scholarly journals An astronomical correspondence to the 1470 year cycle of abrupt climate change

2015 ◽  
Vol 11 (5) ◽  
pp. 4895-4915 ◽  
Author(s):  
A. M. Kelsey ◽  
F. W. Menk ◽  
P. T. Moss
Keyword(s):  
Climate Change ◽  
Southern Oscillation ◽  
Anthropogenic Impacts ◽  
Atmospheric Temperature ◽  
Climatic Conditions ◽  
Abrupt Climate Change ◽  
Temperature Cycle ◽  
Causal Mechanism ◽  
Climate Stability ◽  
Ird Events

Abstract. The existence of a ~ 1470 year cycle of abrupt climate change is well-established, manifesting in Bond ice-rafting debris (IRD) events, Dansgaard–Oeschger atmospheric temperature cycle, and cyclical climatic conditions precursory to increased El Niño/Southern Oscillation (ENSO) variability and intensity. This cycle is central to questions on Holocene climate stability and hence anthropogenic impacts on climate (deMenocal et al., 2000). To date no causal mechanism has been identified, although solar forcing has been previously suggested. Here we show that interacting combination of astronomical variables related to Earth's orbit may be causally related to this cycle and several associated key isotopic spectral signals. The ~ 1470 year climate cycle may thus be regarded as a high frequency extension of the Milankovitch precessional cycle, incorporating orbital, solar and lunar forcing through interaction with the tropical and anomalistic years and Earth's rotation.

scholarly journals The effects of ENSO, climate change and human activities on the water level of Lake Toba, Indonesia: a critical literature review

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hendri Irwandi ◽  
Mohammad Syamsu Rosid ◽  
Terry Mart
Keyword(s):  
Climate Change ◽  
Water Level ◽  
Human Activities ◽  
Southern Oscillation ◽  
Climatic Conditions ◽  
Water Levels ◽  
Dominant Factor ◽  
Climate Projections ◽  
Continuous Increase ◽  
The Future

AbstractThis research quantitatively and qualitatively analyzes the factors responsible for the water level variations in Lake Toba, North Sumatra Province, Indonesia. According to several studies carried out from 1993 to 2020, changes in the water level were associated with climate variability, climate change, and human activities. Furthermore, these studies stated that reduced rainfall during the rainy season due to the El Niño Southern Oscillation (ENSO) and the continuous increase in the maximum and average temperatures were some of the effects of climate change in the Lake Toba catchment area. Additionally, human interventions such as industrial activities, population growth, and damage to the surrounding environment of the Lake Toba watershed had significant impacts in terms of decreasing the water level. However, these studies were unable to determine the factor that had the most significant effect, although studies on other lakes worldwide have shown these factors are the main causes of fluctuations or decreases in water levels. A simulation study of Lake Toba's water balance showed the possibility of having a water surplus until the mid-twenty-first century. The input discharge was predicted to be greater than the output; therefore, Lake Toba could be optimized without affecting the future water level. However, the climate projections depicted a different situation, with scenarios predicting the possibility of extreme climate anomalies, demonstrating drier climatic conditions in the future. This review concludes that it is necessary to conduct an in-depth, comprehensive, and systematic study to identify the most dominant factor among the three that is causing the decrease in the Lake Toba water level and to describe the future projected water level.

The suitability of montane ecotones as indicators of global climatic change

1996 ◽  
Vol 20 (3) ◽  
pp. 253-272 ◽  
Author(s):  
John A. Kupfer ◽  
David M. Cairns
Keyword(s):  
Climate Change ◽  
Climatic Change ◽  
Fossil Fuel ◽  
Global Climate ◽  
Atmospheric Temperature ◽  
Climatic Conditions ◽  
Global Climatic Change ◽  
Altitudinal Shift ◽  
Site Water ◽  
Projected Changes

Because of the difficulties involved with separating natural fluctuations in climatic variables from possible directional changes related to human activities (e.g., heightened atmospheric CO2 concentrations related to fossil fuel consumption), some researchers have focused on developing alternative indicators to detect hypothesized climate changes. It has, for example, been suggested that the locations of ecotones, transitions between adjacent ecosystems or biomes, should be monitored. It is assumed that changes in climate, especially increases in atmospheric temperature, will result in shifts in the location (altitude or latitude) of ecotones as plants respond to the newly imposed climatic conditions. In this article, we address the use of two montane ecotones, the alpine tree-line ecotone and the deciduous/Boreal forest ecotone, in monitoring global climatic change. In so doing, we 1) outline the factors that create and maintain each ecotone's position at a given location; 2) assess the projected response of the ecotones to various aspects of global warming; and 3) discuss the usefulness of both ecotones as indicators of global climate change. While it is likely that extended periods of directional climate change would bring about an altitudinal shift in the ranges of montane species and the associated ecotones, we question whether the response at either ecotone will be at a timescale useful for detecting climate change (a few decades) owing to disequilibrium related to upslope edaphic limitations and competitive interactions with established canopy and subcanopy indi viduals. Further, limitations related to the prediction of the complex and interacting effects of projected changes in temperature, precipitation and site water balance on photosynthetic pro cesses of plant species raise uncertainties about the expected responses of both ecotones.

scholarly journals Climate change alters impacts of extreme climate events on a tropical perennial tree crop

2021 ◽  
Author(s):  
Thomas Creedy ◽  
Rebecca A. Asare ◽  
Alexandra C. Morel ◽  
Mark Hirons ◽  
Yadvinder Malhi ◽  
...  
Keyword(s):  
Climate Change ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Climate Extremes ◽  
Climatic Conditions ◽  
Perennial Crop ◽  
Time Period ◽  
Cocoa Production ◽  
Increasing Temperature

Abstract Anthropogenic climate change causes more frequent and intense fluctuations in the El Niño Southern Oscillation (ENSO). Understanding the effects of ENSO on agricultural systems is crucial for predicting and ameliorating impacts on lives and livelihoods, particularly in perennial tree crops, which may show both instantaneous and delayed responses. Using cocoa production in Ghana as a model system, here we show that in recent times, El Niño years experience reductions in cocoa production followed by several years of increased production, a significantly different pattern than prior to the 1980s. ENSO phase affects the climate in Ghana, and over the same time period, we see concomitant significant shifts in the climatic conditions resulting from ENSO extremes, with increasing temperature and water stress. Our results illustrate the big data analyses necessary to improve understanding of perennial crop responses to climate change in general, and climate extremes in particular.

scholarly journals The condition of coral reefs in Timor-Leste before and after the 2016–2017 marine heatwave

2020 ◽  
Author(s):  
Catherine JS Kim ◽  
Chris Roelfsema ◽  
Sophie Dove ◽  
Ove Hoegh-Guldberg
Keyword(s):  
Climate Change ◽  
Coral Reefs ◽  
Southern Oscillation ◽  
Anthropogenic Impacts ◽  
Coral Cover ◽  
Nutrient Concentrations ◽  
Virtual Station ◽  
Timor Leste ◽  
Before And After

AbstractEl Niño Southern Oscillation global coral bleaching events are increasing in frequency; however, the severity of bleaching is not geographically uniform. There were two major objectives of the present project: 1) assess the state of reefs and coral health at several sites and 2) explore water quality and climate change impacts on Timorese reefs. The impacts of climate change (principally by following coral mortality) were surveyed on coral reefs before and after the 2016–2017 underwater heatwave, using temperature loggers deployed between surveys which were compared to Coral Reef Watch (CRW) experimental virtual station sea surface temperature (SST). CRW is an important and widely used tool; however, we found the SST was significantly warmer (> 1°C) than in situ temperature during the austral summer accruing 5.79 degree heating weeks. In situ temperature showed no accumulation. Change in coral cover between surveys was attributed to reef heterogeneity. There were significant differences in coral cover, coral diversity, and nutrient concentrations between site and depth and a low prevalence of disease recorded in both years. The comparison of temperature and SST indicate that bleaching stress in Timor-Leste is potentially mitigated by seasonal and oceanographic dynamics. This is corroborated by Timor-Leste’s location within the Indonesian ThroughFlow. Timor-Leste is a climate refugium and the immediate conservation work lies in the management of localized anthropogenic impacts on coral reefs such as sedimentation and fishing.

Evaluating human responses to ENSO driven climate change during the Holocene in northwest Australia through macrobotanical analyses

The Holocene ◽  
2020 ◽  
Vol 30 (12) ◽  
pp. 1728-1740 ◽  
Author(s):  
India Ella Dilkes-Hall ◽  
Jane Balme ◽  
Sue O’Connor ◽  
Emilie Dotte-Sarout
Keyword(s):  
Climate Change ◽  
Late Holocene ◽  
Southern Oscillation ◽  
Climatic Conditions ◽  
Food Plants ◽  
Regional Patterns ◽  
Climatic Fluctuations ◽  
The Holocene ◽  
Plant Use ◽  
Monsoon Rainforest

The Holocene is recognised as a period through which a number of climatic fluctuations and environmental stresses occur—associated with intensifying El Niño–Southern Oscillation (ENSO) climatic conditions from c. 5000 years—contemporaneous with technological and social changes in Australian Aboriginal lifeways. In the Kimberley region of northwest Western Australia, human responses to ENSO driven climate change are most evident archaeologically in technological transformations observed in lithic records, with little research on changes in plant use during this time. Using nine archaeological sites across the Kimberley, this paper synthesises previously published macrobotanical data (Carpenter’s Gap 1, Moonggaroonggoo, Mount Behn, and Riwi), reports unpublished data (Brooking Gorge 1, Djuru, and Wandjina rockshelter), and presents results of sites reanalysed for this study (Widgingarri Shelters 1 and 2) to develop a picture of localised and regional patterns of plant use during the Holocene. We conclude that food plants associated with monsoon rainforest environments dominate both mid- and late Holocene macrobotanical records and, although monsoon rainforest likely retreated to some extent because of decreased precipitation during the late Holocene, no human responses associated with ENSO driven climate change occurred in relation to human uses of plants.

VARIABILIDAD CLIMÁTICA, CAMBIO CLIMÁTICO Y PESQUERÍAS EN EL ECUADOR.

2012 ◽  
Vol 1 (1) ◽  
Author(s):  
Johnny Chavarría Viteri ◽  
Dennis Tomalá Solano
Keyword(s):  
Climate Change ◽  
Climate Variability ◽  
Pacific Decadal Oscillation ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Current Action ◽  
Palabras Clave

La variabilidad climática es la norma que ha modulado la vida en el planeta. Este trabajo demuestra que las pesquerías y acuicultura costera ecuatorianas no son la excepción, puesto que tales actividades están fuertemente influenciadas por la variabilidad ENSO (El Niño-Oscilación del Sur) y PDO (Oscilación Decadal del Pacífico), planteándose que la señal del cambio climático debe contribuir a esta influencia. Se destaca también que, en el análisis de los efectos de la variabilidad climática sobre los recursos pesqueros, el esfuerzo extractivo también debe ser considerado. Por su parte, la acción actual de la PDO está afectando la señal del cambio climático, encontrándose actualmente en fases opuestas. Se espera que estas señales entren en fase a finales de esta década, y principalmente durante la década de los 20 y consecuentemente se evidencien con mayor fuerza los efectos del Cambio Climático. Palabras Clave: Variabilidad Climática, Cambio Climático, ENSO, PDO, Pesquerías, Ecuador. ABSTRACT Climate variability is the standard that has modulated life in the planet. This work shows that the Ecuadorian  fisheries and aquaculture are not the exception, since such activities are strongly influenced by ENSO variability (El Niño - Southern Oscillation) and PDO (Pacific Decadal Oscillation), considering that the signal of climate change should contribute to this influence. It also emphasizes that in the analysis of the effects of climate variability on the fishing resources, the extractive effort must also be considered. For its part, the current action of the PDO is affecting the signal of climate change, now found on opposite phases. It is hoped that these signals come into phase at the end of this decade, and especially during the decade of the 20’s and more strongly evidencing the effects of climate change. Keywords: Climate variability, climate change, ENSO (El Niño - Southern Oscillation) and PDO  (Pacific Decadal Oscillation); fisheries, Ecuador. Recibido: mayo, 2012Aprobado: agosto, 2012

Effect of Weather Factors on the Variability of Economic Characteristics in Sunflower Hybrids

2019 ◽  
pp. 70-84
Keyword(s):  
Climate Change ◽  
Climatic Conditions ◽  
Economic Traits ◽  
Weather Factors

This article presents the results of twelve-year trials of the Region and Ryabota simple hybrids and the three-line hybrid Kameniar breeding laboratory of IOC NAANU hybrid labs, and analyzes their adaptation to ongoing climate change. The purpose of our work was to determine the formation of major economic traits in sunflower hybrids, depending on the agro-climatic conditions of the year.

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