Abstract:
:The economic and ecological costs of wildfire in the United States have risen substantially in recent decades. Although climate change has likely enabled a portion of the increase in wildfire activity, the direct role of people in increasing wildfire activity has been largely overlooked. We evaluate over 1.5 million government records of wildfires that had to be extinguished or managed by state or federal agencies from 1992 to 2012, and examined geographic and seasonal extents of human-ignited wildfires relative to lightning-ignited wildfires. Humans have vastly expanded the spatial and seasonal "fire niche" in the coterminous United States, accounting for 84% of all wildfires and 44% of total area burned. During the 21-y time period, the human-caused fire season was three times longer than the lightning-caused fire season and added an average of 40,000 wildfires per year across the United States. Human-started wildfires disproportionally occurred where fuel moisture was higher than lightning-started fires, thereby helping expand the geographic and seasonal niche of wildfire. Human-started wildfires were dominant (>80% of ignitions) in over 5.1 million km2, the vast majority of the United States, whereas lightning-started fires were dominant in only 0.7 million km2, primarily in sparsely populated areas of the mountainous western United States. Ignitions caused by human activities are a substantial driver of overall fire risk to ecosystems and economies. Actions to raise awareness and increase management in regions prone to human-started wildfires should be a focus of United States policy to reduce fire risk and associated hazards.
journal_name
Proc Natl Acad Sci U S Aauthors
Balch JK,Bradley BA,Abatzoglou JT,Nagy RC,Fusco EJ,Mahood ALdoi
10.1073/pnas.1617394114subject
Has Abstractpub_date
2017-03-14 00:00:00pages
2946-2951issue
11eissn
0027-8424issn
1091-6490pii
1617394114journal_volume
114pub_type
杂志文章abstract::Inhibitory gamma-aminobutyric acid-mediated synaptic currents were studied in dissociated primary cultures of neonatal rat cortex with the whole-cell patch-clamp technique. Immunocytochemical staining of the cultures showed the presence of a large number of glutamic acid decarboxylase-containing neurons, and electrica...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.83.23.9269
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.92.13.5900
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.96.16.8855
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doi:10.1073/pnas.88.5.1726
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1983-06-01 00:00:00
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更新日期:1992-08-01 00:00:00
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更新日期:1985-01-01 00:00:00