The Role of China in Mitigating Climate Change

http://globalchange.mit.edu/research/publications/2265We explore short- and long-term implications of several energy scenarios of China’s role in efforts to mitigate global climate risk. The focus is on the impacts on China’s energy system and GDP growth, and on global climate indicators such as greenhouse gas concentrations, radiative forcing, and global temperature change. We employ the MIT Integrated Global System Model (IGSM) framework and its economic component, the MIT Emissions Prediction and Policy Analysis (EPPA) model. We demonstrate that China’s commitments for 2020, made during the UN climate meetings in Copenhagen and Cancun, are reachable at very modest cost. Alternative actions by China in the next 10 years do not yield any substantial changes in GHG concentrations or temperature due to inertia in the climate system. Consideration of the longer-term climate implications of the Copenhagen-type of commitments requires an assumption about policies after 2020, and the effects differ drastically depending on the case. Meeting a 2°C target is problematic unless radical GHG emission reductions are assumed in the short-term. Participation or non-participation of China in global climate architecture can lead by 2100 to a 200–280 ppm difference in atmospheric GHG concentration, which can result in a 1.1°C to 1.3°C change by the end of the century. We conclude that it is essential to engage China in GHG emissions mitigation policies, and alternative actions lead to substantial differences in climate, energy, and economic outcomes. Potential channels for engaging China can be air pollution control and involvement in sectoral trading with established emissions trading systems in developed countries

Impacts of CO2 Mandates for New Cars in the European Union

CO2 emissions mandates for new light-duty passenger vehicles have recently been adopted in the European Union (EU), which require steady reductions to 95 g CO2/km in 2021. Using a computable general equilibrium (CGE) model, we analyze the impact of the mandates on oil demand, CO2 emissions, and economic welfare, and compare the results to an emission trading scenario that achieves identical emissions reductions. We find that the mandates lower oil expenditures by about €6 billion, but at a net added cost of €12 billion in 2020. Emissions from transport are about 50MtCO2 lower with the vehicle emission standards, but with the economy-wide emission trading, lower emissions in transport allow an equal increase in emissions elsewhere in the economy. We estimate that tightening CO2 standards further after 2020 would cost the EU economy an additional €24–63 billion in 2025 compared with achieving the same reductions with an economy-wide emission trading system.The paper benefitted from comments of participants on an earlier draft of the paper presented at a workshop on the EU fuels standards held in Brussels on February 26, 2015, organized by General Motors. The MIT Joint Program on the Science and Policy of Global Change, where the authors are affiliated, is supported by the U.S. Department of Energy, Office of Science under grants DE-FG02-94ER61937, DE-FG02-08ER64597, DE-FG02-93ER61677, DE-SC0003906, DE-SC0007114, XEU-0-9920-01; the U.S. Department of Energy, Oak Ridge National Laboratory under Subcontract 4000109855; the U.S. Environmental Protection Agency under grants XA-83240101, PI-83412601-0, RD-83427901-0, XA-83505101-0, XA-83600001-1, and subcontract UTA12-000624; the U.S. National Science Foundation under grants AGS-0944121, EFRI-0835414, IIS-1028163, ECCS-1128147, ARC-1203526, EF-1137306, AGS-1216707, and SES-0825915; the U.S. National Aeronautics and Space Administration under grants NNX06AC30A, NNX07AI49G, NNX11AN72G and Sub Agreement No. 08-SFWS-209365.MIT; the U.S. Federal Aviation Administration under grants 06-C-NE-MIT, 09-C-NE-MIT, Agmt. No. 4103-30368; the U.S. Department of Transportation under grant DTRT57-10-C-10015; the Electric Power Research Institute under grant EP-P32616/C15124, EP-P8154/C4106; the U.S. Department of Agriculture under grant 58-6000-2-0099, 58-0111-9-001; and a consortium of 35 industrial and foundation sponsors (for the complete list see: http://globalchange.mit.edu/sponsors/all)

QED Corrections to Planck's Radiation Law and Photon Thermodynamics

Leading corrections to Planck's formula and photon thermodynamics arising from the pair-mediated photon-photon interaction are calculated. This interaction is attractive and causes an increase in occupation number for all modes. Possible consequences, including the role of the cosmic photon gas in structure formation, are considered.Comment: 15 pages, Revtex 3.

One-loop self-energy correction to the 1s and 2s hyperfine splitting in H-like systems

The one-loop self-energy correction to the hyperfine splitting of the 1s and 2s levels in H-like low-Z atoms is evaluated to all orders in Z\alpha. The results are compared to perturbative calculations. The residual higher-order contribution is evaluated. Implications to the specific difference of the hyperfine structure intervals 8\Delta \nu_2 - \Delta \nu_1 in He^+ are investigated.Comment: 17 pages, RevTeX, 3 figure

Breit interaction correction to the hyperfine constant of an external s-electron in many-electron atom

Correction to the hyperfine constant $A$ of an external s-electron in many-electron atom caused by the Breit interaction is calculated analytically: $\delta A/A =0.68 Z\alpha^2$. Physical mechanism for this correction is polarization of the internal electronic shells (mainly $1s^2$ shell) by the magnetic field of the external electron. This mechanism is similar to the polarization of vacuum considered by Karplus and Klein long time ago. The similarity is the reason why in both cases (Dirac sea polarization and internal atomic shells polarization) the corrections have the same dependence on the nuclear charge and fine structure constant. In conclusion we also discuss $Z\alpha^2$ corrections to the parity violation effects in atoms.Comment: 8 pages, 2 figure

Free energies of crystalline solids: a lattice-switch Monte Carlo method

We present a method for the direct evaluation of the difference between the free energies of two crystalline structures, of different symmetry. The method rests on a Monte Carlo procedure which allows one to sample along a path, through atomic-displacement-space, leading from one structure to the other by way of an intervening transformation that switches one set of lattice vectors for another. The configurations of both structures can thus be sampled within a single Monte Carlo process, and the difference between their free energies evaluated directly from the ratio of the measured probabilities of each. The method is used to determine the difference between the free energies of the fcc and hcp crystalline phases of a system of hard spheres.Comment: 5 pages Revtex, 3 figure

Thermodynamically Important Contacts in Folding of Model Proteins

We introduce a quantity, the entropic susceptibility, that measures the thermodynamic importance-for the folding transition-of the contacts between amino acids in model proteins. Using this quantity, we find that only one equilibrium run of a computer simulation of a model protein is sufficient to select a subset of contacts that give rise to the peak in the specific heat observed at the folding transition. To illustrate the method, we identify thermodynamically important contacts in a model 46-mer. We show that only about 50% of all contacts present in the protein native state are responsible for the sharp peak in the specific heat at the folding transition temperature, while the remaining 50% of contacts do not affect the specific heat.Comment: 5 pages, 5 figures; to be published in PR

Towards Landslide Predictions: Two Case Studies

In a previous work [Helmstetter, 2003], we have proposed a simple physical model to explain the accelerating displacements preceding some catastrophic landslides, based on a slider-block model with a state and velocity dependent friction law. This model predicts two regimes of sliding, stable and unstable leading to a critical finite-time singularity. This model was calibrated quantitatively to the displacement and velocity data preceding two landslides, Vaiont (Italian Alps) and La Clapi\`ere (French Alps), showing that the former (resp. later) landslide is in the unstable (resp. stable) sliding regime. Here, we test the predictive skills of the state-and-velocity-dependent model on these two landslides, using a variety of techniques. For the Vaiont landslide, our model provides good predictions of the critical time of failure up to 20 days before the collapse. Tests are also presented on the predictability of the time of the change of regime for la Clapi\`ere landslide.Comment: 30 pages with 12 eps figure

One Loop Multiphoton Helicity Amplitudes

We use the solutions to the recursion relations for double-off-shell fermion currents to compute helicity amplitudes for $n$-photon scattering and electron-positron annihilation to photons in the massless limit of QED. The form of these solutions is simple enough to allow {\it all}\ of the integrations to be performed explicitly. For $n$-photon scattering, we find that unless $n=4$, the amplitudes for the helicity configurations (+++...+) and (-++...+) vanish to one-loop order.Comment: 27 pages + 4 uuencoded figures (included), Fermilab-Pub-93/327-T, RevTe

Photon-Graviton Amplitudes from the Effective Action

We report on the status of an ongoing effort to calculate the complete one-loop low-energy effective actions in Einstein-Maxwell theory with a massive scalar or spinor loop, and to use them for obtaining the explicit form of the corresponding M-graviton/N-photon amplitudes. We present explicit results for the effective actions at the one-graviton four-photon level, and for the amplitudes at the one-graviton two-photon level. As expected on general grounds, these amplitudes relate in a simple way to the corresponding four-photon amplitudes. We also derive the gravitational Ward identity for the 1PI one-graviton -- N photon amplitude.Comment: 9 pages, 2 figures, talk given by C. Schubert at "Supersymmetries and Quantum Symmetries - SQS`2011", JINR Dubna, July 18 - 23, 2011 (to appear in the Proceedings