Synonyms for carbon dating
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.
* 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.
The paper found that 92% of these stations are positioned in sites that can cause errors of 1.8ºF (1ºC) or more.  For example, some stations are located over asphalt (making them hotter at certain times), and others are located in partial shade (making them cooler at certain times).
K., the Earth’s average temperature warmed by 1.4ºF (0.8ºC) between the 1850s and 2000s, mostly during 1911-19-1998: * Sources of uncertainty in surface temperature data involve “very incomplete” temperature records in the earlier years, “systematic changes in measurement methods,” “calculation and reporting errors,”       data adjustments that are performed when instruments are moved to different locations, instrument precision, instrument positioning, and missing documentation/raw data.  definitive assessment of uncertainties is impossible, because it is always possible that some unknown error has contaminated the data, and no quantitative allowance can be made for such unknowns. * Oceans constitute about 71% of the Earth’s surface. Changes in air temperature over the world’s oceans are typically based on measurements of water temperature at depths varying from less than 3 feet to more than 49 feet.  This data is combined with changes in air temperature over land areas to produce global averages.  contrasted water and air temperature changes in the tropical Pacific Ocean using three sources of measurements.
One of these was a series of buoys, each containing thermometers located ten feet above the water and at one foot below the water.
The largest gap between any of the datasets in any year was 0.38ºF (0.21ºC), and the smallest gap was 0ºF/C: * To reconstruct global average temperatures in the era before instrumental measurements were made on a global scale, scientists use proxies that respond to changes in climate, such as the widths of tree rings and certain elements of the geological record, to estimate temperature variations in the past.  * The Intergovernmental Panel on Climate Change (IPCC) is a scientific body established in 1988 by the United Nations and World Meteorological Organization.
It is the “leading international body for the assessment of climate change,” * The first IPCC report (1990) contains the following graph of average global temperature changes over the past 1,000 years based upon proxies.