scholarly journals Tropical forests did not recover from the strong 2015–2016 El Niño event

2020 ◽  
Vol 6 (6) ◽  
pp. eaay4603 ◽  
Author(s):  
Jean-Pierre Wigneron ◽  
Lei Fan ◽  
Philippe Ciais ◽  
Ana Bastos ◽  
Martin Brandt ◽  
...  
Keyword(s):  
Tropical Forests ◽  
El Niño ◽  
El Nino ◽  
Low Frequency ◽  
Climatic Conditions ◽  
Carbon Stocks ◽  
Severe Drought ◽  
Carryover Effects ◽  
El Niño Event ◽  
Tropical Vegetation

Severe drought and extreme heat associated with the 2015–2016 El Niño event have led to large carbon emissions from the tropical vegetation to the atmosphere. With the return to normal climatic conditions in 2017, tropical forest aboveground carbon (AGC) stocks are expected to partly recover due to increased productivity, but the intensity and spatial distribution of this recovery are unknown. We used low-frequency microwave satellite data (L-VOD) to feature precise monitoring of AGC changes and show that the AGC recovery of tropical ecosystems was slow and that by the end of 2017, AGC had not reached predrought levels of 2014. From 2014 to 2017, tropical AGC stocks decreased by 1.31.21.5 Pg C due to persistent AGC losses in Africa (−0.9−1.1−0.8 Pg C) and America (−0.5−0.6−0.4 Pg C). Pantropically, drylands recovered their carbon stocks to pre–El Niño levels, but African and American humid forests did not, suggesting carryover effects from enhanced forest mortality.

SMOS-IC L-VOD reveals that tropical forests did not recover from the strong 2015–2016 El Niño event

2020 ◽  
Author(s):  
Lei Fan ◽  
Jean-pierre Wigneron ◽  
Philippe Ciais ◽  
Ana Bastos ◽  
Martin Brandt ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Land Surface ◽  
Atmospheric Transport ◽  
Low Frequency ◽  
Climatic Conditions ◽  
Severe Drought ◽  
Global Carbon Budget ◽  
Large Spread ◽  
The Tropics ◽  
Atmospheric Inversions

<p>Severe drought and extreme heat associated with the 2015–2016 El Niño event have led to large carbon emissions from the tropical vegetation to the atmosphere. With the return to normal climatic conditions in 2017, tropical forest aboveground carbon (AGC) stocks are expected to partly recover due to increased productivity, but the intensity and spatial distribution of this recovery are unknown. Simulations from land-surface models used in the global carbon budget (GCB) suggest a strong reinvigoration of the tropical land sink after the 2015–2016 El Niño. However, models and atmospheric inversions display large divergences in tropical CO<sub>2</sub> fluxes during the 2017 recovery event. For instance, models predict a total net land sink recovery (2017 sink minus the 2015–2016 average sink) ranging from 0.3 to 2.6 Pg C, and the land sink recovery estimated from five atmospheric inversions ranges from −0.08 to +1.92 Pg C. The results of different inversions show a large spread in the tropics due to the scarcity of stations and uncertainties in atmospheric transport simulations.</p><p>We used low-frequency microwave satellite data (L-VOD) to feature precise monitoring of AGC changes and show that the AGC recovery of tropical ecosystems was slow and that by the end of 2017, AGC had not reached predrought levels of 2014<sup>1</sup>. From 2014 to 2017, tropical AGC stocks decreased by 1.3 Pg C due to persistent AGC losses in Africa (-0.9 Pg C) and America (-0.5 Pg C). Pantropically, drylands recovered their carbon stocks to pre–El Niño levels, but African and American humid forests did not, suggesting carryover effects from enhanced forest mortality.</p><p> </p><p><strong>Reference</strong></p><ol><li>J.-P. Wigneron, L. Fan, P. Ciais, A. Bastos, M. Brandt, J. Chave, S. Saatchi, A. Baccini, R. Fensholt, Tropical forests did not recover from the strong 2015–2016 El Niño event. Science Advances. 6, eaay4603 (2020).</li> </ol>

scholarly journals Resistance of African tropical forests to an extreme climate anomaly

2021 ◽  
Vol 118 (21) ◽  
pp. e2003169118
Author(s):  
Amy C. Bennett ◽  
Greta C. Dargie ◽  
Aida Cuni-Sanchez ◽  
John Tshibamba Mukendi ◽  
Wannes Hubau ◽  
...  
Keyword(s):  
Tropical Forests ◽  
El Niño ◽  
Tree Mortality ◽  
El Nino ◽  
Southern Oscillation ◽  
Carbon Sink ◽  
El Niño Event ◽  
Dry Conditions ◽  
Carbon Losses

The responses of tropical forests to environmental change are critical uncertainties in predicting the future impacts of climate change. The positive phase of the 2015–2016 El Niño Southern Oscillation resulted in unprecedented heat and low precipitation in the tropics with substantial impacts on the global carbon cycle. The role of African tropical forests is uncertain as their responses to short-term drought and temperature anomalies have yet to be determined using on-the-ground measurements. African tropical forests may be particularly sensitive because they exist in relatively dry conditions compared with Amazonian or Asian forests, or they may be more resistant because of an abundance of drought-adapted species. Here, we report responses of structurally intact old-growth lowland tropical forests inventoried within the African Tropical Rainforest Observatory Network (AfriTRON). We use 100 long-term inventory plots from six countries each measured at least twice prior to and once following the 2015–2016 El Niño event. These plots experienced the highest temperatures and driest conditions on record. The record temperature did not significantly reduce carbon gains from tree growth or significantly increase carbon losses from tree mortality, but the record drought did significantly decrease net carbon uptake. Overall, the long-term biomass increase of these forests was reduced due to the El Niño event, but these plots remained a live biomass carbon sink (0.51 ± 0.40 Mg C ha−1 y−1) despite extreme environmental conditions. Our analyses, while limited to African tropical forests, suggest they may be more resistant to climatic extremes than Amazonian and Asian forests.

scholarly journals Impact of Severe Drought during the Strong 2015/2016 El Nino on the Phenology and Survival of Secondary Dry Dipterocarp Species in Western Thailand

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 967
Author(s):  
Rungnapa Kaewthongrach ◽  
Yann Vitasse ◽  
Taninnuch Lamjiak ◽  
Amnat Chidthaisong
Keyword(s):  
El Niño ◽  
Tree Mortality ◽  
Secondary Forest ◽  
El Nino ◽  
Leaf Phenology ◽  
Severe Drought ◽  
Deciduous Species ◽  
El Niño Event ◽  
El Niño Events ◽  
El Nino Events

Secondary forest areas are increasing worldwide and understanding how these forests interact with climate change including frequent and extreme events becomes increasingly important. This study aims to investigate the effects of the strong 2015/2016 El Niño-induced drought on species-specific leaf phenology, dieback and tree mortality in a secondary dry dipterocarp forest (DDF) in western Thailand. During the 2015/2016 El Niño event, rainfall and soil water content were lower than 25 mm and 5% during 5–6 consecutive months. The dry season was 3–4 months longer during the El Niño than during non-El Niño events. We found that this prolonged drought induced the earlier shedding and a delay in leaf emergence of the DDF. The deciduousness period was also longer during the El Niño event (5 months instead of 2–3 months during non-El Niño event). We found that the DDF species showed different phenological responses and sensitivities to the El Niño-induced drought. The leaf phenology of stem succulent species Lannea coromandelica (Houtt.) Merr. and a complete deciduous species with low wood density. Sindora siamensis Teijsm. ex Miq. was only slightly affected by the El Niño-induced drought. Conversely, a semi-deciduous species such as Dipterocarpus obtusifolius Teijsm. ex Miq. showed a higher degree of deciduousness during the El Niño compared to non-El Niño events. Our results also highlight that dieback and mortality during El Niño were increased by 45 and 50%, respectively, compared to non-El Niño events, pointing at the importance of such events to shape DDF ecosystems.

scholarly journals Age of a charcoal band in fluvial sediments, Keiyasi, Sigatoka Valley, Fiji: possible indicator of a severe drought throughout the Southwest Pacific 4500-5000 years ago

2001 ◽  
Vol 19 (1) ◽  
pp. 5 ◽  
Author(s):  
P. D. Nunn ◽  
R. R. Thaman ◽  
L. Duffy ◽  
S. Finikaso ◽  
N. Ram ◽  
...  
Keyword(s):  
El Niño ◽  
New Caledonia ◽  
El Nino ◽  
Severe Drought ◽  
Fluvial Sediments ◽  
Last Interglacial ◽  
Southwest Pacific ◽  
The Past ◽  
El Niño Event ◽  
Local Extirpation

A 14C date for a charcoal band near the base of the High (10 m) Terrace in the middle Sigatoka Valley (western Viti Levu Island, Fiji) shows that this terrace accumulated mostly within the past 4-5000 years showing it to be a Holocene rather than a Pleistocene (Last Interglacial) landform as previously thought. The charcoal band also indicates that there was extensive, perhaps catastrophic, burning of forests and perhaps an associated local extirpation/extinction of forest taxa. The notion that humans may have been responsible for the forest burning represented by this charcoal band is rejected on account of its age predating known human arrival by at least one thousand years. Attention is drawn to the contemporaneity of this charcoal band and those found in Bonatoa Bog (southeast Viti Levu Island) and in New Caledonia, some 1300 km southwest of Fiji, suggesting that catastrophic forest burning during this period may have been widespread and a regionwide response to a period of prolonged aridity 4500-5000 years ago, possibly associated with a unusually severe El Niño event.

The 1982–1983 El Niño event recorded in dentinal growth layers in teeth of Peruvian dusky dolphins (Lagenorhynchus obscurus)

1989 ◽  
Vol 67 (9) ◽  
pp. 2120-2125 ◽  
Author(s):  
Silvia R. Manzanilla
Keyword(s):  
El Niño ◽  
El Nino ◽  
Environmental Influence ◽  
Climatic Conditions ◽  
Convincing Evidence ◽  
Lagenorhynchus Obscurus ◽  
El Niño Event ◽  
Engraulis Ringens ◽  
Dusky Dolphins

Dusky dolphins (Lagenorhynchus obscurus) recorded the effects of the 1982–1983 El Niño event in the form of anomalous dentine deposited during 1983. This anomaly, which I call the El Niño mark (ENM), consists of a pair of hypocalcified incremental layers about 75 μm in width, located within the 1983 growth layer group. The anomaly was present in 15 of 18 mature females, 1 of 9 immature females, and only 1 of 14 mature and immature males. Teeth from other species inhabiting the upwelling system were examined and revealed no ENM. Dusky dolphins feed primarily on anchoveta (Engraulis ringens), the stocks of which collapsed during the 1983 El Niño; this collapse severely affected other anchoveta predators. It is possible that the ENM reflects the presumably low foraging success experienced by dusky dolphins in 1983. However, it is unclear why the ENM is present in most mature females and absent from most male specimens. The discovery of the El Niño mark in dusky dolphins provides the first convincing evidence in odontocete cetaceans of a direct environmental influence on the mineral quality of dentine deposited during a period of markedly abnormal climatic conditions.

scholarly journals ENSO diversity driving low-frequency change in mesoscale activity off Peru and Chile

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Carlos Conejero ◽  
Boris Dewitte ◽  
Véronique Garçon ◽  
Joël Sudre ◽  
Ivonne Montes
Keyword(s):  
El Niño ◽  
El Nino ◽  
Low Frequency ◽  
Altimeter Data ◽  
Central Pacific El Niño ◽  
Central Chile ◽  
El Niño Event ◽  
El Niño Events ◽  
Ep El Niño ◽  
El Nino Events

Abstract Transient mesoscale oceanic eddies in Eastern Boundary Upwelling Systems are thought to strongly affect key regional scale processes such as ocean heat transport, coastal upwelling and productivity. Understanding how these can be modulated at low-frequency is thus critical to infer their role in the climate system. Here we use 26 years of satellite altimeter data and regional oceanic modeling to investigate the modulation of eddy kinetic energy (EKE) off Peru and Chile by ENSO, the main mode of natural variability in the tropical Pacific. We show that EKE tends to increase during strong Eastern Pacific (EP) El Niño events along the Peruvian coast up to northern Chile and decreases off central Chile, while it is hardly changed during Central Pacific El Niño and La Niña events. However the magnitude of the EKE changes during strong EP El Niño events is not proportional to their strength, with in particular the 1972/1973 El Niño event standing out as an extreme event in terms of EKE increase off Peru reaching an amplitude three times as large as that during the 1997/1998 El Niño event, and the 2015/2016 El Niño having instead a weak impact on EKE. This produces decadal changes in EKE, with a similar pattern than that of strong EP El Niño events, resulting in a significant negative (positive) long-term trend off Peru (central Chile).

scholarly journals Forecasting the Hydroclimatic Signature of the 2015/16 El Niño Event on the Western United States

2017 ◽  
Vol 18 (1) ◽  
pp. 177-186 ◽  
Author(s):  
N. Wanders ◽  
A. Bachas ◽  
X. G. He ◽  
H. Huang ◽  
A. Koppa ◽  
...  
Keyword(s):  
United States ◽  
Pacific Northwest ◽  
El Niño ◽  
El Nino ◽  
Western United States ◽  
Fire Season ◽  
Severe Drought ◽  
Forecast Performance ◽  
The North ◽  
El Niño Event

Abstract Dry conditions in 2013–16 in much of the western United States were responsible for severe drought and led to an exceptional fire season in the Pacific Northwest in 2015. Winter 2015/16 was forecasted to relieve drought in the southern portion of the region as a result of increased precipitation due to a very strong El Niño signal. A student forecasting challenge is summarized in which forecasts of winter hydroclimate across the western United States were made on 1 January 2016 for the winter hydroclimate using several dynamical and statistical forecast methods. They show that the precipitation forecasts had a large spread and none were skillful, while anomalously high observed temperatures were forecasted with a higher skill and precision. The poor forecast performance, particularly for precipitation, is traceable to high uncertainty in the North American Multi-Model Ensemble (NMME) forecast, which appears to be related to the inability of the models to predict an atmospheric blocking pattern over the region. It is found that strong El Niño sensitivities in dynamical models resulted in an overprediction of precipitation in the southern part of the domain. The results suggest the need for a more detailed attribution study of the anomalous meteorological patterns of the 2015/16 El Niño event compared to previous major events.

scholarly journals Species-Specific Shifts in Diurnal Sap Velocity Dynamics and Hysteretic Behavior of Ecophysiological Variables During the 2015–2016 El Niño Event in the Amazon Forest

2019 ◽  
Vol 10 ◽  
Author(s):  
Bruno O. Gimenez ◽  
Kolby J. Jardine ◽  
Niro Higuchi ◽  
Robinson I. Negrón-Juárez ◽  
Israel de Jesus Sampaio-Filho ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Hysteretic Behavior ◽  
Amazon Forest ◽  
El Niño Event ◽  
Species Specific

scholarly journals Declines and recovery in endangered Galapagos pinnipeds during the El Niño event

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Diego Páez-Rosas ◽  
Jorge Torres ◽  
Eduardo Espinoza ◽  
Adrian Marchetti ◽  
Harvey Seim ◽  
...  
Keyword(s):  
El Niño ◽  
Environmental Variability ◽  
El Nino ◽  
Population Decline ◽  
Annual Rate ◽  
Population Fluctuations ◽  
Galapagos Archipelago ◽  
Population Decrease ◽  
El Niño Event ◽  
Zalophus Wollebaeki

AbstractCurrently, the Galapagos sea lion (GSL, Zalophus wollebaeki) and Galapagos fur seal (GFS, Arctocephalus galapagoensis) are among the most important endemic species for conservation in the Galapagos Archipelago. Both are classified as “Endangered” since their populations have undergone drastic declines over the last several decades. In this study we estimated the abundance of both otariids, and their population trends based using counts conducted between 2014 and 2018 in all their rookeries, and we analyzed the influence of environmental variability on pup production. The GSL population size in 2018 in the archipelago was estimated to be between 17,000 to 24,000 individuals and has increased at an average annual rate of 1% over the last five years after applying correction factors. The highest number of GSL counted in the archipelago was in 2014 followed by a population decline of 23.8% in 2015 that was associated with the El Niño event that occurred during that year. Following this event, the population increased mainly in the northern, central and southeastern rookeries. The GSL pup abundance showed a decreasing trend with the increase in intensity of the El Niño. The GFS population in 2018 was counted in 3,093 individuals and has increased at an annual rate of 3% from 2014 to 2018. A high number of GFS counted in 2014 was followed by a population decrease of 38% in 2015, mainly in the western rookeries. There was interannual population fluctuations and different growth trends among regions of the archipelago. GSL and GFS pup abundance has a strong decreasing tendency with the increase in the subthermocline temperature (ST) and the El Niño 1 + 2 index. Our results provide evidence that both species are highly vulnerable to periodic oceanographic-atmospheric events in the Galapagos Archipelago which impact prey abundance and the flow of energy in the unique Galapagos ecosystem.

scholarly journals A Chronology of El Niño Events from Primary Documentary Sources in Northern Peru*

2008 ◽  
Vol 21 (9) ◽  
pp. 1948-1962 ◽  
Author(s):  
R. Garcia-Herrera ◽  
D. Barriopedro ◽  
E. Hernández ◽  
H. F. Diaz ◽  
R. R. Garcia ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Low Frequency ◽  
Primary Sources ◽  
Proxy Data ◽  
Documentary Sources ◽  
Low Frequency Variability ◽  
Northern Peru

Abstract The authors present a chronology of El Niño (EN) events based on documentary records from northern Peru. The chronology, which covers the period 1550–1900, is constructed mainly from primary sources from the city of Trujillo (Peru), the Archivo General de Indias in Seville (Spain), and the Archivo General de la Nación in Lima (Peru), supplemented by a reassessment of documentary evidence included in previously published literature. The archive in Trujillo has never been systematically evaluated for information related to the occurrence of El Niño–Southern Oscillation (ENSO). Abundant rainfall and river discharge correlate well with EN events in the area around Trujillo, which is very dry during most other years. Thus, rain and flooding descriptors, together with reports of failure of the local fishery, are the main indicators of EN occurrence that the authors have searched for in the documents. A total of 59 EN years are identified in this work. This chronology is compared with the two main previous documentary EN chronologies and with ENSO indicators derived from proxy data other than documentary sources. Overall, the seventeenth century appears to be the least active EN period, while the 1620s, 1720s, 1810s, and 1870s are the most active decades. The results herein reveal long-term fluctuations in warm ENSO activity that compare reasonably well with low-frequency variability deduced from other proxy data.

Sign in / Sign up

Export Citation Format

Share Document