Dry days, associated temperature anomalies and inter-annual variations in spring phenology

2021 ◽  
Author(s):  
Pierluigi Calanca
Keyword(s):  
Climate Change ◽  
Future Climate Change ◽  
Summer Drought ◽  
Forage Production ◽  
Spring Phenology ◽  
Temperature Anomalies ◽  
Annual Variations ◽  
Grassland Ecosystems ◽  
Grassland Plants ◽  
Recent Climate

<p>The imprint of recent climate change on plant phenology has been the subject of several investigations during the last few decades. Results of such studies have repeatedly documented the advances of key phenological stages in spring. More recently, they have also shown that global warming has induced changes in temperature sensitivity and led to more uniform phenology across elevations. While awareness of trends in phenology undoubtedly contributes to inform ecosystem management, the provision of ecosystem services also necessitates knowledge and understanding of how spring phenology varies from year to year. For instance, in view of growing exposure of grassland ecosystems to summer drought, in Alpine countries forage production increasingly relies on exploiting at best spring growth, which in turn requires an accurate timing of field operations, depending on the progress of herbage development.</p><p>Employing long-term phenological observations on forest trees and grassland plants and weather records from Switzerland, in this contribution I examine year-to-year variations in spring phenology in light of anomalies in the seasonal mean temperature for the months of February to April, and reflect on how the latter can be related to number of dry days and associated temperature anomalies. Based on these findings and results from other studies, I discuss possible implications of future climate change for the variability of spring phenology.</p>

scholarly journals Projecting malaria hazard from climate change in eastern Africa using large ensembles to estimate uncertainty

2016 ◽  
Vol 11 (1s) ◽  
Author(s):  
Joseph Leedale ◽  
Adrian M. Tompkins ◽  
Cyril Caminade ◽  
Anne E. Jones ◽  
Grigory Nikulin ◽  
...  
Keyword(s):  
Climate Change ◽  
Malaria Transmission ◽  
Climate Models ◽  
Climate Model ◽  
Eastern Africa ◽  
Future Climate Change ◽  
Climate Projections ◽  
Model Ensemble ◽  
East African Community ◽  
Recent Climate

The effect of climate change on the spatiotemporal dynamics of malaria transmission is studied using an unprecedented ensemble of climate projections, employing three diverse bias correction and downscaling techniques, in order to partially account for uncertainty in climate- driven malaria projections. These large climate ensembles drive two dynamical and spatially explicit epidemiological malaria models to provide future hazard projections for the focus region of eastern Africa. While the two malaria models produce very distinct transmission patterns for the recent climate, their response to future climate change is similar in terms of sign and spatial distribution, with malaria transmission moving to higher altitudes in the East African Community (EAC) region, while transmission reduces in lowland, marginal transmission zones such as South Sudan. The climate model ensemble generally projects warmer and wetter conditions over EAC. The simulated malaria response appears to be driven by temperature rather than precipitation effects. This reduces the uncertainty due to the climate models, as precipitation trends in tropical regions are very diverse, projecting both drier and wetter conditions with the current state-of-the-art climate model ensemble. The magnitude of the projected changes differed considerably between the two dynamical malaria models, with one much more sensitive to climate change, highlighting that uncertainty in the malaria projections is also associated with the disease modelling approach.

scholarly journals Energy and indoor thermal comfort performance of a Swedish residential building under future climate change conditions

2020 ◽  
Vol 172 ◽  
pp. 02001
Author(s):  
Ambrose Dodoo
Keyword(s):  
Climate Change ◽  
Thermal Comfort ◽  
Residential Building ◽  
Adaptation Strategies ◽  
Future Climate ◽  
Future Climate Change ◽  
Climate Projections ◽  
Mean Annual Temperature ◽  
Indoor Thermal Comfort ◽  
Recent Climate

The latest climate change projections for Sweden suggest mean annual temperature increase of up to 5.5 °C by 2100, compared to 1961-1990 levels. In this study we investigate the potential impacts of climate change on the energy demand for space conditioning, overheating risk and indoor thermal comfort of a modern multi-storey residential building in Sweden. We explore climate change adaptation strategies to improve the building’s performance under the climate change conditions, including increased ventilation, solar shading, improved windows and mechanical cooling. The building is analysed under future climate projections for the 2050-2059 time frame, with representative concentration pathway (RCP) 2.6, 4.5 and 8.5 scenarios. The building’s performances under these future climates are compared to those under the historical climate of 1961-1990 and recent climate of 1981-2010. The results suggest that climate change will significantly influence energy performance and indoor comfort conditions of buildings in the Swedish context. Overheating hours and Predicted Percentage of Dissatisfied (PPD) increased significantly under the future climate scenarios. Furthermore space heating demand is reduced and cooling demand is increased for the studied building. However, effective adaptation strategies significantly improved the buildings’ energy and indoor climate performances under both current and future climate conditions.

scholarly journals The influence of atmospheric circulation on the mid-Holocene climate of Europe: a data–model comparison

2014 ◽  
Vol 10 (5) ◽  
pp. 1925-1938 ◽  
Author(s):  
A. Mauri ◽  
B. A. S. Davis ◽  
P. M. Collins ◽  
J. O. Kaplan
Keyword(s):  
Climate Change ◽  
Atmospheric Circulation ◽  
Data Model ◽  
Atmospheric Dynamics ◽  
Future Climate Change ◽  
Seasonal Temperature ◽  
Holocene Climate ◽  
Model Simulations ◽  
Recent Climate

Abstract. The atmospheric circulation is a key area of uncertainty in climate model simulations of future climate change, especially in mid-latitude regions such as Europe where atmospheric dynamics have a significant role in climate variability. It has been proposed that the mid-Holocene was characterized in Europe by a stronger westerly circulation in winter comparable with a more positive AO/NAO, and a weaker westerly circulation in summer caused by anti-cyclonic blocking near Scandinavia. Model simulations indicate at best only a weakly positive AO/NAO, whilst changes in summer atmospheric circulation have not been widely investigated. Here we use a new pollen-based reconstruction of European mid-Holocene climate to investigate the role of atmospheric circulation in explaining the spatial pattern of seasonal temperature and precipitation anomalies. We find that the footprint of the anomalies is entirely consistent with those from modern analogue atmospheric circulation patterns associated with a strong westerly circulation in winter (positive AO/NAO) and a weak westerly circulation in summer associated with anti-cyclonic blocking (positive SCAND). We find little agreement between the reconstructed anomalies and those from 14 GCMs that performed mid-Holocene experiments as part of the PMIP3/CMIP5 project, which show a much greater sensitivity to top-of-the-atmosphere changes in solar insolation. Our findings are consistent with data–model comparisons on contemporary timescales that indicate that models underestimate the role of atmospheric circulation in recent climate change, whilst also highlighting the importance of atmospheric dynamics in explaining interglacial warming.

scholarly journals Observed groundwater temperature response to recent climate change

2014 ◽  
Vol 18 (11) ◽  
pp. 4453-4466 ◽  
Author(s):  
K. Menberg ◽  
P. Blum ◽  
B. L. Kurylyk ◽  
P. Bayer
Keyword(s):  
Climate Change ◽  
Heat Transfer ◽  
Air Temperature ◽  
Shallow Groundwater ◽  
Regime Shifts ◽  
Future Climate Change ◽  
Groundwater Temperature ◽  
Recent Climate Change ◽  
Recent Climate ◽  
Groundwater Dependent Ecosystems

Abstract. Climate change is known to have a considerable influence on many components of the hydrological cycle. Yet, the implications for groundwater temperature, as an important driver for groundwater quality, thermal use and storage, are not yet comprehensively understood. Furthermore, few studies have examined the implications of climate-change-induced groundwater temperature rise for groundwater-dependent ecosystems. Here, we examine the coupling of atmospheric and groundwater warming by employing stochastic and deterministic models. Firstly, several decades of temperature time series are statistically analyzed with regard to climate regime shifts (CRSs) in the long-term mean. The observed increases in shallow groundwater temperatures can be associated with preceding positive shifts in regional surface air temperatures, which are in turn linked to global air temperature changes. The temperature data are also analyzed with an analytical solution to the conduction–advection heat transfer equation to investigate how subsurface heat transfer processes control the propagation of the surface temperature signals into the subsurface. In three of the four monitoring wells, the predicted groundwater temperature increases driven by the regime shifts at the surface boundary condition generally concur with the observed groundwater temperature trends. Due to complex interactions at the ground surface and the heat capacity of the unsaturated zone, the thermal signals from distinct changes in air temperature are damped and delayed in the subsurface, causing a more gradual increase in groundwater temperatures. These signals can have a significant impact on large-scale groundwater temperatures in shallow and economically important aquifers. These findings demonstrate that shallow groundwater temperatures have responded rapidly to recent climate change and thus provide insight into the vulnerability of aquifers and groundwater-dependent ecosystems to future climate change.

Downscaled Climate Change Projections for Wa District in the Savanna Zone of Ghana

2014 ◽  
Vol 9 (4) ◽  
pp. 422-431 ◽  
Author(s):  
Emmanuel Tachie-Obeng ◽  
◽  
Bruce Hewitson ◽  
Edwin Akonno Gyasi ◽  
Mark Kofi Abekoe ◽  
...  
Keyword(s):  
Climate Change ◽  
Local Level ◽  
Control Period ◽  
Dry Season ◽  
Future Climate ◽  
Future Climate Change ◽  
Wet Season ◽  
Annual Variations ◽  
Near Future ◽  
Savanna Zone

The possibility of future climate change in Ghana has received much attention due to repeated droughts and floods over the last decades. The savanna zone which is described as the food basket of Ghana is highly susceptible to climate change impact. Scenarios from 20-year time slices of the near future – 2046-2065 – and the far future – 2081-2100 – climate change meant to help guide policy remain a challenge. Empirical downscaling performed at the local-scale of Wa District in the savanna zone of Ghana under the IPCC A2 SRES emissions scenario showed evidence of probable climate change with mean annual temperatures expected to increase over an estimated range of 1.5°C to 2.3°C in the near future, with number of cool nights becoming less frequent, especially during the Harmattan1 period. The dry season is expected to be warmer than the wet season, with high inter-annual variations projected in both maximum (Tmax) and minimum (Tmin) temperatures. Given an average of 1 day of Tmax > 40°C per month in the control period of 1961-2000, the number of hot days is expected to increase to 12 by 2046-2065. An increase in total rainfall is projected with possible shifts in distribution toward the end of the year, with a slight increase in rainfall during the dry season and an increase of rainfall at the onset and toward the end of the wet season. However, a decrease in June rainfall is projected in the wet season. The objective of this paper is to improve the understanding of future climate as a guide to local level medium-term development plans of effective adaptation options for Wa district in the savanna zone of Ghana.

scholarly journals Seasonal variation in the nitrogen nutrition and carbon assimilation in wild and cultivated Aspalathus linearis (rooibos tea)

2014 ◽  
Vol 62 (1) ◽  
pp. 65 ◽  
Author(s):  
Daleen Lötter ◽  
Emma Archer van Garderen ◽  
Mark Tadross ◽  
Alexander J. Valentine
Keyword(s):  
Climate Change ◽  
Nitrogen Nutrition ◽  
Carbon Assimilation ◽  
Wild Plants ◽  
Future Climate Change ◽  
Summer Drought ◽  
N Nutrition ◽  
Biological N2 Fixation ◽  
Aspalathus Linearis ◽  
Rooibos Tea

The Fynbos Biome of southern Africa is a Mediterranean-climate ecosystem with highly infertile soil. It is home to the endemic leguminous shrub Aspalathus linearis (rooibos tea), which is both an invaluable wild resource and commercially cultivated plant. Wild rooibos has a narrow geographic range and is confined to mountain ranges of the Cederberg Region. Under projected climate change, warmer and more arid conditions may place additional pressure on these range-restricted plants to survive in an already resource-limited environment. To understand the adaptive strategies that may allow rooibos to persist in its habitat under future climate change, the present study evaluated changes in the photosynthetic activity and nutrient cycling of wild and cultivated A. linearis, at the temperature and rainfall extremes of summer and winter. Wild and cultivated rooibos tea had different methods of adapting to nitrogen (N) nutrition and carbon (C) assimilation during wet and dry seasons. In particular, the wild plants were better able to tolerate summer drought by increased water use efficiency and maintaining higher levels of biological N2 fixation than was the cultivated tea.

scholarly journals Improving the Assessment of Potential and Actual Impacts of Climate Change and Extreme Events Through a Parallel Modeling of Climatic and Societal Changes at Different Scales

2017 ◽  
Vol 04 (04) ◽  
pp. 1850003 ◽  
Author(s):  
Stefan Greiving ◽  
Sophie Arens ◽  
Dennis Becker ◽  
Mark Fleischhauer ◽  
Florian Hurth
Keyword(s):  
Climate Change ◽  
Case Studies ◽  
Climate Change Impacts ◽  
Climate Impacts ◽  
Future Climate Change ◽  
Land Use Patterns ◽  
Intergovernmental Panel ◽  
Adaptation Measures ◽  
Modeling Approach ◽  
Recent Climate

Any adaptation activity needs a reliable evidence basis for the climate itself as well as for the exposition and sensitivity of the social, economic or ecological system and its elements. This requires an assessment of recent climate impacts as well as potential future climate change impacts in order to select tailor-made adaptation measures. For a methodologically coherent assessment, the Intergovernmental Panel on Climate Change (IPCC) had introduced the requirement of a parallel modeling approach which means that demographic and socioeconomic changes are projected in parallel to the changes of the climatic system. This paper discusses a conceptual framework of a parallel modeling approach and presents its application in four case studies of climate change impact assessments in Germany, covering the national, regional and local scale. The results from the different applications prove the hypothesis that the change in sensitivity (i.e., demographic change, economic change and change in land-use patterns) often determines the magnitude of climate- and weather-related impacts in the near future significantly. The case studies, however, also show that adaptation processes have to be organized in a collaborative way, which takes the knowledge, and also the concerns of the addressees into full account. A broad mandate from all social groups is especially needed when political decisions are based on uncertain knowledge — which is the case whenever climate change impacts are assessed.

scholarly journals Observed groundwater temperature response to recent climate change

2014 ◽  
Vol 11 (3) ◽  
pp. 3637-3673 ◽  
Author(s):  
K. Menberg ◽  
P. Blum ◽  
B. L. Kurylyk ◽  
P. Bayer
Keyword(s):  
Climate Change ◽  
Heat Transfer ◽  
Air Temperature ◽  
Shallow Groundwater ◽  
Regime Shifts ◽  
Future Climate Change ◽  
Groundwater Temperature ◽  
Recent Climate Change ◽  
Recent Climate ◽  
Groundwater Dependent Ecosystems

Abstract. Climate change is known to have a considerable influence on many components of the hydrological cycle. Yet, the implications for groundwater temperature, as an important driver for groundwater quality, thermal use and storage, are not yet comprehensively understood. Furthermore, few studies have examined the implications of climate change-induced groundwater temperature rise for groundwater-dependent ecosystems. Here, we examine the coupling of atmospheric and groundwater warming by employing stochastic and deterministic models. Firstly, several decades of temperature time-series are statistically analyzed with regard to abrupt climate regime shifts (CRS) in the long-term mean. The observed abrupt increases in shallow groundwater temperatures can be associated with preceding positive shifts in regional surface air temperatures, which are in turn linked to global air temperature changes. The temperature data are also analyzed with an analytical solution to the conduction-advection heat transfer equation to investigate how subsurface heat transfer processes control the propagation of the surface temperature signals into the subsurface. In three of the four monitoring wells, the predicted groundwater temperature increases driven by the regime shifts at the surface boundary condition generally concur with the observed groundwater temperature trends. Due to complex interactions at the ground surface and the heat capacity of the unsaturated zone, the thermal signals from distinct changes in air temperature are damped and delayed in the subsurface, causing a more gradual increase in groundwater temperatures. These signals can have a significant impact on large-scale groundwater temperatures in shallow and economically important aquifers. These findings demonstrate that shallow groundwater temperatures have responded rapidly to recent climate change and thus provide insight into the vulnerability of aquifers and groundwater-dependent ecosystems to future climate change.

scholarly journals Coherence among the Northern Hemisphere land, cryosphere, and ocean responses to natural variability and anthropogenic forcing during the satellite era

2016 ◽  
Vol 7 (3) ◽  
pp. 717-734 ◽  
Author(s):  
Alemu Gonsamo ◽  
Jing M. Chen ◽  
Drew T. Shindell ◽  
Gregory P. Asner
Keyword(s):  
Climate Change ◽  
Solar Radiation ◽  
Sea Ice ◽  
Interannual Variability ◽  
Northern Hemisphere ◽  
Natural Variability ◽  
Spring Phenology ◽  
Anthropogenic Forcing ◽  
Recent Climate

Abstract. A lack of long-term measurements across Earth's biological and physical systems has made observation-based detection and attribution of climate change impacts to anthropogenic forcing and natural variability difficult. Here we explore coherence among land, cryosphere and ocean responses to recent climate change using 3 decades (1980–2012) of observational satellite and field data throughout the Northern Hemisphere. Our results show coherent interannual variability among snow cover, spring phenology, solar radiation, Scandinavian Pattern, and North Atlantic Oscillation. The interannual variability of the atmospheric peak-to-trough CO2 amplitude is mostly impacted by temperature-mediated effects of El Niño/Southern Oscillation (ENSO) and Pacific/North American Pattern (PNA), whereas CO2 concentration is affected by Polar Pattern control on sea ice extent dynamics. This is assuming the trend in anthropogenic CO2 emission remains constant, or the interannual changes in the trends are negligible. Our analysis suggests that sea ice decline-related CO2 release may outweigh increased CO2 uptake through longer growing seasons and higher temperatures. The direct effects of variation in solar radiation and leading teleconnections, at least in part via their impacts on temperature, dominate the interannual variability of land, cryosphere and ocean indicators. Our results reveal a coherent long-term changes in multiple physical and biological systems that are consistent with anthropogenic forcing of Earth's climate and inconsistent with natural drivers.

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