{"id":274,"date":"2024-08-07T05:07:43","date_gmt":"2024-08-07T05:07:43","guid":{"rendered":"https:\/\/climate-reality.net\/?page_id=274"},"modified":"2024-09-11T09:16:52","modified_gmt":"2024-09-11T09:16:52","slug":"how-large-are-short-term-climate-fluctuations-and-what-causes-them","status":"publish","type":"page","link":"https:\/\/climate-reality.net\/?page_id=274","title":{"rendered":"How large are short-term climate fluctuations, and what causes them?"},"content":{"rendered":"\n

<\/p>\n\n\n\n

The temperatures in the chart below are anomalies<\/strong>, that is how much the temperature in any month differs from the average for that month for the period 1991 to 2020. Although, obviously, the general trend is up, there are huge swings up and down, in some cases as much as 0.8\u00ba C (1.4\u00ba F). Before discussing this, I would like to show the graph for the much larger annual swing of the earth’s temperature of 3.7\u00baC:<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n
\"\"<\/figure>\n\n\n\n

This swing in temperatures is because there is 35% more land in the northern hemisphere, and land does not retain heat as well as oceans.<\/p>\n\n\n\n

In another question I discuss how sparse our sampling is below the ocean surface and how we know almost nothing about the deep ocean under 2,000 meters. We do know that ocean surface temperatures shift dramatically from year to year, even month to month, but we cannot predict the timing of the shifts, or in many cases the reasons. For example, between March of 2020 and March of 2021 the satellite measured temperatures of the air above the oceans worldwide cooled by 0.41\u00baC (0.31\u00baC north of 20\u00baN, 0.61\u00baC in the tropics, and 0.67\u00baC south of 20\u00baS). And those March 2021 temperatures worldwide were 0.29 C below the January and February temperatures of that year.1<\/a><\/sup> Would you like me to explain? I can only guess: There must be massive currents coursing through the oceans that nobody has heard of.<\/p>\n\n\n\n

We do know about certain oscillations. The most famous is the El Ni\u00f1o Southern Oscillation (ENSO),2<\/a><\/sup> that describes an alternation between calm, El Ni\u00f1o and an upwelling, La Ni\u00f1a, off the coast of South America.  It has no name when the upwelling is moderate. El Ni\u00f1o takes place when the westerly trade winds that normally are weak blow sun-heated surface water away from the South American coast. Cold water at the South American coast is denser and therefore heavier than warm surface water, but when the surface water is removed, colder water will upwell to replace it or Cold water at the South American coast is denser and therefore heavier than warm surface water, but when the surface water is removed, colder water will upwell to replace it or arrive by the cold northward current along the South American coast from the Antarctic, where it is replaced by deeper water. Even though ENSO has been unpredictable,<\/em> this has not stopped oceanographers from creating models; there are many of them. <\/em><\/p>\n\n\n\n

The strongest El Ni\u00f1o and La Ni\u00f1a events have been correlated with increases and decreases of worldwide temperatures.\u00a0 Very strong El Ni\u00f1os are followed the same and next year by 0.1\u00ba to 0.2\u00ba C increases in worldwide temperatures and very strong La Ni\u00f1as by 0.3\u00ba C decreases. The average temperature of the tropical seas where El Ni\u00f1o and La Ni\u00f1a occur are 22-28\u00ba C3<\/a><\/sup>; while the average temperature of the earth\u2019s land is 8.6\u00ba C.4<\/a><\/sup>\u00a0 The data I have looked at (my calculations) show that land temperatures increase more than ocean temperatures by very roughly 2.5 times during and after strong El Ni\u00f1os, and that they decrease more than ocean temperatures by about 1.8 times during strong La Ni\u00f1as.
<\/p>\n\n\n\n

The \u201creservoir\u201d for El Ni\u00f1o water is the western Pacific.\u00a0 In normal and La Ni\u00f1a years, the trade wind and the equatorial current push warm water to the western pacific near Borneo, where it literally \u201cpiles up\u201d and also becomes deeper.\u00a0 The mixing layer is much thicker in the western Pacific, as was illustrated in the graphic above; it can vary from 100 to 300 meters in depth.\u00a0\u00a0 Recent studies find it has gotten deeper and more stratified. The western Pacific mixing layer can warm the planet if it spreads out.<\/strong>\u00a0 I have only seen this discussed very recently, but it is in fact rather obvious.<\/em>\u00a0 An animated graphic of sea surface temperatures from month to month over many years shows than in warmer years the high temperature layer on the surface is expanded \u2014 north and south, and sometimes west all the way to the Indian sub-continent, sometimes at the same time as it has spread east in El Ni\u00f1os.<\/p>\n\n\n\n

Temperature readings are taken from the very top skin of the ocean, and it is this layer that transfers heat to the winds.  (The tropical ocean is warmer, on average, than the air above it.)  So, it is evident that hotter temperatures worldwide can arise from the mixing layer of the ocean \u2014 whether caused by the movement of water by winds or by the pressure of deep ocean currents.  <\/p>\n\n\n\n

There are many other powerful upwelling oscillations<\/strong>, as well as large fluctuations in ocean currents, all of which have a strong effect on regional and world climate.5<\/a><\/sup>  Many of these occur in areas that have poor historical records and are only being considered today.<\/p>\n\n\n\n

Variations in upwelling, in ocean currents and surface spreading, and in the winds that affect them surely are responsible for most year-to-year fluctuations in the earth\u2019s temperature, and they may also alter the climate for decades or longer. If the warming of the ocean surface is causing a weakening of ocean currents, as is postulated, it does not bode well for the earth’s temperature.<\/p>\n\n\n\n

<\/p>\n\n\n\n

<\/p>\n\n\n\n

<\/p>\n\n\n

  1. A description of the upwelling processes is here: https:\/\/en.wikipedia.org\/wiki\/Upwelling<\/a> \u21a9\ufe0e<\/a><\/li>
  2. A description of the upwelling processes is here: https:\/\/en.wikipedia.org\/wiki\/Upwelling<\/a> \u21a9\ufe0e<\/a><\/li>
  3. https:\/\/www.cen.uni-hamburg.de\/en\/icdc\/data\/ocean\/hadisst1.html<\/a> \u21a9\ufe0e<\/a><\/li>
  4. https:\/\/berkeleyearth.org\/data\/<\/a> \u21a9\ufe0e<\/a><\/li>
  5. \u00a0https:\/\/www.whoi.edu\/know-your-ocean\/ocean-topics\/how-the-ocean-works\/ocean-circulation\/el-nio-other-oscillations\/ \u21a9\ufe0e<\/a><\/li><\/ol>","protected":false},"excerpt":{"rendered":"

    The temperatures in the chart below are anomalies, that is how much the temperature in any month differs from the […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":"[{\"content\":\"A description of the upwelling processes is here: https:\/\/en.wikipedia.org\/wiki\/Upwelling<\/a>\",\"id\":\"935caa57-d430-490b-a8bf-8513e9c2eac9\"},{\"content\":\"A description of the upwelling processes is here: https:\/\/en.wikipedia.org\/wiki\/Upwelling<\/a>\",\"id\":\"1bf25f50-5b24-4588-b3d9-9112f4d6109b\"},{\"content\":\"https:\/\/www.cen.uni-hamburg.de\/en\/icdc\/data\/ocean\/hadisst1.html<\/a>\",\"id\":\"efc08f17-6c50-469e-b34c-a8f468b2bd5b\"},{\"content\":\"https:\/\/berkeleyearth.org\/data\/<\/a>\",\"id\":\"846919b0-2619-4fda-8b1a-4e5abef4dadb\"},{\"content\":\"\u00a0https:\/\/www.whoi.edu\/know-your-ocean\/ocean-topics\/how-the-ocean-works\/ocean-circulation\/el-nio-other-oscillations\/\",\"id\":\"41eceb1b-3399-4d07-aeee-5636a3ef6365\"}]"},"class_list":["post-274","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/climate-reality.net\/index.php?rest_route=\/wp\/v2\/pages\/274","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/climate-reality.net\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/climate-reality.net\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/climate-reality.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/climate-reality.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=274"}],"version-history":[{"count":6,"href":"https:\/\/climate-reality.net\/index.php?rest_route=\/wp\/v2\/pages\/274\/revisions"}],"predecessor-version":[{"id":519,"href":"https:\/\/climate-reality.net\/index.php?rest_route=\/wp\/v2\/pages\/274\/revisions\/519"}],"wp:attachment":[{"href":"https:\/\/climate-reality.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=274"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}