We present a framework for allocating a global carbon reduction target among nations, in which the concept of ''common but differentiated responsibilities'' refers to the emissions of individuals instead of nations. We use the income distribution of a country to estimate how its fossil fuel CO2 emissions are distributed among its citizens, from which we build up a global CO2 distribution. We then propose a simple rule to derive a universal cap on global individual emissions and find corresponding limits on national aggregate emissions from this cap. All of the world's high CO2-emitting individuals are treated the same, regardless of where they live. Any future global emission goal (target and time frame) can be converted into national reduction targets, which are determined by ''Business as Usual'' projections of national carbon emissions and in-country income distributions. For example, reducing projected global emissions in 2030 by 13 GtCO2 would require the engagement of 1.13 billion high emitters, roughly equally distributed in 4 regions: the U.S., the OECD minus the U.S., China, and the non-OECD minus China. We also modify our methodology to place a floor on emissions of the world's lowest CO2 emitters and demonstrate that climate mitigation and alleviation of extreme poverty are largely decoupled.climate change ͉ climate equity ͉ climate policy ͉ individual emissions ͉ inequality T he 1992 United Nations Framework Convention on Climate Change (UNFCCC) created a 2-tier world. It called upon the developed (''Annex I'') countries to ''take the lead'' in reducing carbon emissions, and, under the principle of ''common but differentiated responsibilities,'' established no time frame for developing countries to follow. However, a consensus is now emerging in favor of low stabilization targets. These targets cannot be achieved without the participation of developing countries, which today emit about half of global CO 2 emissions and whose future emissions increase faster than the emissions of industrialized countries under ''business as usual '' scenarios (1).On what terms should developing countries participate? There are many proposals, each buttressed by some appeal to ''fairness.'' Per capita allocation is widely acknowledged to represent the only equitable goal in the long term, but intermediate steps are required in the short-to-medium term. Uniform percentage reductions in emissions across all countries are rightly rejected by all parties, on the grounds that industrialized countries must create headroom for developing countries. Here, we offer a different approach: An allocation of national targets for fossilfuel CO 2 emissions derived from a fairness principle based on the ''common but differentiated responsibilities'' of individuals, rather than nations. Our proposal moves beyond per capita considerations to identify the world's high-emitting individuals, who are present in all countries.Our approach is designed to blend parsimony, fairness, and pragmatism-treat equally those with the same emissions, whe...

Energy poverty alleviation has become an important political issue in the most recent years. Several initiatives and policies have been proposed to deal with poor access to modern sources of energy in many developing countries. Given the large number of people lacking basic energy services, an important question is whether providing universal access to modern energy could significantly increase energy demand and associated CO 2 emissions. This paper provides one of the few formal assessments of this problem by means of a simple but robust model of current and future energy consumption. The model allows mapping energy consumption globally for different classes of energy use, quantifying current and future imbalances in the distribution of energy consumption. Our results indicate that an encompassing energy poverty eradication policy to be met by 2030 would increase global final energy consumption by about 7% (roughly 20 EJ). The same quantity of energy could be saved by reducing by 15% energy consumption of individuals with standards above current European levels. The additional energy infrastructure needed to eradicate energy poverty would produce 44-183 GtCO 2 over the 21st century and contribute at most 0.13°C of additional warming.

The ground state of a spin 1 2 nearest neighbor quantum Heisenberg antiferromagnet on the pyrochlore lattice is investigated using a large N SU (N ) fermionic mean field theory. We find several mean field states, of which the state of lowest energy upon Gutzwiller projection, is a parity and time reversal breaking chiral phase with a unit monopole flux exiting each tetrahedron. This "monopole flux" state has a Fermi surface consisting of 4 lines intersecting at a point. At mean field the lowenergy excitations about the Fermi surface are gapless spinons. An analysis using the projective symmetry group of this state suggests that the state is stable to small fluctuations which neither induce a gap, nor alter the unusual Fermi surface.

We describe a mechanism for localising branes in ambient space. When a 3-form flux is turned on in a Taub-NUT space, an M5-brane gets an effective potential that pins it to the center of the space. A similar effect occurs for M2-branes and D-branes with appropriate fluxes. In carefully chosen limits of the external parameters, this leads to new theories that are decoupled from gravity and appear to break Lorentz invariance.For example, we predict the existence of a new 5+1D theory that breaks Lorentz invariance at high-energy and has a low-energy description of N tensor multiplets with N = (1, 0) supersymmetry. We also predict a new type of theory that, similarly to the little-string theory decouples from gravity by a dynamical (rather than kinematical) argument.

Global warming requires a response characterized by forward-looking management of atmospheric carbon and respect for ethical principles. Both safety and fairness must be pursued, and there are severe trade-offs as these are intertwined by the limited headroom for additional atmospheric CO 2 emissions. This paper provides a simple numerical mapping at the aggregated level of developed vs. developing countries in which safety and fairness are formulated in terms of cumulative emissions and cumulative per capita emissions respectively. It becomes evident that safety and fairness cannot be achieved simultaneously for strict definitions of both. The paper further posits potential global trading in future cumulative emissions budgets in a world where financial transactions compensate for physical emissions: the safe vs. fair tradeoff is less severe but remains formidable. Finally, we explore very large deployment of engineered carbon sinks and show that roughly 1,000 Gt CO 2 of cumulative negative emissions over the century are required to have a significant effect, a remarkable scale of deployment. We also identify the unexplored issue of how such sinks might be treated in sub-global carbon accounting.

Energy poverty alleviation has become an important political issue in the most recent years. Several initiatives and policies have been proposed to deal with poor access to modern sources of energy in many developing countries. Given the large number of people lacking basic energy services, an important question is whether providing universal access to modern energy could significantly increase energy demand and associated CO 2 emissions. This paper provides one of the few formal assessments of this problem by means of a simple but robust model of current and future energy consumption. The model allows mapping energy consumption globally for different classes of energy use, quantifying current and future imbalances in the distribution of energy consumption. Our results indicate that an encompassing energy poverty eradication policy to be met by 2030 would increase global final energy consumption by about 7% (roughly 20 EJ). The same quantity of energy could be saved by reducing by 15% energy consumption of individuals with standards above current European levels. The additional energy infrastructure needed to eradicate energy poverty would produce 44-183 GtCO 2 over the 21st century and contribute at most 0.13°C of additional warming.

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A sero-prevalence survey in Delhi measured an infection rate of 23.48% and an implied infection fatality rate (IFR) of 0.06%. Modeling using age group based IFRs from France, Spain and Lombardia project an average IFR that is significantly higher than currently estimated. We show that at least 1500-2500 COVID-19 deaths in the 60+ age group are missing.