Browsing by Author "Shindell, D"

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Open Access
Global labor loss due to humid heat exposure underestimated for outdoor workers
(Environmental Research Letters, 2022-01-01) Parsons, LA; Masuda, YJ; Kroeger, T; Shindell, D; Wolff, NH; Spector, JT
Humid heat impacts a large portion of the world's population that works outdoors. Previous studies have quantified humid heat impacts on labor productivity by relying on exposure response functions that are based on uncontrolled experiments under a limited range of heat and humidity. Here we use the latest empirical model, based on a wider range of temperatures and humidity, for studying the impact of humid heat and recent climate change on labor productivity. We show that globally, humid heat may currently be associated with over 650 billion hours of annual lost labor (148 million full time equivalent jobs lost), 400 billion hours more than previous estimates. These differences in labor loss estimates are comparable to losses caused by the COVID-19 pandemic. Globally, annual heat-induced labor productivity losses are estimated at 2.1 trillion in 2017 PPP$, and in several countries are equivalent to more than 10% of gross domestic product. Over the last four decades, global heat-related labor losses increased by at least 9% (>60 billion hours annually using the new empirical model) highlighting that relatively small changes in climate (<0.5 C) can have large impacts on global labor and the economy.
Open Access
Impacts of warming on outdoor worker well-being in the tropics and adaptation options
(One Earth, 2024-03-15) Masuda, YJ; Parsons, LA; Spector, JT; Battisti, DS; Castro, B; Erbaugh, JT; Game, ET; Garg, T; Kalmus, P; Kroeger, T; Mishra, V; Shindell, D; Tigchelaar, M; Wolff, NH; Vargas Zeppetello, LR
Over a billion outdoor workers live in the tropics, where nearly a fifth of all hours in the year are hot and humid enough to exceed recommended safety thresholds for workers conducting heavy labor. Reviews have focused on heat impacts on worker health, well-being, and productivity, but synthesis on how to increase resilience to heat for outdoor workers is lacking. Here we assess current and future heat exposure in the tropics and review four bodies of literature on heat impacts on workers. We also synthesize knowledge about mitigation and adaptation uncertainties as well as the actions that can be taken to strengthen worker resilience. We show that under an additional 1°C of warming, ∼800 million people in the tropics will live in areas where heavy work should be limited for over half of the hours in the year. Our review provides primary, secondary, and tertiary solutions that will inform policies and practices as well as research that is needed to bolster worker resilience and well-being.
Open Access
Modeling the QBO-Improvements resulting from higher-model vertical resolution.
(J Adv Model Earth Syst, 2016-09) Geller, Marvin A; Zhou, Tiehan; Shindell, D; Ruedy, R; Aleinov, I; Nazarenko, L; Tausnev, NL; Kelley, M; Sun, S; Cheng, Y; Field, RD; Faluvegi, G
Using the NASA Goddard Institute for Space Studies (GISS) climate model, it is shown that with proper choice of the gravity wave momentum flux entering the stratosphere and relatively fine vertical layering of at least 500 m in the upper troposphere-lower stratosphere (UTLS), a realistic stratospheric quasi-biennial oscillation (QBO) is modeled with the proper period, amplitude, and structure down to tropopause levels. It is furthermore shown that the specified gravity wave momentum flux controls the QBO period whereas the width of the gravity wave momentum flux phase speed spectrum controls the QBO amplitude. Fine vertical layering is required for the proper downward extension to tropopause levels as this permits wave-mean flow interactions in the UTLS region to be resolved in the model. When vertical resolution is increased from 1000 to 500 m, the modeled QBO modulation of the tropical tropopause temperatures increasingly approach that from observations, and the "tape recorder" of stratospheric water vapor also approaches the observed. The transport characteristics of our GISS models are assessed using age-of-air and N2O diagnostics, and it is shown that some of the deficiencies in model transport that have been noted in previous GISS models are greatly improved for all of our tested model vertical resolutions. More realistic tropical-extratropical transport isolation, commonly referred to as the "tropical pipe," results from the finer vertical model layering required to generate a realistic QBO.
Open Access
Premature Deaths in Africa Due To Particulate Matter Under High and Low Warming Scenarios.
(GeoHealth, 2022-05) Shindell, D; Faluvegi, G; Parsons, L; Nagamoto, E; Chang, J
Sustainable development and climate change mitigation can provide enormous public health benefits via improved air quality, especially in polluted areas. We use the latest state-of-the-art composition-climate model simulations to contrast human exposure to fine particulate matter in Africa under a "baseline" scenario with high material consumption, population growth, and warming to that projected under a sustainability scenario with lower consumption, population growth, and warming. Evaluating the mortality impacts of these exposures, we find that under the low warming scenario annual premature deaths due to PM_2.5 are reduced by roughly 515,000 by 2050 relative to the high warming scenario (100,000, 175,000, 55,000, 140,000, and 45,000 in Northern, West, Central, East, and Southern Africa, respectively). This reduction rises to ∼800,000 by the 2090s, though by that time much of the difference is attributable to the projected differences in population. By contrast, during the first half of the century benefits are driven predominantly by emissions changes. Depending on the region, we find large intermodel spreads of ∼25%-50% in projected future exposures owing to different physics across the ensemble of 6 global models. The spread of projected deaths attributable to exposure to fine particulate matter, including uncertainty in the exposure-response function, are reduced in every region to ∼20%-35% by the non-linear exposure-response function. Differences between the scenarios have an even narrower spread of ∼5%-25% and are highly statistically significant in all regions for all models. These results provide valuable information for policy-makers to consider when working toward climate change mitigation and sustainable development goals.