] can make is to fall over his own [data].
Ambrose Bierce (as modified by me)
Truth does not change because it is, or is not, believed by a majority of the people.
Truth is so precious that [it] should always be attended by a bodyguard of lies.
From Wikipedia: Garbage In, Garbage Out (coined as a pun on the phrase First In, First Out, a merchandising phrase) is an aphorism in the field of information technology. It is used primarily to call attention to the fact that computers will unquestioningly process the most nonsensical of input data (garbage in) and produce nonsensical output (garbage out).
Norse seafaring and colonization around the North Atlantic at the end of the 9th century indicated that regional North Atlantic climate was warmer during medieval times. Paleo-climatic records have made it apparent that the “Medieval Warm Period” temperatures were comparable to temperatures during the 20th Century. The “Little Ice Age” then followed this warm period and lasted from the 15th to the 19th Centuries [Medieval Warm Period – 9th to 13th Centuries (from the National Climate Data Center)].
What caused the Medieval Warm Period to end and the Little Ice Age to come and then go? Modern climate scientists do not understand how various alignments of solar, cosmic, oceanic, atmospheric and planetary forces control the warm-cool rhythms of planet earth. However, what cannot be disputed is that these highly significant temperature shifts occurred in the absence of anthropomorphically generated CO2 production. Indeed, man-made CO2 production didn’t begin in earnest until after World War II.
“At the end of the little ice age (which, by the by, produced the devastating winter at Valley Forge, 1777-1778, and the “Year without Summer,” 1816), the initial warming of 1850-1900 was followed by perhaps an additional overall 1.3 degrees Fahrenheit (0.8 degrees Celsius) of warming during the twentieth century. However, it was not a steady rise in temperatures, proportionate to increasing atmospheric carbon dioxide levels, as “manmade climate disaster” themes suggest. Instead, Earth warmed noticeably from 1900-1940, cooled slightly 1940-1975 (“most scientists” worried about another little ice age), warmed again 1975-1995 (“most scientists” feared global warming), and exhibited little change from then to the present. 2000-2010 was “the hottest decade ever,” and 2010 “is shaping up to be the hottest year on record,” NASA and NOAA breathlessly announced … on July 28. But before you say kaddish or “requiescat in pace” for Mother Earth, keep the previous caveats in mind and note a few other realities. One, only a few hundredths of a degree separate the 2010 decade from the similarly very warm 1930s – and, two, NASA and other researchers refuse to release their raw temperature data and analytical methods, so that independent researchers can examine their calculations and claims.” (Do You Believe In Magic Numbers? by Paul Driessen).
The Moscow-based Institute of Economic Analysis (IEA) accused the Hadley Center of Britain’s Meteorological Office stating they deliberately relied on a carefully selected 25% of Russia’s weather stations that fit its theory of global warming. By ignoring those that don’t, the Russians say, the CRU overestimated warming in the country by more than half a degree Celsius. Russia accounts for 12.5% of the earth’s land mass and has weather stations throughout, so ignoring vast swaths of it can greatly skew any analysis. The IEA says CRU ignored data covering 40% of Russia, preferring data from urban centers and data that showed a warming trend. On the final page of the IEA report is a chart that shows the CRU’s selective use of Russian data produced 0.64C more warming than using all the data would have done (ClimateGate Fallout: Russian Think Tank Says Temperature Data was ‘Cherry-Picked,’ by Julia Seymour).
In a March 2004 email from CRU director Phil Jones he admits that he: “Recently rejected two papers (one for JGR and for GRL) from people saying CRU has it wrong over Siberia. Went to town in both reviews, hopefully successfully. If either appears (in these journals) I will be very surprised, but you never know with GRL.” (JGR is the Journal of Geophysical Research and GRL is the official publication of the American Geophysical Union). Siberia has played another role in the “garbage in” data analysis. In 1995, a paper by the CRU asserted the medieval warm period was actually really cold. It relied on tree ring data from trees on Siberia’s Yamal Peninsula. Here too data were carefully selected. Those from just 12 trees from 252 cores in the Yamal data set were used. A larger set of 34 tree cores from the vicinity shows no dramatic recent warming, and warmer temperatures in the Middle Ages. They weren’t used.
“The temperature records cannot be relied on as indicators of global change,” said John Christy, professor of atmospheric science at the University of Alabama in Huntsville, a former lead author on the IPCC. The doubts of Christy and a number of other researchers focus on the thousands of weather stations around the world, which have been used to collect temperature data over the past 150 years. These stations, they believe, have been seriously compromised by factors such as urbanisation, changes in land use and, in many cases, being moved from site to site.
Christy has published research papers looking at these effects in three different regions: east Africa, and the American states of California and Alabama. “The story is the same for each one,” he said. “The popular data sets show a lot of warming but the apparent temperature rise was actually caused by local factors affecting the weather stations, such as land development.”
The IPCC faces similar criticisms from Ross McKitrick, professor of economics at the University of Guelph, Canada, who was invited by the panel to review its last report. The experience turned him into a strong critic and he has since published a research paper questioning its methods. “We concluded, with overwhelming statistical significance, that the IPCC’s climate data are contaminated with surface effects from industrialisation and data quality problems. These add up to a large warming bias,” he said.
It would actually be heartening if this were simply bad science. I have seen lots of that in my 40 years in academics. But I believe that data were cherry-picked. Global warming science is badly contaminated and not just with faulty data. So, garbage in, garbage out.