* The second IPCC report (1995) states that “data prior to 1400 are too sparse to allow the reliable estimation of global mean temperature” and shows a graph of proxy-derived temperatures for Earth’s Northern Hemisphere from 1400 onward with different details but a similar overall trend to the first report. * The third IPCC report (2001) states that the latest proxy studies indicate “the conventional terms of ‘Little Ice Age’ and ‘Medieval Warm Period’ appear to have limited utility in describing …global mean temperature changes in past centuries.” The report contains the following graph of average temperature changes in Earth’s Northern Hemisphere, showing higher temperatures at present than at any time in the past 1,000 years.
We hereby release a random selection of correspondence, code, and documents.* This graph is called the “hockey stick graph” because the curve looks like a hockey stick laid on its side (click on the footnote for a graphic illustration). The red part of the curve represents modern instrument-measured surface temperatures, the blue represents proxy data, the black line is a smoothed average of the proxy data, and the gray represents the margin of error with 95% confidence.  * This graph has been the subject of disputes in scientific journals,  congressional hearings,  and legal proceedings including a Freedom of Information Act lawsuit.  Just Facts presently does not have the resources to conclusively assess all the competing claims on this issue, but the facts we have verified are as follows: medieval warmth,” and shows the following graph of temperature changes for the Northern Hemisphere over the past 1,300 years.This graph, which is called a “spaghetti graph,” is constructed with data from 12 proxy studies spliced with instrument-measured surface temperatures (the dark black line): * The fifth IPCC report (2013) states that challenges persist in reconstructing temperatures before the time of the instrumental record “due to limitations of spatial sampling, uncertainties in individual proxy records and challenges associated with the statistical methods used to calibrate and integrate multi-proxy information.” This report contains the following spaghetti graphs of proxy studies spliced with instrument-measured surface temperatures (the black lines): * In 2009, an unknown individual(s) released more than 1,000 emails (many dealing with proxy studies) from the University of East Anglia’s Climatic Research Unit (CRU).Hopefully it will give some insight into the science and the people behind it.  Look at the instrumental record!There are huge differences between different regions - Alaska has warmed substantially while eastern North America cooled after the 1950s.