{"id":437044,"date":"2026-04-03T11:29:52","date_gmt":"2026-04-03T18:29:52","guid":{"rendered":"https:\/\/climatescience.press\/?p=437044"},"modified":"2026-04-03T11:29:54","modified_gmt":"2026-04-03T18:29:54","slug":"breakthrough-exposes-volcanic-corruption-of-global-temperature-data-for-50-years","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=437044","title":{"rendered":"Breakthrough Exposes Volcanic Corruption of Global Temperature Data for 50 Years"},"content":{"rendered":"\n<figure class=\"wp-block-image size-large\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"723\" height=\"485\" data-attachment-id=\"437046\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=437046\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-Breakthrough-Exposes-Volcanic-Corruption-of-Global-Temperature-Data-for-50-Years.jpg?fit=1168%2C784&amp;ssl=1\" data-orig-size=\"1168,784\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"0 Breakthrough Exposes Volcanic Corruption of Global Temperature Data for 50 Years\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-Breakthrough-Exposes-Volcanic-Corruption-of-Global-Temperature-Data-for-50-Years.jpg?fit=723%2C485&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-Breakthrough-Exposes-Volcanic-Corruption-of-Global-Temperature-Data-for-50-Years.jpg?resize=723%2C485&#038;ssl=1\" alt=\"\" class=\"wp-image-437046\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-Breakthrough-Exposes-Volcanic-Corruption-of-Global-Temperature-Data-for-50-Years.jpg?resize=1024%2C687&amp;ssl=1 1024w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-Breakthrough-Exposes-Volcanic-Corruption-of-Global-Temperature-Data-for-50-Years.jpg?resize=300%2C201&amp;ssl=1 300w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-Breakthrough-Exposes-Volcanic-Corruption-of-Global-Temperature-Data-for-50-Years.jpg?resize=768%2C516&amp;ssl=1 768w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-Breakthrough-Exposes-Volcanic-Corruption-of-Global-Temperature-Data-for-50-Years.jpg?resize=640%2C430&amp;ssl=1 640w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-Breakthrough-Exposes-Volcanic-Corruption-of-Global-Temperature-Data-for-50-Years.jpg?w=1168&amp;ssl=1 1168w\" sizes=\"auto, (max-width: 723px) 100vw, 723px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">From <a href=\"https:\/\/wattsupwiththat.com\/2026\/04\/01\/breakthrough-exposes-volcanic-corruption-of-global-temperature-data-for-50-years\/\">Watts Up With That?<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">By <a href=\"https:\/\/wattsupwiththat.com\/author\/jeeztheadmin\/\">Charles Rotter<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">[editor\u2019s note, because this April 1st prank was done well, many people believe it and it\u2019s being circulated as a skeptic point. Here is the official disclaimer: There is no temperature station named CR-<mark><strong><em>VOLC-EL-INFIERNO<\/em><\/strong><\/mark>-01 sitting in an active caldera~charles]<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Charles Rotter<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A persistent assumption underlies modern global temperature reconstructions: that individual station errors, even when large, are diluted through spatial averaging and homogenization. That assumption deserves closer inspection. Recent analysis of station-level data suggests that under certain conditions\u2014specifically when extreme outliers evade quality control and are subsequently incorporated into homogenization routines\u2014localized anomalies can propagate nonlinearly through the global record.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The present investigation began with a routine audit of tropical station residuals within the GHCN (Global Historical Climatology Network) dataset. The initial objective was unremarkable: quantify the distribution of post-homogenization adjustments across low-latitude stations. What emerged instead was a persistent and statistically anomalous signal centered on a single station in Costa Rica, hereafter designated CR-VOLC-EL-INFIERNO-01.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The anomaly first appears in the late 1970s, coinciding with documented volcanic activity in the Talamanca Range. At face value, elevated temperatures in proximity to geothermal activity are not unexpected. What is unexpected is the magnitude, persistence, and downstream influence of those readings once introduced into the global processing pipeline.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Raw observations from CR-VOLC-EL-INFIERNO-01 indicate sustained daily maximum temperatures exceeding 300\u00b0C over multiple reporting intervals. Such values would ordinarily trigger immediate exclusion under standard quality control thresholds. Yet archival flags associated with this station indicate no such exclusion occurred. Instead, the readings were retained and subjected to standard homogenization procedures.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">To understand how such values could persist, it is necessary to examine the homogenization framework itself. Modern temperature datasets rely on relative homogenization techniques, wherein each station is adjusted based on comparisons with neighboring stations. The fundamental assumption is that neighboring stations share a common climate signal, allowing discontinuities (instrument changes, relocations) to be corrected through statistical alignment.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This approach can be represented in simplified form as:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">T\u1d62\u2032 = T\u1d62 + \u03a3\u2c7c w\u1d62\u2c7c (T\u2c7c \u2212 T\u1d62)<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Where T\u1d62\u2032 is the adjusted temperature for station i, T\u2c7c represents neighboring stations, and w\u1d62\u2c7c are weighting coefficients derived from spatial proximity and correlation.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Under ordinary conditions, this method dampens noise and corrects for local biases. Under extraordinary conditions\u2014such as the inclusion of a station reporting temperatures exceeding 300\u00b0C\u2014the same mechanism can act as an amplifier.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Consider a simplified network of stations surrounding CR-VOLC-EL-INFIERNO-01. Let the anomalous station report a temperature T\u2090 \u2248 573 K (300\u00b0C), while neighboring stations report typical tropical values T\u2099 \u2248 300 K (27\u00b0C). The difference \u0394T \u2248 273 K introduces a gradient orders of magnitude larger than typical inter-station variability.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">During homogenization, neighboring stations are adjusted upward to reduce this discrepancy. Even with modest weighting coefficients (w \u2248 0.05), the adjustment per iteration becomes:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u0394T\u2099 \u2248 0.05 \u00d7 (573 \u2212 300) \u2248 13.65 K<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This is not a subtle correction. It is a step change. When applied iteratively across multiple passes\u2014as is common in homogenization algorithms\u2014the effect compounds. Neighboring stations begin to exhibit elevated baselines, which in turn influence their neighbors, and so on.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"723\" height=\"482\" data-attachment-id=\"437051\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=437051\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_55-AM-1.png?fit=1536%2C1024&amp;ssl=1\" data-orig-size=\"1536,1024\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"0ChatGPT-Image-Apr-1-2026-11_55_55-AM\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_55-AM-1.png?fit=723%2C482&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_55-AM-1.png?resize=723%2C482&#038;ssl=1\" alt=\"\" class=\"wp-image-437051\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_55-AM-1.png?resize=1024%2C683&amp;ssl=1 1024w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_55-AM-1.png?resize=300%2C200&amp;ssl=1 300w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_55-AM-1.png?resize=768%2C512&amp;ssl=1 768w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_55-AM-1.png?resize=640%2C427&amp;ssl=1 640w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_55-AM-1.png?resize=1200%2C800&amp;ssl=1 1200w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_55-AM-1.png?w=1536&amp;ssl=1 1536w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_55-AM-1.png?w=1446&amp;ssl=1 1446w\" sizes=\"auto, (max-width: 723px) 100vw, 723px\" \/><figcaption class=\"wp-element-caption\">Figure 1: A singular, extreme thermal anomaly localized to CR-VOLC-EL-INFIERNO-01, sharply diverging from the surrounding field.<\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"723\" height=\"543\" data-attachment-id=\"437053\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=437053\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_49-AM.png?fit=1447%2C1086&amp;ssl=1\" data-orig-size=\"1447,1086\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"0,ChatGPT-Image-Apr-1-2026-11_55_49-AM\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_49-AM.png?fit=723%2C543&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_49-AM.png?resize=723%2C543&#038;ssl=1\" alt=\"\" class=\"wp-image-437053\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_49-AM.png?resize=1024%2C769&amp;ssl=1 1024w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_49-AM.png?resize=300%2C225&amp;ssl=1 300w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_49-AM.png?resize=768%2C576&amp;ssl=1 768w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_49-AM.png?resize=640%2C480&amp;ssl=1 640w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_49-AM.png?resize=1200%2C901&amp;ssl=1 1200w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_49-AM.png?resize=800%2C600&amp;ssl=1 800w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_49-AM.png?resize=600%2C450&amp;ssl=1 600w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_49-AM.png?resize=400%2C300&amp;ssl=1 400w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_49-AM.png?resize=200%2C150&amp;ssl=1 200w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-11_55_49-AM.png?w=1447&amp;ssl=1 1447w\" sizes=\"auto, (max-width: 723px) 100vw, 723px\" \/><figcaption class=\"wp-element-caption\">Figure 2 The first-order propagation: adjacent stations showing upward adjustments, forming a halo of elevated temperatures.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">By the third or fourth iteration, the anomaly ceases to be local. It becomes a regional bias. By the tenth iteration, it begins to influence hemispheric averages.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The question arises: why did standard quality control fail to intercept such values? Examination of the station metadata provides a clue. CR-VOLC-EL-INFIERNO-01 is categorized as a \u201chigh-variability geothermal site,\u201d a designation that appears to relax certain threshold checks under the assumption that extreme values may be physically plausible.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">That assumption, while perhaps reasonable for transient spikes, becomes problematic when sustained values are treated as climatologically relevant. The system, in effect, interprets the volcano as a persistent heat source representative of broader regional conditions.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Further complicating matters is the temporal alignment of the anomaly with the baseline period used for anomaly calculations (typically 1951\u20131980 or similar). Because the most extreme values occur after the baseline period, they manifest as positive anomalies rather than being normalized away.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">To quantify the global impact, a sensitivity analysis was conducted. Two reconstructions were produced:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>A standard reconstruction including all stations.<\/li>\n\n\n\n<li>A modified reconstruction excluding CR-VOLC-EL-INFIERNO-01.<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">The results are instructive.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In the standard reconstruction, global mean temperature anomalies show an increase of approximately 0.9\u00b0C from 1975 to present. In the modified reconstruction, the increase is reduced to approximately 0.02\u00b0C over the same period.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"723\" height=\"482\" data-attachment-id=\"437056\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=437056\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_19_37-PM.png?fit=1536%2C1024&amp;ssl=1\" data-orig-size=\"1536,1024\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"0ChatGPT-Image-Apr-1-2026-12_19_37-PM\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_19_37-PM.png?fit=723%2C482&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_19_37-PM.png?resize=723%2C482&#038;ssl=1\" alt=\"\" class=\"wp-image-437056\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_19_37-PM.png?resize=1024%2C683&amp;ssl=1 1024w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_19_37-PM.png?resize=300%2C200&amp;ssl=1 300w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_19_37-PM.png?resize=768%2C512&amp;ssl=1 768w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_19_37-PM.png?resize=640%2C427&amp;ssl=1 640w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_19_37-PM.png?resize=1200%2C800&amp;ssl=1 1200w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_19_37-PM.png?w=1536&amp;ssl=1 1536w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_19_37-PM.png?w=1446&amp;ssl=1 1446w\" sizes=\"auto, (max-width: 723px) 100vw, 723px\" \/><figcaption class=\"wp-element-caption\">Figure 3. The divergence begins in the late 1970s, expands through the 1980s and 1990s, and stabilizes in the early 2000s. The visual impression is difficult to ignore: the vast majority of the reported warming trend aligns temporally with the inclusion and propagation of the volcanic station anomaly.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">One might object that a single station cannot plausibly influence a global dataset to this extent. That objection assumes linearity. The homogenization process is not strictly linear. It is iterative, spatially weighted, and sensitive to outliers in ways that are not always intuitive.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">To illustrate, consider a simplified global grid divided into N cells, each influenced by k neighboring cells. If a single cell contains an extreme value and influences k neighbors per iteration, the number of cells after n iterations can be approximated as:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C\u2099 \u2248 k\u207f<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Even with modest k (e.g., k = 3), after 10 iterations the influence extends to nearly 60,000 cells. While real-world grids impose constraints that limit such exponential growth, the principle remains: repeated smoothing spreads anomalies far beyond their origin.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Additional evidence emerges when examining variance structures. The inclusion of CR-VOLC-EL-INFIERNO-01 significantly increases the variance of the tropical temperature field, particularly in the lower troposphere. This increased variance is then partially \u201ccorrected\u201d by homogenization, which redistributes the excess energy across the network.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In practical terms, the system attempts to reconcile an impossibly hot volcano with a planet that is, on average, far cooler. The reconciliation takes the form of a modest warming everywhere.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">There is also a subtle interaction with sea surface temperature datasets. Coastal grid cells influenced by the adjusted land stations feed into blended land-ocean products. The volcanic signal, already diffused across land, begins to imprint itself on adjacent ocean cells through interpolation routines.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">By the time the data reach the stage of global aggregation, the original source\u2014the volcano\u2014has been thoroughly obscured. What remains is a smooth, coherent warming trend that appears internally consistent.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">At no point in the standard processing pipeline is there a step explicitly designed to detect this type of cascading anomaly. Quality control focuses on individual station plausibility. Homogenization focuses on relative consistency. Aggregation assumes the preceding steps have produced a reliable field.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Each step, in isolation, behaves as intended. The interaction between steps produces the outcome observed.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">It is worth noting that CR-VOLC-EL-INFIERNO-01 is not flagged as an outlier in the final dataset. On the contrary, after homogenization, its values are partially moderated, bringing them closer to neighboring stations. The volcano, in effect, becomes less extreme, while its neighbors become more so.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This symmetry gives the appearance of robustness. The dataset looks well-behaved. The underlying distortion is distributed rather than concentrated.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A secondary analysis examined the effect of truncating extreme values prior to homogenization. By capping all station readings at 60\u00b0C\u2014a threshold well above typical terrestrial temperatures but far below volcanic conditions\u2014the resulting global trend closely matches the modified reconstruction excluding the volcanic station entirely.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This suggests that the critical factor is not merely the presence of the station, but the magnitude of its reported values. Once those values exceed a certain threshold, the homogenization process transitions from correction to propagation.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">There are, of course, broader implications. If a single station can exert such influence under specific conditions, the robustness of global temperature reconstructions depends heavily on the effectiveness of outlier detection and the assumptions embedded in homogenization algorithms.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">None of this implies intent or malfeasance. The system behaves according to its design. The design, however, rests on assumptions that may not hold in the presence of extreme, persistent anomalies.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">CR-VOLC-EL-INFIERNO-01 represents a particularly vivid case because the source of the anomaly\u2014a volcano actively emitting heat\u2014is unambiguous. One could hardly ask for a more literal example of localized thermal contamination.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The more interesting question is whether less obvious anomalies\u2014urban heat islands, instrument drift, undocumented relocations\u2014might produce similar, if smaller, effects that accumulate over time.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Returning to the Costa Rican station, archival imagery (Figure 4) places the instrument array on the southern flank of an active vent, within visible proximity to fumarolic activity. The siting would be difficult to improve upon if the objective were to measure geothermal output rather than ambient air temperature.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"723\" height=\"482\" data-attachment-id=\"437059\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=437059\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_24_54-PM.png?fit=1536%2C1024&amp;ssl=1\" data-orig-size=\"1536,1024\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"0ChatGPT-Image-Apr-1-2026-12_24_54-PM\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_24_54-PM.png?fit=723%2C482&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_24_54-PM.png?resize=723%2C482&#038;ssl=1\" alt=\"\" class=\"wp-image-437059\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_24_54-PM.png?resize=1024%2C683&amp;ssl=1 1024w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_24_54-PM.png?resize=300%2C200&amp;ssl=1 300w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_24_54-PM.png?resize=768%2C512&amp;ssl=1 768w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_24_54-PM.png?resize=640%2C427&amp;ssl=1 640w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_24_54-PM.png?resize=1200%2C800&amp;ssl=1 1200w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_24_54-PM.png?w=1536&amp;ssl=1 1536w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0ChatGPT-Image-Apr-1-2026-12_24_54-PM.png?w=1446&amp;ssl=1 1446w\" sizes=\"auto, (max-width: 723px) 100vw, 723px\" \/><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">Yet in the dataset, it is treated as one station among many.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The final point concerns interpretation. Global temperature trends are often presented with a degree of precision that implies a high level of confidence in both measurement and methodology. The analysis presented here suggests that under certain conditions, that confidence may be overstated.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">When a single station\u2014reporting temperatures more commonly associated with industrial furnaces than meteorological observations\u2014can, through entirely procedural means, influence a global metric, it raises questions about the sensitivity of the system to edge cases.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Those questions do not require dramatic conclusions. They do, however, warrant careful examination.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">At minimum, the findings suggest that extreme-value handling in global temperature datasets deserves closer scrutiny, particularly in regions where environmental conditions can produce readings far outside the typical range of atmospheric temperatures.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Further investigation into the prevalence of similar anomalies, as well as the robustness of homogenization algorithms under such conditions, would be a reasonable next step.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A persistent assumption underlies modern global temperature reconstructions: that individual station errors, even when large, are diluted through spatial averaging and homogenization. That assumption deserves closer inspection. Recent analysis of station-level data suggests that under certain conditions\u2014specifically when extreme outliers evade quality control and are subsequently incorporated into homogenization routines\u2014localized anomalies can propagate nonlinearly through the global record.<\/p>\n","protected":false},"author":121246920,"featured_media":437046,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[1],"tags":[691842160,691842159,691842156,691842155,691842157,691840127],"class_list":["post-437044","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","tag-air-temperature-sensors","tag-el-infierno","tag-cr-volc-el-infierno-01","tag-ghcn-global-historical-climatology-network","tag-global-temperature-reconstructions","tag-land-surface-air-temperature-data","fallback-thumbnail"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-Breakthrough-Exposes-Volcanic-Corruption-of-Global-Temperature-Data-for-50-Years.jpg?fit=1168%2C784&ssl=1","jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/paxLW1-1PH6","jetpack-related-posts":[{"id":437008,"url":"https:\/\/climatescience.press\/?p=437008","url_meta":{"origin":437044,"position":0},"title":"Chinese AI Model Excels at Reconstructing Sparse Antarctic Temperatures","author":"uwe.roland.gross","date":"04\/03\/2026","format":false,"excerpt":"Antarctica remains one of the most data-poor regions on Earth for surface air temperature (SAT) monitoring. Even after the 1957\u201358 International Geophysical Year expanded stations, effective observational coverage over the continent is often ~10% or less in gridded products. Vast interior areas (e.g., the East Antarctic Plateau) and pre-1961 records\u2026","rel":"","context":"In \"AI Model\"","block_context":{"text":"AI Model","link":"https:\/\/climatescience.press\/?tag=ai-model"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-focus-on-a-specific-period-like-1979%E2%80%932024.jpg?fit=784%2C1168&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-focus-on-a-specific-period-like-1979%E2%80%932024.jpg?fit=784%2C1168&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-focus-on-a-specific-period-like-1979%E2%80%932024.jpg?fit=784%2C1168&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-focus-on-a-specific-period-like-1979%E2%80%932024.jpg?fit=784%2C1168&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":249673,"url":"https:\/\/climatescience.press\/?p=249673","url_meta":{"origin":437044,"position":1},"title":"Re-imaging Tasmania\u2019s Temperature History, Part 1","author":"uwe.roland.gross","date":"03\/26\/2023","format":false,"excerpt":"It suggests that maximum temperatures in Tasmania are not as high now as they were back in the early 20th century, and that there was a period of cooling to about 1950.","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/03\/image-1102.png?fit=1200%2C800&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/03\/image-1102.png?fit=1200%2C800&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/03\/image-1102.png?fit=1200%2C800&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/03\/image-1102.png?fit=1200%2C800&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/03\/image-1102.png?fit=1200%2C800&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":268770,"url":"https:\/\/climatescience.press\/?p=268770","url_meta":{"origin":437044,"position":2},"title":"Heatwave hysteria","author":"uwe.roland.gross","date":"07\/21\/2023","format":false,"excerpt":"Climate change extremism and the tendency to alarm first and analyse later is destroying clear and thoughtful environmental reporting.","rel":"","context":"In \"BBC\"","block_context":{"text":"BBC","link":"https:\/\/climatescience.press\/?tag=bbc"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/07\/image-641.png?fit=1024%2C1024&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/07\/image-641.png?fit=1024%2C1024&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/07\/image-641.png?fit=1024%2C1024&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/07\/image-641.png?fit=1024%2C1024&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":251716,"url":"https:\/\/climatescience.press\/?p=251716","url_meta":{"origin":437044,"position":3},"title":"Why We Need An Independent Global Climate Temperature Database","author":"uwe.roland.gross","date":"04\/07\/2023","format":false,"excerpt":"All of the temperature data stations used to make determinations about the state of Earth\u2019s temperature are controlled by governments. And, all of the data on global temperature reported in the media are from government reports.","rel":"","context":"In \"Climate change\"","block_context":{"text":"Climate change","link":"https:\/\/climatescience.press\/?tag=climate-change"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/0wp6946279.jpg?fit=1200%2C900&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/0wp6946279.jpg?fit=1200%2C900&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/0wp6946279.jpg?fit=1200%2C900&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/0wp6946279.jpg?fit=1200%2C900&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/0wp6946279.jpg?fit=1200%2C900&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":251586,"url":"https:\/\/climatescience.press\/?p=251586","url_meta":{"origin":437044,"position":4},"title":"Why We Need an Independent Global Climate Temperature Database","author":"uwe.roland.gross","date":"04\/06\/2023","format":false,"excerpt":"Ever since the beginning of the global warming debate, now labeled \u201cclimate change,\u201d there has been one immutable yet little-known fact: All of the temperature data stations used to make determinations about the state of Earth\u2019s temperature are controlled by governments.","rel":"","context":"In \"Melting world\"","block_context":{"text":"Melting world","link":"https:\/\/climatescience.press\/?tag=melting-world"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/0World-Melting.webp?fit=1200%2C675&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/0World-Melting.webp?fit=1200%2C675&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/0World-Melting.webp?fit=1200%2C675&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/0World-Melting.webp?fit=1200%2C675&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/0World-Melting.webp?fit=1200%2C675&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":278256,"url":"https:\/\/climatescience.press\/?p=278256","url_meta":{"origin":437044,"position":5},"title":"Controversy surrounding the Sun\u2019s role in climate change","author":"uwe.roland.gross","date":"09\/11\/2023","format":false,"excerpt":"Most of the groups generating global temperature records from the weather station data rely on the temperature homogenization computer programs mentioned above to automatically adjust the original temperature records to remove \u201cnon-climatic biases\u201d from the data.","rel":"","context":"In \"Climate change\"","block_context":{"text":"Climate change","link":"https:\/\/climatescience.press\/?tag=climate-change"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/09\/image-335.png?fit=1200%2C600&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/09\/image-335.png?fit=1200%2C600&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/09\/image-335.png?fit=1200%2C600&ssl=1&resize=525%2C300 1.5x, 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