Proceedings of the Conference on Human and Economic Resources

The validity of the Hotelling’s rule, the fundamental theorem of nonrenewable resource economics, is limited by its partial equilibrium nature. One symptom of this limitation may be the disagreement between the empirical evidence, showing stable or declining resource prices, and the rule, predicting exponentially increasing prices. In this paper, we study the optimal depletion of a nonrenewable resource in a dynamic general equilibrium framework. We show that, in the long run, the price of a nonrenewable (i) is constant when the nonrenewable is essential in production, and (ii) increases only if the rate of return of capital is larger than the capital depreciation rate and the non-renewable is an inessential input in production. We believe that our model offers a theoretical explanation to non-growing nonrenewable prices and hence at least partially solves the paradox between the Hotelling’s rule and the empirical regularity. We also show that two factors play a crucial role in determining the long run behavior of nonrenewable prices, namely the elasticity of substitution between input factors, and the long run behavior of the real interest rate. Another major achievement of this study is the full analytical solution of the model under a Cobb-Douglas technology.

How overconfident are current projections of anthropogenic carbon dioxide emissions?

Analyzing the risks of anthropogenic climate change requires sound probabilistic projections of CO2 emissions. Previous projections have broken important new ground, but many rely on out-of-range projections, are limited to the 21st century, or provide only implicit probabilistic information. Here we take a step towards resolving these problems by assimilating globally aggregated observations of population size, economic output, and CO2 emissions over the last three centuries into a simple economic model. We use this model to derive probabilistic projections of business-as-usual CO2 emissions to the year 2150. We demonstrate how the common practice to limit the calibration timescale to decades can result in biased and overconfident projections. The range of several CO2 emission scenarios (e.g., from the Special Report on Emission Scenarios) misses potentially important tails of our projected probability density function. Studies that have interpreted the range of CO2 emission scenarios as an approximation for the full forcing uncertainty may well be biased towards overconfident climate change projections.economics of climate change, scenarios, data assimilation

Coherent manipulation of electron spins up to ambient temperatures in Cr5+^{5+}(S=1/2) doped K3_3NbO8_8

We report coherent spin manipulation on Cr$^{5+}$ (\emph{S} = 1/2, \emph{I} = 0) doped K$_3$NbO$_8$, which constitutes a dilute two-level model relevant for use as a spin qubit. Rabi oscillations are observed for the first time in a spin system based on transition metal oxides up to room temperature. At liquid helium temperature the phase coherence relaxation time \emph{$T_2$} reaches $\sim 10$ $\mu$s and, with a Rabi frequency of 20 MHz, yields a single qubit figure of merit \emph{$Q_M$} of about 500. This shows that a diluted ensemble of Cr$^{5+}$ (\emph{S} = 1/2) doped K$_3$NbO$_8$ is a potential candidate for solid-state quantum information processing.Comment: 4 page

How Overconfident are Current Projections of Anthropogenic Carbon Dioxide Emissions?

Analyzing the risks of anthropogenic climate change requires sound probabilistic projections of CO2 emissions. Previous projections have broken important new ground, but many rely on out-of-range projections, are limited to the 21st century, or provide only implicit probabilistic information. Here we take a step towards resolving these problems by assimilating globally aggregated observations of population size, economic output, and CO2 emissions over the last three centuries into a simple economic model. We use this model to derive probabilistic projections of business-as-usual CO2 emissions to the year 2150. We demonstrate how the common practice to limit the calibration timescale to decades can result in biased and overconfident projections. The range of several CO2 emission scenarios (e.g., from the Special Report on Emission Scenarios) misses potentially important tails of our projected probability density function. Studies that have interpreted the range of CO2 emission scenarios as an approximation for the full forcing uncertainty may well be biased towards overconfident climate change projections.Carbon Dioxide, Emissions, Scenarios, Data Assimilation, Markov Chain Monte Carlo

The Hotelling's Rule Revisited in a Dynamic General Equilibrium Model

The validity of the Hotelling?s rule, the fundamental theorem of nonrenewable resource eco- nomics, is limited by its partial equilibrium nature. One symptom of this limitation may be the disagreement between the empirical evidence, showing stable or declining resource prices, and the rule, predicting exponentially increasing prices. In this paper, we study the optimal depletion of a nonrenewable resource in a dynamic general equilibrium framework.We show that in, the long run, the price of a nonrenewable (i) is constant when the nonrenewable is essential in production, and (ii) it increases only if the rate of return of capital is larger than the capital depreciation rate and if the non-renewable is an inessential input in production. We believe that our model offers a theoretical explanation to non-growing nonrenewable prices and hence at least partially solves the paradox between the Hotelling's rule and the empirical regularities. We also show that two factors play a crucial role in determining the long run behavior of non-renewable prices, namely the elasticity of substitution between input factors, and the long run behavior of the real interest rate. Another major achievement of this study is the full analytical solution of the model under a Cobb-Douglas technology.Nonrenewable resources; One-sector growth model, Hotelling?s Rule, Sustainability

Potential of the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor for the monitoring of terrestrial chlorophyll fluorescence

Global monitoring of sun-induced chlorophyll fluorescence (SIF) is improving our knowledge about the photosynthetic functioning of terrestrial ecosystems. The feasibility of SIF retrievals from spaceborne atmospheric spectrometers has been demonstrated by a number of studies in the last years. In this work, we investigate the potential of the upcoming TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor satellite mission for SIF retrieval. TROPOMI will sample the 675–775 nm spectral window with a spectral resolution of 0.5 nm and a pixel size of 7 km × 7 km. We use an extensive set of simulated TROPOMI data in order to assess the uncertainty of single SIF retrievals and subsequent spatio-temporal composites. Our results illustrate the enormous improvement in SIF monitoring achievable with TROPOMI with respect to comparable spectrometers currently in-flight, such as the Global Ozone Monitoring Experiment-2 (GOME-2) instrument. We find that TROPOMI can reduce global uncertainties in SIF mapping by more than a factor of 2 with respect to GOME-2, which comes together with an approximately 5-fold improvement in spatial sampling. Finally, we discuss the potential of TROPOMI to map other important vegetation parameters at a global scale with moderate spatial resolution and short revisit time. Those include leaf photosynthetic pigments and proxies for canopy structure, which will complement SIF retrievals for a self-contained description of vegetation condition and functioning

Submicron active-passive integration for InP-based membranes on silicon

The high vertical index contrast and the small thickness of thin InP-based membrane structures bonded with BCB on Silicon allow the realization of very small devices. To make photonic integrated circuits with both passive and active components in these membranes, active-passive integration on a small scale is essential. In this paper we will present our results on sub-micrometer active areas for membrane applications

How Overconfident are Current Projections of Anthropogenic Carbon Dioxide Emissions?

Analyzing the risks of anthropogenic climate change requires sound probabilistic projections of CO2 emissions. Previous projections have broken important new ground, but many rely on out-of-range projections, are limited to the 21st century, or provide only implicit probabilistic information. Here we take a step towards resolving these problems by assimilating globally aggregated observations of population size, economic output, and CO2 emissions over the last three centuries into a simple economic model. We use this model to derive probabilistic projections of business-as-usual CO2 emissions to the year 2150. We demonstrate how the common practice to limit the calibration timescale to decades can result in biased and overconfident projections. The range of several CO2 emission scenarios (e.g., from the Special Report on Emission Scenarios) misses potentially important tails of our projected probability density function. Studies that have interpreted the range of CO2 emission scenarios as an approximation for the full forcing uncertainty may well be biased towards overconfident climate change projections

Faint Infrared Flares from the Microquasar GRS 1915+105

We present simultaneous infrared and X-ray observations of the Galactic microquasar GRS 1915+105 using the Palomar 5-m telescope and Rossi X-ray Timing Explorer on July 10, 1998 UT. Over the course of 5 hours, we observed 6 faint infrared (IR) flares with peak amplitudes of $\sim 0.3-0.6$ mJy and durations of $\sim 500-600$ seconds. These flares are associated with X-ray soft-dip/soft-flare cycles, as opposed to the brighter IR flares associated with X-ray hard-dip/soft-flare cycles seen in August 1997 by Eikenberry et al. (1998). Interestingly, the IR flares begin {\it before} the X-ray oscillations, implying an ``outside-in'' origin of the IR/X-ray cycle. We also show that the quasi-steady IR excess in August 1997 is due to the pile-up of similar faint flares. We discuss the implications of this flaring behavior for understanding jet formation in microquasars.Comment: 10 pages, 4 figures Accepted for publication in ApJ Letter

Global column‐averaged methane mixing ratios from 2003 to 2009 as derived from SCIAMACHY: Trends and variability

After a decade of stable or slightly decreasing global methane concentrations, ground-based in situ data show that CH_4 began increasing again in 2007 and that this increase continued through 2009. So far, space-based retrievals sensitive to the lower troposphere in the time period under consideration have not been available. Here we report a long-term data set of column-averaged methane mixing ratios retrieved from spectra of the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) instrument onboard Envisat. The retrieval quality after 2005 was severely affected by degrading detector pixels within the methane 2ν_3 absorption band. We identified the most crucial problems in SCIAMACHY detector degradation and overcame the problem by applying a strict pixel mask as well as a new dark current characterization. Even though retrieval precision after the end of 2005 is invariably degraded, consistent methane retrievals from 2003 through 2009 are now possible. Regional time series in the Sahara, Australia, tropical Africa, South America, and Asia show the methane increase in 2007–2009, but we cannot yet draw a firm conclusion concerning the origin of the increase. Tropical Africa even seems to exhibit a negative anomaly in 2006, but an impact from changes in SCIAMACHY detector degradation cannot be excluded yet. Over Assakrem, Algeria, we observed strong similarities between SCIAMACHY measurements and ground-based data in deseasonalized time series. We further show long-term SCIAMACHY xCH_4 averages at high spatial resolution that provide further insight into methane variations on regional scales. The Red Basin in China exhibits, on average, the highest methane abundance worldwide, while other localized features such as the Sudd wetlands in southern Sudan can also be identified in SCIAMACHY xCH_4 averages