Countries with sustained greenhouse gas emissions reductions: an analysis of trends and progress by sector

While global greenhouse gas (GHG) emissions are still rising, a number of countries have emerged with a sustained record of emissions reductions. In this article, we identify these countries and examine their progress, exploring how fast, how deep, and in which sectors they have reduced emissions. We analyse changes in all major GHG emissions sources, with both production – and consumption-based accounting, but exclude very small countries with high volatility, along with land-use, land-use change and forestry CO2 emissions. We find that 24 countries have sustained reductions in annual CO2 and GHG emissions between 1970 and 2018, in total equalling 3.2 GtCO2eq since their respective emissions peaks. In all but three countries, overall GHG reductions are less than energy and industrial CO2 reductions alone. We group countries into three types of emissions pathway: six former Eastern Bloc countries, where emissions declined rapidly in the 1990s and have continued on a downward trajectory since; six Long-term decline countries, which have sustained reductions since the 1970s; and 12 Recent peak countries, whose emissions decline began in the 2000s. In all cases, emissions reductions were achieved primarily in the energy systems sector, specifically in electricity and heat generation, which still remains the largest source of emissions in most countries. By contrast, in the transport sector, emissions tend to be stable or increasing. Transport is the second largest source of current emissions in Recent peak and Long-term decline countries. While the total GHG reductions of these 24 countries are trivial compared to recent global emissions growth, some have achieved a decline of up to 50% in their annual emissions, showing what is possible even under very moderate climate action. Most countries achieved emissions reductions alongside sustained economic growth, and some approached the fast annual rates of change that will be needed across the world in the coming decades to limit warming to 2°C. This raises the hope that more substantive climate policy, as planned in a growing number of countries, may bring about deeper and more rapid emissions reductions than some may expect today

Four agendas for research and policy on emissions mitigation and well-being

The climate crisis requires nations to achieve human well-being with low national levels of carbon emissions. Countries vary from one another dramatically in how effectively they convert resources into well-being, and some nations with low levels of emissions have relatively high objective and subjective well-being. We identify urgent research and policy agendas for four groups of countries with either low or high emissions and well-being indicators. Least studied are those with low well-being and high emissions. Understanding social and political barriers to switching from high-carbon to lower-carbon modes of production and consumption, and ways to overcome them, will be fundamental

Socio-economic conditions for satisfying human needs at low energy use: an international analysis of social provisioning

Meeting human needs at sustainable levels of energy use is fundamental for avoiding catastrophic climate change and securing the well-being of all people. In the current political-economic regime, no country does so. Here, we assess which socio-economic conditions might enable societies to satisfy human needs at low energy use, to reconcile human well-being with climate mitigation. Using a novel analytical framework alongside a novel multivariate regression-based moderation approach and data for 106 countries, we analyse how the relationship between energy use and six dimensions of human need satisfaction varies with a wide range of socio-economic factors relevant to the provisioning of goods and services ('provisioning factors'). We find that higher achievements in factors such as income equality, democratic quality, electricity access, and public service quality are linked to greater need satisfaction and lower energy requirements (‘beneficial provisioning factors’). Conversely, higher levels of economic growth and extractivism are associated with lower need satisfaction and greater energy dependence (‘detrimental provisioning factors’). Our results suggest that improving beneficial provisioning factors and abandoning detrimental ones could enable countries to provide sufficient need satisfaction within sustainable levels of energy use. However, as key pillars of the required changes in provisioning run contrary to the dominant political-economic regime, a broader political-economic transformation may be required to prioritise, and organise provisioning for, the satisfaction of human needs at low energy use

Fast growing research on negative emissions

Generating negative emissions by removing carbon dioxide from the atmosphere is a key requirement for limiting global warming to well below 2 °C, or even 1.5 °C, and therefore for achieving the long-term climate goals of the recent Paris Agreement. Despite being a relatively young topic, negative emission technologies (NETs) have attracted growing attention in climate change research over the last decade. A sizeable body of evidence on NETs has accumulated across different fields that is by today too large and too diverse to be comprehensively tracked by individuals. Yet, understanding the size, composition and thematic structure of this literature corpus is a crucial pre-condition for effective scientific assessments of NETs as, for example, required for the new special report on the 1.5 °C by the Intergovernmental Panel on Climate Change (IPCC). In this paper we use scientometric methods and topic modelling to identify and characterize the available evidence on NETs as recorded in the Web of Science. We find that the development of the literature on NETs has started later than for climate change as a whole, but proceeds more quickly by now. A total number of about 2900 studies have accumulated between 1991 and 2016 with almost 500 new publications in 2016. The discourse on NETs takes place in distinct communities around energy systems, forests as well as biochar and other soil carbon options. Integrated analysis of NET portfolios—though crucial for understanding how much NETs are possible at what costs and risks—are still in their infancy and do not feature as a theme across the literature corpus. Overall, our analysis suggests that NETs research is relatively marginal in the wider climate change discourse despite its importance for global climate policy

Discourses of climate delay

‘Discourses of climate delay’ pervade current debates on climate action. These discourses accept the existence of climate change, but justify inaction or inadequate efforts. In contemporary discussions on what actions should be taken, by whom and how fast, proponents of climate delay would argue for minimal action or action taken by others. They focus attention on the negative social effects of climate policies and raise doubt that mitigation is possible. Here, we outline the common features of climate delay discourses and provide a guide to identifying them

Accreting Millisecond X-Ray Pulsars

Accreting Millisecond X-Ray Pulsars (AMXPs) are astrophysical laboratories without parallel in the study of extreme physics. In this chapter we review the past fifteen years of discoveries in the field. We summarize the observations of the fifteen known AMXPs, with a particular emphasis on the multi-wavelength observations that have been carried out since the discovery of the first AMXP in 1998. We review accretion torque theory, the pulse formation process, and how AMXP observations have changed our view on the interaction of plasma and magnetic fields in strong gravity. We also explain how the AMXPs have deepened our understanding of the thermonuclear burst process, in particular the phenomenon of burst oscillations. We conclude with a discussion of the open problems that remain to be addressed in the future.Comment: Review to appear in "Timing neutron stars: pulsations, oscillations and explosions", T. Belloni, M. Mendez, C.M. Zhang Eds., ASSL, Springer; [revision with literature updated, several typos removed, 1 new AMXP added

Exploring the Ecological History of a Tropical Agroforestry Landscape Using Fossil Pollen and Charcoal Analysis from Four Sites in Western Ghats, India

Contrary to expectations, some human-modified landscapes are considered to sustain both human activities and biodiversity over the long-term. Agroforestry systems are among these landscapes where crops are planted under native shade trees. In this context, ancient agroforestry systems can provide insight into how farmers managed the landscape over time. Such insight can help to quantify the extent to which tropical forests (especially habitat-specialist trees) are responding to local and landscape-level management. Here, we extracted fossil pollen (indicator of past vegetation changes) and macroscopic charcoal (indicator of biomass burning) from four forest hollows’ sedimentary sequences in an ancient agroforestry system in Western Ghats, India. We used a mixed-modelling approach and a principal components analysis (PCA) to determine past trajectories of forest change and species composition dynamics for the last 900 years. In addition, we reconstructed the long-term forest canopy dynamics and examined the persistence of habitat-specialist trees over time. Our results show that the four sites diverged to a surprising degree in both taxa composition and dynamics. However, despite these differences, forest has persisted over 900 years under agricultural activities within agroforestry systems. This long-term analysis highlights the importance of different land-use legacies as a framework to increase the effectiveness of management across tropical agricultural lands

Molecular and cellular mechanisms underlying the evolution of form and function in the amniote jaw.

The amniote jaw complex is a remarkable amalgamation of derivatives from distinct embryonic cell lineages. During development, the cells in these lineages experience concerted movements, migrations, and signaling interactions that take them from their initial origins to their final destinations and imbue their derivatives with aspects of form including their axial orientation, anatomical identity, size, and shape. Perturbations along the way can produce defects and disease, but also generate the variation necessary for jaw evolution and adaptation. We focus on molecular and cellular mechanisms that regulate form in the amniote jaw complex, and that enable structural and functional integration. Special emphasis is placed on the role of cranial neural crest mesenchyme (NCM) during the species-specific patterning of bone, cartilage, tendon, muscle, and other jaw tissues. We also address the effects of biomechanical forces during jaw development and discuss ways in which certain molecular and cellular responses add adaptive and evolutionary plasticity to jaw morphology. Overall, we highlight how variation in molecular and cellular programs can promote the phenomenal diversity and functional morphology achieved during amniote jaw evolution or lead to the range of jaw defects and disease that affect the human condition

Unequal household carbon footprints in China

Households’ carbon footprints are unequally distributed among the rich and poor due to differences in the scale and patterns of consumption. We present distributional focused carbon footprints for Chinese households and use a carbon-footprint-Gini coefficient to quantify inequalities. We find that in 2012 the urban very rich, comprising 5% of population, induced 19% of the total carbon footprint from household consumption in China, with 6.4 tCO2/cap. The average Chinese household footprint remains comparatively low (1.7 tCO2/cap), while those of the rural population and urban poor, comprising 58% of population, are 0.5–1.6 tCO2/cap. Between 2007 and 2012 the total footprint from households increased by 19%, with 75% of the increase due to growing consumption of the urban middle class and the rich. This suggests that a transformation of Chinese lifestyles away from the current trajectory of carbon-intensive consumption patterns requires policy interventions to improve living standards and encourage sustainable consumption