The Antarctic Centennial Oscillation: A Natural Paleoclimate Cycle in the Southern Hemisphere That Influences Global Temperature

Abstract

Abstract:We report a previously-unexplored natural temperature cycle recorded in ice cores from Antarctica-the Antarctic Centennial Oscillation (ACO)-that has oscillated for at least the last 226 millennia. Here we document the properties of the ACO and provide an initial assessment of its role in global climate. We analyzed open-source databases of stable isotopes of oxygen and hydrogen as proxies for paleo-temperatures. We find that centennial-scale spectral peaks from temperature-proxy records at Vostok over the last 10,000 years occur at the same frequencies (±2.4%) in three other paleoclimate records from drill sites distributed widely across the East Antarctic Plateau (EAP), and >98% of individual ACOs evaluated at Vostok match 1:1 with homologous cycles at the other three EAP drill sites and conversely. Identified ACOs summate with millennial periodicity to form the Antarctic Isotope Maxima (AIMs) known to precede Dansgaard-Oeschger (D-O) oscillations recorded in Greenland ice cores. Homologous ACOs recorded at the four EAP drill sites during the last glacial maximum appeared first at lower elevations nearest the ocean and centuries later on the high EAP, with latencies that exceed dating uncertainty >30-fold. ACO homologs at different drill sites became synchronous, however, during the warmer Holocene. Comparative spectral analysis suggests that the millennial-scale AIM cycle declined in period from 1500 to 800 years over the last 70 millennia. Similarly, over the last 226 millennia ACO repetition period (mean 352 years) declined by half while amplitude (mean 0.67 • C) approximately doubled. The period and amplitude of ACOs oscillate in phase with glacial cycles and related surface insolation associated with planetary orbital forces. We conclude that the ACO: encompasses at least the EAP; is the proximate source of D-O oscillations in the Northern Hemisphere; therefore affects global temperature; propagates with increased velocity as temperature increases; doubled in intensity over geologic time; is modulated by global temperature variations associated with planetary orbital cycles; and is the probable paleoclimate precursor of the contemporary Antarctic Oscillation (AAO). Properties of the ACO/AAO are capable of explaining the current global warming signal.

Change in the Recent Warming Trend of Sea Surface Temperature in the East Sea (Sea of Japan) over Decades (1982–2018)

“…The findings of the present study could be attributed to the regional-scale imprints of the large-scale global warming hiatus (GWH) that is referred to as the global warming slowdown, on a period of relatively small warming in the surface temperature of the Earth [12,13]. Additionally, it is suggested that the Antarctic Oscillation (AAO), also known as the Southern Annular Mode (SAM), which is a low-frequency mode of atmospheric variability of the Southern Hemisphere, can affect not only the climate change in the Southern Hemisphere but also in the Northern Hemisphere [49][50][51]. The AAO is capable of influencing the AO through remotely connected atmospheric variability.…”

Peak Carbon Emissions in China: Status, Key Factors and Countermeasures—A Literature Review

“…IPCC AR5 further confirmed that the greenhouse gas emissions from human activities are the major causes of current climate change [2]. Recently, some studies have shown that CO 2 and global temperature may not be coupled as tightly as previously believed, some other physical mechanisms are also possible candidates for causing the contemporary global warming [3], but each country should not reduce the urgency to regulate anthropogenic carbon emissions because of a possible connection between carbon emissions and biodiversity extinction [4].The main sources of anthropogenic carbon emissions are fossil fuels, and of these, coal produces the largest emissions. To achieve the goal of 2 • C temperature control, countries must strengthen actions to reduce greenhouse gas emissions.…”

The Origin and Propagation of the Antarctic Centennial Oscillation

“…Previous investigators have observed that "despite the clear importance of the SAM (i.e., AAO) in the modern/future climate, very little is known regarding its behavior during pre-industrial times" [13] (p. 1). If the ACO and the AAO/SAM are the same natural climate cycle, discovery of the ACO in multiple paleoclimate records over hundreds of millennia before the onset of the Industrial Age ( [11], this paper) promises to provide the missing historical record of the AAO. In this case, understanding the ACO is expected to illuminate the AAO, and conversely.…”

“…Forces external to the Earth, such as periodic variation in solar insolation at the surface induced by natural perturbations of Earth's orbital cycles, drive at least some of these natural climate cycles [3], but in no case are the Earth's internal responses to such external forcing fully understood. In the present study we investigate one such cycle, the Antarctic Centennial Oscillation (ACO) [11] over the past approximately 21,000 y from the Last Glacial Maximum (LGM) to the present. The primary purpose of our study is to elucidate the internal climate dynamics of the ACO, including its regional distribution, teleconnection, geographic source, and method of generation.…”

“…Growing evidence suggests that the ACO and the AAO/SAM are the same natural climate cycle manifested at different times in paleoclimate history. To cite just one congruence, over the last millennium, the ACO as manifest in paleoclimate data oscillated at a mean period of 146 y [11] (Supplementary Material (SM), Table S1), placing it near the median order-of-magnitude ranking of periodicity for known climate cycles. Over the same time period, the AAO as manifest in contemporary climate data oscillated at a mean period of 143 y [12] (blue curve in their Figure 1a), comparable within likely error limits to the repetition frequency of the ACO.…”