Big ocean-induced drag <\/p>\n
Soja and his colleagues refer to this phenomenon as \u201ccontinental-ocean mass redistribution\u201d in their research, including their latest published<\/a> Tuesday in the Journal of Geophysical Research: Solid Earth. As melt from polar ice sheets and mountain glaciers pools down into Earth\u2019s oceans, extra water weight builds up in those wider lower latitudes of the globe near the equator, where all this extra mass is more likely to drag on Earth\u2019s spin.<\/p>\n Soja\u2019s coauthor, Mostafa Kiani Shahvandi, likened the phenomena in a press statement to \u201ca figure skater who spins more slowly once they stretch their arms, and more rapidly once they keep their hands close to their body.\u201d<\/p>\n \u201cOnly one time\u2014around 2 million years ago\u2014the rate of change in length of day was nearly comparable, but never before or after that has the planetary \u2018figure skater\u2019 raised her arms and sea levels so quickly as in 2000 to 2020,\u201d according to Kiani Shahvandi, a postdoctoral researcher with the University of Vienna\u2019s Department of Meteorology and Geophysics.<\/p>\n Tiny marine fossils, one large dataset <\/p>\n Soja and Kiani Shahvandi turned to a vast trove of sea-level fluctuation data for their new research, harvested from the fossils of tiny, shelled, single-celled marine organisms called benthic foraminifera.<\/p>\n \u201cFrom the chemical composition of the foraminifera fossils,\u201d Kiani Shahvandi said, \u201cwe can infer sea-level fluctuations and then mathematically derive the corresponding changes in day length.\u201d<\/p>\n These calculations required that the duo develop a new deep-learning method based on what\u2019s called a Physics-Informed Diffusion Model<\/a> (PIDM). In short, PIDMs take the powerful, predictive power of a probability-based, machine-learning AI and guide it within the strict constraints of physics-informed neural networks (PINNs), built on scientifically derived natural laws.<\/p>\n \u201cThis model captures the physics of sea-level change, while remaining robust to the large uncertainties inherent in paleoclimate data,\u201d Kiani Shahvandi noted.<\/p>\n Small thousandths of a second matter <\/p>\n Granted, the lengths of Earth\u2019s days have proven to be highly, albeit minutely, variable, with recent stretches where its rotation has also sped up. On July 4th, 2024, for example, Earth clocked a personal planetary record<\/a>, completing one full spin 1.66 ms (or 0.00166 seconds) faster than usual. Everything from the hot roiling of our planet\u2019s molten core to atmospheric pressure and wind to the shifting orbit of the Moon can and does have an impact on Earth\u2019s daily rotation<\/a>.<\/p>\n However, the new research is focused on long-term trends: Earth\u2019s behaviors across decades of the 21st century as compared to its rotational rate trends spanning millions of years.<\/p>\n And crucially, according to Soja, today\u2019s increasing oceanic weight in Earth\u2019s thick equatorial middle\u2014an undeniable consequence of climate change\u2014will increasingly become a dominant factor influencing Earth\u2019s rotation speed.<\/p>\n \u201cBy the end of the 21st century, climate change is expected to affect day length even more strongly than the moon,\u201d Soja noted in a press statement. \u201cEven though the changes are only milliseconds, they can cause problems in many areas, for example in precise space navigation, which requires accurate information on Earth\u2019s rotation.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"It often feels like the world is spinning faster and faster, just out of control these days, right?…\n","protected":false},"author":2,"featured_media":539741,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[64,63,2255,2565,128,17712],"class_list":{"0":"post-539740","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-au","9":"tag-australia","10":"tag-earth-science","11":"tag-machine-learning","12":"tag-science","13":"tag-sea-level-rise"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/539740","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/comments?post=539740"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/539740\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media\/539741"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media?parent=539740"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/categories?post=539740"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/tags?post=539740"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"Fossils](\"https:\/\/www.newsbeep.com\/au\/wp-content\/uploads\/2026\/03\/fossils-of-single-celled-marine-organisms-called-benthic-foraminifera.jpg\")
Credit: ETH Zurich. Above, fossils of single-celled marine organisms, called Benthic Foraminifera, like those used by the new study to determine ancient global sea levels. <\/p>\n