scholarly journals Quantifying immediate carbon emissions from El Niño-mediated wildfires in humid tropical forests

2018 ◽  
Vol 373 (1760) ◽  
pp. 20170312 ◽  
Author(s):  
Kieran Withey ◽  
Erika Berenguer ◽  
Alessandro Ferraz Palmeira ◽  
Fernando D. B. Espírito-Santo ◽  
Gareth D. Lennox ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Carbon Emissions ◽  
El Niño ◽  
Secondary Forest ◽  
El Nino ◽  
Fire Intensity ◽  
Secondary Forests ◽  
Study Region ◽  
Fire Emissions ◽  
The Impact

Wildfires produce substantial CO 2 emissions in the humid tropics during El Niño-mediated extreme droughts, and these emissions are expected to increase in coming decades. Immediate carbon emissions from uncontrolled wildfires in human-modified tropical forests can be considerable owing to high necromass fuel loads. Yet, data on necromass combustion during wildfires are severely lacking. Here, we evaluated necromass carbon stocks before and after the 2015–2016 El Niño in Amazonian forests distributed along a gradient of prior human disturbance. We then used Landsat-derived burn scars to extrapolate regional immediate wildfire CO 2 emissions during the 2015–2016 El Niño. Before the El Niño, necromass stocks varied significantly with respect to prior disturbance and were largest in undisturbed primary forests (30.2 ± 2.1 Mg ha −1 , mean ± s.e.) and smallest in secondary forests (15.6 ± 3.0 Mg ha −1 ). However, neither prior disturbance nor our proxy of fire intensity (median char height) explained necromass losses due to wildfires. In our 6.5 million hectare (6.5 Mha) study region, almost 1 Mha of primary (disturbed and undisturbed) and 20 000 ha of secondary forest burned during the 2015–2016 El Niño. Covering less than 0.2% of Brazilian Amazonia, these wildfires resulted in expected immediate CO 2 emissions of approximately 30 Tg, three to four times greater than comparable estimates from global fire emissions databases. Uncontrolled understorey wildfires in humid tropical forests during extreme droughts are a large and poorly quantified source of CO 2 emissions. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.

scholarly journals Impact of the 2015/2016 El Niño on the terrestrial carbon cycle constrained by bottom-up and top-down approaches

2018 ◽  
Vol 373 (1760) ◽  
pp. 20170304 ◽  
Author(s):  
Ana Bastos ◽  
Pierre Friedlingstein ◽  
Stephen Sitch ◽  
Chi Chen ◽  
Arnaud Mialon ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
El Niño ◽  
El Nino ◽  
Carbon Sink ◽  
Terrestrial Carbon ◽  
Fire Emissions ◽  
Terrestrial Carbon Cycle ◽  
Depth Analysis ◽  
The Tropics ◽  
The Impact

Evaluating the response of the land carbon sink to the anomalies in temperature and drought imposed by El Niño events provides insights into the present-day carbon cycle and its climate-driven variability. It is also a necessary step to build confidence in terrestrial ecosystems models' response to the warming and drying stresses expected in the future over many continents, and particularly in the tropics. Here we present an in-depth analysis of the response of the terrestrial carbon cycle to the 2015/2016 El Niño that imposed extreme warming and dry conditions in the tropics and other sensitive regions. First, we provide a synthesis of the spatio-temporal evolution of anomalies in net land–atmosphere CO 2 fluxes estimated by two in situ measurements based on atmospheric inversions and 16 land-surface models (LSMs) from TRENDYv6. Simulated changes in ecosystem productivity, decomposition rates and fire emissions are also investigated. Inversions and LSMs generally agree on the decrease and subsequent recovery of the land sink in response to the onset, peak and demise of El Niño conditions and point to the decreased strength of the land carbon sink: by 0.4–0.7 PgC yr −1 (inversions) and by 1.0 PgC yr −1 (LSMs) during 2015/2016. LSM simulations indicate that a decrease in productivity, rather than increase in respiration, dominated the net biome productivity anomalies in response to ENSO throughout the tropics, mainly associated with prolonged drought conditions. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.

scholarly journals Precipitation–fire linkages in Indonesia (1997–2015)

2017 ◽  
Vol 14 (18) ◽  
pp. 3995-4008 ◽  
Author(s):  
Thierry Fanin ◽  
Guido R. van der Werf
Keyword(s):  
Time Series ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Fire Season ◽  
Coefficient Of Determination ◽  
Fire Intensity ◽  
Rainfall Time Series ◽  
Fire Emissions ◽  
Active Fire

Abstract. Over the past decades, fires have burned annually in Indonesia, yet the strength of the fire season is for a large part modulated by the El Niño Southern Oscillation (ENSO). The two most recent very strong El Niño years were 2015 and 1997. Both years involved high incidences of fire in Indonesia. At present, there is no consistent satellite data stream spanning the full 19-year record, thereby complicating a comparison between these two fire seasons. We have investigated how various fire and precipitation datasets can be merged to better compare the fire dynamics in 1997 and 2015 as well as in intermediary years. We combined nighttime active fire detections from the Along Track Scanning Radiometer (ATSR) World Fire Atlas (WFA) available from 1997 until 2012 and the nighttime subset of the Moderate-Resolution Imaging Spectroradiometer (MODIS) sensor from 2001 until now. For the overlapping period, MODIS detected about 4 times more fires than ATSR, but this ratio varied spatially. Although the reasons behind this spatial variability remain unclear, the coefficient of determination for the overlapping period was high (R2 = 0. 97, based on monthly data) and allowed for a consistent time series. We then constructed a rainfall time series based on the Global Precipitation Climatology Project (GPCP, 1997–2015) and the Tropical Rainfall Measurement Mission Project (TRMM, 1998–2015). Relations between antecedent rainfall and fire activity were not uniform in Indonesia. In southern Sumatra and Kalimantan, we found that 120 days of rainfall accumulation had the highest coefficient of determination with annual fire intensity. In northern Sumatra, this period was only 30 days. Thresholds of 200 and 305 mm average rainfall accumulation before each active fire were identified to generate a high-incidence fire year in southern Sumatra and southern Kalimantan, respectively. The number of active fires detected in 1997 was 2.2 times higher than in 2015. Assuming the ratio between nighttime and total active fires did not change, the 1997 season was thus about twice as severe as the one in 2015. Although large, the difference is smaller than found in fire emission estimates from the Global Fire Emissions Database (GFED). Besides different rainfall amounts and patterns, the two-fold difference between 1997 and 2015 may be attributed to a weaker El Niño and neutral Indian Ocean Dipole (IOD) conditions in the later year. The fraction of fires burning in peatlands was higher in 2015 compared to 1997 (61 and 45 %, respectively). Finally, we found that the non-linearity between rainfall and fire in Indonesia stems from longer periods without rain in extremely dry years.

scholarly journals The impact decades-long dependence on hydropower in El Niño impact-prone Zambia is having on carbon emissions through backup diesel generation

2020 ◽  
Vol 15 (12) ◽  
pp. 124031
Author(s):  
Imaduddin Ahmed ◽  
Priti Parikh ◽  
Graham Sianjase ◽  
D’Maris Coffman
Keyword(s):  
Carbon Emissions ◽  
El Niño ◽  
El Nino ◽  
The Impact

scholarly journals Inter-comparison and assessment of gridded climate products over tropical forests during the 2015/2016 El Niño

2018 ◽  
Vol 373 (1760) ◽  
pp. 20170406 ◽  
Author(s):  
C. Burton ◽  
S. Rifai ◽  
Y. Malhi
Keyword(s):  
Southeast Asia ◽  
Tropical Forest ◽  
Tropical Forests ◽  
Air Temperature ◽  
El Niño ◽  
El Nino ◽  
Congo Basin ◽  
Wide Range ◽  
Spatio Temporal ◽  
The Impact

To understand the impacts of extreme climate events, it is first necessary to understand the spatio-temporal characteristics of the event. Gridded climate products are frequently used to describe climate patterns but have been shown to perform poorly over data-sparse regions such as tropical forests. Often, they are uncritically employed in a wide range of studies linking tropical forest processes to large-scale climate variability. Here, we conduct an inter-comparison and assessment of near-surface air temperature fields supplied by four state-of-the-art reanalysis products, along with precipitation estimates supplied by four merged satellite-gauge rainfall products. Firstly, spatio-temporal patterns of temperature and precipitation anomalies during the 2015–2016 El Niño are shown for each product to characterize the impact of the El Niño on the tropical forest biomes of Equatorial Africa, Southeast Asia and South America. Using meteorological station data, a two-stage assessment is then conducted to determine which products most reliably model tropical climates during the 2015–2016 El Niño, and which perform best over the longer-term satellite observation period (1980–2016). Results suggest that eastern Amazonia, parts of the Congo Basin and mainland Southeast Asia all experienced significant monthly mean temperature anomalies during the El Niño, while northeastern Amazonia, eastern Borneo and southern New Guinea experienced significant precipitation deficits. Our results suggest ERA-Interim and MERRA2 are the most reliable air temperature datasets, while TRMM 3B42 V7 and CHIRPS v2.0 are the best-performing rainfall datasets. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.

scholarly journals Spatio-temporal patterns of thermal anomalies and drought over tropical forests driven by recent extreme climatic anomalies

2018 ◽  
Vol 373 (1760) ◽  
pp. 20170300 ◽  
Author(s):  
Juan C. Jimenez ◽  
Jonathan Barichivich ◽  
Cristian Mattar ◽  
Ken Takahashi ◽  
Andrés Santamaría-Artigas ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Spatial Patterns ◽  
El Niño ◽  
El Nino ◽  
The Other ◽  
Extreme Drought ◽  
Drought Severity ◽  
Tropical Regions ◽  
Temperature Anomalies ◽  
The Impact

The recent 2015–2016 El Niño (EN) event was considered as strong as the EN in 1997–1998. Given such magnitude, it was expected to result in extreme warming and moisture anomalies in tropical areas. Here we characterize the spatial patterns of temperature anomalies and drought over tropical forests, including tropical South America (Amazonia), Africa and Asia/Indonesia during the 2015–2016 EN event. These spatial patterns of warming and drought are compared with those observed in previous strong EN events (1982–1983 and 1997–1998) and other moderate to strong EN events (e.g. 2004–2005 and 2009–2010). The link between the spatial patterns of drought and sea surface temperature anomalies in the central and eastern Pacific is also explored. We show that indeed the EN2015–2016 led to unprecedented warming compared to the other EN events over Amazonia, Africa and Indonesia, as a consequence of the background global warming trend. Anomalous accumulated extreme drought area over Amazonia was found during EN2015–2016, but this value may be closer to extreme drought area extents in the other two EN events in 1982–1983 and 1997–1998. Over Africa, datasets disagree, and it is difficult to conclude which EN event led to the highest accumulated extreme drought area. Our results show that the highest values of accumulated drought area over Africa were obtained in 2015–2016 and 1997–1998, with a long-term drying trend not observed over the other tropical regions. Over Indonesia, all datasets suggest that EN 1982–1983 and EN 1997–1998 (or even the drought of 2005) led to a higher extreme drought area than EN2015–2016. Uncertainties in precipitation datasets hinder consistent estimates of drought severity over tropical regions, and improved reanalysis products and station records are required.This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’.

scholarly journals Monitoring emissions from the 2015 Indonesian fires using CO satellite data

2018 ◽  
Vol 373 (1760) ◽  
pp. 20170307 ◽  
Author(s):  
Narcisa Nechita-Banda ◽  
Maarten Krol ◽  
Guido R. van der Werf ◽  
Johannes W. Kaiser ◽  
Sudhanshu Pandey ◽  
...  
Keyword(s):  
Satellite Data ◽  
El Niño ◽  
El Nino ◽  
Air Pollutant ◽  
Satellite Observations ◽  
Total Carbon ◽  
Atmospheric Composition ◽  
Burned Area ◽  
Fire Emissions ◽  
The Impact

Southeast Asia, in particular Indonesia, has periodically struggled with intense fire events. These events convert substantial amounts of carbon stored as peat to atmospheric carbon dioxide (CO 2 ) and significantly affect atmospheric composition on a regional to global scale. During the recent 2015 El Niño event, peat fires led to strong enhancements of carbon monoxide (CO), an air pollutant and well-known tracer for biomass burning. These enhancements were clearly observed from space by the Infrared Atmospheric Sounding Interferometer (IASI) and the Measurements of Pollution in the Troposphere (MOPITT) instruments. We use these satellite observations to estimate CO fire emissions within an inverse modelling framework. We find that the derived CO emissions for each sub-region of Indonesia and Papua are substantially different from emission inventories, highlighting uncertainties in bottom-up estimates. CO fire emissions based on either MOPITT or IASI have a similar spatial pattern and evolution in time, and a 10% uncertainty based on a set of sensitivity tests we performed. Thus, CO satellite data have a high potential to complement existing operational fire emission estimates based on satellite observations of fire counts, fire radiative power and burned area, in better constraining fire occurrence and the associated conversion of peat carbon to atmospheric CO 2 . A total carbon release to the atmosphere of 0.35–0.60 Pg C can be estimated based on our results. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.

scholarly journals Precipitation-fire linkages in Indonesia (1997–2015)

2016 ◽  
Author(s):  
Thierry Fanin ◽  
Guido van der Werf
Keyword(s):  
Time Series ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Fire Season ◽  
Fire Intensity ◽  
Rainfall Time Series ◽  
Night Time ◽  
Fire Emissions ◽  
Active Fire

Abstract. Over the past decades, fires have burned annually in Indonesia, yet the strength of the fire season is for a large part modulated by the El Niño Southern Oscillation (ENSO). The two most recent very strong El Niño years were 2015 and 1997. Both years involved high incidences of fire in Indonesia. At present, there is no consistent satellite data stream spanning the full 19-year record, thereby complicating a comparison between these two fire seasons. We have investigated how various fire and precipitation datasets can be merged to better compare the fire dynamics in 1997 and 2015 as well as intermediary years. We combined night-time active fire detections from the Along Track Scanning Radiometer (ATSR) World Fire Atlas (WFA) available from 1997 until 2012 and the night-time subset of the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor from 2001 until now. For the overlapping period, MODIS detected about 4 times more fires than ATSR, but this ratio varied spatially. Although the reasons behind this spatial variability remain unclear, the temporal correlation for the overlapping period was high (R2 = 0.97) and allowed for a consistent time series. We then constructed a rainfall time series based on the Global Precipitation Climatology Project (GPCP, 1997–2015) and the Tropical Rainfall Measurement Mission Project (TRMM, 1998–2015). Relations between antecedent rainfall and fire activity were not uniform in Indonesia. In southern Sumatra and Kalimantan, we found that 120 days of rainfall accumulation had the highest correlation with annual fire intensity. In northern Sumatra, this period was only 30 days. Thresholds of 200mm and 305mm average rainfall accumulation before each active fire were identified to generate a high fire year in southern Sumatra and southern Kalimantan, respectively. The number of active fires detected in 1997 was 2.2 times higher than in 2015. Assuming the ratio between night-time and total active fires did not change, the 1997 season was thus about twice as fierce as the one in 2015. Although large, the difference is smaller than found in the Global Fire Emissions Database (GFED). Besides different rainfall amounts and patterns, the two-fold difference between 1997 and 2015 may be attributed to a weaker El Niño and neutral IOD conditions in the later year. The fraction of fires burning in peatlands was higher in 2015 compared to 1997 (61 % and 45 %, respectively). Finally, we found that the non-linearity between rainfall and fire in Indonesia stems from longer periods without rain in extremely dry years.

scholarly journals The impact of forest fire on air-quality and visibility in Palangka Raya

2019 ◽  
Vol 3 (1) ◽  
pp. 16
Author(s):  
Sumaryati Sumaryati ◽  
Nani Cholianawati ◽  
Asri Indrawati
Keyword(s):  
Air Quality ◽  
Forest Fire ◽  
Forest Fires ◽  
El Niño ◽  
El Nino ◽  
Ambient Air ◽  
Average Concentration ◽  
Pm10 Concentration ◽  
Fire Intensity ◽  
The Impact

<p>It has been analyzed impact of forest fire on the air quality using PM10 parameter and visibility during 2000 – 2014 in Palangka Raya, Central Kalimantan province. Palangka Raya is an affected forest fire area with a monsoonal rainfall type which has one peak of the rainy season in January and one peak of the dry season in August. Drought condition has an impact on rising forest fire intensity causes increasing of PM10 concentration and decresing of visibility in July to November moreover when there is an El Niño phenomenon. The result of PM10 analysis shows that the air quality index in Palangka Raya during December - June is in a good  level category and still below the ambient air quality standard with an average concentration of 19 µg/m3. The impact of forest fire on declining air quality due to increasing of PM10 concentration occurred in July – November with an average concentration rising of 129 µg/m3. The El Niño phenomenon rises the PM10 concentration due to increasing of forest fires, but the increasing of PM10 is not comparable to the strength of El Niño, because of combustion condition and and human activities that play a role in forest fires. The worst impact of El Niño occurred in 2002, although the El Niño strength was only moderate, which is a half the time from July to November Palangka Raya covered air quality with dangerous levels with PM10 concentrations of more than µg/m3. A high PM10 concentration environment reduces the visibility significantly, which is visibility in the no fire condition about 8 km, but when the huge forest fire the visibility drops to 0.1 km.</p>

scholarly journals Fires in Amazonian Blackwater Floodplain Forests: Causes, Human Dimension, and Implications for Conservation

2021 ◽  
Vol 4 ◽  
Author(s):  
Tayane Costa Carvalho ◽  
Florian Wittmann ◽  
Maria Teresa Fernandez Piedade ◽  
Angélica Faria de Resende ◽  
Thiago Sanna Freire Silva ◽  
...  
Keyword(s):  
Time Series ◽  
El Niño ◽  
El Nino ◽  
Historical Background ◽  
Burned Area ◽  
Human Populations ◽  
Floodplain Forests ◽  
Fire Scars ◽  
Study Region ◽  
The Impact

The Amazon basin is being increasingly affected by anthropogenic fires, however, most studies focus on the impact of fires on terrestrial upland forests and do not consider the vast, annually inundated floodplains along the large rivers. Among these, the nutrient-poor, blackwater floodplain forests (igapós) have been shown to be particularly susceptible to fires. In this study we analyzed a 35-year time series (1982/1983–2016/2017) of Landsat Thematic Mapper from the Jaú National Park (Central Amazonia) and its surroundings. Our overall objective was to identify and delineate fire scars in the igapó floodplains and relate the resulting time series of annual burned area to the presence of human populations and interannual variability of regional hydroclimatic factors. We estimated hydroclimatic parameters for the study region using ground-based instrumental data (maximum monthly temperature–Tmax, precipitation–P, maximum cumulative water deficit–MCWD, baseflow index–BFI, minimum water level–WLmin90 of the major rivers) and large-scale climate anomalies (Oceanic Niño Index–ONI), considering the potential dry season of the non-flooded period of the igapó floodplains from September to February. Using a wetland mask, we identified 518,135 ha of igapó floodplains in the study region, out of which 17,524 ha (3.4%) burned within the study period, distributed across 254 fire scars. About 79% of the fires occurred close to human settlements (&lt;10 km distance), suggesting that human activities are the main source of ignition. Over 92.4% of the burned area is associated with El Niño events. Non-linear regression models indicate highly significant relationships (p &lt; 0.001) with hydroclimatic parameters, positive with Tmax (R2adj. = 0.83) and the ONI (R2adj. = 0.74) and negative with P (R2adj. = 0.88), MCWD (R2adj. = 0.90), WLmin90 (R2adj. = 0.61) and BFI (R2adj. = 0.80). Hydroclimatic conditions were of outstanding magnitude in particular during the El Niño event in 2015/2016, which was responsible for 42.8% of the total burned floodplain area. We discuss these results under a historical background of El Niño occurrences and a political, demographic, and socioeconomic panorama of the study region considering the past 400 years, suggesting that disturbance of igapós by fires is not a recent phenomenon. Concluding remarks focus on current demands to increase the conservation to prevent and mitigate the impacts of fire in this vulnerable ecosystem.

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