{"id":349662,"date":"2024-10-31T18:22:39","date_gmt":"2024-10-31T17:22:39","guid":{"rendered":"https:\/\/climatescience.press\/?p=349662"},"modified":"2024-10-31T18:22:41","modified_gmt":"2024-10-31T17:22:41","slug":"manns-amoc-collapse-hoax","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=349662","title":{"rendered":"Mann\u2019s AMOC Collapse\u00a0Hoax"},"content":{"rendered":"\n
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From Science Matters<\/a><\/p>\n\n\n\n

By\u00a0Ron Clutz<\/a><\/p>\n\n\n\n

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Dr. Kevin E. Trenberth, a distinguished scholar at the National Center for Atmospheric Research, commented on this movie: \u201cI don\u2019t recall a lot except that the whole science was incredibly wrong,\u201d, \u201cone does not get an ice age out of global warming.\u201d<\/figcaption><\/figure>\n\n\n\n

Likely you\u2019ve heard the recent and previous warnings from Mann and friends about the ocean conveyor belt (including the Gulf Stream) slowing down and freezing us all.  With the COP gathering next month, something scary must be proclaimed, and Global Freezing is it, replacing Global Boiling earlier this year. The declaration signed by Mann and 43 other scientists was Open Letter by Climate Scientists to the Nordic Council of Ministers<\/a>,<\/strong> Reykjavik, October 2024. Preface:<\/p>\n\n\n\n

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\u201cWe, the undersigned, are scientists working in the field of climate research and feel it is urgent to draw the attention of the Nordic Council of Ministers to the serious risk of a major ocean circulation change in the Atlantic. A string of scientific studies in the past few years suggests that this risk has so far been greatly underestimated. Such an ocean circulation change would have devastating and irreversible impacts especially for Nordic countries, but also for other parts of the world.\u201d<\/p>\n\n\n\n

\u201cGiven the increasing evidence for a higher risk of an AMOC collapse, we believe it is of critical importance that Arctic tipping point risks, in particular the AMOC risk, are taken seriously in governance and policy. Even with a medium likelihood of occurrence, given that the outcome would be catastrophic and impacting the entire world for centuries to come, we believe more needs to be done to minimize this risk.\u201d<\/p>\n<\/blockquote>\n\n\n\n

The Warning is based on Fear, not Facts<\/h4>\n\n\n\n

1.  The AMOC has been stable for the last four decades.<\/strong><\/h5>\n\n\n\n

Florida Current transport observations reveal four decades of steady state<\/strong><\/a> Volkov et al 2024<\/p>\n\n\n\n

Abstract<\/strong><\/p>\n\n\n\n

The potential weakening<\/strong> of<\/strong> the Atlantic Meridional Overturning Circulation (AMOC<\/strong>) in response to anthropogenic forcing, suggested by climate models,<\/strong> is at the forefront of scientific debate. A key AMOC component, the Florida Current (FC), has been measured<\/strong> using submarine cables between Florida and the Bahamas at 27\u00b0N nearly continuously since 1982<\/strong>. A decrease in the FC strength could be indicative of the AMOC weakening. Here, we reassess motion-induced voltages measured on a submarine cable and reevaluate the overall trend in the inferred FC transport. We find that the cable record beginning in 2000 requires a correction for the secular change in the geomagnetic field.<\/strong> This correction removes a spurious trend in the record<\/strong>, revealing that the FC has remained remarkably stable. The recomputed AMOC estimates at ~26.5\u00b0N result in a significantly weaker negative trend than that which is apparent in the AMOC time series obtained with the uncorrected FC transports.<\/em><\/p>\n\n\n\n

Fig. 1: The Western Boundary Time Series<\/strong>
observing network in the Straits of Florida.<\/strong><\/p>\n\n\n

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The network consists of the submarine telecommunications cable between West Palm Beach and Grand Bahama Island (cyan curve), ship sections across the Florida Current (FC) at 27\u00b0N with in situ measurements at nine stations (white circles), two bottom pressure gauges on both sides of the FC at 27\u00b0N (yellow stars), and along-track satellite altimetry measurements (magenta dotted line). CTD Conductivity-Temperature-Depth, LADCP Lowered Acoustic Doppler Current Profiler, XBT expendable bathythermograph.<\/figcaption><\/figure>\n<\/div>\n\n\n

Fig. 6: Florida Current (FC) volume transports corrected for<\/strong>
the secular change in the Earth\u2019s Magnetic Field (EMF).<\/strong><\/p>\n\n\n\n

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a The time series of the daily FC volume transport: (blue) not corrected for the secular change in the EMF, (red) corrected for the secular change in the EMF. The linear trends of the FC transport not corrected and corrected for the EMF are shown by the blue and red lines, respectively. b The differences between the cable and ship section transport for the cable data (blue squares) not corrected for the EMF and (red circles) corrected for the EMF. The linear trends of the differences (\u0394T) not corrected and corrected for the EMF are shown by the blue and red lines, respectively.<\/figcaption><\/figure>\n\n\n
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Daily transport estimates from the cable record (black; prior to corrections applied in this study); estimates from the Pegasus (orange diamonds) and Pegasus in dropsonde mode (Pegasus-DM; light blue circles) sections; estimates from the dropsonde sections (blue circles); and estimates from the Lowered Acoustic Doppler Current Profiler (LADCP) sections (red circles). The linear trends for 1982\u20132023, 1982\u20131998, and 2000\u20132023 periods are shown by the orange, cyan, and magenta lines, respectively.<\/figcaption><\/figure>\n<\/div>\n\n\n
2.  Paleo records show past AMOC changes due to seafloor shifts not climate change.<\/strong><\/h5>\n\n\n\n

Controlling factors for the global meridional overturning circulation: A lesson from the Paleozoic<\/strong><\/a>, Yuan et al. 2024.<\/p>\n\n\n\n

Abstract<\/strong><\/em><\/p>\n\n\n\n

The global meridional overturning circulation (GMOC) is important<\/strong> for redistributing heat and, thus, determining global climate, but what determines its strength over Earth\u2019s history remains unclear.<\/strong> On the basis of two sets of climate simulations for the Paleozoic characterized by a stable GMOC direction, our research reveals that GMOC strength primarily depends on continental configuration while climate variations have a minor impact.<\/strong> In the mid- to high latitudes, the volume of continents largely dictates the speed of westerly winds,<\/strong> which in turn controls upwelling and the strength of the GMOC<\/strong>. At low latitudes, open seaways also play an important role in the strength of the GMOC. An open seaway in one hemisphere allows stronger westward ocean currents, which support higher sea surface heights (SSH)<\/strong> in this hemisphere than that in the other. The meridional SSH gradient drives a stronger cross-equatorial flow in the upper ocean, resulting in a stronger GMOC. This latter finding enriches the current theory for GMOC.<\/em><\/p>\n\n\n\n

On the basis of a series of simulations for the Paleozoic, we find that the GMOC is primarily controlled by:<\/em><\/p>\n\n\n\n