Implications of current net zero targets for long-term emissions pathways and warming levels

<div data-node-type="line"><span>In 2020, c</span><span>limate target</span><span> announcements</span><span> were dominated by net-zero </span><span>commitments, including</span> <span>by a number of</span><span> major emitters. Despite the urgency of more ambitious ND</span><span>Cs</span><span> in </span><span>the </span><span>short term, long-term net-zero targets are important for the transition to global zero emissions. </span><span>Tracking progress towards and assessing the adequacy of these targets requires an assessment of what they mean for transition pathways and associated emissions trajectories at both national and global levels. </span></div><div data-node-type="line"></div><div data-node-type="line"><span>We present an</span><span> assessment of net-zero targets of the </span><span>major emitting</span><span> countries</span><span> and their implications for long-term emissions trajectories and warming levels.</span><span> Based on the work of the Climate Action Tracker, country</span><span>-</span><span>specific analys</span><span>e</span><span>s are aggregated to a global emission</span><span>s</span><span> pathway to derive a best estimate for a resulting global warming in 2100. </span><span>Undertaking this analysis requires assumptions to be made regarding projected emissions and removals from the land-use sector, non-CO2 emissions, and the trajectory of total net emissions after net-zero, which we explain and explore. For example, by computing the cumulative emissions of our aggregated net-zero target emissions pathway, we can compare this pathway with modelled global emissions pathways from the IPCC's SR1.5 Special Report, to draw broad conclusions over what current net-zero commitments might mean for carbon dioxide removal and non-CO2 emissions, and the uncertainties therein.</span></div>

Global zero-relaxation limit of the non-isentropic Euler–Poisson system for ion dynamics

This paper is concerned with smooth solutions of the non-isentropic Euler–Poisson system for ion dynamics. The system arises in the modeling of semi-conductor, in which appear one small parameter, the momentum relaxation time. When the initial data are near constant equilibrium states, with the help of uniform energy estimates and compactness arguments, we rigorously prove the convergence of the system for all time, as the relaxation time goes to zero. The limit system is the drift-diffusion system.

Nuclear Disarmament without the Nuclear-Weapon States: The Nuclear Weapon Ban Treaty

The 2017 Treaty on the Prohibition of Nuclear Weapons (tpnw) represents a daring act of self-empowerment: nuclear have-nots produced an international disarmament treaty without the involvement of the nuclear-weapon states or their allies. In this essay, we assess how the new treaty relates to the existing nuclear order and its four central norms: constraints on use, political restraint, non-proliferation, and disarmament. We discuss the tpnw's origin in and impact on this contested order. At the heart of contestation are two security concepts: deterrence versus the immediate ban of nuclear arms, which result in fundamentally different ideas on how to pursue the road to “global zero.” Whether or not the tpnw and the Treaty on the Non-Proliferation of Nuclear Weapons are compatible depends on how the opponents handle their controversies. The key is to overcome the emotionalized polarization and rediscover a common basis in order to prevent damage to the existing nuclear order and bring forward nuclear disarmament in practice.

The Politicization of Women’s Rights in Malaysia: The Drive Behind the Impasse of Fatwa Obligating Female Circumcision

Under the new premiership of Najib Razak in 2009, a fatwa obligating female circumcision for all Muslim women in Malaysia was issued. It was issued following the 2008 “Political Tsunami” despite the heightened promotion of global zero tolerance towards the practice. The dilemma between adhering to Malaysia’s obligation under CEDAW and CRC and the need to regain control amidst domestic political upheaval has led the fatwa to be left on impasse, until date. Thus, this article aims to find the reason behind the Malaysian government’s decision to leave the fatwa on the impasse focusing on two stages of public policy analysis. The analysis of cost and benefit in the policy formulation stage has resulted in equal cost and benefit to each policy option –to accept or reject the fatwa. The result of the equal cost and benefit analysis is also due to the variety of actors in the decision-making process with different positions, interests and bargaining positions. From using a rational model of the decision-making process, the reason why the Malaysian government leaves the fatwa on impasse was driven by the Malaysian goal under Najib Razak, which required not only domestic stability but also vast international support.

The tilt of the velocity ellipsoid in the Milky Way with Gaia DR2

The velocity distribution of stars is a sensitive probe of the gravitational potential of the Galaxy, and hence of its dark matter distribution. In particular, the shape of the dark halo (e.g. spherical, oblate, or prolate) determines velocity correlations, and different halo geometries are expected to result in measurable differences. Here we explore and interpret the correlations in the (vR, vz)-velocity distribution as a function of position in the Milky Way. We selected a high-quality sample of stars from the Gaia DR2 catalogue and characterised the orientation of the velocity distribution or tilt angle over a radial distance range of [4 − 13] kpc and up to 3.5 kpc away from the Galactic plane while taking into account the effects of the measurement errors. We find that the tilt angles change from spherical alignment in the inner Galaxy (R ∼ 4 kpc) towards more cylindrical alignments in the outer Galaxy (R ∼ 11 kpc) when using distances that take a global zero-point offset in the parallax of −29 μas. However, if the amplitude of this offset is underestimated, then the inferred tilt angles in the outer Galaxy only appear shallower and are intrinsically more consistent with spherical alignment for an offset as large as −54 μas. We further find that the tilt angles do not seem to strongly vary with Galactic azimuth and that different stellar populations depict similar tilt angles. Therefore we introduce a simple analytic function that describes the trends found over the full radial range. Since the systematic parallax errors in Gaia DR2 depend on celestial position, magnitude, and colour in complex ways, it is not possible to fully correct for them. Therefore it will be particularly important for dynamical modelling of the Milky Way to thoroughly characterise the systematics in astrometry in future Gaia data releases.