An official website of the United States government
The possibility of overshooting global emissions targets has triggered a de-bate about the role of solar geoengineering (SGE)—using technologies to reflect solar radiation away from Earth—in managing climate change. One major concern is thatSGE technologies are relatively cheap and could potentially be deployed by a single country (the “free driver”). We develop a model to analyze how opportunities to de-ploy SGE impact global abatement and the effectiveness of international environ-mental agreements (IEAs). We show that noncooperative abatement may increase or decrease under the threat of SGE, depending on how damaging the free driver’s level of deployment is to others. When free-driver externalities are significant, other countries have additional incentives to abate—called anti-driver incentives—to reduce the free driver’s deployment. We also show that compared to a world withoutSGE opportunities, stable IEAs can be large (small) if anti-driver incentives are relatively strong (weak).
more »
« less
Solar Geoengineering, Free-Driving and Conflict: An Experimental Investigation
As the international community continues to fall short on reducing emissions to avoid disastrous impacts of climate change, some scientists have called for more research into solar geoengineering (SGE) as a potential temporary fix. Others, however, have adamantly rejected the notion of considering SGE in climate policy discussions. One prominent concern with considering SGE technologies to help manage climate change is the so-called “free driver” conjecture. The prediction is that among countries with different preferences for the level of SGE, the country that prefers the most will deploy levels higher than the global optimum. This paper tests the free-driver hypothesis experimentally under different conditions and institutions. We find that aggregate deployment of SGE is inefficiently high in all settings, but slightly less so when players are heterogeneous in endowments or when aggregate deployment is determined by a best-shot technology. Despite persistent inefficiencies in SGE deployment, free-driver behavior, on average, is less extreme than the theoretical predictions.
more »
« less
- Award ID(s):
- 2033855
- PAR ID:
- 10527196
- Publisher / Repository:
- Springer
- Date Published:
- Journal Name:
- Environmental and Resource Economics
- Volume:
- 87
- Issue:
- 4
- ISSN:
- 0924-6460
- Page Range / eLocation ID:
- 1045 to 1060
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Because climate change broadcasts a large aggregate risk to the overall macroeconomy and the global financial system, we investigate how a temperature anomaly and/or its volatility affect the accuracy of forecasts of stock return volatility. To this end, we do not apply only the classical GARCH and GARCHX models, but rather we apply newly proposed model-free prediction methods, and use GARCH-NoVaS and GARCHX-NoVaS models to compute volatility predictions. These two models are based on a normalizing and variance-stabilizing transformation (NoVaS transformation) and are guided by a so-called model-free prediction principle. Applying the new models to data for South Africa, we find that climate-related information is helpful in forecasting stock return volatility. Moreover, the novel model-free prediction method can incorporate such exogenous information better than the classical GARCH approach, as revealed by the the squared prediction errors. More importantly, the forecast comparison test reveals that the advantage of applying exogenous information related to climate risks in prediction of the South African stock return volatility is significant over a century of monthly data (February 1910–February 2023). Our findings have important implications for academics, investors, and policymakers.more » « less
-
Abstract In 1921, Otto Stern conceived the idea for an experiment that would decide between a classical and a quantum description of atomic behavior, as epitomized by the Bohr–Sommerfeld–Debye model of the atom. This model entailed not only the quantization of the magnitude of the orbital electronic angular momentum but also of the projection of the angular momentum on an external magnetic field – the so‐called space quantization. Stern recognized that space quantization would have observable consequences: namely, that the magnetic dipole moment due to the orbital angular momentum would be space quantized as well, taking two opposite values for atoms whose only unpaired electron has just one quantum of orbital angular momentum. When acted upon by a suitable inhomogeneous magnetic field, a beam of such atoms would be split into two beams consisting of deflected atoms with opposite projections of the orbital angular momentum on the magnetic field. In contradistinction, if atoms behaved classically, the atomic beam would only broaden along the field gradient and have maximum intensity at zero deflection, i. e., where there would be a minimum or no intensity for a beam split due to space quantization. Stern anticipated that, although simple in principle, the experiment would be difficult to carry out – and invited Walther Gerlach to team up with him. Gerlach's realism and experimental skills together with his sometimes stubborn determination to make things work proved invaluable for the success of the Stern–Gerlach experiment (SGE). After a long struggle, Gerlach finally saw, on 8 February 1922, the splitting of a beam of silver atoms in a magnetic field. The absence of the concept of electron spin confused and confounded the interpretation of the SGE, as the silver atoms were, in fact, in a2S state, with zero orbital andspin angular momentum. However, a key quantum feature whose existence the SGE was designed to test – namely space quantization of electronic angular momentum – was robust enough to transpire independent of whether the electronic angular momentum was orbital or due to spin. The SGE entails other key aspects of quantum mechanics such as quantum measurement, state preparation, coherence, and entanglement. Confronted with the outcome of the SGE, Stern noted: “I still have objections to the idea of beauty of quantum mechanics. But she is correct.”more » « less
-
Multithreaded programs can have deadlocks, even after deployment, so users may want to run deadlock tools on deployed programs. However, current deadlock predictors such as MagicLock and UnDead have large overheads that make them impractical for end-user deployment and confine their use to development time. Such overhead stems from running an exponential-time algorithm on a large execution trace. In this paper, we present the first low-overhead deadlock predictor, called AirLock, that is fit for both in-house testing and deployed programs. AirLock maintains a small predictive lock reachability graph, searches the graph for cycles, and runs an exponential-time algorithm only for each cycle. This approach lets AirLock find the same deadlocks as MagicLock and UnDead but with much less overhead because the number of cycles is small in practice. Our experiments with real-world benchmarks show that the average time overhead of AirLock is 3.5%, which is three orders of magnitude less than that of MagicLock and UnDead. AirLock's low overhead makes it suitable for use with fuzz testers like AFL and on-the-fly after deployment.more » « less
-
Abstract This study investigates how entrainment’s diluting effect on cumulonimbus updraft buoyancy is affected by the temperature of the troposphere, which is expected to increase by the end of the century. A parcel model framework is constructed that allows for independent variations in the temperature (T), the entrainment rateε, the free-tropospheric relative humidity (RH), and the convective available potential energy (CAPE). Using this framework, dilution of buoyancy is evaluated withTand RH independently varied and with CAPE either held constant or increased with temperature. When CAPE is held constant, buoyancy decreases asTincreases, with parcels in warmer environments realizing substantially smaller fractions of their CAPE as kinetic energy (KE). This occurs because the increased moisture difference between an updraft and its surroundings at warmer temperatures drives greater updraft dilution. Similar results are found in midlatitude and tropical conditions when CAPE is increased with temperature. With the expected 6%–7% increase in CAPE per kelvin of warming, KE only increases at 2%–4% K−1in narrow updrafts but tracks more closely with CAPE at 4%–6% in wider updrafts. Interestingly, the rate of increase in the KE withTbecomes larger than that of CAPE when the later quantity increases at more than 10% K−1. These findings emphasize the importance of considering entrainment in studies of moist convection’s response to climate change, as the entrainment-driven dilution of buoyancy may partially counteract the influence of increases in CAPE on updraft intensity. Significance StatementCumulonimbus clouds mix air with their surrounding environment through a process called entrainment, which controls how efficiently environmental energy is converted into upward speed in thunderstorm updrafts. Our research shows that warmer temperatures will exacerbate the moisture difference between cumulonimbus updrafts and their surroundings, leading to greater mixing and less efficient conversion of environmental energy into updraft speeds. This effect should be considered in future research that investigates how climate change will affect cumulonimbus clouds.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1007/s10640-024-00854-1
