Hockey stick graph

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A "hockey pencil" imitating the shape of an ice hockey stick, with the eraser being the blade; its bottom edge here is a fair representation of a hockey stick graph. If the graph starts above zero and drops a little before rising, it may be called a J curve. Hockey pencil.jpg
A "hockey pencil" imitating the shape of an ice hockey stick, with the eraser being the blade; its bottom edge here is a fair representation of a hockey stick graph. If the graph starts above zero and drops a little before rising, it may be called a J curve.

A hockey stick graph or hockey stick curve is a graph, or curve shape, that resembles an ice hockey stick, in that it turns sharply from a nearly flat "blade" to a long "handle".

In economics, [1] [2] marketing, [3] and dose–response relationships, [4] [5] a hockey stick graph is one in which the "blade" is near zero (hugging the floor) before the graph turns upward to a long nearly straight increasing section. By contrast, in climate science, the well-known hockey stick graph (global temperature) describing 1000 years of global or hemispheric temperature has the "handle" horizontal and "blade" turning upward. [6] This difference of viewpoint is remarked on in a 2020 novel about climate change:

Insurance companies in a panic at last year's reports. Pay-outs at about one hundred billion USD a year now, going higher fast, as in hockey stick graph. Insurance companies insured by re-insurance. These now holding short end of stick (tall end of stick?).

Kim Stanley Robinson, The Ministry for the Future: A Novel
The northern hemisphere hockey stick graph - smoothed curve shown in blue with its uncertainty range in light blue, overlaid with green dots showing the 30-year global average of the 2013 reconstruction. The red curve shows measured global mean temperature, according to HadCRUT4 data from 1850 to 2013. T comp 61-90.pdf
The northern hemisphere hockey stick graph – smoothed curve shown in blue with its uncertainty range in light blue, overlaid with green dots showing the 30-year global average of the 2013 reconstruction. The red curve shows measured global mean temperature, according to HadCRUT4 data from 1850 to 2013.
Functions with a hockey stick curve shape that bound or approximate the median of a gamma distribution Gamma distribution median Lyon bounds.png
Functions with a hockey stick curve shape that bound or approximate the median of a gamma distribution

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<span class="mw-page-title-main">Blade</span> Sharp cutting part of a weapon or tool

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<span class="mw-page-title-main">Temperature record of the last 2,000 years</span> Temperature trends in the Common Era

The temperature record of the last 2,000 years is reconstructed using data from climate proxy records in conjunction with the modern instrumental temperature record which only covers the last 170 years at a global scale. Large-scale reconstructions covering part or all of the 1st millennium and 2nd millennium have shown that recent temperatures are exceptional: the Intergovernmental Panel on Climate Change Fourth Assessment Report of 2007 concluded that "Average Northern Hemisphere temperatures during the second half of the 20th century were very likely higher than during any other 50-year period in the last 500 years and likely the highest in at least the past 1,300 years." The curve shown in graphs of these reconstructions is widely known as the hockey stick graph because of the sharp increase in temperatures during the last century. As of 2010 this broad pattern was supported by more than two dozen reconstructions, using various statistical methods and combinations of proxy records, with variations in how flat the pre-20th-century "shaft" appears. Sparseness of proxy records results in considerable uncertainty for earlier periods.

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<span class="mw-page-title-main">Hockey stick graph (global temperature)</span> Graph in climate science

Hockey stick graphs present the global or hemispherical mean temperature record of the past 500 to 2000 years as shown by quantitative climate reconstructions based on climate proxy records. These reconstructions have consistently shown a slow long term cooling trend changing into relatively rapid warming in the 20th century, with the instrumental temperature record by 2000 exceeding earlier temperatures.

<span class="mw-page-title-main">Ice hockey stick</span>

An ice hockey stick is a piece of equipment used in ice hockey to shoot, pass, and carry the puck across the ice. Ice hockey sticks are approximately 150–200 cm long, composed of a long, slender shaft with a flat extension at one end called the blade. National Hockey League (NHL) sticks are up to 63 inches long. The blade is the part of the stick used to contact the puck, and is typically 25 to 40 cm long. Stick dimensions can vary widely, as they are usually built to suit a particular player's size and preference. The blade is positioned at roughly a 135° angle from the axis of the shaft, giving the stick a partly 'L-shaped' appearance. The shaft of the stick is fairly rigid, but is slightly elastic to improve shot performance.

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Malcolm K. Hughes is a meso-climatologist and Regents' Professor of Dendrochronology in the Laboratory for Tree-Ring Research at the University of Arizona.

<i>The Hockey Stick Illusion</i> 2010 book by Andrew Montford

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The Wegman Report was prepared in 2006 by three statisticians led by Edward Wegman at the request of Rep. Joe Barton of the United States House Committee on Energy and Commerce to validate criticisms made by Stephen McIntyre and Ross McKitrick of reconstructions of the temperature record of the past 1000 years, in particular the reconstructions by Mann, Bradley and Hughes of what had been dubbed the hockey stick graph.

The North Report was a 2006 report evaluating reconstructions of the temperature record of the past two millennia, providing an overview of the state of the science and the implications for understanding of global warming. It was produced by a National Research Council committee, chaired by Gerald North, at the request of Representative Sherwood Boehlert as chairman of the U.S. House of Representatives Committee on Science.

References

  1. Society of Plastics Engineers. Technical Conference Proceedings, Part I. Society of Plastics Engineers. 1985. Retrieved 17 August 2022. The hockey-stick graph, which shows a magnificent turnaround in our business starting tomorrow, is familiar to all. This is partly the fault of marketing managers who, by nature, tend to be optimists; but it is also the fault of top management, who will not accept any project that promises less than spectacular results.
  2. Taylor, John B. (1995). Economics. Houghton Mifflin. p. 33. ISBN   9780395660300 . Retrieved 17 August 2022. The long handle of the hockey stick is the sharp increase in the debt in the 1980s and 1990s. The part of the hockey stick that you hit the ball or puck with represents slower increases ...
  3. Halfmill, Tom (July 1999). "Who Will Wire Your Home?". Maximum PC: 37. Retrieved 17 August 2022. As usual, industry pundits are trotting out their all-purpose hockey-stick graphs to show that home networking will soon be a huge market.
  4. Yanagimoto, Takemi; Eiji Yamamoto (1979). "Estimation of safe doses: critical review of the hockey stick regression method". Environmental Health Perspectives. 32: 193–199. doi:10.1289/ehp.7932193. PMC   1637920 . PMID   540593. The hockey stick regression method is a convenient method to estimate safe doses, which is a kind of regression method using segmented lines.
  5. Cornfield, Jerome (18 November 1977). "Carcinogenic Risk Assessment". Science. 198 (4318): 693–699. Bibcode:1977Sci...198..693C. doi:10.1126/science.910152. PMID   910152 . Retrieved 17 August 2022. A simplified model in which a toxic substance is activated and deactivated in separate and simultaneous reactions is presented and the dose response curve implied by the model is deduced. This curve has the general form of a hockey stick, with the striking part flat or nearly flat until the dose administered saturates the deactivation system, after which the probability of a response rises rapidly.
  6. Kerr, Richard A (2006). "Yes, it's been getting warmer in here since the CO2 began to rise". Science. 312 (5782): 1854. doi:10.1126/science.312.5782.1854. PMID   16809492. S2CID   8266929. The resulting temperature curve sloped gently downward for most of the millennium (the handle of the hockey stick), then rose sharply into the 20th century (the blade) ...