scholarly journals Effects of heat extremes on wheat yields in Australia

2016 ◽  
Vol 66 (3) ◽  
pp. 314
Author(s):  
Ben Hague ◽  
Karl Braganza ◽  
David Jones
Keyword(s):  
Climate Change ◽  
Western Australia ◽  
El Niño ◽  
El Nino ◽  
Wheat Yield ◽  
Extreme Heat ◽  
Maximum Temperature ◽  
Future Climate Change ◽  
Daily Maximum Temperature ◽  
The Impact

Many agricultural studies have identified that wheat yield is sensitive to seasonal rainfall and extreme high temperatures. We investigate the impact of extreme heat events, in particular on wheat yields in South-East Australia (SEA) and South-West Western Australia (SWWA).We define a 'heat-day' as a day where the daily maximum temperature exceeds the 1911–2013 90th percentile for the respective calendar month. We find that the number of heat-days has experienced statistically significant increases across most months across much of Australia, particularly in South Australia, Western Australia, the Northern Territory and Tasmania. The trends are especially marked in winter, including in key wheat-growing regions. The temperatures recorded on these hottest days have also shown a statistically significant increase over the last 100 years.We find that, while wheat yields are more strongly correlated with rainfall than with the number of heat-days, there is substantial evidence to suggest that during drought conditions wheat yields are sensitive to the number of heat-days recorded in August and September in SEA and September and October in SWWA. Extreme heat and rainfall have a stronger association with below-average yields than above-average yields.Extreme temperatures and rainfall in these regions are related to major Australian climate drivers which form the basis of seasonal prediction models and are important for natural variability and long-term climate change. Here we assess the degree to which wheat yields in both regions can be related to the El Niño Southern Oscillation (ENSO), Indian Ocean Dipole (IOD) and Southern Annular Mode (SAM). We find that positive IOD events and El Niño events are both associated with reductions in wheat yields in SEA, but that the co-incidence of these events have no additional wheat yield reductions than would be expected if either a positive IOD or El Niño event occurs. The average annual wheat yield loss associated with El Niño state and/or positive IOD state in SEA is estimated to around sixteen to twenty one per cent.This paper provides insights into the historical relationships between wheat yields, extreme heat and climatic modes of variability in Australia, and discusses the possibilities for changes in wheat yields under a future climate change scenario.

scholarly journals Dry and hot: the hydraulic consequences of a climate change–type drought for Amazonian trees

2018 ◽  
Vol 373 (1760) ◽  
pp. 20180209 ◽  
Author(s):  
Clarissa G. Fontes ◽  
Todd E. Dawson ◽  
Kolby Jardine ◽  
Nate McDowell ◽  
Bruno O. Gimenez ◽  
...  
Keyword(s):  
Climate Change ◽  
El Niño ◽  
Physiological Stress ◽  
El Nino ◽  
Stomatal Closure ◽  
Vapour Pressure Deficit ◽  
Future Climate Change ◽  
Safety Margins ◽  
The Impact ◽  
Amazonian Trees

How plants respond physiologically to leaf warming and low water availability may determine how they will perform under future climate change. In 2015–2016, an unprecedented drought occurred across Amazonia with record-breaking high temperatures and low soil moisture, offering a unique opportunity to evaluate the performances of Amazonian trees to a severe climatic event. We quantified the responses of leaf water potential, sap velocity, whole-tree hydraulic conductance ( K wt ), turgor loss and xylem embolism, during and after the 2015–2016 El Niño for five canopy-tree species. Leaf/xylem safety margins (SMs), sap velocity and K wt showed a sharp drop during warm periods. SMs were negatively correlated with vapour pressure deficit, but had no significant relationship with soil water storage. Based on our calculations of canopy stomatal and xylem resistances, the decrease in sap velocity and K wt was due to a combination of xylem cavitation and stomatal closure. Our results suggest that warm droughts greatly amplify the degree of trees' physiological stress and can lead to mortality. Given the extreme nature of the 2015–2016 El Niño and that temperatures are predicted to increase, this work can serve as a case study of the possible impact climate warming can have on tropical trees. 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 Climate Change Implications Found in Winter Extreme Sea Level Height Records around Korea

2021 ◽  
Vol 9 (4) ◽  
pp. 377
Author(s):  
Dong Eun Lee ◽  
Jaehee Kim ◽  
Yujin Heo ◽  
Hyunjin Kang ◽  
Eun Young Lee
Keyword(s):  
Climate Change ◽  
Thermal Expansion ◽  
Sea Level ◽  
El Niño ◽  
El Nino ◽  
Winter Season ◽  
Storm Tracks ◽  
Daily Maximum ◽  
The Impact ◽  
Level Height

The impact of climatic variability in atmospheric conditions on coastal environments accompanies adjustments in both the frequency and intensity of coastal storm surge events. The top winter season daily maximum sea level height events at 20 tidal stations around South Korea were examined to assess such impact of winter extratropical cyclone variability. As the investigation focusses on the most extreme sea level events, the impact of climate change is found to be invisible. It is revealed that the measures of extreme sea level events—frequency and intensity—do not correlate with the local sea surface temperature anomalies. Meanwhile, the frequency of winter extreme events exhibits a clear association with the concurrent climatic indices. It was determined that the annual frequency of the all-time top 5% winter daily maximum sea level events significantly and positively correlates with the NINO3.4 and Pacific Decadal Oscillation (PDO) indices at the majority of the 20 tidal stations. Hence, this indicates an increase in extreme event frequency and intensity, despite localized temperature cooling. This contradicts the expectation of increases in local extreme sea level events due to thermal expansion and global climate change. During El Nino, it is suggested that northward shifts of winter storm tracks associated with El Nino occur, disturbing the sea level around Korea more often. The current dominance of interannual storm track shifts, due to climate variability, over the impact of slow rise on the winter extreme sea level events, implies that coastal extreme sea level events will change through changes in the mechanical drivers rather than thermal expansion. The major storm tracks are predicted to continue shifting northward. The winter extreme sea level events in the midlatitude coastal region might not go through a monotonic change. They are expected to occur more often and more intensively in the near future, but might not continue doing so when northward shifting storm tracks move away from the marginal seas around Korea, as is predicted by the end of the century.

Seasonal climate summary for the southern hemisphere (autumn 2017): the Great Barrier Reef experiences coral bleaching during El Niño–Southern Oscillation neutral conditions

2019 ◽  
Vol 69 (1) ◽  
pp. 310
Author(s):  
Grant A. Smith
Keyword(s):  
Western Australia ◽  
Coral Bleaching ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Maximum Temperature ◽  
Sea Ice Extent ◽  
Antarctic Sea Ice ◽  
Dry Conditions ◽  
The Mean

Austral autumn 2017 was classified as neutral in terms of the El Niño–Southern Oscillation (ENSO), although tropical rainfall and sub-surface Pacific Ocean temperature anomalies were indicative of a weak La Niña. Despite this, autumn 2017 was anomalously warm formost of Australia, consistent with the warming trend that has been observed for the last several decades due to global warming. The mean temperatures for Queensland, New South Wales, Victoria, Tasmania and South Australiawere all amongst the top 10. The mean maximum temperature for all of Australia was seventh warmest on record, and amongst the top 10 for all states but Western Australia, with a region of warmest maximum temperature on record in western Queensland. The mean minimum temperature was also above average nationally, and amongst top 10 for Queensland, Victoria and Tasmania. In terms of rainfall, there were very mixed results, with wetter than average for the east coast, western Victoria and parts of Western Australia, and drier than average for western Tasmania, western Queensland, the southeastern portion of the Northern Territory and the far western portion of Western Australia. Dry conditions in Tasmania and southwest Western Australia were likely due to a positive Southern Annular Mode, and the broader west coast and central dry conditions were likely due to cooler eastern Indian Ocean sea-surface temperatures (SSTs) that limited the supply of moisture available to the atmosphere across the country. Other significant events during autumn 2017 were the coral bleaching in the Great Barrier Reef (GBR), cyclone Debbie andmuch lower than average Antarctic sea-ice extent. Coral bleaching in the GBR is usually associated on broad scales with strong El Niño events but is becoming more common in ENSO neutral years due to global warming. The southern GBR was saved from warm SST anomalies by severe tropical cyclone Debbie which caused ocean cooling in late March and flooding in Queensland and New SouthWales. The Antarctic sea-ice extent was second lowest on record for autumn, with the March extent being lowest on record.

scholarly journals The influence of El Niño–Southern Oscillation regimes on eastern African vegetation and its future implications under the RCP8.5 warming scenario

2017 ◽  
Vol 14 (18) ◽  
pp. 4355-4374 ◽  
Author(s):  
Istem Fer ◽  
Britta Tietjen ◽  
Florian Jeltsch ◽  
Christian Wolff
Keyword(s):  
Climate Change ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Rainfall Variability ◽  
Future Climate ◽  
Future Climate Change ◽  
El Nino Southern Oscillation ◽  
Vegetation Response ◽  
African Rainfall

Abstract. The El Niño–Southern Oscillation (ENSO) is the main driver of the interannual variability in eastern African rainfall, with a significant impact on vegetation and agriculture and dire consequences for food and social security. In this study, we identify and quantify the ENSO contribution to the eastern African rainfall variability to forecast future eastern African vegetation response to rainfall variability related to a predicted intensified ENSO. To differentiate the vegetation variability due to ENSO, we removed the ENSO signal from the climate data using empirical orthogonal teleconnection (EOT) analysis. Then, we simulated the ecosystem carbon and water fluxes under the historical climate without components related to ENSO teleconnections. We found ENSO-driven patterns in vegetation response and confirmed that EOT analysis can successfully produce coupled tropical Pacific sea surface temperature–eastern African rainfall teleconnection from observed datasets. We further simulated eastern African vegetation response under future climate change as it is projected by climate models and under future climate change combined with a predicted increased ENSO intensity. Our EOT analysis highlights that climate simulations are still not good at capturing rainfall variability due to ENSO, and as we show here the future vegetation would be different from what is simulated under these climate model outputs lacking accurate ENSO contribution. We simulated considerable differences in eastern African vegetation growth under the influence of an intensified ENSO regime which will bring further environmental stress to a region with a reduced capacity to adapt effects of global climate change and food security.

scholarly journals The effect of climate change on rainfall pattern and deficit of water in tea plantation

2017 ◽  
Vol 19 (2) ◽  
Author(s):  
Salwa Lubnan Dalimoenthe ◽  
Y Apriana ◽  
T June
Keyword(s):  
Climate Change ◽  
Water Deficit ◽  
El Niño ◽  
El Nino ◽  
Soil Surface ◽  
Rainfall Data ◽  
Rainfall Pattern ◽  
Tea Plantation ◽  
Water Index ◽  
The Impact

<p><em>Climate change has been influencing rainfall pattern so that it would be necessary to see the impact of that changed on tea plantation. The experimental area coverage lowland (600 m asl), midland (800-1000m asl) and highland (&gt;1.000 m asl) tea plantation and each altituted represented by three tea estate in West Java. The rainfall data collected since 2005 up to 2014 from each estate and water deficit has been count through the method develop by Wijaya (1996). The results showed that the rainfall pattern has been changed by La-Nina and El-Nino during 2005-2014 in tea estate either in lowland, midland or highland in the last decade. The climate change caused  rainfall decreasing and increasing on dry month (the rainfall &lt; 100 mm). Eventhough on 2009 there is an significantly increasing of the rainfall but after 2009 until 2014, the rainfall tend to decrease. After El-Nino on late 2009 and early 2010, lowland tea estate on Subang Regency facing water deficit until 5 months with R (defisit water index) far below 1 even there is no El Nino. The tea plantation at midland area (Cianjur Regency) facing 5 months water deficit per year, but the R index close to 1. While in highland tea plantation (Bandung Regency), the water deficit only happend on certain month on certain year although there is a month with zero rainfall. Water deficit could be happend because of runoff on soil surface stimulate by low ability of soil to keep the water.</em></p>

scholarly journals Effects of the 2016 El Niño on the Galapagos artisanal coastal fin-fish fishery

2018 ◽  
Author(s):  
Jose R Marin Jarrin ◽  
Pelayo Salinas-de-León
Keyword(s):  
Climate Change ◽  
Fish Species ◽  
El Niño ◽  
El Nino ◽  
Predatory Fish ◽  
Trophic Chain ◽  
El Niño Events ◽  
Catch Composition ◽  
The Impact ◽  
El Nino Events

El Niño events heavily influence physical characteristics in the Tropical Eastern Pacific and lead to a decrease in nutrient and phytoplankton concentrations and to variation in the composition of the marine trophic chain. However, El Niño events can also provide an opportunity to evaluate the possible effects climate change may have on marine ecosystems. The Galapagos Marine Reserve coastal fin-fish fishery supports approximately 400 fishers that target species that include benthic/demersal predatory fish such as the endemic Galapagos whitespotted sandbass (Paralabrax albomaculatus), the regional endemic sailfin grouper (Mycteroperca olfax) and mottled scorpion fish (Pontinus clemensi), and the misty grouper (Hyporthodon mystacinus). The first two species are listed as vulnerable and endangered, respectively, on the IUCN red list of threatened species. Despite their potential effects on the biota, at present it is unclear how El Niño events influence artisanal fin-fish fisheries in the Galapagos. To study the impacts of El Niño events on the fishery, numerical percentage catch composition at the largest dock in Santa Cruz Island was recorded during March and April 2013, 2014 and 2016 and compared. Compositions were significantly different between 2016 and both 2013 and 2014, but not between 2013 and 2014. These differences appear to have been due to the appearance of uncommon demersal/benthic predatory fish such as Grape eye seabass (Hemilutjanus macrophthalmos) and Pacific dog snapper (Lutjanus novemfasciatus). Size frequency distributions also varied, with significantly larger sizes of several species observed in 2016 when compared to 2013 or 2014. These changes in catch composition and size may be a product of a reduction in nutrient concentration and primary production that led to an increase in water clarity and decrease in prey biomass that forced these benthic fish species to change their feeding behavior and strike at baits that usually would not be easily detected. Because of the conservative life history many of these benthic predatory fish exhibit and the absence of any form of management for fish species in the GMR, El Niño events may have profound effects on their populations due to the elimination of the largest individuals. Management actions, such as size and catch limits and closures, directed at reducing the impact of the fishery on these important fish populations in the near- (El Niños) and long-term (climate change) future should be encouraged.

scholarly journals Impact Assessment of Climate Change on Paddy Yield: A Case Study of Nepal Agriculture Research Council (NARC), Tarahara, Nepal

1970 ◽  
Vol 8 (3) ◽  
pp. 147-167 ◽  
Author(s):  
Yam K Rai ◽  
Bhakta B Ale ◽  
Jawed Alam
Keyword(s):  
Climate Change ◽  
Solar Radiation ◽  
Research Council ◽  
Crop Yields ◽  
Rice Yield ◽  
Weather Data ◽  
Maximum Temperature ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
The Impact

Climate change and global warming are burning issues, which significantly threat agriculture and global food security. Change in solar radiation, temperature and precipitation will influence the change in crop yields and hence economy of agriculture. It is possible to understand the phenomenon of climate change on crop production and to develop adaptation strategies for sustainability in food production, using a suitable crop simulation model. CERES-Rice model of DSSAT v4.0 was used to simulate the rice yield of the region under climate change scenarios using the historical weather data at Nepal Agriculture Research Council (NARC) Tarahara (1989-2008). The Crop Model was calibrated using the experimental crop data, climate data and soil data for two years (2000-2001) and was validated by using the data of the year 2002 at NARC Tarahara. In this study various scenarios were undertaken to analyze the rice yield. The change in values of weather parameters due to climate change and its effects on the rice yield were studied. It was observed that increase in maximum temperature up to 2°C and 1°C in minimum temperature have positive impact on rice yield but beyond that temperature it was observed negative impact in both cases of paddy production in ambient temperature. Similarly, it was observed that increased in mean temperature, have negative impacts on rice yield. The impact of solar radiation in rice yield was observed positive during the time of study period. Adjustments were made in the fertilizer rate, plant density per square meter, planting date and application of water rate to investigate suitable agronomic options for adaptation under the future climate change scenarios. Highest yield was obtained when the water application was increased up to 3 mm depth and nitrogen application rate was 140 kg/ha respectively. DOI: http://dx.doi.org/10.3126/jie.v8i3.5941 JIE 2011; 8(3): 147-167

scholarly journals The Impact of Different Phases of the El Niño-Southern Oscillation Phenomenon on Goiás State Rainfalls and Temperature Characteristics Across Three Decades

2021 ◽  
Author(s):  
David Henriques da Matta ◽  
Caio Augusto dos Santos Coelho ◽  
Leydson Lara dos Santos ◽  
Luis Fernando Stone ◽  
Alexandre Bryan Heinemann
Keyword(s):  
El Niño ◽  
Minimum Temperature ◽  
El Nino ◽  
Southern Oscillation ◽  
La Niña ◽  
El Niño Southern Oscillation ◽  
Maximum Temperature ◽  
El Nino Southern Oscillation ◽  
La Nina ◽  
The Impact

Abstract Rainfall and temperature are the two key parameters of crop development. Studying the characteristics of these parameters under El Niño-Southern Oscillation (ENSO) conditions is important to better understand the impacts of the different phases of this phenomenon (El Niño, Neutral, and La Niña conditions) on agriculture. This study analyzes 32 years (1980–2011) of climatic data from 128 weather stations across Goiás State in Brazil to determine the behavior of temperature and rainfall time series over three periods (1980–1989; 1990–1999 and 2000–2011) under El Niño, Neutral, and La Niña conditions. The analysis revealed no major impacts of ENSO conditions on accumulated rainfall characteristics, a feature particularly marked in the most recent period (2000–2011). ENSO impacting temperature was identified but presented considerable variability across the periods investigated. These impacts were marked in the first two periods as for maximum temperature and increased from the first to the last period as for minimum temperature. These features were noticed in both analyses in the entire Goiás State and most of the investigated mega-regions, except for the East and Northeast mega-regions as for minimum temperature. There were increases in maximum temperature values throughout the rainfed season (October to March) for all ENSO conditions and investigated periods. Minimum temperature also increased across the three investigated periods, and this was marked in the beginning of the rainfed season (October) under El Niño and Neutral conditions.

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