scholarly journals Multiyear variations in High Arctic river temperatures in response to climate variability

2018 ◽  
Vol 4 (4) ◽  
pp. 605-623 ◽  
Author(s):  
Christopher Bolduc ◽  
Scott F. Lamoureux

Water temperature measurements (2004–2016) from two small rivers in the High Arctic were analyzed to determine the effects of climate variability on thermal regime and the sensitivity to climate change. The East and West rivers (unofficial names) drain similar watersheds (11.6 and 8.0 km2, respectively) and are located at the Cape Bounty Arctic Watershed Observatory (CBAWO), Melville Island, Canada (74°55′N, 109°35′W). Differences in seasonal timing of river temperatures were evident when comparing the coldest and warmest years of the study period, and across different discharge conditions. Snowmelt runoff is characterized by uniformly cold water (∼0–1 °C) over a wide range of discharge conditions, followed by warming water temperatures during flow recession. The rivers showed varying sensitivity to mid-summer air temperature conditions in a given year, with warmer years indicating high correlation (r2 = 0.794–0.929), whereas colder years showed reduced correlation (r2 = 0.368–0.778). River temperatures reached levels which are reported to negatively affect fish and other cold-water aquatic species (>18 °C) with greater frequency and duration during the warmest years. These results provide a basis to further enhance prediction of river thermal conditions to assess ecosystem health in a river system and to refine insights into the effects of climate change on High Arctic aquatic ecosystems.

Author(s):  
Shu-Ying Tseng ◽  
Po-Yu Liu ◽  
Yi-Hsuan Lee ◽  
Zong-Yen Wu ◽  
Chiu-Chen Huang ◽  
...  

Shewanella algaeis a rod-shaped Gram-negative marine bacterium frequently found in nonhuman sources such as aquatic ecosystems and has been shown to be the pathogenic agent in various clinical cases due to the ingestion of raw seafood. The results of this study showed thatS. algaewas present in approximately one in four samples, including water and shellfish samples. Positive reactions (API systems) inS. algaestrains were seen for gelatinase (gelatin); however, negative reactions were found for indole production (tryptophan).S. algaeis adapted to a wide range of temperatures (4°C, 25°C, 37°C, and 42°C) and salinity. Temperature is a key parameter in the pathogenicity ofS. algaeas it appears to induce hemolysis at 25°C and 37°C.S. algaeexhibits pathogenic characteristics at widely varying temperatures, which suggests that it may have the ability to adapt to climate change.


2021 ◽  
Vol 12 (4) ◽  
pp. 1393-1411
Author(s):  
Keith B. Rodgers ◽  
Sun-Seon Lee ◽  
Nan Rosenbloom ◽  
Axel Timmermann ◽  
Gokhan Danabasoglu ◽  
...  

Abstract. While climate change mitigation targets necessarily concern maximum mean state changes, understanding impacts and developing adaptation strategies will be largely contingent on how climate variability responds to increasing anthropogenic perturbations. Thus far Earth system modeling efforts have primarily focused on projected mean state changes and the sensitivity of specific modes of climate variability, such as the El Niño–Southern Oscillation. However, our knowledge of forced changes in the overall spectrum of climate variability and higher-order statistics is relatively limited. Here we present a new 100-member large ensemble of climate change projections conducted with the Community Earth System Model version 2 over 1850–2100 to examine the sensitivity of internal climate fluctuations to greenhouse warming. Our unprecedented simulations reveal that changes in variability, considered broadly in terms of probability distribution, amplitude, frequency, phasing, and patterns, are ubiquitous and span a wide range of physical and ecosystem variables across many spatial and temporal scales. Greenhouse warming in the model alters variance spectra of Earth system variables that are characterized by non-Gaussian probability distributions, such as rainfall, primary production, or fire occurrence. Our modeling results have important implications for climate adaptation efforts, resource management, seasonal predictions, and assessing potential stressors for terrestrial and marine ecosystems.


Eos ◽  
2019 ◽  
Vol 100 ◽  
Author(s):  
Sarah Stanley

Understanding how temperatures of cold-water streams respond to global warming could help clarify the impacts of climate change on aquatic ecosystems.


2021 ◽  
Author(s):  
Keith B. Rodgers ◽  
Sun-Seon Lee ◽  
Nan Rosenbloom ◽  
Axel Timmermann ◽  
Gokhan Danabasoglu ◽  
...  

Abstract. While climate change mitigation targets necessarily concern maximum mean state change, understanding impacts and developing adaptation strategies will be largely contingent on how climate variability responds to increasing anthropogenic perturbations. Thus far Earth system modeling efforts have primarily focused on projected mean state changes and the sensitivity of specific modes of climate variability, such as the El Niño-Southern Oscillation. However, our knowledge of forced changes in the overall spectrum of climate variability and higher order statistics is relatively limited. Here we present a new 100-member large ensemble of climate change projections conducted with the Community Earth System Model version 2 to examine the sensitivity of internal climate fluctuations to greenhouse warming. Our unprecedented simulations reveal that changes in variability, considered broadly in terms of probability, distribution, amplitude, frequency, phasing, and patterns, are ubiquitous and span a wide range of physical and ecosystem variables across many spatial and temporal scales. Greenhouse warming will in particular alter variance spectra of Earth system variables that are characterized by non-Gaussian probability distributions, such as rainfall, primary production, or fire occurrence. Our modeling results have important implications for climate adaptation efforts, resource management, seasonal predictions, and for assessing potential stressors for terrestrial and marine ecosystems.


2021 ◽  
Author(s):  
Keith Rodgers ◽  
Sun-Seon Lee ◽  
Nan Rosenbloom ◽  
Axel Timmermann ◽  
Gokhan Danabasoglu ◽  
...  

While climate change mitigation targets necessarily concern maximum mean state changes, understanding impacts and developing adaptation strategies will be largely contingent on how climate variability responds to increasing anthropogenic perturbations. Here we present a new 100-member large ensemble of climate change projections conducted with the Community Earth System Model version 2 to examine the sensitivity of internal climate fluctuations to greenhouse warming. Our unprecedented simulations reveal that changes in variability, considered broadly in terms of probability distribution, amplitude, frequency, phasing, and patterns, are ubiquitous and span a wide range of physical and ecosystem variables across many spatial and temporal scales. Greenhouse warming will in particular alter variance spectra of Earth system variables that are characterized by non-Gaussian probability distributions, such as rainfall, primary production or fire occurrence. Our modeling results have important implications for climate adaptation efforts, resource management, and for seasonal predictions.


2005 ◽  
Vol 81 (3) ◽  
pp. 369-374 ◽  
Author(s):  
Jeremy S Littell ◽  
David L Peterson

Borrowing from landscape ecology, atmospheric science, and integrated assessment, we aim to understand the complex interactions that determine productivity in montane forests and utilize such relationships to forecast montane forest vulnerability under global climate change. Specifically, we identify relationships for precipitation and temperature that govern the spatiotemporal variability in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) growth by seeking similarities in patterns of growth/climate models across a significant portion of the climatological range of the species. In the 21st century and beyond, sustainable forestry will depend on successful adaptation to the impacts of climate change and climate variability on forest structure and function. The combination of these foci will allow improved prediction of the fate of montane forests over a wide range of biogeoclimatic conditions in western North America and thus allow improved management strategies for adapting to climate change. We describe a multi-disciplinary strategy for analyzing growth variability as a function of climate over a broad range of local-to-regional influences and demonstrate the efficacy of this sampling method in defining regional gradients of growth-limiting factors. Key words: Douglas-fir, Pseudotsuga menziesii, climate variability, climate impacts, mechanism-response, tree rings, growth-climate relationships


Author(s):  
Atta-ur Rahman ◽  
Shakeel Mahmood ◽  
Mohammad Dawood ◽  
Ghani Rahman ◽  
Fang Chen

This chapter analyzes the impacts of climate change on flood factors and extent of associated damages in the Hindu Kush (HK) region. HK mountains system is located in the west of the Himalayas and Karakorum. It is the greatest watershed of the River Kabul, River Chitral, River Panjkora, and River Swat in the eastern Hindu Kush and River Amu in western Hindu Kush. The Hindu Kush system hosts numerous glaciers, snow-clad mountains, and fertile river valleys; it also supports large populations and provides year-round water to recharge streams and rivers. The study region is vulnerable to a wide range of hazards including floods, earthquakes, landslides, desertification, and drought. Flash floods and riverine floods are the deadliest extreme hydro-meteorological events. The upper reaches experience characteristics of flash flooding, whereas the lower reach is where river floods occur. Flash floods are more destructive and sudden. Almost every year in summer, monsoonal rainfall and high temperature join hands with heavy melting of glaciers and snow accelerating discharge in the river system. In the face of climate change, a significant correlation between rainfall patterns, trends in temperature, and resultant peaks in river discharge have been recorded. A rising trend was found in temperature, which leads to early and rapid melting of glaciers and snow in the headwater region. The analysis reveals that during the past three decades, radical changes in the behavior of numerous valley glaciers have been noted. In addition, the spatial and temporal scales of violent weather events have been growing, since the 1980s. Such changes in water regimes including the frequent but substantial increase in heavy precipitation events and rapid melting of snow in the headwater region, siltation in active channels, excessive deforestation, and human encroachments onto the active flood channel have further escalated the flooding events. The HK region is beyond the reach of existing weather RADAR network, and hence forecasting and early warning is ineffective. Here, almost every year, the floods cause damages to infrastructure, scarce farmland, and sources of livelihood.


2012 ◽  
Vol 1 (1) ◽  
Author(s):  
Johnny Chavarría Viteri ◽  
Dennis Tomalá Solano

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


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