The number of people in food crisis around the world is increasing, exacerbated by COVID-19, conflict, and climate change. Major crop yields are projected to decrease in low-latitude regions, making ...tropical and sub-tropical food systems particularly vulnerable. Increased cultivation of breadfruit (
Artocarpus altilis
), a neglected and underutilized species (NUS), has the potential to enhance climate resilience and overall sustainability of low-latitude agricultural systems. To better understand breadfruit’s cultivation suitability and geographic range in current and future climates, we use breadfruit presence data collected from previous studies and a global citizen science database, and a selection of bioclimactic variables, to build an ensemble of 6 species distribution models that delineate the current climatically viable breadfruit range. We then assess the climatically viable future breadfruit range (2061–2080) under stabilization and high emission scenarios using an ensemble of 8 global circulation model (GCM) projections. The area of suitable breadfruit range within the global tropics and subtropics is projected to decrease ~4.4% in the stabilization scenario and ~4.5% in the high emission scenario. In Southeast Asia and the Pacific Islands, yield quality and consistency show minimal decreases under the high emission scenario, with increases in total suitable area under both. In contrast, in Latin America and the Caribbean, the current suitable breadfruit range is projected to contract ~10.1–11.5% (stabilization-high emission). Present and future model suitability outputs suggest opportunities to successfully expand breadfruit cultivation over the next decades in sub-Saharan Africa, where food insecurity is coincidentally high. However, in all regions, high emission scenario conditions reduce the overall consistency and quality of breadfruit yields compared to the stabilization scenario. Our results have the potential to inform global food security adaptation planning, highlighting breadfruit as an ideal NUS to incorporate in food security adaptation strategies.
Nitrogen dioxide (NO2) is a regulated pollutant that is associated with numerous health impacts. Recent advances in epidemiology indicate high confidence linking NO2 exposure with increased ...mortality, an association that recent studies suggest persists even at concentrations below regulatory thresholds. While large disparities in NO2 exposure among population subgroups have been reported, U.S. NO2-attributable mortality rates and their disparities remain unquantified. Here we provide the first estimate of NO2-attributable all-cause mortality across the contiguous U.S. (CONUS) at the census tract-level. We leverage fine-scale, satellite-informed, land use regression model NO2 concentrations and census tract-level baseline mortality data to characterize the associated disparities among different racial/ethnic subgroups. Across CONUS, we estimate that the NO2-attributable all-cause mortality is ∼170,850 (95% confidence interval: 43,970, 251,330) premature deaths yr–1 with large variability across census tracts and within individual cities. Additionally, we find that higher NO2 concentrations and underlying susceptibilities for predominately Black communities lead to NO2-attributable mortality rates that are ∼47% higher compared to CONUS-wide average rates. Our results highlight the substantial U.S. NO2 mortality burden, particularly in marginalized communities, and motivate adoption of more stringent standards to protect public health.
Contrasting views of the size, duration, and history of the Gondwanan continental ice sheets have been proposed from late Paleozoic glaciological and sedimentological evidence. To evaluate these ...differing views, a coupled ice sheet‐climate model is used to simulate continental ice sheets under a wide range of late Paleozoic orbital and pCO2 conditions. The model experiments indicate that orbital variations at pCO2 concentrations below 2X pre‐industrial atmospheric levels (PAL; 280 ppm) produce large changes in late Paleozoic ice volume (∼1.3 × 108 km3) and sea level (∼20 to 245 m). Between 2 and 8X PAL Gondwana continental ice is simulated only under the most extreme Southern Hemisphere cold summer orbit, but still produces significant ice volumes (∼8–12 × 107 km3). Our results highlight the important role of atmospheric CO2 in determining the distribution, volume, and stability of late Paleozoic ice sheets, factors that ultimately impacted sea level, cyclothem deposition, and global climate, and reconcile disparate views of the Late Paleozoic Ice Age.
High‐impact poor air quality events, such as Beijing's so‐called “Airpocalypse” in January 2013, demonstrate that short‐lived poor air quality events can have significant effects on health and ...economic vitality. Poor air quality events result from the combination of the emission of pollutants and meteorological conditions favorable to their accumulation, which include limited scavenging, dispersion, and ventilation. The unprecedented nature of events such as the 2013 Airpocalypse, in conjunction with our nonstationary climate, motivate an assessment of whether climate change has altered the meteorological conditions conducive to poor winter air quality in Beijing. Using three indices designed to quantify the meteorological conditions that support poor air quality and drawing on the attribution methods of Diffenbaugh et al. (2017, https://doi.org/10.1073/pnas.1618082114), we assess (i) the contribution of observed trends to the magnitude of events, (ii) the contribution of observed trends to the probability of events, (iii) the return interval of events in the observational record, preindustrial model‐simulated climate and historical model‐simulated climate, (iv) the probability of the observed trend in the preindustrial and historical model‐simulated climates, and (v) the relative influences of anthropogenic forcing and natural variability on the observed trend. We find that anthropogenic influence has had a small effect on the probability of the January 2013 event in all three indices but has increased the probability of a long‐term positive trend in two out of three indices. This work provides a framework for both further understanding the role of climate change in air quality and expanding the scope of event attribution.
Key Points
Extreme air quality conditions present in Beijing during January 2013 represented by three indices of air quality meteorology
Natural variability found to have a larger influence on extreme air quality events than anthropogenic forcing
Anthropogenic forcing drove long‐term positive trends in two out of three indices, despite small effect on individual events
Severe drought in California between 2013 and 2016 has been linked to the multiyear persistence of anomalously high atmospheric pressure over the northeastern Pacific Ocean, which deflected the ...Pacific storm track northward and suppressed regional precipitation during California's winter “rainy season.” Multiple hypotheses have emerged regarding why this high pressure ridge near the west coast of North America was so resilient—including unusual sea surface temperature patterns in the Pacific Ocean, reductions in Arctic sea ice, random atmospheric variability, or some combination thereof. Here we explore relationships between previously documented atmospheric conditions over the North Pacific and several potential remote oceanic and cryospheric influences using both observational data and a large ensemble of climate model simulations. Our results suggest that persistent wintertime atmospheric ridging similar to that implicated in California's 2013–2016 drought can at least partially be linked to unusual Pacific sea surface temperatures and that Pacific Ocean conditions may offer some degree of cool‐season foresight in this region despite the presence of substantial internal variability.
Plain Language Summary
Severe drought in California between 2013 and 2016 has previously been linked to the persistence of atmospheric high atmospheric pressure over the Pacific Ocean (nicknamed the “Ridiculously Resilient Ridge”), which prevented winter storms from reaching the coast over several consecutive years. There has been much discussion regarding why this high‐pressure system has been so persistent—and some scientists have previously suggested that unusual ocean temperature patterns in the Pacific, reductions in Arctic sea ice, or random weather variations may have played a role. In this study, we investigate relationships between atmospheric high pressure over the North Pacific and possible links to ocean conditions using both real‐world observations and climate model simulations. Our results suggest that persistent atmospheric high pressure similar to that which occurred during California's 2013–2016 drought can be partially linked to unusual Pacific Ocean temperatures and that knowledge of such ocean conditions may offer foresight regarding the potential for future droughts in this region.
Key Points
North Pacific atmospheric high pressure similar to that responsible for the 2013–2016 California drought linked to unusual ocean conditions
Simulations from climate model ensemble reproduce observed relationships between Pacific Ocean temperatures and atmospheric circulation
Autumn sea surface temperatures, particularly in the tropical western Pacific Ocean, may enhance foresight of anomalous West Coast winter ridging
The contribution of host T-cell immunity and HLA class I alleles to the control of human immunodeficiency virus (HIV-1) replication in natural infection is widely recognized. We assessed whether ...vaccine-induced T-cell immunity, or expression of certain HLA alleles, impacted HIV-1 control after infection in the Step MRKAd5/HIV-1 gag/pol/nef study. Vaccine-induced T cells were associated with reduced plasma viremia, with subjects targeting ≥3 gag peptides presenting with half-log lower mean viral loads than subjects without Gag responses. This effect was stronger in participants infected proximal to vaccination and was independent of our observed association of HLA-B*27, -B*57 and -B*58:01 alleles with lower HIV-1 viremia. These findings support the ability of vaccine-induced T-cell responses to influence postinfection outcome and provide a rationale for the generation of T-cell responses by vaccination to reduce viremia if protection from acquisition is not achieved. Clinical trials identifier: NCT00095576.
...the flood region recorded the highest total accumulated June precipitation in the 1951-2013 record, with the previous maximum June total equaled by 17 June and exceeded by 31% by the end of the ...month (Fig. 17.1b). ...the co-occurrence of upper-level blocking with tropical moisture advection is similar to the conditions identified during the July 2010 Pakistan floods and during heavy precipitation events that occur during the core monsoon season (Hong et al. 2011; Houze et al. 2011; Lau and Kim 2011; Ullah and Shouting 2013; Webster et al. 2011).\n2 (Supplementary Fig.
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