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The snow-induced radiative forcing (S_nRF) measures the instantaneous perturbation to Earth's shortwave radiation at the top of the atmosphere (TOA) caused by the presence of snow cover. Land surface albedo (a_s) is a key parameter in estimation of S_nRF. Previous studies have focused on using satellite or reanalysis a_s data in S_nRF quantifications. However, their spatial and temporal differences remain unclear. In this study, S_nRF over the Northern Hemisphere (NH) estimates from two satellite and four reanalysis a_s datasets were compared for the overlapping period of 1982–2012. The 31-year annual-mean S_nRF was estimated at −1.81 to −1.59 W m⁻² from satellite a_s datasets, with a peak of −4.01 W m⁻² and Standard Deviation (SD) of 1.54 W m⁻² in April. The comparable S_nRF from reanalysis a_s was −1.48 to −2.30 W m⁻², with a peak of −4.77 W m⁻² and SD of 0.81 W m⁻² in the same month. In the seasonal cycle, S_nRF from satellite a_s displayed lower values from October to January, but higher values from February to July, compared with S_nRF using reanalysis a_s. Moreover, the annual-mean S_nRF declined by 0.39–1.25 W m⁻² during 1982–2012 from satellite a_s datasets, which is much smaller than the results using reanalysis a_s datasets. Furthermore, changes in monthly-mean S_nRF from satellite a_s displayed an enhance trend in snow accumulation seasons, which are largely different with the comparable changes from reanalysis-based S_nRF, indicating that there are large interannual and intra-annual biases between S_nRF estimates from satellite and reanalysis a_s datasets. Based on above results, we conclude that the large discrepancies between S_nRF estimations from satellite and reanalysis a_s should be considered in evaluating the response and feedback of snow cover to Earth climate change in future studies, especially in radiation budget anomalies.

Cigarette littering in public spaces is an environmental and aesthetic problem. Broken windows theory posits that visible signs of anti-social behavior such as littering create the perception of a social norm in built environments. Cigarette butts on the ground then encourage people to drop theirs as well. We test this theory on benches of a university campus in a field experiment with two treatments: (1) a clean environment with no cigarette butts on the ground and (2) a dirty environment with 25 cigarette butts on the ground. Our outcome variable is the number of additional cigarette butts on the ground after two hours. We find a small effect of approximately 0.5 butts less per 2-hour period on clean grounds. Increased cleaning efforts can thus reduce littering, but the effect is probably too small to justify additional cleaning costs.

Vegetation fires across the tropics emit fine particulate matter (PM_2.5) to the atmosphere, degrading regional air quality and impacting human health. Extensive vegetation fires occur regularly across the Amazon basin, but there have been no detailed assessments of the impacts on air quality or human health. We used updated exposure-response relationships and a regional climate-chemistry model, evaluated against a comprehensive set of observational data, to provide the first in-depth assessment of the potential public health benefits due to fire prevention across the Amazon Basin. We focused on 2012, a year with emissions similar to the 11-year average (2008 to 2018). Vegetation fires contributed >80% of simulated dry season mean surface PM_2.5 in the western Amazon region particularly in Bolivia and Brazilian states of Rondônia, Acre, and Mato Grosso. We estimate that the prevention of vegetation fires would have averted 16 800 (95UI: 16 300–17 400) premature deaths and 641 000 (95UI: 551 900–741 300) disability adjusted life years (DALYs) across South America, with 26% of the avoided health burden located within the Amazon Basin. The health benefits of fire prevention in the Amazon are comparable to those found in Equatorial Asia.

Global climate change mitigation is often framed in public discussions as a tradeoff between environmental protection and harm to the economy. However, climate-economy models have consistently calculated that the immediate implementation of greenhouse gas emissions restriction (via e.g. a global carbon price) would be in humanity's best interest on purely economic grounds. Despite this, the implementation of global climate policy has been notoriously difficult to achieve. This evokes an apparent paradox: if the implementation of a global carbon price is not only beneficial to the environment, but is also 'economically optimal', why has it been so difficult to enact? One potential reason for this difficulty is that economically optimal greenhouse gas emissions restrictions are not economically beneficial for the generation of people that launch them. The purpose of this article is to explore this issue by introducing the concept of the break-even year, which we define as the year when the economically optimal policy begins to produce global mean net economic benefits. We show that in a commonly used climate-economy model (DICE), the break-even year is relatively far into the future—around 2080 for mitigation policy beginning in the early 2020s. Notably, the break-even year is not sensitive to the uncertain magnitudes of the costs of climate change mitigation policy or the costs of economic damages from climate change. This result makes it explicit and understandable why an economically optimal policy can be difficult to implement in practice.

Efforts to reduce the health and ecological burdens of household biomass combustion are underway in Ghana, principally by promoting clean cookstoves and fuels. Recent studies have focused on the sustained use of clean cookstoves, but sometimes household adopt a new cookstove and then end use of that stove. In this study, we introduce a novel framework for understanding and encouraging household transitions to cleaner cooking: clean fuel discontinuance. We leveraged data from the Ghana Randomized Air Pollution and Health Study (GRAPHS) (N = 1412) where pregnant women received either improved biomass (BioLite) or dual burner LPG stoves for free. LPG users were given free LPG refills during GRAPHS. Weekly questionnaires were administered. Stove use monitors tracked a sub-cohort (n = 220) 6 months before and after the fuel subsidy. We examined social and ecological determinants of stove use and discontinuance. Overall intervention stove use adherence was high throughout GRAPHS, with self-reported use at 69% and 86% of participant-weeks for BioLite and LPG arms respectively. Participants used intervention stoves less for meals requiring vigorous stirring. Burns from intervention stoves decreased use among BioLite (RR: 0.96, p = 0.009), but not LPG users. Device breakage was mentioned as an impediment in 18% of free-text responses for LPG users and 1% for BioLite. Tree canopy within a spatial buffer—a plausible proxy for biomass fuels access—was the only variable explaining LPG discontinued stove use in adjusted Cox time-to-event analyses (HR = −0.56, p < 0.001). Future studies should consider the stove use discontinuance framework.