Stochastic effects on phase-space holes and clumps in kinetic systems near marginal stability

The creation and subsequent evolution of marginally-unstable modes have been observed in a wide range of fusion devices. This behaviour has been successfully explained, for a single frequency shifting mode, in terms of phase-space structures known as a `hole' and `clump'. Here, we introduce stochasticity into a 1D kinetic model, affecting the formation and evolution of resonant modes in the system. We find that noise in the fast particle distribution or electric field leads to a shift in the asymptotic behaviour of a chirping resonant mode; this noise heuristically maps onto microturbulence via canonical toroidal momentum scattering, affecting hole and clump formation. The profile of a single bursting event in mode amplitude is shown to be stochastic, with small changes in initial conditions affecting the lifetime of a hole and clump. As an extension to the work of Lang and Fu, we find that an intermediate regime exists where noise serves to decrease the effective collisionality, where microturbulence works against pitch-angle scattering

Gridded fossil CO2 emissions and related O2 combustion consistent with national inventories 1959-2018

Quantification of CO2 fluxes at the Earth’s surface is required to evaluate the causes and drivers of observed increases in atmospheric CO2 concentrations. Atmospheric inversion models disaggregate observed variations in atmospheric CO2 concentration to variability in CO2 emissions and sinks. They require prior constraints fossil CO2 emissions. Here we describe GCP-GridFED (version 2019.1), a gridded fossil emissions dataset that is consistent with the national CO2 emissions reported by the Global Carbon Project (GCP). GCP-GridFEDv2019.1 provides monthly fossil CO2 emissions estimates for the period 1959-2018 at a spatial resolution of 0.1°. Estimates are provided separately for oil, coal and natural gas, for mixed international bunker fuels, and for the calcination of limestone during cement production. GCP-GridFED also includes gridded estimates of O2 uptake based on oxidative ratios for oil, coal and natural gas. It will be updated annually and made available for atmospheric inversions contributing to GCP global carbon budget assessments, thus aligning the prior constraints on top-down fossil CO2 emissions with the bottom-up estimates compiled by the GCP

Broadening scientific engagement and inclusivity in IPCC reports through collaborative technology platforms

Abstract The growing number of scientific publications on climate change has outstripped the capacity of individuals to keep up with the literature, even when confined to selected sub-topics such as chapter sections of IPCC reports. The IPCC would benefit from the assistance of modern technology, the engagement and insights of a far larger pool of experts, and more frequent updates. Here we describe how technology can be tailored to provide asynchronous and connected platforms that can enhance expert’s collaborations through their potential for scalability and inclusivity, and help keep assessments up-to-date. We detail our experience with the ScienceBrief.org platform, which was developed and used during 2017–2021. We show that the timely release of short scientific briefs (e.g. on wildfires), made possible by the platform, led to broad and accurate coverage of science in mainstream and social media, including policy-oriented websites, and therefore served to broaden public exposure and understanding of science, and counter climate misinformation. While a good visual interface and user flow were necessary, incentives were key for expert’s engagement with the platform, which, while positive, remained low. We suggest that a collaborative technology platform like ScienceBrief, tailored to support a modernised process of elaborating IPCC reports, could greatly enhance IPCC assessments by making them more open and accessible, further increasing transparency. It would also enable the comprehensive inclusion of evidence and facilitate broad and high-quality scientific engagement, including from early careers and scientists from around the world. This could first be tested at the scoping stage