Amazonian forest dieback under climate-carbon cycle projections for the 21st century

Cox, Peter M.; Betts, Richard; Collins, Matthew; Harris, Phil; Huntingford, Chris; Jones, Chris D.

doi:10.1007/s00704-004-0049-4

Cited by 658 publications

(624 citation statements)

References 23 publications

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“…The future climate is driven by SSTs produced by the Hadley Centre coupled ocean-atmosphere GCM (HadCM3) run with IS92a emissions for the year 2090-2100 (i.e. doubled CO 2 ) (Johns et al, 2003;Cox et al, 2004). In the radiation scheme, the same present-day O 3 climatology from Li and Shine (1995) is used for all model runs; other trace gases mixing ratios are fixed at present-day levels with only CO 2 doubled in the future climate runs.…”

Section: Methodsmentioning

confidence: 99%

“…A number of mechanisms can lead to increased O 3 production following increased temperature: 1) favoured production of HO x due to mostly positive temperature-dependencies of CH 4 /VOC oxidation reaction rate constant which fuel ozone formation; our calculations show that increases of HO x correlate closely to the increase in O 3 (although, especially in this hugely complex system, cause and effect are often difficult to disentangle), and 2) the faster decomposition of PAN which releases NO 2 leading to regionally increase of ozone production, especially in the NH polluted regions. Over Amazonia, southern Africa and southern Europe the model predicts a reduced humidity following the increased temperature which is associated with reduced soil moisture (Cox et al, 2004), reducing the O 3 destruction in those regions.…”

Section: Response To Climate Changementioning

confidence: 98%

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Impact of climate change on tropospheric ozone and its global budgets

2008

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Abstract.We present the chemistry-climate model UM CAM in which a relatively detailed tropospheric chemical module has been incorporated into the UK Met Office's Unified Model version 4.5. We obtain good agreements between the modelled ozone/nitrogen species and a range of observations including surface ozone measurements, ozone sonde data, and some aircraft campaigns.Four 2100 calculations assess model responses to projected changes of anthropogenic emissions (SRES A2), climate change (due to doubling CO 2 ), and idealised climate change-associated changes in biogenic emissions (i.e. 50% increase of isoprene emission and doubling emissions of soil-NO x ). The global tropospheric ozone burden increases significantly for all the 2100 A2 simulations, with the largest response caused by the increase of anthropogenic emissions. Climate change has diverse impacts on O 3 and its budgets through changes in circulation and meteorological variables. Increased water vapour causes a substantial ozone reduction especially in the tropical lower troposphere (>10 ppbv reduction over the tropical ocean). On the other hand, an enhanced stratosphere-troposphere exchange of ozone, which increases by 80% due to doubling CO 2 , contributes to ozone increases in the extratropical free troposphere which subsequently propagate to the surface. Projected higher temperatures favour ozone chemical production and PAN decomposition which lead to high surface ozone levels in certain regions. Enhanced convection transports ozone precursors more rapidly out of the boundary layer resulting in an increase of ozone production in the free troposphere. Lightning-produced NO x increases by about 22% in the doubled CO 2 climate and contributes to ozone production.The response to the increase of isoprene emissions shows that the change of ozone is largely determined by background NO x levels: high NO x environment increases ozone producCorrespondence to: G. Zeng (guang.zeng@atm.ch.cam.ac.uk) tion; isoprene emitting regions with low NO x levels see local ozone decreases, and increase of ozone levels in the remote region due to the influence of PAN chemistry. The calculated ozone changes in response to a 50% increase of isoprene emissions are in the range of between −8 ppbv to 6 ppbv. Doubling soil-NO x emissions will increase tropospheric ozone considerably, with up to 5 ppbv in source regions.

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Section: Methodsmentioning

confidence: 99%

Section: Response To Climate Changementioning

confidence: 98%

Impact of climate change on tropospheric ozone and its global budgets

2008

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“…Alguns modelos climáticos prognosticam aumentos no período de seca (COX et al, 2004). Num estudo prévio, Mendes e Marenco (2010) observaram que a capacidade fotossintética aparentemente não é influenciada pela sazonalidade das chuvas na Amazônia Central.…”

Section: Introductionunclassified

Crescimento e eficiência fotossintética de uso do nitrogênio e fósforo em espécies florestais da Amazônia na fase juvenil

Mendes

Marenco²,

Magalhães³

2013

Rev. Árvore

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RESUMO -Na Floresta Amazônica, a fotossíntese e o crescimento das árvores podem ser limitados pela disponibilidade de nutrientes. O objetivo deste trabalho foi determinar o efeito do conteúdo de nitrogênio (N) e fósforo (P) foliar na fotossíntese e a eficiência do uso destes nutrientes nas taxas fotossintéticas, bem como avaliar o efeito da luminosidade no crescimento em 10 espécies florestais da Amazônia Central. Os dados foram coletados em janeiro de 2008. A capacidade fotossintética (A pot ) foi positivamente relacionada com o conteúdo de N e P, mas a capacidade fotossintética da folha foi responsiva apenas quanto à eficiência no uso do P. Os conteúdos de N e P aumentaram com a irradiância do sub-bosque. Observou-se relação positiva entre o conteúdo de N e a relação N/P, mas a razão N/P não teve efeito na eficiência do uso do P. A área foliar específica Correlacionou negativamente com N e P, e a eficiência no uso do N diminuiu com o aumento da razão N/P, que não teve efeito na eficiência do uso do P. O crescimento em diâmetro aumentou com a luminosidade do sub-bosque. Conclui-se que as arvoretas têm alta sensibilidade às variações no ambiente luminoso e o P é utilizado de forma altamente eficiente nas espécies estudadas.Palavras-chave: Área foliar específica; Irradiância do sub-bosque; Teor de nutrientes foliar GROWTH AND PHOTOSYNTHETIC USE EFFICIENCY OF NITROGEN AND PHOSPHORUS IN SAPLINGS OF AMAZONIAN TREE SPECIES

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“…It is well known that changes in land-cover can be a driver of climate change through a number of feedback loops (Cox et al, 2004;Malhi et al, 2008;Nepstad et al, 2008). On the other hand, current climate trends may unbalance the Amazon ecosystem and, in association with land use changes, may be shifting the region from a carbon sink to a carbon source (Vergara and Scholz, 2011).…”

Section: A B C Dmentioning

confidence: 99%

“…Various global and regional climate-modeling approaches, combining climate change impacts, deforestation and fire effects, have predicted a large-scale substitution of Amazon forest by savannah-like vegetation, a phenomenon known as dieback (Cox et al, 2004;Malhi et al, 2008;Nepstad et al, 2008;Vergara and Scholz, 2011). These studies have shown that forest fires, drought and logging engender further burning while deforestation and smoke can inhibit rainfall, exacerbating fire risk.…”

Section: A B C Dmentioning

confidence: 99%

Advances in the study of giant otter (Pteronura brasiliensis): ecology, behavior, and conservation: a review

Duplaix

Evangelista

Rosas

2015

Lat. Am. J. Aquat. Mamm.

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Giant otters, once targeted by the pelt trade to near extinction, are now legally protected and have made a comeback in some parts of their range. Our state of knowledge about the behavior and ecology of this apex predator has increased substantially since the first studies in the 1970s but remains incomplete. Negative anthropogenic pressures and conflicts affecting giant otters are intensifying and now take many forms, from extensive habitat loss and degradation, pollution, ecotourism with heavy impacts, to gold mining. We review the corpus of giant otter field research and findings since 1980 and discuss new findings and our shortfall of knowledge and their implications for the long-term conservation of the species.Resumo: O abate de ariranhas para o comércio de suas peles no passado levou a espécie quase à extinção. Atualmente a caça à ariranha está proibida e algumas populações têm dado sinais de recuperação em partes de sua distribuição. O conhecimento acerca do comportamento e ecologia deste predador de topo de cadeia aumentou substancialmente desde a realização do primeiro estudo com a espécie na década de 1970, mas permanece incompleto. Conflitos e pressões antrópicas negativas têm se intensificado e abrangem desde a perda extensiva de habitat, poluição, ecoturismo pobremente manejado ou planejado, até a mineração de ouro. Neste artigo nós revisamos o conhecimento atual gerado pelas pesquisas com ariranha após 1980 e discutimos as novas informações, as deficiências de conhecimento ainda existentes e suas implicações para a conservação desta espécie. †

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Amazonian forest dieback under climate-carbon cycle projections for the 21st century

Cited by 658 publications

References 23 publications

Impact of climate change on tropospheric ozone and its global budgets

Impact of climate change on tropospheric ozone and its global budgets

Crescimento e eficiência fotossintética de uso do nitrogênio e fósforo em espécies florestais da Amazônia na fase juvenil

Advances in the study of giant otter (Pteronura brasiliensis): ecology, behavior, and conservation: a review

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