{"id":303363,"date":"2026-01-25T19:51:10","date_gmt":"2026-01-25T19:51:10","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/303363\/"},"modified":"2026-01-25T19:51:10","modified_gmt":"2026-01-25T19:51:10","slug":"scientists-solve-66-million-year-old-mystery-of-how-earths-greenhouse-age-ended-2","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/303363\/","title":{"rendered":"Scientists solve 66 million-year-old mystery of how Earth\u2019s greenhouse age ended"},"content":{"rendered":"

A 66 million-year-old mystery behind how our planet transformed
\nfrom a tropical greenhouse to the ice-capped world of today has
\nbeen unravelled by scientists, Azernews<\/strong> reports
\nciting EurekAlert<\/a>.<\/p>\n

Their new study has revealed that Earth\u2019s massive drop in
\ntemperature after the dinosaurs went extinct could have been caused
\nby a large decrease in calcium levels in the ocean.<\/p>\n

An international team of experts led by the University of
\nSouthampton discovered that concentrations of calcium in the sea
\ndropped by more than half across the last 66 million years.<\/p>\n

The study, published in Proceeding of the National Academy of
\nSciences (PNAS), showed that the dramatic calcium shift may have
\nsucked carbon dioxide \u2013 a major greenhouse gas \u2013 out of the
\natmosphere, driving global cooling.<\/p>\n

Lead author Dr David Evans, an ocean and earth scientist from
\nSouthampton, said that large changes in the composition of seawater
\nchemistry may have been a key driver for climate change.<\/p>\n

He added: “Our results show that dissolved calcium levels were
\ntwice as high at the start of the Cenozoic Era, shortly after
\ndinosaurs roamed the planet, compared to today.<\/p>\n

\u201cWhen these levels were high, the oceans worked differently,
\nacting to store less carbon in seawater and releasing carbon
\ndioxide into the air.<\/p>\n

\u201cAs those levels decreased, CO2 was sucked out of the
\natmosphere, and the Earth\u2019s temperature followed, dropping our
\nclimate by as much as 15 to 20 degrees Celsius.”<\/p>\n

The Southampton researchers behind the study worked in
\ncollaboration with scientists from China, the USA, Israel, Denmark,
\nGermany, Belgium and Netherlands.<\/p>\n

They used fossilised remains of tiny sea creatures dug up from
\nsediments at the seafloor to construct the most detailed record of
\nocean chemistry to date.<\/p>\n

The chemical composition of the fossils, called foraminifera,
\nshowed a close link between the amount of calcium in seawater and
\nthe level of carbon dioxide in the air.<\/p>\n

Using computer-made models, the team showed that high levels of
\ncalcium change how much carbon is \u201cfixed\u201d by marine life, such as
\ncorals and plankton, said Dr Evans.<\/p>\n

This effectively locked it away from the ocean and atmosphere by
\nstoring it in sediments on the seafloor.<\/p>\n

As dissolved calcium levels decreased across millions of years,
\nit altered how these organisms produced and buried calcium
\ncarbonate on the seafloor, added co-author Dr Xiaoli Zhou of Tongji
\nUniversity in China.<\/p>\n

She added: \u201cThe process effectively pulls carbon dioxide out of
\nthe atmosphere and locks it away.<\/p>\n

\u201cThis shift could have changed the composition of the
\natmosphere, effectively turning down the planet\u2019s thermostat.\u201d<\/p>\n

The experts also revealed that the drop in calcium closely
\nmatched the slowing down of seafloor spreading \u2013 the volcanic
\nprocess that continuously creates new ocean floors.<\/p>\n

As the rate of seafloor production slowed, the chemical exchange
\nbetween the rocks and sea water changed, leading to a gradual
\ndecline in dissolved calcium concentrations, said co-author
\nProfessor Yair Rosenthal from Rutgers University, USA.<\/p>\n

He added: “Seawater chemistry is typically viewed as something
\nthat responds to other factors that lead to changes in our climate,
\nrather than being the cause itself.<\/p>\n

\u201cBut our new evidence suggests that we must look to changing
\nseawater chemistry to understand our planet\u2019s climate history.<\/p>\n

\u201cIt may be that changes in these deep Earth processes are
\nultimately responsible for much of the large climatic shifts that
\nhave taken place over geological time.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"A 66 million-year-old mystery behind how our planet transformed from a tropical greenhouse to the ice-capped world of…\n","protected":false},"author":2,"featured_media":303364,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[77],"tags":[4106,2859,8580,8577,9,207,4621,179,18,8579,19,17,8578,790,133,8576,385,66],"class_list":{"0":"post-303363","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-analytics","9":"tag-azerbaijan","10":"tag-azernews","11":"tag-baku","12":"tag-breaking-news","13":"tag-business-news","14":"tag-company-news","15":"tag-economy","16":"tag-eire","17":"tag-financial-news","18":"tag-ie","19":"tag-ireland","20":"tag-oil-and-gas-news","21":"tag-politics","22":"tag-science","23":"tag-socar","24":"tag-turkey","25":"tag-world-news"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/115957483663000532","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/303363","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=303363"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/303363\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/303364"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=303363"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=303363"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=303363"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}