Hydrogen-bond complexation constants determined by Taylor and co-workers using 1,1,1-trichloroethane (TCE) solvent have been analysed through the α₂ ^Hβ₂ ^H relationship; α₂ ^H and β₂ ^H are the solute hydrogen-bond acidity and basicity parameters obtained from complexation constants in tetrachloromethane. Constants for three alcohol/N-methylpyrrolidinone complexations have been determined in TCE, and if these are used instead of the original alcohol/N-methylpyrrolidinone complexation constants, a good relationship is obtained, eqn. (i) . The slope in eqn. (i) is smaller than that for the α₂ ^Hβ₂ ^H relationship in tetrachloromethane, but the intercept is the same. Eqn. (i) has been used to obtain 25 new α₂ ^H values for acids; these include acetanilides, sulfonamides, triazoles and tetrazoles. The latter two types of compound have very large α₂ ^H values; that for 5-phenyl-1,2,3,4-tetrazole (0.88) being near the value for dichloroacetic acid (0.90). Values of β₂ ^H for 31 hydrogen-bond bases have also been calculated using eqn. (i). These include bases with heterocyclic moieties to which β₂ ^H values had not previously been assigned, e.g. oxazole, isoxazole, triazoles and a tetrazole.

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.

The Antarctic Centennial Oscillation (ACO) is a paleoclimate temperature cycle that originates in the Southern Hemisphere, is the presumptive evolutionary precursor of the contemporary Antarctic Oscillation (AAO), and teleconnects to the Northern Hemisphere to influence global temperature. In this study we investigate the internal climate dynamics of the ACO over the last 21 millennia using stable water isotopes frozen in ice cores from 11 Antarctic drill sites as temperature proxies. Spectral and time series analyses reveal that ACOs occurred at all 11 sites over all time periods evaluated, suggesting that the ACO encompasses all of Antarctica. From the Last Glacial Maximum through the Last Glacial Termination (LGT), ACO cycles propagated on a multicentennial time scale from the East Antarctic coastline clockwise around Antarctica in the streamline of the Antarctic Circumpolar Current (ACC). The velocity of teleconnection (VT) is correlated with the geophysical characteristics of drill sites, including distance from the ocean and temperature. During the LGT, the VT to coastal sites doubled while the VT to inland sites decreased fourfold, correlated with increasing solar insolation at 65°N. These results implicate two interdependent mechanisms of teleconnection, oceanic and atmospheric, and suggest possible physical mechanisms for each. During the warmer Holocene, ACOs arrived synchronously at all drill sites examined, suggesting that the VT increased with temperature. Backward extrapolation of ACO propagation direction and velocity places its estimated geographic origin in the Southern Ocean east of Antarctica, in the region of the strongest sustained surface wind stress over any body of ocean water on Earth. ACO period is correlated with all major cycle parameters except cycle symmetry, consistent with a forced, undamped oscillation in which the driving energy affects all major cycle metrics. Cycle period and symmetry are not discernibly different for the ACO and AAO over the same time periods, suggesting that they are the same climate cycle. We postulate that the ACO/AAO is generated by relaxation oscillation of Westerly Wind velocity forced by the equator-to-pole temperature gradient and propagated regionally by identified air-sea-ice interactions.

There is a widespread policy assumption that anthropogenic greenhouse gases are the main driver of the observed 1 °C rise in global surface air temperatures since ‘pre-industrial’ times. This paper demonstrates that the onset of the current warming trend began in the mid-19th century and is consistent with the rising phase of variable global warming and cooling cycles in both the Northern and Southern Hemispheres. Hemispheres. The last trough of the millennial cycle, the Little Ice Age, coincides approximately with the baseline of pre-industrial times used to calculate the impact of Anthropogenic Global Warming. Yet, half of the observed 20th century temperature rise occurred before 1950 when carbon dioxide levels remained low, with the remaining half happening at a similar rate of warming despite the much higher concentrations of greenhouse gases in the atmosphere. This study shows that when the amplitudes and rates of change of the long-term global cycles are considered, the anthropogenic component of warming can be reduced to 38% (using factors derived from the latest IPCC Working Group reports) to as little as 25% (using observational flux data of dominant Short Wave Absorbed Surface Radiation). These global climate cycles can be extrapolated into the future and the implications for policy of a large natural component to climate change are explored—in particular, the potential for mitigation strategies to have minimal impact and for the climate to cool consequent upon a cyclic down-phase.