{"id":457794,"date":"2026-07-25T10:53:37","date_gmt":"2026-07-25T17:53:37","guid":{"rendered":"https:\/\/climatescience.press\/?p=457794"},"modified":"2026-07-25T10:53:39","modified_gmt":"2026-07-25T17:53:39","slug":"of-climate-models-and-black-boxes","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=457794","title":{"rendered":"Of Climate Models And Black Boxes"},"content":{"rendered":"\n<figure class=\"wp-block-image size-large\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"723\" height=\"482\" data-attachment-id=\"457796\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=457796\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/0-ChatGPT-Of-Climate-Models-And-Black-Boxes.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;,&quot;alt&quot;:&quot;&quot;}\" data-image-title=\"0 ChatGPT  Of Climate Models And Black Boxes\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/0-ChatGPT-Of-Climate-Models-And-Black-Boxes.png?fit=723%2C482&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/0-ChatGPT-Of-Climate-Models-And-Black-Boxes.png?resize=723%2C482&#038;ssl=1\" alt=\"\" class=\"wp-image-457796\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/0-ChatGPT-Of-Climate-Models-And-Black-Boxes.png?resize=1024%2C683&amp;ssl=1 1024w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/0-ChatGPT-Of-Climate-Models-And-Black-Boxes.png?resize=300%2C200&amp;ssl=1 300w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/0-ChatGPT-Of-Climate-Models-And-Black-Boxes.png?resize=768%2C512&amp;ssl=1 768w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/0-ChatGPT-Of-Climate-Models-And-Black-Boxes.png?resize=640%2C427&amp;ssl=1 640w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/0-ChatGPT-Of-Climate-Models-And-Black-Boxes.png?resize=1200%2C800&amp;ssl=1 1200w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/0-ChatGPT-Of-Climate-Models-And-Black-Boxes.png?w=1536&amp;ssl=1 1536w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/0-ChatGPT-Of-Climate-Models-And-Black-Boxes.png?w=1446&amp;ssl=1 1446w\" sizes=\"auto, (max-width: 723px) 100vw, 723px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">From <a href=\"https:\/\/wattsupwiththat.com\/2026\/07\/23\/of-climate-models-and-black-boxes\/\">Watts Up With That?<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong><em>Guest Post by<\/em><\/strong> <a href=\"https:\/\/wattsupwiththat.com\/author\/weschenbach\/\">Willis Eschenbach<\/a> <strong><em>(@WEschenbach on X, my personal blog is&nbsp;<a href=\"https:\/\/rosebyanyothernameblog.wordpress.com\/\" target=\"_blank\" rel=\"noopener\">here<\/a>.)<\/em><\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Well, for my usual lack of reasons, I got to thinking about updating the subject of my three previous posts relating the input and the output of climate models. To my surprise, the most recent of these was a shocking fifteen years ago \u2026 tempus fuggit, as they say \u2026<\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-wp-embed is-provider-watts-up-with-that wp-block-embed-watts-up-with-that\"><div class=\"wp-block-embed__wrapper\">\n<blockquote class=\"wp-embedded-content\" data-secret=\"hwijSNixtT\"><a href=\"https:\/\/wattsupwiththat.com\/2011\/05\/14\/life-is-like-a-black-box-of-chocolates\/\">Life is Like a Black Box of Chocolates<\/a><\/blockquote><iframe loading=\"lazy\" class=\"wp-embedded-content\" sandbox=\"allow-scripts\" security=\"restricted\" style=\"position: absolute; visibility: hidden;\" title=\"\u201cLife is Like a Black Box of Chocolates\u201d \u2014 Watts Up With That?\" src=\"https:\/\/wattsupwiththat.com\/2011\/05\/14\/life-is-like-a-black-box-of-chocolates\/embed\/#?secret=QzfmMJy7jO#?secret=hwijSNixtT\" data-secret=\"hwijSNixtT\" width=\"600\" height=\"338\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\n<\/div><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">In that post, I discussed the idea of a \u201cblack box\u201d analysis. This is where you have both the input and the output of some unknown process, and the challenge is to figure out what is happening&nbsp;<strong>functionally<\/strong>&nbsp;inside the black box. Here was my illustration showing the CCSM3 climate model as a black box, with the input being the \u201cforcing\u201d and the output representing the global annual surface temperature.<br><br>And what is \u201cforcing\u201d when it\u2019s at home? Well, per the IPCC, it\u2019s short for \u2018radiative forcing\u2019, which they define as<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\">The change in the net, downward minus upward, radiative&nbsp;<em>flux<\/em>&nbsp;(expressed in W m\u22122) at the tropopause or top of&nbsp;<em>atmosphere<\/em>&nbsp;due to a change in an (external)&nbsp;<em>driver<\/em>&nbsp;of&nbsp;<em>climate change<\/em>, such as a change in the concentration of&nbsp;<em>carbon dioxide (CO<\/em>2<em>)<\/em>, the concentration of volcanic&nbsp;<em>aerosols<\/em>&nbsp;or the output of the Sun.&nbsp;<\/p>\n<\/blockquote>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"723\" height=\"407\" data-attachment-id=\"457804\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=457804\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-206.png?fit=829%2C467&amp;ssl=1\" data-orig-size=\"829,467\" 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;,&quot;alt&quot;:&quot;&quot;}\" data-image-title=\"image\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-206.png?fit=723%2C407&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-206.png?resize=723%2C407&#038;ssl=1\" alt=\"\" class=\"wp-image-457804\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-206.png?w=829&amp;ssl=1 829w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-206.png?resize=300%2C169&amp;ssl=1 300w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-206.png?resize=768%2C433&amp;ssl=1 768w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-206.png?resize=640%2C361&amp;ssl=1 640w\" sizes=\"auto, (max-width: 723px) 100vw, 723px\" \/><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">Note that the result of a black box analysis may be totally different from what is&nbsp;<strong>actually<\/strong>&nbsp;happening inside the black box. The only requirement is that it takes the same input and produces the same output.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In the post linked to above, I showed that you can almost perfectly emulate the model output that represents the global annual surface temperature \u2026 and not only that, you can do it with a bozo-simple, one-line equation with only two tuned parameters. All that the equation does is to resize and lag the input forcing, and like some magic trick, it gives you the output temperature.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Now, there has been an intermittent series of climate model comparisons under the umbrella of something called the Climate Model Intercomparison Program. At that time, they were on the third comparison, called \u201cCMIP3\u201d. Since we\u2019re now up to CMIP6, I thought I should take another look to see what changes have occurred.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">I\u2019m going to present the equation, and for those of you who are allergic to math, here is the trigger warning\u2014avert your eyes&nbsp;\u2026<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"583\" height=\"720\" data-attachment-id=\"457809\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=457809\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-207.png?fit=583%2C720&amp;ssl=1\" data-orig-size=\"583,720\" 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;,&quot;alt&quot;:&quot;&quot;}\" data-image-title=\"image\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-207.png?fit=583%2C720&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-207.png?resize=583%2C720&#038;ssl=1\" alt=\"\" class=\"wp-image-457809\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-207.png?w=583&amp;ssl=1 583w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-207.png?resize=243%2C300&amp;ssl=1 243w\" sizes=\"auto, (max-width: 583px) 100vw, 583px\" \/><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">With the trigger warning out of the way, here is the equation that rescales and lags the forcing to emulate the output temperature:<br><br>========================== Math Averse, skip this section ==========================<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>T<sub>(n+1)<\/sub>&nbsp;= T<sub>(n)<\/sub>+\u03bb \u2206F<sub>(n+1)<\/sub>&nbsp;* (1- exp( -1 \/ \u03c4 )) + \u0394T<sub>(n)<\/sub>&nbsp;exp( -1 \/ \u03c4 )<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">OK, now lets render this equation in English. It looks complex, but it\u2019s not.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>T<sub>(n)<\/sub><\/strong>&nbsp;is pronounced \u201cT sub n\u201d. It is the temperature \u201c<strong>T<\/strong>\u201d at time \u201cn\u201d. So T sub n plus one, written as&nbsp;<strong>T<sub>(n+1)<\/sub><\/strong>, is the temperature during the following time period. In this case we\u2019re using years, so it would be the next year\u2019s temperature.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>F<\/strong>&nbsp;is the forcing, in watts per square metre. This is the total of all of the forcings under consideration. The same time convention is followed, so&nbsp;<strong>F(n)&nbsp;<\/strong>means the forcing \u201c<strong>F<\/strong>\u201d in time period \u201c<strong>n<\/strong>\u201d.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Delta, or \u201c<strong>\u2206<\/strong>\u201d, means \u201cthe change in\u201d. So&nbsp;<strong>\u2206T<sub>(n)<\/sub><\/strong>&nbsp;is the change in temperature since the previous period, or&nbsp;<strong>T<sub>(n)<\/sub><\/strong>&nbsp;minus the previous temperature&nbsp;<strong>T(<sub>n-1)<\/sub><\/strong>.&nbsp;<strong>\u2206F(<sub>n)<\/sub><\/strong>, correspondingly, is the change in forcing since the previous time period&nbsp;<strong>F<sub>(n-1)<\/sub><\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Lambda, or \u201c<strong>\u03bb<\/strong>\u201d, is the scaling factor.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tau, or \u201c<strong>\u03c4<\/strong>\u201d, is the lag time constant. The time constant establishes the amount of the lag in the response of the system to forcing. And finally, \u201c<strong>exp(-1\/\u03c4)<\/strong>\u201d means the number 2.71828 to the power of -1\/<strong>\u03c4<\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">========================== End of the section to skip ==========================<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">So in English, this means that the temperature next year, or<strong>&nbsp;T<sub>(n+1)<\/sub><\/strong>, is equal to the temperature this year&nbsp;<strong>T(n)<\/strong>, plus the immediate temperature increase due to the change in forcing,<strong>&nbsp;\u03bb F<sub>(n+1)<\/sub>&nbsp;(1-exp( -1 \/ \u03c4 ))<\/strong>, plus the lag term,<strong>&nbsp;\u0394T<sub>(n)<\/sub>&nbsp;exp( -1 \/ \u03c4 ),<\/strong>&nbsp;which is the temperature increase from the previous forcing. This lag term is necessary because the effects of the changes in forcing are not instantaneous.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Now, regarding the choice of the computer model and the data. I used the GISS-E2.1 model for a simple reason. It\u2019s one of the few where the modelers published the forcings that they used. Here are the&nbsp;<a href=\"https:\/\/data.giss.nasa.gov\/modelforce\/Miller_et_al21\/ERFs_SSP245_MillerFig10_2021.txt\" target=\"_blank\" rel=\"noopener\">forcing data<\/a>&nbsp;and the&nbsp;<a href=\"https:\/\/climexp.knmi.nl\/selectfield_cmip6_knmi23.cgi?id=someone@somewhere\" target=\"_blank\" rel=\"noopener\">model temperature output<\/a>. The temperature output at that source (KNMI) shows five individual model runs and, as is the custom, I\u2019ve used the average of the runs. There\u2019s a discussion of the use of the GISS-E2.1 model in the study entitled \u201c<a href=\"https:\/\/agupubs.onlinelibrary.wiley.com\/doi\/10.1029\/2019MS002034\" target=\"_blank\" rel=\"noopener\">CMIP6 Historical Simulations (1850\u20132014) With GISS-E2.1<\/a>\u201c. The E2.1 model is described as&nbsp;<em>\u201can updated and more skillful version of the GISS-E2 model used in CMIP5\u201d.<\/em><br><br>The forcings that they used are divided into three groups: greenhouse gases (except water vapor), anthropogenic aerosols, and \u201cnatural\u201d forcings. Here are those forcings, from the link above:<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"720\" height=\"649\" data-attachment-id=\"457813\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=457813\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-208.png?fit=720%2C649&amp;ssl=1\" data-orig-size=\"720,649\" 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;,&quot;alt&quot;:&quot;&quot;}\" data-image-title=\"image\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-208.png?fit=720%2C649&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-208.png?resize=720%2C649&#038;ssl=1\" alt=\"\" class=\"wp-image-457813\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-208.png?w=720&amp;ssl=1 720w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-208.png?resize=300%2C270&amp;ssl=1 300w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-208.png?resize=640%2C577&amp;ssl=1 640w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\" \/><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">So without further ado, here is the result of my black box analysis.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"720\" height=\"709\" data-attachment-id=\"457816\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=457816\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-209.png?fit=720%2C709&amp;ssl=1\" data-orig-size=\"720,709\" 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;,&quot;alt&quot;:&quot;&quot;}\" data-image-title=\"image\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-209.png?fit=720%2C709&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-209.png?resize=720%2C709&#038;ssl=1\" alt=\"\" class=\"wp-image-457816\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-209.png?w=720&amp;ssl=1 720w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-209.png?resize=300%2C295&amp;ssl=1 300w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-209.png?resize=640%2C630&amp;ssl=1 640w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-209.png?resize=60%2C60&amp;ssl=1 60w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/image-209.png?resize=50%2C50&amp;ssl=1 50w\" sizes=\"auto, (max-width: 720px) 100vw, 720px\" \/><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">As you can see, the simple one-line two-parameter equation above emulates the model results to a ludicrous degree of accuracy and precision. Even the smallest changes are captured by the black box emulation.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">So \u2026 what can we conclude from this?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">My conclusion is that despite the many hundreds of thousands of lines of code in the GISS E2.1 model, in reality, nothing makes a difference in the outcome except for the claimed forcings.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Modulation of the North Atlantic Oscillation; changes in the frequency and strength of the&nbsp;<a href=\"https:\/\/wattsupwiththat.com\/2018\/07\/16\/the-la-nina-pump\/\">La Nina Pump<\/a>; variations in the Gulf Stream; alterations in cloud type, cover, and time of emergence (except those due to aerosols); differences in where the forcing is occurring on the planetary surface; increasing or decreasing water vapor; variations in cloud albedo; the oft-predicted weakening of the Atlantic Meridional Overturning Circulation \u2026 none of that makes any difference in the model.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>We know that because if any of them did make a difference, we couldn\u2019t reproduce the output so exactly using just the input forcings.<\/strong><br><br>And of course, the corollary of that conclusion is that the current generation and type of climate models is completely unfit for the purposes to which they are put. If their output is just a simple scaled and lagged version of their input, they cannot forecast the climate in the year 2100. They cannot tell us if a given drought is made more or less likely by \u201cclimate change\u201d. In short, they are of little use for any serious purpose.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Here\u2019s the thing. Climate models can only do what the modelers tell them to do. In this case, all of the models are running under the central paradigm of mainstream climate science, which says that changes in temperature are a linear function of changes in forcing. Expressed mathematically, that is<br><br><strong>\u2206T = \u03bb \u2206F<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">So of course the models\u2019 output is a scaled, lagged version of their input. It\u2019s what the models have been told to tell us \u2026 so that\u2019s what they tell us.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">So that\u2019s Part 1 of my look at the GISS E2.1 model. When the madness next strikes me, I\u2019ll write up Part 2, which will be about the success of the model in hindcasting the past \u2026 or the lack thereof.<br><br>Late night here, a foggy evening after an overcast day. Must be climate change \u2026<br><br>My very best to everyone,<br><br>w.<br><br><strong>I know, I know, you\u2019ve heard it before:<\/strong>&nbsp;When you comment, please QUOTE the exact words you are discussing. I choose my words carefully and can defend them. I can\u2019t defend what you might think they mean.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Climate models are tools, not crystal balls. They excel at &#8220;what if&#8221; scenarios (e.g., different emissions pathways) but require careful interpretation of uncertainty.<\/p>\n","protected":false},"author":121246920,"featured_media":457796,"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_seo_schema_type":"","_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_wpcom_ai_launchpad_first_post":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"Climate models are tools, not crystal balls. They excel at \"what if\" scenarios (e.g., different emissions pathways) but require careful interpretation of uncertainty.","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"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":[691818153],"class_list":["post-457794","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","tag-climate-models","fallback-thumbnail"],"jetpack_publicize_connections":[],"jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/paxLW1-1V5M","jetpack-related-posts":[{"id":281157,"url":"https:\/\/climatescience.press\/?p=281157","url_meta":{"origin":457794,"position":0},"title":"Climate model provides data-driven answer to major goal of climate research","author":"uwe.roland.gross","date":"09\/29\/2023","format":false,"excerpt":"UAH\u2019s Dr. John Christy reviews results from the one-dimensional climate model Dr. Roy W. Spencer developed. Credit: Liz Junod From Phys.org by Dr. Roy W. Spencer,\u00a0University of Alabama in Huntsville A\u00a0new research study\u00a0from The University of Alabama in Huntsville, a part of the University of Alabama System, addresses a central\u2026","rel":"","context":"In \"CO2\"","block_context":{"text":"CO2","link":"https:\/\/climatescience.press\/?tag=co2"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/09\/00climate-model-provides.jpg?fit=1200%2C675&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/09\/00climate-model-provides.jpg?fit=1200%2C675&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/09\/00climate-model-provides.jpg?fit=1200%2C675&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/09\/00climate-model-provides.jpg?fit=1200%2C675&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/09\/00climate-model-provides.jpg?fit=1200%2C675&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":298481,"url":"https:\/\/climatescience.press\/?p=298481","url_meta":{"origin":457794,"position":1},"title":"Hot Climate Models Not Fit For\u00a0Policymaking","author":"uwe.roland.gross","date":"01\/27\/2024","format":false,"excerpt":"While the climate system has warmed somewhat over the past five decades, the popular perception of a \u201cclimate crisis\u201d and resulting calls for economically significant regulation of CO2 emissions is not supported by science.","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\/08\/0climate-models-epic-fail.webp?fit=999%2C775&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/08\/0climate-models-epic-fail.webp?fit=999%2C775&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/08\/0climate-models-epic-fail.webp?fit=999%2C775&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/08\/0climate-models-epic-fail.webp?fit=999%2C775&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":414140,"url":"https:\/\/climatescience.press\/?p=414140","url_meta":{"origin":457794,"position":2},"title":"Just How Good Were the Early Climate Models?","author":"uwe.roland.gross","date":"11\/21\/2025","format":false,"excerpt":"An article by Nadir Jeevanjee, a Research Physical Scientist at the National Oceanic and Atmospheric Administration (NOAA),\u00a0recently published in\u00a0The Conversationand\u00a0reprinted by\u00a0Space.Com, suggests that climate models are being given a bad rap. It cites a recent\u00a0Department of Energy report\u00a0as using the complexity of climate models as the primary reason why these\u2026","rel":"","context":"In \"carbon dioxide (CO\u2082)\"","block_context":{"text":"carbon dioxide (CO\u2082)","link":"https:\/\/climatescience.press\/?tag=carbon-dioxide-co%e2%82%82"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/11\/0AQPfyVJuzU2YZPS3qjGCc0SWMv_LS7-T1CUyWvz8-yjsS3-Xl6kdgV8mSjqyHbjBBLyP-rpazW0VDXg9W85Fe_cW6hPterNb2PSUBy3HFnGrDLCCwC0oSkwl7nbNDbxE-1.jpeg?fit=1200%2C923&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/11\/0AQPfyVJuzU2YZPS3qjGCc0SWMv_LS7-T1CUyWvz8-yjsS3-Xl6kdgV8mSjqyHbjBBLyP-rpazW0VDXg9W85Fe_cW6hPterNb2PSUBy3HFnGrDLCCwC0oSkwl7nbNDbxE-1.jpeg?fit=1200%2C923&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/11\/0AQPfyVJuzU2YZPS3qjGCc0SWMv_LS7-T1CUyWvz8-yjsS3-Xl6kdgV8mSjqyHbjBBLyP-rpazW0VDXg9W85Fe_cW6hPterNb2PSUBy3HFnGrDLCCwC0oSkwl7nbNDbxE-1.jpeg?fit=1200%2C923&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/11\/0AQPfyVJuzU2YZPS3qjGCc0SWMv_LS7-T1CUyWvz8-yjsS3-Xl6kdgV8mSjqyHbjBBLyP-rpazW0VDXg9W85Fe_cW6hPterNb2PSUBy3HFnGrDLCCwC0oSkwl7nbNDbxE-1.jpeg?fit=1200%2C923&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/11\/0AQPfyVJuzU2YZPS3qjGCc0SWMv_LS7-T1CUyWvz8-yjsS3-Xl6kdgV8mSjqyHbjBBLyP-rpazW0VDXg9W85Fe_cW6hPterNb2PSUBy3HFnGrDLCCwC0oSkwl7nbNDbxE-1.jpeg?fit=1200%2C923&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":271457,"url":"https:\/\/climatescience.press\/?p=271457","url_meta":{"origin":457794,"position":3},"title":"New Study: Climate Models Mired In \u2018Terra Incognita\u2019 \u2013 Lack The Resolution To Model Climate Change","author":"uwe.roland.gross","date":"08\/04\/2023","format":false,"excerpt":"\u201c\u2026models are pushing further and further into the domain of the \u2018terra incognita.'\u201d \u2013 Stephens et al., 2023","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\/08\/0Global_Climate_Model-1024x673-1.jpg?fit=1024%2C673&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/08\/0Global_Climate_Model-1024x673-1.jpg?fit=1024%2C673&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/08\/0Global_Climate_Model-1024x673-1.jpg?fit=1024%2C673&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/08\/0Global_Climate_Model-1024x673-1.jpg?fit=1024%2C673&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":421404,"url":"https:\/\/climatescience.press\/?p=421404","url_meta":{"origin":457794,"position":4},"title":"Tropical Tropospheric Temperature Trends, 1979-2025: The Epic Climate Model Failure Continues","author":"uwe.roland.gross","date":"01\/15\/2026","format":false,"excerpt":"As a follow-on to my\u00a0recent post\u00a0regarding global surface air temperature trends (1979-2025) and how they compare to climate models, this is an update on a similar comparison for tropical tropospheric temperature trends, courtesy of tabulations made by John Christy. It also represents an update to my popular\u00a0\u201cepic fail\u201d blog post\u00a0from\u2026","rel":"","context":"In \"anthropogenic greenhouse gas (GHG)\"","block_context":{"text":"anthropogenic greenhouse gas (GHG)","link":"https:\/\/climatescience.press\/?tag=anthropogenic-greenhouse-gas-ghg"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/01\/0Screenshot-2026-01-15-101000.png?fit=1200%2C602&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/01\/0Screenshot-2026-01-15-101000.png?fit=1200%2C602&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/01\/0Screenshot-2026-01-15-101000.png?fit=1200%2C602&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/01\/0Screenshot-2026-01-15-101000.png?fit=1200%2C602&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/01\/0Screenshot-2026-01-15-101000.png?fit=1200%2C602&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":407486,"url":"https:\/\/climatescience.press\/?p=407486","url_meta":{"origin":457794,"position":5},"title":"A Submission to the Australian Senate Investigation into Climate Misinformation","author":"uwe.roland.gross","date":"10\/10\/2025","format":false,"excerpt":"When the Australian government set up a \u201cSenate select committee to investigate misinformation and disinformation in climate science and energy\u201d, I didn\u2019t find out until a few hours before the deadline for submissions from the general public. Things were made a little more complicated by the fact that I was\u2026","rel":"","context":"In \"Australian Government\"","block_context":{"text":"Australian Government","link":"https:\/\/climatescience.press\/?tag=australian-government"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/10\/0Screenshot-2025-10-10-144810.png?fit=1200%2C788&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/10\/0Screenshot-2025-10-10-144810.png?fit=1200%2C788&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/10\/0Screenshot-2025-10-10-144810.png?fit=1200%2C788&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/10\/0Screenshot-2025-10-10-144810.png?fit=1200%2C788&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/10\/0Screenshot-2025-10-10-144810.png?fit=1200%2C788&ssl=1&resize=1050%2C600 3x"},"classes":[]}],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/0-ChatGPT-Of-Climate-Models-And-Black-Boxes.png?fit=1536%2C1024&ssl=1","_links":{"self":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/457794","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/users\/121246920"}],"replies":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=457794"}],"version-history":[{"count":14,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/457794\/revisions"}],"predecessor-version":[{"id":457821,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/457794\/revisions\/457821"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/media\/457796"}],"wp:attachment":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=457794"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=457794"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=457794"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}