{"id":414093,"date":"2025-11-21T10:26:56","date_gmt":"2025-11-21T09:26:56","guid":{"rendered":"https:\/\/climatescience.press\/?p=414093"},"modified":"2025-11-21T10:26:58","modified_gmt":"2025-11-21T09:26:58","slug":"the-deep-ocean-may-be-colder-today-than-any-time-in-the-last-4-5-million-years","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=414093","title":{"rendered":"The Deep Ocean May Be Colder Today Than Any Time in the Last 4.5 million Years"},"content":{"rendered":"\n
\"A<\/figure>\n\n\n\n

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

From No Trick Zone<\/a><\/p>\n\n\n\n

By\u00a0Kenneth Richard<\/a><\/em><\/p>\n\n\n\n

A new study<\/a><\/strong> finds Earth\u2019s bottom water temperatures (BWTs) have cooled by 2-3\u00b0C over the last 4.5 million years through to the pre-industrial era (1750).<\/p>\n\n\n\n

Since 1750, however, global BWTs have not risen in a detectable way, nor have they exceeded the warmth achieved during the Medieval Warm Period (Gebbie and Huybers, 2019<\/a><\/strong>). The Pacific Ocean as a whole has continued to cool in the last centuries.<\/p>\n\n\n\n

\"Graph
Image Source:\u00a0Clark et al., 2025<\/a><\/strong>\u00a0and\u00a0Gebbie and Huybers, 2019<\/a><\/strong><\/figcaption><\/figure>\n\n\n\n

Regionally, today\u2019s North Atlantic\u2019s bottom water temperatures hover around 4\u00b0C \u2013 just as they did throughout the Late Holocene. The BWTs averaged ~5\u00b0C, or \u201cslightly warmer than present-day,\u201d during the last glacial, with anomalies reaching 10\u00b0C both 13 and 16 thousand years ago and about 7\u00b0C both 15 and 19 thousand years ago (Yasuhara et al., 2019<\/a><\/strong>).<\/p>\n\n\n\n

\"Scientific
Image Source:\u00a0Yasuhara et al., 2019<\/a><\/strong><\/figcaption><\/figure>\n\n\n\n

As recently as 10,000 years ago, the Arctic Ocean\u2019s bottom water temperatures were 6-10\u00b0C warmer than they are today (Beierlein et al., 2015<\/a><\/strong>).<\/p>\n\n\n\n

\"Graph
Image Source:\u00a0Beierlein et al., 2015<\/a><\/strong><\/figcaption><\/figure>\n\n\n\n

These global and regional BWT reconstructions do not support the narrative that modern ocean temperatures are unprecedentedly warm due to human activity.<\/p>\n\n\n\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

A\u00a0new study\u00a0finds Earth\u2019s bottom water temperatures (BWTs) have cooled by 2-3\u00b0C over the last 4.5 million years through to the pre-industrial era (1750).<\/p>\n","protected":false},"author":121246920,"featured_media":414101,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","_crdt_document":"","advanced_seo_description":"Discover how Earth's bottom water temperatures have changed over millions of years and what's happening with today's climate.","jetpack_seo_html_title":"Historic Cooling of Earth's Bottom Water Temperatures Revealed","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_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","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":true,"token":"eyJpbWciOiJodHRwczpcL1wvY2xpbWF0ZS1zY2llbmNlLnByZXNzXC93cC1jb250ZW50XC91cGxvYWRzXC8yMDI1XC8xMVwvMEFRTUFWU1ZtaUEzeDUzMFZWNUk2c3Fyb2JUQTBhZzkzZHpmUFF1elRNaEt1V1Y4eFlOWE01MVhrYVpWdk9VVkRpY3RSTW1PYUp5ZGlRRjFVcWQ3ZzdTYUJHTkhic01QQTBoN1hHMFNSa2RrdU1Ka25UUF9hVUN1OGp6aTE0cDBfLTEtMTAyNHg2MDYuanBlZyIsInR4dCI6IlRoZSBEZWVwIE9jZWFuIE1heSBCZSBDb2xkZXIgVG9kYXkgVGhhbiBBbnkgVGltZSBpbiB0aGUgTGFzdCA0LjUgbWlsbGlvbiBZZWFycyIsInRlbXBsYXRlIjoiaGlnaHdheSIsImZvbnQiOiIiLCJibG9nX2lkIjoxNTU4MTI0NDl9.EEhLnixUcnDynhDQDeTfhR5wCQutLWJIrzACBEPMOaAMQ"},"version":2},"jetpack_post_was_ever_published":false},"categories":[1],"tags":[691839751,691834263,691839752],"class_list":{"0":"post-414093","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","6":"hentry","7":"category-uncategorized","8":"tag-bottom-water-temperatures-bwts","9":"tag-late-holocene-2","10":"tag-sea-surface-temperature-sst-2","12":"fallback-thumbnail"},"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/11\/0AQMAVSVmiA3x530VV5I6sqrobTA0ag93dzfPQuzTMhKuWV8xYNXM51XkaZVvOUVDictRMmOaJydiQF1Uqd7g7SaBGNHbsMPA0h7XG0SRkdkuMJknTP_aUCu8jzi14p0_-1.jpeg?fit=1706%2C1009&ssl=1","jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/paxLW1-1JIV","jetpack-related-posts":[{"id":248275,"url":"https:\/\/climatescience.press\/?p=248275","url_meta":{"origin":414093,"position":0},"title":"Tree 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