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2.
Nature ; 575(7781): 109-118, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31695205

RESUMO

The current trajectory for crop yields is insufficient to nourish the world's population by 20501. Greater and more consistent crop production must be achieved against a backdrop of climatic stress that limits yields, owing to shifts in pests and pathogens, precipitation, heat-waves and other weather extremes. Here we consider the potential of plant sciences to address post-Green Revolution challenges in agriculture and explore emerging strategies for enhancing sustainable crop production and resilience in a changing climate. Accelerated crop improvement must leverage naturally evolved traits and transformative engineering driven by mechanistic understanding, to yield the resilient production systems that are needed to ensure future harvests.


Assuntos
Produção Agrícola/métodos , Produção Agrícola/estatística & dados numéricos , Produtos Agrícolas/genética , Abastecimento de Alimentos/métodos , Abastecimento de Alimentos/estatística & dados numéricos , Aquecimento Global/estatística & dados numéricos , Desenvolvimento Sustentável/tendências , Aclimatação/genética , Aclimatação/fisiologia , Animais , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/microbiologia , Produtos Agrícolas/virologia , Fertilizantes , Humanos , Doenças das Plantas/genética , Doenças das Plantas/prevenção & controle , Doenças das Plantas/estatística & dados numéricos , Chuva
10.
Nature ; 571(7766): 550-554, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31341300

RESUMO

Earth's climate history is often understood by breaking it down into constituent climatic epochs1. Over the Common Era (the past 2,000 years) these epochs, such as the Little Ice Age2-4, have been characterized as having occurred at the same time across extensive spatial scales5. Although the rapid global warming seen in observations over the past 150 years does show nearly global coherence6, the spatiotemporal coherence of climate epochs earlier in the Common Era has yet to be robustly tested. Here we use global palaeoclimate reconstructions for the past 2,000 years, and find no evidence for preindustrial globally coherent cold and warm epochs. In particular, we find that the coldest epoch of the last millennium-the putative Little Ice Age-is most likely to have experienced the coldest temperatures during the fifteenth century in the central and eastern Pacific Ocean, during the seventeenth century in northwestern Europe and southeastern North America, and during the mid-nineteenth century over most of the remaining regions. Furthermore, the spatial coherence that does exist over the preindustrial Common Era is consistent with the spatial coherence of stochastic climatic variability. This lack of spatiotemporal coherence indicates that preindustrial forcing was not sufficient to produce globally synchronous extreme temperatures at multidecadal and centennial timescales. By contrast, we find that the warmest period of the past two millennia occurred during the twentieth century for more than 98 per cent of the globe. This provides strong evidence that anthropogenic global warming is not only unparalleled in terms of absolute temperatures5, but also unprecedented in spatial consistency within the context of the past 2,000 years.


Assuntos
Temperatura Baixa , Aquecimento Global/história , Aquecimento Global/estatística & dados numéricos , Temperatura Alta , Indústrias/história , Indústrias/estatística & dados numéricos , História do Século XV , História do Século XVI , História do Século XVII , História do Século XVIII , História do Século XIX , História do Século XX , História do Século XXI , História Antiga , História Medieval , Atividades Humanas , Camada de Gelo , Análise Espaço-Temporal
11.
Artigo em Inglês | MEDLINE | ID: mdl-31349658

RESUMO

National committed greenhouse gas emission reduction actions are the center of the Paris Agreement, and are known as 'Intended Nationally Determined Contributions' (INDC) that aim to slow down global warming. The climate response to INDC emission reduction is a focus in climate change science. In this study, data from 32 global climate models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) were applied to investigate the changes in the mean and extreme high temperatures in Central Asia (CA) under the INDC scenario above the present-day level. The results show that the magnitude of warming in CA is remarkably higher than the global mean. Almost all the regions in CA will experience more intense, more frequent, and longer-lasting extreme high-temperature events. In comparison with the INDC scenario, the reduced warming of the 2.0 °C/1.5 °C target scenarios will help avoid approximately 44-61%/65-80% of the increase in extreme temperature events in terms of the intensity, frequency, and duration in CA. These results contribute to an improved understanding of the benefits of limiting global warming to the 2.0 °C/1.5 °C targets, which is paramount for mitigation and adaptation planning.


Assuntos
Mudança Climática/estatística & dados numéricos , Monitoramento Ambiental/métodos , Aquecimento Global/prevenção & controle , Aquecimento Global/estatística & dados numéricos , Efeito Estufa/prevenção & controle , Temperatura Alta , Ásia , Efeito Estufa/estatística & dados numéricos , Modelos Teóricos
12.
Nature ; 571(7765): 335-342, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31316194

RESUMO

Research reported during the past decade has shown that global warming is roughly proportional to the total amount of carbon dioxide released into the atmosphere. This makes it possible to estimate the remaining carbon budget: the total amount of anthropogenic carbon dioxide that can still be emitted into the atmosphere while holding the global average temperature increase to the limit set by the Paris Agreement. However, a wide range of estimates for the remaining carbon budget has been reported, reducing the effectiveness of the remaining carbon budget as a means of setting emission reduction targets that are consistent with the Paris Agreement. Here we present a framework that enables us to track estimates of the remaining carbon budget and to understand how these estimates can improve over time as scientific knowledge advances. We propose that application of this framework may help to reconcile differences between estimates of the remaining carbon budget and may provide a basis for reducing uncertainty in the range of future estimates.


Assuntos
Atmosfera/química , Dióxido de Carbono/análise , Aquecimento Global/prevenção & controle , Aquecimento Global/estatística & dados numéricos , Metas , Modelos Teóricos , Temperatura Ambiente , Política Ambiental/legislação & jurisprudência , Retroalimentação , Aquecimento Global/legislação & jurisprudência , Atividades Humanas/legislação & jurisprudência , Cooperação Internacional/legislação & jurisprudência , Paris , Reprodutibilidade dos Testes , Fatores de Tempo , Incerteza
13.
Nature ; 571(7765): 393-397, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31316195

RESUMO

Existing estimates of sea surface temperatures (SSTs) indicate that, during the early twentieth century, the North Atlantic and northeast Pacific oceans warmed by twice the global average, whereas the northwest Pacific Ocean cooled by an amount equal to the global average1-4. Such a heterogeneous pattern suggests first-order contributions from regional variations in forcing or in ocean-atmosphere heat fluxes5,6. These older SST estimates are, however, derived from measurements of water temperatures in ship-board buckets, and must be corrected for substantial biases7-9. Here we show that correcting for offsets among groups of bucket measurements leads to SST variations that correlate better with nearby land temperatures and are more homogeneous in their pattern of warming. Offsets are identified by systematically comparing nearby SST observations among different groups10. Correcting for offsets in German measurements decreases warming rates in the North Atlantic, whereas correcting for Japanese measurement offsets leads to increased and more uniform warming in the North Pacific. Japanese measurement offsets in the 1930s primarily result from records having been truncated to whole degrees Celsius when the records were digitized in the 1960s. These findings underscore the fact that historical SST records reflect both physical and social dimensions in data collection, and suggest that further opportunities exist for improving the accuracy of historical SST records9,11.


Assuntos
Conjuntos de Dados como Assunto/normas , Aquecimento Global/estatística & dados numéricos , Água do Mar/análise , Temperatura Ambiente , Ar/análise , Oceano Atlântico , Conjuntos de Dados como Assunto/história , Mapeamento Geográfico , Alemanha , Aquecimento Global/história , História do Século XX , Japão , Oceano Pacífico , Reprodutibilidade dos Testes
20.
Nature ; 569(7754): 108-111, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31019302

RESUMO

Understanding which species and ecosystems will be most severely affected by warming as climate change advances is important for guiding conservation and management. Both marine and terrestrial fauna have been affected by warming1,2 but an explicit comparison of physiological sensitivity between the marine and terrestrial realms has been lacking. Assessing how close populations live to their upper thermal limits has been challenging, in part because extreme temperatures frequently drive demographic responses3,4 and yet fauna can use local thermal refugia to avoid extremes5-7. Here we show that marine ectotherms experience hourly body temperatures that are closer to their upper thermal limits than do terrestrial ectotherms across all latitudes-but that this is the case only if terrestrial species can access thermal refugia. Although not a direct prediction of population decline, this thermal safety margin provides an index of the physiological stress caused by warming. On land, the smallest thermal safety margins were found for species at mid-latitudes where the hottest hourly body temperatures occurred; by contrast, the marine species with the smallest thermal safety margins were found near the equator. We also found that local extirpations related to warming have been twice as common in the ocean as on land, which is consistent with the smaller thermal safety margins at sea. Our results suggest that different processes will exacerbate thermal vulnerability across these two realms. Higher sensitivities to warming and faster rates of colonization in the marine realm suggest that extirpations will be more frequent and species turnover faster in the ocean. By contrast, terrestrial species appear to be more vulnerable to loss of access to thermal refugia, which would make habitat fragmentation and changes in land use critical drivers of species loss on land.


Assuntos
Organismos Aquáticos/fisiologia , Temperatura Corporal/fisiologia , Ecossistema , Aquecimento Global/estatística & dados numéricos , Temperatura Alta , Animais , Biodiversidade , Conservação dos Recursos Naturais/tendências , Oceanos e Mares , Fatores de Tempo
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