scholarly journals Phenological and water-use patterns underlying maximum growing season length at the highest elevations: implications under climate change

2012 ◽  
Vol 32 (2) ◽  
pp. 161-170 ◽  
Author(s):  
J. C. Linares ◽  
F. Covelo ◽  
J. A. Carreira ◽  
J. A. Merino
Keyword(s):  
Climate Change ◽  
Water Use ◽  
Growing Season ◽  
Season Length ◽  
Use Patterns ◽  
Growing Season Length ◽  
Water Use Patterns

scholarly journals Exploring changes in water use patterns, demand and stress along the Nile River Basin through the lens of Kenya and Egypt

2020 ◽  
Vol 71 (11) ◽  
pp. 1478
Author(s):  
Anne Wambui Mumbi ◽  
Li Fengting
Keyword(s):  
Climate Change ◽  
Economic Development ◽  
Spatial Distribution ◽  
Water Stress ◽  
Water Use ◽  
Water Demand ◽  
Nile Basin ◽  
Transboundary Water ◽  
Use Patterns ◽  
Water Use Patterns

Noting the geopolitical implications of water demand and stress issues on water resources worldwide, this study investigated water demand, changes in water use patterns and water stress developments in the Nile Basin transboundary water resource by comparing Egypt and Kenya. Using an integrative literature review, the study summarises past research, drawing overall conclusions and highlighting unresolved issues. The findings demonstrate increased water withdrawals and a growing unmet demand in both countries. In addition to changing water use patterns towards municipal and industrial use, hydropower development in Kenya and navigation in Egypt are being driven by factors such as heightened upstream use, population growth and settlement patterns, economic development and climate change. In addition, spatial distribution of water stress was demonstrated, whereby downstream countries such as Egypt remain critically vulnerable, although upper riparian countries such as Kenya are gradually also facing emerging water stress problems. This water stress and its spatial distribution are being driven by supply–demand imbalances related to population growth and economic development, escalating upstream water use, deteriorating water quality, inefficient and ineffective water use and climate change. The findings inform a discussion of the crucial socioeconomic, geopolitical and policy implications for riparian countries in the Nile Basin and other transboundary water resources worldwide.

scholarly journals Impacts of Climate Change on the Growing Season in the United States

2011 ◽  
Vol 15 (33) ◽  
pp. 1-17 ◽  
Author(s):  
Daniel E. Christiansen ◽  
Steven L. Markstrom ◽  
Lauren E. Hay
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Emission Scenario ◽  
Growing Season ◽  
The United States ◽  
Emission Scenarios ◽  
Season Length ◽  
Mountainous Regions ◽  
Growing Season Length ◽  
Total Length

AbstractUnderstanding the effects of climate change on the vegetative growing season is key to quantifying future hydrologic water budget conditions. The U.S. Geological Survey modeled changes in future growing season length at 14 basins across 11 states. Simulations for each basin were generated using five general circulation models with three emission scenarios as inputs to the Precipitation-Runoff Modeling System (PRMS). PRMS is a deterministic, distributed-parameter, watershed model developed to simulate the effects of various combinations of precipitation, climate, and land use on watershed response. PRMS was modified to include a growing season calculation in this study. The growing season was examined for trends in the total length (annual), as well as changes in the timing of onset (spring) and the end (fall) of the growing season. The results showed an increase in the annual growing season length in all 14 basins, averaging 27–47 days for the three emission scenarios. The change in the spring and fall growing season onset and end varied across the 14 basins, with larger increases in the total length of the growing season occurring in the mountainous regions and smaller increases occurring in the Midwest, Northeast, and Southeast regions. The Clear Creek basin, 1 of the 14 basins in this study, was evaluated to examine the growing season length determined by emission scenario, as compared to a growing season length fixed baseline condition. The Clear Creek basin showed substantial variation in hydrologic responses, including streamflow, as a result of growing season length determined by emission scenario.

scholarly journals Analysis of future climate scenarios and their impact on agriculture in eastern Arkansas, United States

2018 ◽  
Vol 37 (1) ◽  
pp. 97-112 ◽  
Author(s):  
John W. Magugu ◽  
Song Feng ◽  
Qiuqiong Huang ◽  
Yongjun Zhang ◽  
Grant H. West
Keyword(s):  
Climate Change ◽  
Extreme Precipitation ◽  
Growing Season ◽  
Future Climate ◽  
Growing Degree Days ◽  
Total Precipitation ◽  
Season Length ◽  
Degree Days ◽  
Spring Frost ◽  
Growing Season Length

Abstract Impact of climate change on crop growth is dynamic and difficult to quantify due to heterogeneity of the associated effects and their interactions within the Earth system. The main objective of this study is to establish how future climate change might affect agriculture, through an assessment of temperature and precipitation driven parameters. These include percentage number of rainy days with extreme precipitation, percentage of extreme precipitation relative to wet days, first fall frost days, last spring frost days, growing degree days, growing season length and the total precipitation. Results show modest increase in total precipitation with a slight increase in extreme precipitation, representing up to 2.2% increase by 2060 under representative concentration pathway (RCP 8.5) scenario. There would be late first fall frost days, early last spring frost days and increased growing season length by up to 2 weeks in 2060. The growing degree days are projected to increase under all scenarios for all crops, with cotton showing the largest increase of up to 37% relative to the baseline period.

scholarly journals Drought reduces tree growing season length but increases nitrogen resorption efficiency in a Mediterranean ecosystem

2019 ◽  
Vol 16 (6) ◽  
pp. 1265-1279 ◽  
Author(s):  
Raquel Lobo-do-Vale ◽  
Cathy Kurz Besson ◽  
Maria Conceição Caldeira ◽  
Maria Manuela Chaves ◽  
João Santos Pereira
Keyword(s):  
Climate Change ◽  
Growing Season ◽  
Shoot Elongation ◽  
Mediterranean Ecosystem ◽  
Season Length ◽  
Resorption Efficiency ◽  
Nitrogen Resorption ◽  
Growing Season Length ◽  
Main Driver ◽  
Nitrogen Resorption Efficiency

Abstract. Mediterranean ecosystems are hotspots for climate change, as the highest impacts are forecasted for the Mediterranean region, mainly by more frequent and intense severe droughts. Plant phenology is a good indicator of species' responses to climate change. In this study, we compared the spring phenology of cork oak trees (Quercus suber), an evergreen species, over 2 contrasting years, a mild year (2004) and a dry year (2005), which was the most severe drought since records exist. We evaluated the timing of occurrence, duration, and intensity of bud development, budburst, shoot elongation, trunk growth, and leaf senescence (phenophases) and assessed the nitrogen resorption efficiency from senescent to green leaves. The temperature was the main driver of budburst. Nevertheless, water had the main role of constraining all the other phenophases by strongly reducing the growing season length (−48 %) and consequently the tree growth. Basal area increment was the most affected growth variable (−36 %), although it occurred at a similar rate in the 2 years. Shoot elongation was also reduced (−21 %), yet elongation occurred at a higher rate in the dry year compared to the mild year. Leaf senescence during the bulk period was higher in the dry year, in which leaves were shed at the same rate over a longer period. Nitrogen concentrations in green and senescent leaves were affected by drought and nitrogen resorption efficiency increased remarkably (+22 %). Our results highlight the importance of studying different phenological metrics to improve our understanding of the ecosystem's responses to climate change. The faster dynamics observed in shoot elongation, while all other phenophases developed at the same rate, indicate that leaf area development is privileged in cork oak. Water availability was the main driver of spring growth in this Mediterranean ecosystem; however, growth may be affected by complex interplays between precipitation and temperature, such as higher temperatures during dry winters or heatwaves during spring, that are likely to result in water stress. Longer studies are needed to disentangle those interplays. Finally, a higher nitrogen resorption efficiency in response to drought appears to be an adaptive trait that mitigates the limitation in nitrogen uptake by the roots during drought and contributes to improving tree fitness in the short term but will probably exert a negative feedback on the nitrogen cycle in the long term, which might affect the ecosystem functioning under the forecasted droughts.

scholarly journals Assessment of agrometeorological indices over Southeast Europe in the context of climate change (1961-2018)

Időjárás ◽  
2021 ◽  
Vol 125 (2) ◽  
pp. 255-269
Author(s):  
Hristo Chervenkov ◽  
Kiril Slavov
Keyword(s):  
Climate Change ◽  
System Analysis ◽  
Environmental Changes ◽  
Growing Season ◽  
Season Length ◽  
Economic Returns ◽  
Southeast Europe ◽  
Growing Season Length ◽  
Very High Spatial Resolution ◽  
The Impact

The regional response over Southeast (SE) Europe to the climate warming in global and continental scales has been confirmed to have essential impact on the agriculture and forestry since the middle of twentieth century. Normal variations in weather throughout a growing season cause variations in harvest and, generally, the impact could be large in terms of production amounts and economic returns. Agriculture is sensitive to the changes in weather and climate, and the occurrence of extreme events threaten the agricultural systems. Forests are particularly sensitive to climate change, because the long life-span of trees does not allow for rapid adaptation to environmental changes. This study provides an overview of the spatial patterns and the long-term temporal evolution of the following agrometeorological indices: growing season length, accumulated active temperatures and biologically effective degree days. Hence the focus is on the Growing season length, its start and end dates are analyzed separately. All indices are computed from the daily mean temperatures which, in turn, are derived from the output of the MESCAN-SURFEX system analysis of the collaborative initiative UERRA. The geographical domain of interest is Southeast Europe, and the assessment is performed at a very high spatial resolution on annual basis for the period 1961–2018. We find strong evidences of essential increase in the considered indices which dominates spatially over the low-elevated areas of the domain and is statistically significant at 5% level. Key message is also the revealed asymmetry of the increase in the most relevant index, the growing season length: its total lengthening is linked more to the shifting to earlier date of the start, rather than to its later cessation.

scholarly journals Drought reduces tree growing season length but increases nitrogen resorption efficiency in a Mediterranean ecosystem

2018 ◽  
Author(s):  
Raquel Lobo-do-Vale ◽  
Cathy K. Besson ◽  
Maria C. Caldeira ◽  
Maria M. Chaves ◽  
João S. Pereira
Keyword(s):  
Climate Change ◽  
Growing Season ◽  
Shoot Elongation ◽  
Cork Oak ◽  
Mediterranean Ecosystem ◽  
Season Length ◽  
Resorption Efficiency ◽  
Nitrogen Resorption ◽  
Growing Season Length ◽  
Nitrogen Resorption Efficiency

Abstract. Mediterranean ecosystems are hotspots for climate change, as the highest impacts are forecasted for the Mediterranean region, mainly by more frequent and intense severe droughts. Plant phenology is a good indicator of species' responses to climate change. In this study, we compared phenology of cork oak trees (Quercus suber), an evergreen species, over two contrasting years, including the most severe drought (2005) since records exist. We evaluated not only the timing of occurrence of the vegetative phenophases in spring (bud development, budburst, shoot elongation, trunk growth and leaf senescence), but also their duration and intensity. We also quantified nitrogen in green and senescent leaves and assessed the nitrogen resorption efficiency. Temperature was the main driver for budburst. Nevertheless, water had a main role constraining all the other phenophases, by strongly reducing the growing season length (−48 %) and consequently tree growth. Basal area increment was the most affected growth variable (−38 %), although the rate of increase remained similar among years. Shoot elongation was reduced by −21 % yet elongation occurred at a higher rate in the dry as compared to the mild year. Leaf senescence during the bulk period was higher in the dry year, in which leaves were shed at the same rate over a longer period. Nitrogen concentration in green and senescent leaves were affected by drought and cork oak remarkably increased the nitrogen resorption efficiency (+22 %), which appears to be an adaptive trait that mitigates the limitation in nitrogen uptake by the roots during drought. Water availability was the main driver of the growing season length in this Mediterranean ecosystem, although it may also be affected by complex interplays between precipitation and temperature. Our results highlight the importance of studying different phenological metrics to improve our understanding of the ecosystems responses to climate change. The faster dynamics observed in shoot elongation, in contrast with the other phenophases, are indicative that cork oak privileges leaf area development, while all other phenophases develop at the same rate. Finally, a higher nitrogen resorption efficiency in response to drought may clearly improve tree fitness in the short-term, but will probably exert a negative feedback on the nitrogen cycle in the long-term which might affect the ecosystem functioning under the forecasted droughts.

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