Most climate change policy attention has been addressed to long-term options, such as inducing new, low-carbon energy technologies and creating cap-and-trade regimes for emissions. We use a behavioral approach to examine the reasonably achievable potential for near-term reductions by altered adoption and use of available technologies in US homes and nonbusiness travel. We estimate the plasticity of 17 household action types in 5 behaviorally distinct categories by use of data on the most effective documented interventions that do not involve new regulatory measures. These interventions vary by type of action and typically combine several policy tools and strong social marketing. National implementation could save an estimated 123 million metric tons of carbon per year in year 10, which is 20% of household direct emissions or 7.4% of US national emissions, with little or no reduction in household well-being. The potential of household action deserves increased policy attention. Future analyses of this potential should incorporate behavioral as well as economic and engineering elements.climate mitigation ͉ climate policy ͉ energy efficiency ͉ household behavior ͉ energy consumption

Measurements of internal energy states of atomic ions confined in traps can be used to illustrate fundamental properties of quantum systems, because long relaxation times and observation times are available. In the experiments described here, a single ion or a few identical ions were prepared in well-defined superpositions of two internal energy eigenstates. The populations of the energy levels were then measured. For an individual ion, the outcome of the measurement is uncertain, unless the amplitude for one of the two eigenstates is zero, and is completely uncertain when the magnitudes of the two amplitudes are equal. In one experiment, a single Hg+ ion, confined in a linear rf trap, was prepared in various superpositions of two hyperfine states. In another experiment, groups of Be+ ions, ranging in size from about 5 to about 400 ions, were confined in a Penning trap and prepared in various superposition states. The measured population fluctuations were greater when the state amplitudes were equal than when one of the amplitudes was nearly zero, in agreement with the predictions of quantum mechanics. These fluctuations, which we call quantum projection noise, are the fundamental source of noise for population measurements with a fixed number of atoms. These fluctuations are of practical importance, since they contribute to the errors of atomic frequency standards.

Abstract. Simultaneous in situ measurements of the long-lived trace species N20, CH4, CFC-12, CFC-113, CFC-11, CC14, CH3CC13, H-1211, and SF6 were made in the lower stratosphere and upper troposphere on board the NASA ER-2 high-altitude aircraft during the 1994 campaign Airborne Southern Hemisphere Ozone Experiment/Measurements for Assessing the Effects of Stratospheric Aircraft. The observed extratropical tracer abundances exhibit compact mutual correlations that show little interhemispheric difference or seasonal variability except at higher altitudes in southern hemisphere spring. The environmental impact of the measured source gases depends, among other factors, on the rate at which they release ozone-depleting chemicals in the stratosphere, that is, on their stratospheric lifetimes. We calculate the mean age of the air from the SF 6 measurements and show how stratospheric lifetimes of the other species may be derived semiempirically from their observed gradients with respect to mean age at the extratropical tropopause. We also derive independent stratospheric lifetimes using the CFC-11 lifetime and the slopes of the tracer' s correlations with CFC-11. In both cases, we correct for the influence of tropospheric growth on stratospheric tracer gradients using the observed mean age of the air, time series of observed tropospheric abundances, and model-derived estimates of the width of the stratospheric age spectrum. Lifetime results from the two methods are consistent with each other. Our best estimates for stratospheric lifetimes are 122 + 24 years for N2 ¸, 93 + 18 years for CH4, 87 + 17 years for CFC-12, 100 + 32 years for CFC-113, 32 + 6 years for CC14, 34 + 7 years for CH3CC13, and 24 + 6 years for H-1211. Most of these estimates are significantly smaller than currently recommended lifetimes, which are based largely on photochemical model calculations. Because the derived stratospheric lifetimes are identical to atmospheric lifetimes for most of the species considered, the shorter lifetimes would imply a faster recovery of the ozone layer following the phaseout of industrial halocarbons than currently predicted.

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We report the first observation of interference efI'ects in the light scattered from two trapped atoms. The visibility of the fringes can be explained in the framework of Bragg scattering by a harmonic crystal and simple "which path" considerations of the scattered photons. If the light scattered by the atoms is detected in a polarization-sensitive way, then it is possible to selectively demonstrate either the particle nature or the wave nature of the scattered light.

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Airborne in situ observations of molecules with a wide range of lifetimes (methane, nitrous oxide, reactive nitrogen, ozone, chlorinated halocarbons, and halon-1211), used in a tropical tracer model, show that mid-latitude air is entrained into the tropical lower stratosphere within about 13.5 months; transport is faster in the reverse direction. Because exchange with the tropics is slower than global photochemical models generally assume, ozone at mid-latitudes appears to be more sensitive to elevated levels of industrial chlorine than is currently predicted. Nevertheless, about 45 percent of air in the tropical ascent region at 21 kilometers is of mid-latitude origin, implying that emissions from supersonic aircraft could reach the middle stratosphere.

Wilson, C, et al. 2017 Widespread infilling of tidal channels and navigable waterways in the human-modified tidal deltaplain of southwest Bangladesh. Elem Sci Anth, 5: 78. DOI: https://doi.org/10.1525/elementa.263 RESEARCH ARTICLEWidespread infilling of tidal channels and navigable waterways in the human-modified tidal deltaplain of southwest Bangladesh Since the 1960s, ~5000 km 2 of tidal deltaplain in southwest Bangladesh has been embanked and converted to densely inhabited, agricultural islands (i.e., polders). This landscape is juxtaposed to the adjacent Sundarbans, a pristine mangrove forest, both well connected by a dense network of tidal channels that effectively convey water and sediment throughout the region. The extensive embanking in poldered areas, however, has greatly reduced the tidal prism (i.e., volume of water) transported through local channels. We reveal that >600 km of these major waterways have infilled in recent decades, converting to land through enhanced sedimentation and the direct blocking of waterways by embankments and sluice gates. Nearly all of the observed closures (~98%) have occurred along the embanked polder systems, with no comparable changes occurring in channels of the Sundarbans (<2% change). We attribute most of the channel infilling to the local reduction of tidal prism in poldered areas and the associated decline in current velocities. The infilled channels account for ~90 km 2 of new land in the last 40-50 years, the rate of which, ~2 km 2 /yr, offsets the 4 km 2 /yr that is eroded at the coast, and is equivalent to ~20% of the new land produced naturally at the Ganges-Brahmaputra tidal rivermouth. Most of this new land, called 'khas' in Bengali, has been reclaimed for agriculture or aquaculture, contributing to the local economy. However, benefits are tempered by the loss of navigable waterways for commerce, transportation, and fishing, as well as the forced rerouting of tidal waters and sediments necessary to sustain this low-lying landscape against rising sea level. A more sustainable delta will require detailed knowledge of the consequences of these hydrodynamic changes to support more scientifically-grounded management of water, sediment, and tidal energy distribution.