ملف:Holocene Temperature Variations.png
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Holocene_Temperature_Variations.png (600 × 400 بكسل حجم الملف: 52 كيلوبايت، نوع MIME: image/png)
The main figure shows eight records of local temperature variability on multi-centennial scales throughout the course of the Holocene, and an average of these (thick dark line). The data are for the period from 10000 BC to 2000 AD, which is from 12000 BP to the present time. The records are plotted with respect to the mid 20th century average temperature, and the global average temperature in 2004 is indicated. An inset plot compares the most recent two millennia of the average to other recent reconstructions. At the far right of this insert plot, it is possible to observe the emergence of climate from the last glacial period of the current ice age. During the Holocene itself, there is general scientific agreement that temperatures on the average have been quite stable compared to fluctuations during the preceding glacial period. The above average curve supports this belief. However, there is a slightly warmer period in the middle which might be identified with the proposed Holocene climatic optimum. The magnitude and nature of this warm event is disputed, and it may have been largely limited to high northern latitudes.
Because of the limitations of data sampling, each curve in the main plot was smoothed (see methods below) and consequently, this figure can not resolve temperature fluctuations faster than approximately 300 years. Further, while 2004 appears warmer than any other time in the long-term average, and hence might be a sign of global warming, it should also be noted that the 2004 measurement is from a single year (actually the fourth highest on record, see Image:Short Instrumental Temperature Record.png for comparison). It is impossible to know whether similarly large short-term temperature fluctuations may have occurred at other times, but are unresolved by the available resolution. The next 150 years will determine whether the long-term average centered on the present appears anomalous with respect to this plot.
Since there is no scientific consensus on how to reconstruct global temperature variations during the Holocene, the average shown here should be understood as only a rough, quasi-global approximation to the temperature history of the Holocene. In particular, higher resolution data and better spatial coverage could significantly alter the apparent long-term behavior (see below for further caveats). For another estimate of Holocene temperature fluctuations, see: [1]
While any conclusions to be drawn from the long-term average must be considered crude and potentially controversial, one can comment on a number of well established inferences from the individual curves contributing to the average. First, at many locations, there exist large temperature fluctuations on multi-centennial scales. Hence, climate change lasting for centuries appears to be a common feature of many regions. Assuming the timing information from these records is reasonably accurate, it appears that in many cases large changes at any particular site may occur without correlating to similarly large changes at other sites. Secondly, it is also notable that different locations appear to take different amounts of time to reach typical Holocene conditions following the last glacial termination. Scientists generally agree that warming concluded in the far Southern Hemisphere earlier than in most other regions. In part, the prolonged climate change may be related to prolonged changes in sea level, which took till roughly 6000 years ago to reach near modern levels. Some of the differences may also reflect timescale uncertainties.
Dragons flight's Temperature Record Series |
This figure is part of a series of plots created by Dragons flight to illustrate changes in Earth's temperature and climate across many different time scales. |
Time Period: 25 yrs | 150 yrs | 1 kyr | 2 kyr | 12 kyr | 450 kyr | 5 Myr | 65 Myr | 500 Myr |
For articles related to this topic see: Temperature record |
هذه graph الصورة / الصورتان باستعمال رسومات متجهية ملفات رسوميات شعاعية.It is recommended to name the SVG file "Holocene Temperature Variations.svg" - then the template Vector version available (or Vva) does not need the new image name parameter. |
To construct this plot, eight data sources (listed below) were selected on the basis of good temporal resolution (preferably ~100 years or less per data point) and coverage of the last 12 kyr. Six of the eight specifically reported temperature and were used as is. The other two reported unscaled temperature proxies and were scaled as described in Notes below. Each curve was smoothed by a Gaussian weighted filter to produce a history of the Holocene temperature variations at that site with approximately 300 year resolution (one exception, see notes). These smooth curves were adjusted to have the same mean over the interval 100-6000 years BP. The average of these curves was then constructed, and the alignment relative to modern day determined by comparing the average over the interval 250-1900 AD relative to the three short-term proxies shown in inset (for details on those plots, see: Image:2000 Year Temperature Comparison.png). Note that the short-term proxies are not at all used in constructing the average itself.
The following data sources were used in constructing the main plot:
Additional data used in inset plot and for matching temperature scale to modern values. Colors match those used in Image:2000 Year Temperature Comparison.png.
This figure was prepared by Robert A. Rohde from publicly available data and is incorporated into the Global Warming Art project. Most, but not all, of the original data is available from [3].
يسمح نسخ وتوزيع و/أو تعديل هذه الوثيقة تحت شروط رخصة جنو للوثائق الحرة، الإصدار 1.2 أو أي إصدار لاحق تنشره مؤسسة البرمجيات الحرة؛ دون أقسام ثابتة ودون نصوص أغلفة أمامية ودون نصوص أغلفة خلفية. نسخة من الرخصة تم تضمينها في القسم المسمى GNU Free Documentation License.http://www.gnu.org/copyleft/fdl.htmlGFDLGNU Free Documentation Licensetruetrue |
هذا الملفُّ مُرخَّص بموجب رخصة المشاع الإبداعي نسبة المُصنَّف إِلى مُؤَلِّفه - المشاركة بالمثل 3.0 العامة | ||
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تمت إضافة علامة الترخيص لهذا الملف كجزء من رخصة جنو للوثائق الحرة تحديث الترخيص.http://creativecommons.org/licenses/by-sa/3.0/CC BY-SA 3.0Creative Commons Attribution-Share Alike 3.0truetrue |
أَعمالٌ مُشتقَّة مِن هذا الملفِّ: Variacions de temperatura a l'Holocè.png
اضغط على زمن/تاريخ لرؤية الملف كما بدا في هذا الزمن.
زمن/تاريخ | صورة مصغرة | الأبعاد | مستخدم | تعليق | |
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حالي | 02:02، 7 مايو 2019 | 600 × 400 (52 كيلوبايت) | Tobus | Updated to show 2016 temperature | |
23:50، 19 يوليو 2010 | 600 × 400 (38 كيلوبايت) | SeL media | time axis reversed | ||
22:39، 4 يوليو 2009 | 600 × 400 (35 كيلوبايت) | Falcorian | Lossless compression with pngout. | ||
22:51، 17 ديسمبر 2005 | 600 × 400 (43 كيلوبايت) | Saperaud~commonswiki |
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الدقة الأفقية | 118٫11 دي بي سي |
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الدقة الرأسية | 118٫11 دي بي سي |
تاريخ ووقت تغيير الملف | 07:16، 4 مايو 2019 |