Search

As urban areas are increasingly exposed to high temperatures, lack of access to residential thermal comfort is a challenge with dramatic consequences for human health and well-being. Air-conditioning (AC) can provide relief against heat stress, but a massive AC uptake could entail stark energy demand growth and mitigation challenges. Slums pose additional risks due to poor building quality, failing to provide adequate shelter from severe climatic conditions. Thus, it is unclear how many people in the Global South will still lack access to basic cooling under different future climate and socioeconomic developments. We assess the impact of different shared socioeconomic pathways (SSPs) and climate futures on the extent of population lacking access to cooling where needed—the cooling gap—and energy requirements for basic comfort for a set of 22 megacities in the Global South. We find that different SSPs greatly influence the extent of future cooling gaps, generally larger in SSP3 due low income levels, and consequent limited access to AC and durable housing. Megacities in Sub-Saharan Africa and South Asia have the largest share of population affected, ranging from 33% (SSP1) to 86% (SSP3) by mid-century. Energy requirements to provide basic cooling for all are higher in SSP1 for most megacities, driven by urbanization, and can increase by 7 to 23% moving from 2.0 to 3.0 °C temperature rise levels. Strategies combining improved building design and efficient cooling systems can improve adaptation to heat stress in cities while reducing energy and emission requirements to reach climate and sustainability goals. [ABSTRACT FROM AUTHOR]

It is well established that nighttime radiance, measured from satellites, correlates with economic prosperity across the globe. In developing countries, areas with low levels of detected radiance generally indicate limited development – with unlit areas typically being disregarded. Here we combine satellite nighttime lights and the world settlement footprint for the year 2015 to show that 19% of the total settlement footprint of the planet had no detectable artificial radiance associated with it. The majority of unlit settlement footprints are found in Africa (39%), rising to 65% if we consider only rural settlement areas, along with numerous countries in the Middle East and Asia. Significant areas of unlit settlements are also located in some developed countries. For 49 countries spread across Africa, Asia and the Americas we are able to predict and map the wealth class obtained from ~2,400,000 geo-located households based upon the percent of unlit settlements, with an overall accuracy of 87%. Nighttime lights from satellite are combined with a map of human settlements, showing that 19% of these areas, mainly in Africa, the Middle East and Asia, have no detectable artificial light. These data were then used in models to predict well-being. [ABSTRACT FROM AUTHOR]

Buildings account for 36% of global final energy demand and are key to mitigating climate change. Assessing the evolution of the global building stock and its energy demand is critical to support mitigation strategies. However, most global studies lack granularity and overlook heterogeneity in the building sector, limiting the evaluation of demand transformation scenarios. We develop global residential building scenarios along the shared socio-economic pathways (SSPs) 1–3 and assess the evolution of building stock, energy demand, and CO2 emissions for space heating and cooling with MESSAGEix-Buildings, a modelling framework soft-linked to an integrated assessment framework. MESSAGEix-Buildings combines bottom-up modelling of energy demand, stock turnover, and discrete choice modelling for energy efficiency decisions, and accounts for heterogeneity in geographical contexts, socio-economics, and buildings characteristics. Global CO2 emissions for space heating are projected to decrease between 34.4 (SSP3) and 52.5% (SSP1) by 2050 under energy efficiency improvements and electrification. Space cooling demand starkly rises in developing countries, with CO2 emissions increasing globally by 58.2 (SSP1) to 85.2% (SSP3) by 2050. Scenarios substantially differ in the uptake of energy efficient new construction and renovations, generally higher for single-family homes, and in space cooling patterns across income levels and locations, with most of the demand in the global south driven by medium- and high-income urban households. This study contributes an advancement in the granularity of building sector knowledge to be assessed in integration with other sources of emissions in the context of global climate change mitigation and sustainable development. [ABSTRACT FROM AUTHOR]

Today Africa is a small emitter, but it has a large and faster-than-average growing population and per capita income that could drive future energy demand and, if unconstrained, emissions. This paper uses a multi-model comparison to characterize the potential future energy development for Continental and Sub-Saharan Africa under different assumptions about population and income. Our results suggest that population and economic growth rates will strongly influence Africa's future energy use and emissions. We show that affluence is only one face of the medal and the range of future emissions is also contingent on technological and political factors. Higher energy intensity improvements occur when Africa grows faster. In contrast, climate intensity varies less with economic growth and it is mostly driven by climate policy. African emissions could account for between 5 % and 20 % of global emissions, with Sub-Saharan Africa contributing between 4 % and 10 % of world emissions in 2100. In all scenarios considered, affluence levels remain low until the middle of the century, suggesting that the population could remain dependent on traditional bioenergy to meet most residential energy needs. Although the share of electricity in final energy, electric capacity and electricity use per capita all rise with income, even by mid-century they do not reach levels observed in developed countries today. [ABSTRACT FROM AUTHOR]

Impetus to expand electricity access in developing nations is urgent. Yet aspirations to provide universal access to electricity are often considered potentially conflicting with efforts to mitigate climate change. How much newly electrified, largely poor, households raise emissions, however, remains uncertain. Results from a first retrospective analysis show that improvements in household electricity access contributed 3-4% of national emissions growth in India over the past three decades. Emissions from both the direct and indirect electricity use of more than 650 million people connected since 1981 accounted for 11-25% of Indian emissions growth or, on average, a rise of 0.008-0.018 tons of CO2 per person per year between 1981 and 2011. Although this is a marginal share of global emissions, it does not detract from the importance for developing countries to start reducing the carbon intensities of their electricity generation to ensure sustainable development and avoid future carbon lock-in. Significant ancillary benefits for air quality, health, energy security and efficiency may also make this attractive for reasons other than climate mitigation alone. [ABSTRACT FROM AUTHOR]

The fifth phase of the Coupled Model Intercomparison Project uses four representative concentration pathways (RCPs) that span the literature range of total anthropogenic radiative forcing but not necessarily of each single forcing agent. We here explore a wide range of air-pollutant emissions over the twenty-first century consistent with the global CO2 paths of the RCPs, by varying assumptions on air-pollution controls and accounting for the possible phase-out of CO2-emitting sources. We show that global air-pollutant emissions in the RCPs (including ozone and aerosol precursors) compare well to and are at times higher than cases that assume an extrapolation of current and planned air-pollution legislation in the absence of new policies to improve energy access for the poor. Stringent pollution controls and clean energy policies can thus further reduce the global atmospheric air-pollution loading below the RCP levels. When assuming pollution control frozen at 2005 levels, the RCP8.5-consistent loading of all species either stabilizes or increases during the twenty-first century, in contrast to RCP4.5 and RCP2.6, which see a consistent decrease in the long term. Our results inform the possible range of global aerosol loading. However, the net aerosol forcing depends strongly on the geographical location of emissions. Therefore, a regional perspective is required to further explore the range of compatible forcing projections. [ABSTRACT FROM AUTHOR]

This paper discusses the role and relevance of the shared socioeconomic pathways (SSPs) and the new scenarios that combine SSPs with representative concentration pathways (RCPs) for climate change impacts, adaptation, and vulnerability (IAV) research. It first provides an overview of uses of social-environmental scenarios in IAV studies and identifies the main shortcomings of earlier such scenarios. Second, the paper elaborates on two aspects of the SSPs and new scenarios that would improve their usefulness for IAV studies compared to earlier scenario sets: (i) enhancing their applicability while retaining coherence across spatial scales, and (ii) adding indicators of importance for projecting vulnerability. The paper therefore presents an agenda for future research, recommending that SSPs incorporate not only the standard variables of population and gross domestic product, but also indicators such as income distribution, spatial population, human health and governance. [ABSTRACT FROM AUTHOR]

Air pollution is increasingly recognized as a significant contributor to global health outcomes. A methodological framework for evaluating the global health-related outcomes of outdoor and indoor (household) air pollution is presented and validated for the year 2005. Ambient concentrations of PM2.5 are estimated with a combination of energy and atmospheric models, with detailed representation of urban and rural spatial exposures. Populations dependent on solid fuels are established with household survey data. Health impacts for outdoor and household air pollution are independently calculated using the fractions of disease that can be attributed to ambient air pollution exposure and solid fuel use. Estimated ambient pollution concentrations indicate that more than 80% of the population exceeds the WHO Air Quality Guidelines in 2005. In addition, 3.26 billion people were found to use solid fuel for cooking in three regions of Sub Saharan Africa, South Asia and Pacific Asia in 2005. Outdoor air pollution results in 2.7 million deaths or 23 million disability adjusted life years (DALYs) while household air pollution from solid fuel use and related indoor smoke results in 2.1 million deaths or 41.6 million DALYs. The higher morbidity from household air pollution can be attributed to children below the age of 5 in Sub Saharan Africa and South Asia. The burden of disease from air pollution is found to be significant, thus indicating the importance of policy interventions. [ABSTRACT FROM AUTHOR]

Spatially explicit data on electricity access and use are essential for effective policy-making and infrastructure planning in low-income, data-scarce regions. We present and validate a 1-km resolution electricity access dataset covering sub-Saharan Africa built on gridded nighttime light, population, and land cover data. Using light radiance probability distributions, we define electricity consumption tiers for urban and rural areas and estimate the by-tier split of consumers living in electrified areas. The approach provides new insight into the spatial distribution and temporal evolution of electricity access, and a measure of its quality beyond binary access. We find our estimates to be broadly consistent with recently published province- and national-level statistics. Moreover, we demonstrate consistency between the estimated electricity access quality indicators and survey-based consumption levels defined in accordance with the World Bank Multi-Tier Framework. The dataset is readily reproduced and updated using an open-access scientific computing framework. The data and approach can be applied for improving the assessment of least-cost electrification options, and examining links between electricity access and other sustainable development objectives. Design Type(s) modeling and simulation objective • observational design • data integration objective Measurement Type(s) Electricity Technology Type(s) digital curation Factor Type(s) temporal_interval • geographic location Sample Characteristic(s) Sub-Saharan Africa • anthropogenic habitat Machine-accessible metadata file describing the reported data (ISA-Tab format) [ABSTRACT FROM AUTHOR]