Climate Sensitivity Runs and Regional Hydrologic Modeling for Predicting the Response of the Greater Florida Everglades Ecosystem to Climate Change

2014 ◽  
Vol 55 (4) ◽  
pp. 749-762 ◽  
Author(s):  
Jayantha Obeysekera ◽  
Jenifer Barnes ◽  
Martha Nungesser
Keyword(s):  
Climate Change ◽  
Climate Sensitivity ◽  
Hydrologic Modeling ◽  
Florida Everglades

scholarly journals Zuwachs und Klimasensitivität von Baumarten im Ökogramm der kollinen und submontanen Stufe

2015 ◽  
Vol 166 (6) ◽  
pp. 380-388 ◽  
Author(s):  
Pascale Weber ◽  
Caroline Heiri ◽  
Mathieu Lévesque ◽  
Tanja Sanders ◽  
Volodymyr Trotsiuk ◽  
...  
Keyword(s):  
Climate Change ◽  
Soil Properties ◽  
Climate Sensitivity ◽  
Tree Species ◽  
Ring Width ◽  
Basal Area ◽  
Growth Potential ◽  
Basal Area Increment ◽  
Tree Ring Data ◽  
Mean Sensitivity

Growth potential and climate sensitivity of tree species in the ecogram for the colline and submontane zone In forestry practice a large amount of empirical knowledge exists about the productivity of individual tree species in relation to site properties. However, so far, only few scientific studies have investigated the influence of soil properties on the growth potential of various tree species along gradients of soil water as well as nutrient availability. Thus, there is a research gap to estimate the productivity and climate sensitivity of tree species under climate change, especially regarding productive sites and forest ad-mixtures in the lower elevations. Using what we call a «growth ecogram», we demonstrate species- and site-specific patterns of mean annual basal area increment and mean sensitivity of ring width (strength of year-to-year variation) for Fagus sylvatica, Quercus spp., Fraxinus excelsior, Picea abies, Abies alba and Pinus sylvestris, based on tree-ring data from 508 (co-)dominant trees on 27 locations. For beech, annual basal area increment ( average 1957–2006) was significantly correlated with tree height of the dominant sampling trees and proved itself as a possible alternative for assessing site quality. The fact that dominant trees of the different tree species showed partly similar growth potential within the same ecotype indicates comparable growth limitation by site conditions. Mean sensitivity of ring width – a measure of climate sensitivity – had decreased for oak and ash, while it had increased in pine. Beech showed diverging reactions with increasing sensitivity at productive sites (as measured by the C:N ratio of the topsoil), suggesting an increasing limitation by climate at these sites. Hence, we derive an important role of soil properties in the response of forests to climate change at lower elevations, which should be taken into account when estimating future forest productivity.

scholarly journals Estimates of climate system properties incorporating recent climate change

2018 ◽  
Vol 4 (1/2) ◽  
pp. 19-36 ◽  
Author(s):  
Alex G. Libardoni ◽  
Chris E. Forest ◽  
Andrei P. Sokolov ◽  
Erwan Monier
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
21St Century ◽  
Climate Sensitivity ◽  
Temperature Rise ◽  
Heat Content ◽  
Climate System ◽  
Model Parameters ◽  
Aerosol Forcing ◽  
Global Mean

Abstract. Historical time series of surface temperature and ocean heat content changes are commonly used metrics to diagnose climate change and estimate properties of the climate system. We show that recent trends, namely the slowing of surface temperature rise at the beginning of the 21st century and the acceleration of heat stored in the deep ocean, have a substantial impact on these estimates. Using the Massachusetts Institute of Technology Earth System Model (MESM), we vary three model parameters that influence the behavior of the climate system: effective climate sensitivity (ECS), the effective ocean diffusivity of heat anomalies by all mixing processes (Kv), and the net anthropogenic aerosol forcing scaling factor. Each model run is compared to observed changes in decadal mean surface temperature anomalies and the trend in global mean ocean heat content change to derive a joint probability distribution function for the model parameters. Marginal distributions for individual parameters are found by integrating over the other two parameters. To investigate how the inclusion of recent temperature changes affects our estimates, we systematically include additional data by choosing periods that end in 1990, 2000, and 2010. We find that estimates of ECS increase in response to rising global surface temperatures when data beyond 1990 are included, but due to the slowdown of surface temperature rise in the early 21st century, estimates when using data up to 2000 are greater than when data up to 2010 are used. We also show that estimates of Kv increase in response to the acceleration of heat stored in the ocean as data beyond 1990 are included. Further, we highlight how including spatial patterns of surface temperature change modifies the estimates. We show that including latitudinal structure in the climate change signal impacts properties with spatial dependence, namely the aerosol forcing pattern, more than properties defined for the global mean, climate sensitivity, and ocean diffusivity.

scholarly journals The Consequences of Uncertainty: Climate Sensitivity and Economic Sensitivity to the Climate

2018 ◽  
Vol 10 (1) ◽  
pp. 189-205 ◽  
Author(s):  
John Hassler ◽  
Per Krusell ◽  
Conny Olovsson
Keyword(s):  
Climate Change ◽  
Climate Policy ◽  
Climate Sensitivity ◽  
Fossil Fuels ◽  
Carbon Tax ◽  
Green Energy ◽  
Integrated Assessment Model ◽  
Assessment Model ◽  
Energy Sources ◽  
Negative Impacts

We construct an integrated assessment model with multiple energy sources—two fossil fuels and green energy—and use it to evaluate ranges of plausible estimates for the climate sensitivity, as well as for the sensitivity of the economy to climate change. Rather than focusing explicitly on uncertainty, we look at extreme scenarios defined by the upper and lower limits given in available studies in the literature. We compare optimal policy with laissez faire, and we point out the possible policy errors that could arise. By far the largest policy error arises when the climate policy is overly passive; overly zealous climate policy (i.e., a high carbon tax applied when climate change and its negative impacts on the economy are very limited) does not hurt the economy much as there is considerable substitutability between fossil and nonfossil energy sources.

Hotspots of change in major tree species under climate warming

2020 ◽  
Author(s):  
Flurin Babst ◽  
Richard L. Peters ◽  
Rafel O. Wüest ◽  
Margaret E.K. Evans ◽  
Ulf Büntgen ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Sensitivity ◽  
Tree Growth ◽  
Species Distribution ◽  
Tree Species ◽  
Habitat Suitability ◽  
Species Distribution Models ◽  
Sensitivity Index ◽  
Distribution Models ◽  
Bioclimatic Variables

<p>Warming alters the variability and trajectories of tree growth around the world by intensifying or alleviating energy and water limitation. This insight from regional to global-scale research emphasizes the susceptibility of forest ecosystems and resources to climate change. However, globally-derived trends are not necessarily meaningful for local nature conservation or management considerations, if they lack specific information on present or prospective tree species. This is particularly the case towards the edge of their distribution, where shifts in growth trajectories may be imminent or already occurring.</p><p>Importantly, the geographic and bioclimatic space (or “niche”) occupied by a tree species is not only constrained by climate, but often reflects biotic pressure such as competition for resources with other species. This aspect is underrepresented in many species distribution models that define the niche as a climatic envelope, which is then allowed to shift in response to changes in ambient conditions. Hence, distinguishing climatic from competitive niche boundaries becomes a central challenge to identifying areas where tree species are most susceptible to climate change.</p><p>Here we employ a novel concept to characterize each position within a species’ bioclimatic niche based on two criteria: a climate sensitivity index (CSI) and a habitat suitability index (HSI). The CSI is derived from step-wise multiple linear regression models that explain variability in annual radial tree growth as a function of monthly climate anomalies. The HSI is based on an ensemble of five species distribution models calculated from a combination of observed species occurrences and twenty-five bioclimatic variables. We calculated these two indices for 11 major tree species across the Northern Hemisphere.</p><p>The combination of climate sensitivity and habitat suitability indicated hotspots of change, where tree growth is mainly limited by competition (low HSI and low CSI), as well as areas that are particularly sensitive to climate variability (low HSI and high CSI). In the former, we expect that forest management geared towards adjusting the competitive balance between several candidate species will be most effective under changing environmental conditions. In the latter areas, selecting particularly drought-tolerant accessions of a given species may reduce forest susceptibility to the predicted warming and drying.</p>

scholarly journals The Shape of Things to Come: Why Is Climate Change So Predictable?

2009 ◽  
Vol 22 (17) ◽  
pp. 4574-4589 ◽  
Author(s):  
Marcia B. Baker ◽  
Gerard H. Roe
Keyword(s):  
Climate Change ◽  
Probability Distribution ◽  
Climate Sensitivity ◽  
Negative Feedback ◽  
Temperature Response ◽  
Global Scale ◽  
Climate Forcing ◽  
Climate Projections ◽  
Ocean Heat Uptake ◽  
The Impact

Abstract The framework of feedback analysis is used to explore the controls on the shape of the probability distribution of global mean surface temperature response to climate forcing. It is shown that ocean heat uptake, which delays and damps the temperature rise, can be represented as a transient negative feedback. This transient negative feedback causes the transient climate change to have a narrower probability distribution than that of the equilibrium climate response (the climate sensitivity). In this sense, climate change is much more predictable than climate sensitivity. The width of the distribution grows gradually over time, a consequence of which is that the larger the climate change being contemplated, the greater the uncertainty is about when that change will be realized. Another consequence of this slow growth is that further efforts to constrain climate sensitivity will be of very limited value for climate projections on societally relevant time scales. Finally, it is demonstrated that the effect on climate predictability of reducing uncertainty in the atmospheric feedbacks is greater than the effect of reducing uncertainty in ocean feedbacks by the same proportion. However, at least at the global scale, the total impact of uncertainty in climate feedbacks is dwarfed by the impact of uncertainty in climate forcing, which in turn is contingent on choices made about future anthropogenic emissions.

scholarly journals How Well Do We Understand and Evaluate Climate Change Feedback Processes?

2006 ◽  
Vol 19 (15) ◽  
pp. 3445-3482 ◽  
Author(s):  
Sandrine Bony ◽  
Robert Colman ◽  
Vladimir M. Kattsov ◽  
Richard P. Allan ◽  
Christopher S. Bretherton ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Sensitivity ◽  
General Circulation ◽  
External Perturbation ◽  
General Circulation Models ◽  
Lapse Rate ◽  
Climate Feedback ◽  
Climate Feedbacks ◽  
Intergovernmental Panel ◽  
Global Estimates

Abstract Processes in the climate system that can either amplify or dampen the climate response to an external perturbation are referred to as climate feedbacks. Climate sensitivity estimates depend critically on radiative feedbacks associated with water vapor, lapse rate, clouds, snow, and sea ice, and global estimates of these feedbacks differ among general circulation models. By reviewing recent observational, numerical, and theoretical studies, this paper shows that there has been progress since the Third Assessment Report of the Intergovernmental Panel on Climate Change in (i) the understanding of the physical mechanisms involved in these feedbacks, (ii) the interpretation of intermodel differences in global estimates of these feedbacks, and (iii) the development of methodologies of evaluation of these feedbacks (or of some components) using observations. This suggests that continuing developments in climate feedback research will progressively help make it possible to constrain the GCMs’ range of climate feedbacks and climate sensitivity through an ensemble of diagnostics based on physical understanding and observations.

scholarly journals Sources of uncertainty in climate change impacts on river discharge and groundwater in a headwater catchment of the Upper Nile Basin, Uganda

2010 ◽  
Vol 14 (7) ◽  
pp. 1297-1308 ◽  
Author(s):  
D. G. Kingston ◽  
R. G. Taylor
Keyword(s):  
Climate Change ◽  
Air Temperature ◽  
Climate Sensitivity ◽  
River Discharge ◽  
Hydrological Model ◽  
Nile Basin ◽  
Freshwater Resources ◽  
Depth Analysis ◽  
Global Mean ◽  
Impacts Of Climate Change

Abstract. The changing availability of freshwater resources is likely to be one of the most important consequences of projected 21st century climate change for both human and natural systems. However, substantial uncertainty remains regarding the precise impacts of climate change on water resources, due in part due to uncertainty in GCM projections of climate change. Here we explore the potential impacts of climate change on freshwater resources in a humid, tropical catchment (the River Mitano) in the Upper Nile Basin of Uganda. Uncertainty associated with GCM structure and climate sensitivity is explored, as well as parameter specification within hydrological models. These aims are achieved by running pattern-scaled output from seven GCMs through a semi-distributed hydrological model of the catchment (developed using SWAT). Importantly, use of pattern-scaled GCM output allows investigation of specific thresholds of global climate change including the purported 2 °C threshold of "dangerous" climate change. In-depth analysis of results based on the HadCM3 GCM climate scenarios shows that annual river discharge first increases, then declines with rising global mean air temperature. A coincidental shift from a bimodal to unimodal discharge regime also results from a projected reduction in baseflow (groundwater discharge). Both of these changes occur after a 4 °C rise in global mean air temperature. These results are, however, highly GCM dependent, in both the magnitude and direction of change. This dependence stems primarily from projected differences in GCM scenario precipitation rather than temperature. GCM-related uncertainty is far greater than that associated with climate sensitivity or hydrological model parameterisation.

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