A Bayesian Assessment of Climate Change Using Multimodel Ensembles. Part II: Regional and Seasonal Mean Surface Temperatures

2007 ◽  
Vol 20 (12) ◽  
pp. 2769-2790 ◽  
Author(s):  
Seung-Ki Min ◽  
Andreas Hense
Keyword(s):  
Climate Change ◽  
Twentieth Century ◽  
South America ◽  
Regional Scale ◽  
Surface Air Temperature ◽  
Bayesian Decision ◽  
Intergovernmental Panel ◽  
Anthropogenic Forcing ◽  
Model Ensembles ◽  
Multimodel Ensembles

Abstract A Bayesian approach is applied to the observed regional and seasonal surface air temperature (SAT) changes using single-model ensembles (SMEs) with the ECHO-G model and multimodel ensembles (MMEs) of the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) simulations. Bayesian decision classifies observations into the most probable scenario out of six available scenarios: control (CTL), natural forcing (N), anthropogenic forcing (ANTHRO), greenhouse gas (G), sulfate aerosols (S), and natural plus anthropogenic forcing (ALL). Space–time vectors of the detection variable are constructed for six continental regions (North America, South America, Asia, Africa, Australia, and Europe) by combining temporal components of SATs (expressed as Legendre coefficients) from two or three subregions of each continental region. Bayesian decision results show that over most of the regions observed SATs are classified into ALL or ANTHRO scenarios for the whole twentieth century and its second half. Natural forcing and ALL scenarios are decided during the first half of the twentieth century, but only in the low-latitude region (Africa and South America), which might be related to response patterns to solar forcing. Overall seasonal decisions follow annual results, but there are notable seasonal dependences that differ between regions. A comparison of SME and MME results demonstrates that the Bayesian decisions for regional-scale SATs are largely robust to intermodel uncertainties as well as prior probability and temporal scales, as found in the global results.

scholarly journals Multimodel Multisignal Climate Change Detection at Regional Scale

2006 ◽  
Vol 19 (17) ◽  
pp. 4294-4307 ◽  
Author(s):  
Xuebin Zhang ◽  
Francis W. Zwiers ◽  
P. A. Stott
Keyword(s):  
Climate Change ◽  
Twentieth Century ◽  
Greenhouse Gases ◽  
Regional Scale ◽  
Internal Variability ◽  
Anthropogenic Forcing ◽  
Internal Climate Variability ◽  
Aerosol Forcing ◽  
Spatial Domains ◽  
Northern Hemispheric

Abstract Using an optimal detection technique and climate change simulations produced with two versions of two GCMs, we have assessed the causes of twentieth-century temperature changes from global to regional scales. Our analysis is conducted in nine spatial domains: 1) the globe; 2) the Northern Hemisphere; four large regions in the Northern Hemispheric midlatitudes covering 30°–70°N including 3) Eurasia, 4) North America, 5) Northern Hemispheric land only, 6) the entire 30°–70°N belt; and three smaller regions over 7) southern Canada, 8) southern Europe, and 9) China. We find that the effect of anthropogenic forcing on climate is clearly detectable at global through regional scales. The effect of combined greenhouse gases and sulfate aerosol forcing is detectable in all nine domains in annual and seasonal mean temperatures observed during the second half of the twentieth century. The effect of greenhouse gases can also be separated from that of sulfate aerosols over this period at continental and regional scales. Uncertainty in these results is larger in the smaller spatial domains. Detection is improved when an ensemble of models is used to estimate the response to anthropogenic forcing and the underlying internal variability of the climate system. Our detection results hold after removal of North Atlantic Oscillation (NAO)-related variability in temperature observations—variability that may or may not be associated with anthropogenic forcing. They also continue to hold when our estimates of natural internal climate variability are doubled.

Twentieth-Century Surface Air Temperature over China and the Globe Simulated by Coupled Climate Models

2006 ◽  
Vol 19 (22) ◽  
pp. 5843-5858 ◽  
Author(s):  
Tianjun Zhou ◽  
Rucong Yu
Keyword(s):  
Climate Change ◽  
Twentieth Century ◽  
Air Temperature ◽  
Climate Models ◽  
Eastern China ◽  
Surface Air Temperature ◽  
Future Climate Change ◽  
Intergovernmental Panel ◽  
Coupled Climate Models ◽  
Anthropogenic Forcings

Abstract This paper examines variations of the surface air temperature (SAT) over China and the globe in the twentieth century simulated by 19 coupled climate models driven by historical natural and anthropogenic forcings. Most models perform well in simulating both the global and the Northern Hemispheric mean SAT evolutions of the twentieth century. The inclusion of natural forcings improves the simulation, in particular for the first half of the century. The reproducibility of the SAT averaged over China is lower than that of the global and hemispheric averages, but it is still acceptable. The contribution of natural forcings to the SAT over China in the first half of the century is not as robust as that to the global and hemispheric averages. No model could successfully produce the reconstructed warming over China in the 1920s. The prescribed natural and anthropogenic forcings in the coupled climate models mainly produce the warming trends and the decadal- to interdecadal-scale SAT variations with poor performances at shorter time scales. The prominent warming trend in the last half of the century over China and its acceleration in recent decades are weakly simulated. There are discrepancies between the simulated and observed regional features of the SAT trend over China. Few models could produce the summertime cooling over the middle part of eastern China (27°–36°N), while two models acceptably produce the meridional gradients of the wintertime warming trends, with north China experiencing larger warming. Limitations of the current state-of-the-art coupled climate models in simulating spatial patterns of the twentieth-century SAT over China cast a shadow upon their capability toward projecting credible geographical distributions of future climate change through Intergovernmental Panel on Climate Change (IPCC) scenario simulations.

scholarly journals The Benefits of Global High Resolution for Climate Simulation: Process Understanding and the Enabling of Stakeholder Decisions at the Regional Scale

2018 ◽  
Vol 99 (11) ◽  
pp. 2341-2359 ◽  
Author(s):  
M. J. Roberts ◽  
P. L. Vidale ◽  
C. Senior ◽  
H. T. Hewitt ◽  
C. Bates ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Variability ◽  
Time Scales ◽  
Climate Models ◽  
Water Cycle ◽  
Regional Scale ◽  
Coupled Model ◽  
Convective Precipitation ◽  
Climate Simulation ◽  
Intergovernmental Panel

AbstractThe time scales of the Paris Climate Agreement indicate urgent action is required on climate policies over the next few decades, in order to avoid the worst risks posed by climate change. On these relatively short time scales the combined effect of climate variability and change are both key drivers of extreme events, with decadal time scales also important for infrastructure planning. Hence, in order to assess climate risk on such time scales, we require climate models to be able to represent key aspects of both internally driven climate variability and the response to changing forcings. In this paper we argue that we now have the modeling capability to address these requirements—specifically with global models having horizontal resolutions considerably enhanced from those typically used in previous Intergovernmental Panel on Climate Change (IPCC) and Coupled Model Intercomparison Project (CMIP) exercises. The improved representation of weather and climate processes in such models underpins our enhanced confidence in predictions and projections, as well as providing improved forcing to regional models, which are better able to represent local-scale extremes (such as convective precipitation). We choose the global water cycle as an illustrative example because it is governed by a chain of processes for which there is growing evidence of the benefits of higher resolution. At the same time it comprises key processes involved in many of the expected future climate extremes (e.g., flooding, drought, tropical and midlatitude storms).

scholarly journals Anthropocene climate bifurcation

2020 ◽  
Vol 27 (3) ◽  
pp. 391-409
Author(s):  
Kolja Leon Kypke ◽  
William Finlay Langford ◽  
Allan Richard Willms
Keyword(s):  
Climate Change ◽  
Heat Transport ◽  
The Arctic ◽  
Balance Model ◽  
Anthropogenic Activity ◽  
Nonlinear Feedback ◽  
Intergovernmental Panel ◽  
Feedback Mechanisms ◽  
Anthropogenic Forcing ◽  
Positive Feedbacks

Abstract. This article presents the results of a bifurcation analysis of a simple energy balance model (EBM) for the future climate of the Earth. The main focus is on the following question: can the nonlinear processes intrinsic to atmospheric physics, including natural positive feedback mechanisms, cause a mathematical bifurcation of the climate state, as a consequence of continued anthropogenic forcing by rising greenhouse gas emissions? Our analysis shows that such a bifurcation could cause an abrupt change to a drastically different climate state in the EBM, which is warmer and more equable than any climate existing on Earth since the Pliocene epoch. In previous papers, with this EBM adapted to paleoclimate conditions, it was shown to exhibit saddle-node and cusp bifurcations, as well as hysteresis. The EBM was validated by the agreement of its predicted bifurcations with the abrupt climate changes that are known to have occurred in the paleoclimate record, in the Antarctic at the Eocene–Oligocene transition (EOT) and in the Arctic at the Pliocene–Paleocene transition (PPT). In this paper, the EBM is adapted to fit Anthropocene climate conditions, with emphasis on the Arctic and Antarctic climates. The four Representative Concentration Pathways (RCP) considered by the IPCC (Intergovernmental Panel on Climate Change) are used to model future CO2 concentrations, corresponding to different scenarios of anthropogenic activity. In addition, the EBM investigates four naturally occurring nonlinear feedback processes which magnify the warming that would be caused by anthropogenic CO2 emissions alone. These four feedback mechanisms are ice–albedo feedback, water vapour feedback, ocean heat transport feedback, and atmospheric heat transport feedback. The EBM predicts that a bifurcation resulting in a catastrophic climate change, to a pre-Pliocene-like climate state, will occur in coming centuries for an RCP with unabated anthropogenic forcing, amplified by these positive feedbacks. However, the EBM also predicts that appropriate reductions in carbon emissions may limit climate change to a more tolerable continuation of what is observed today. The globally averaged version of this EBM has an equilibrium climate sensitivity (ECS) of 4.34 K, near the high end of the likely range reported by the IPCC.

scholarly journals Evaluation for the vulnerability of climate change affecting to shark catfish farming in An Giang and suggesting some solutions for this case

2021 ◽  
Vol 5 (1) ◽  
pp. first
Author(s):  
Thu Hong Anh Nguyen ◽  
Huyen Khon Nguyen ◽  
Le Quoc Vy ◽  
Tran Thi Hieu ◽  
Tran Trung Kien ◽  
...  
Keyword(s):  
Climate Change ◽  
Regional Scale ◽  
Economic Sectors ◽  
Intergovernmental Panel ◽  
Vulnerability To Climate Change ◽  
Assess Climate Change ◽  
Main Production ◽  
Definition Of ◽  
Production Areas ◽  
Farming Industry

Aquaculture - belonging to the Fisheries group - is one of the high-value economic sectors, accounting for a large part in the structure of the agriculture, forestry and fishery industry in Vietnam. However, the sustainability of this industry is facing many challenges due to climate change process; An Giang is a province that has long had a strong position in aquaculture in Vietnam and is not out of that influence. Therefore, there is an urgent need to assess climate change vulnerability of aquaculture in An Giang based on the predicted changes in temperature and rainfall of the region according to the change scenarios. climate. Unlike previous studies conducted mainly on a national scale, this paper is mainly concerned with Pangasius (Pangasius is one of the aquatic species with high commercial value, with significant contribution). including livelihoods of people in An Giang province) - species raised in the main production areas of An Giang and assess their vulnerability for each area, using an index-based method and Intergovernmental Panel on Climate Change Definition of Vulnerability to overcome constraints in developing specific adaptation strategies at regional scale. First, for each exposure, sensitivity and adaptability, specific and appropriate indicators are chosen. These indicators are then estimated and weighted to analyze vulnerability to climate change. The results show that the level of vulnerability due to climate change to the pangasius farming industry in An Giang province is at a moderate level, of which Chau Phu district is highly vulnerable because the district has the main livelihood of Pangasius farming.

ASSESSMENT OF STATISTICAL CHARACTERISTICS OF THE LONG-TERM RIVER RUNOFF IN THE RUSSIAN ARCTIC IN CHANGING CLIMATE

2017 ◽  
Author(s):  
Victor Kovalenko ◽  
Victor Kovalenko ◽  
Ekaterina Gaidukova ◽  
Ekaterina Gaidukova ◽  
Vitalii Khaustov ◽  
...  
Keyword(s):  
Climate Change ◽  
River Runoff ◽  
Regional Scale ◽  
Response Assessment ◽  
Statistical Characteristics ◽  
Climate Projections ◽  
Russian Arctic ◽  
Coastal Zones ◽  
Intergovernmental Panel ◽  
Flood Peak

The problems related to impact of the expected climate change and hydrological response assessment for the coastal zones of the Russian Arctic are discussed. The study presents the approach, which allows to perform climate-based forecasting of multi-year river runoff in form of probability density function (pdf) using theoretical distributions from K. Pearson's family. The advantage and limitation of the hydrological model allowing to predict the statistical characteristics of multi-year runoff, without producing projected time hydrological time series are discussed. The regional scale assessment of the multi-year the statistical characteristics of the spring flood peak runoff is evaluated using the climate projections from CMIP5 dataset as suggested by the Intergovernmental Panel on Climate Change (IPCC). The alarm regions, where the socio-economical infrastructure and coastal systems have to be adapted to the expected climate are distinguished.

scholarly journals Anthropogenic warming forces extreme annual glacier mass loss

2021 ◽  
Author(s):  
Lauren Vargo ◽  
Brian Anderson ◽  
R Dadić ◽  
Huw Horgan ◽  
AN Mackintosh ◽  
...  
Keyword(s):  
Mass Loss ◽  
Climate Model ◽  
Regional Scale ◽  
Global Scale ◽  
Glacier Mass Balance ◽  
Anthropogenic Forcing ◽  
Temperature And Precipitation ◽  
Extreme Heat Events ◽  
Event Attribution ◽  
Model Ensembles

Glaciers are unique indicators of climate change. While recent global-scale glacier decline has been attributed to anthropogenic forcing, direct links between human-induced climate warming and extreme glacier mass-loss years have not been documented. Here we apply event attribution methods to document this at the regional scale, targeting the highest mass-loss years (2011 and 2018) across New Zealand’s Southern Alps. Glacier mass balance is simulated using temperature and precipitation from multiple climate model ensembles. We estimate extreme mass loss was at least six times (2011) and ten times (2018) (>90% confidence) more likely to occur with anthropogenic forcing than without. This increased likelihood is driven by present-day temperatures ~1.0 °C above the pre-industrial average, confirming a connection between anthropogenic emissions and high annual ice loss. These results suggest that as warming and extreme heat events continue and intensify, there will be an increasingly visible human fingerprint on extreme glacier mass-loss years in the coming decades.

scholarly journals Characteristics and Scenarios Projection of Climate Change on the Tibetan Plateau

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Zhenchun Hao ◽  
Qin Ju ◽  
Weijuan Jiang ◽  
Changjun Zhu
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Climate Models ◽  
Global Climate ◽  
Surface Air Temperature ◽  
Global Climate Models ◽  
The Tibetan Plateau ◽  
Intergovernmental Panel ◽  
Temperature And Precipitation ◽  
Ipcc Ar4

The Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4) presents twenty-two global climate models (GCMs). In this paper, we evaluate the ability of 22 GCMs to reproduce temperature and precipitation over the Tibetan Plateau by comparing with ground observations for 1961~1900. The results suggest that all the GCMs underestimate surface air temperature and most models overestimate precipitation in most regions on the Tibetan Plateau. Only a few models (each 5 models for precipitation and temperature) appear roughly consistent with the observations in annual temperature and precipitation variations. Comparatively, GFCM21 and CGMR are able to better reproduce the observed annual temperature and precipitation variability over the Tibetan Plateau. Although the scenarios predicted by the GCMs vary greatly, all the models predict consistently increasing trends in temperature and precipitation in most regions in the Tibetan Plateau in the next 90 years. The results suggest that the temperature and precipitation will both increase in all three periods under different scenarios, with scenario A1 increasing the most and scenario A1B increasing the least.

scholarly journals Striking Seasonality in the Secular Warming of the Northern Continents: Structure and Mechanisms

2017 ◽  
Vol 30 (16) ◽  
pp. 6521-6541 ◽  
Author(s):  
Sumant Nigam ◽  
Natalie P. Thomas ◽  
Alfredo Ruiz-Barradas ◽  
Scott J. Weaver
Keyword(s):  
Twentieth Century ◽  
Land Surface ◽  
Climate Models ◽  
Linear Trend ◽  
Surface Air Temperature ◽  
Cost Effective ◽  
Secular Change ◽  
Radiative Energy ◽  
Intergovernmental Panel ◽  
Climate Simulations

The linear trend in twentieth-century surface air temperature (SAT)—a key secular warming signal—exhibits striking seasonal variations over Northern Hemisphere continents; SAT trends are pronounced in winter and spring but notably weaker in summer and fall. The SAT trends in historical twentieth-century climate simulations informing the Intergovernmental Panel for Climate Change’s Fifth Assessment show varied (and often unrealistic) strength and structure, and markedly weaker seasonal variation. The large intra-ensemble spread of winter SAT trends in some historical simulations was surprising, especially in the context of century-long linear trends, with implications for the detection of the secular warming signal. The striking seasonality of observed secular warming over northern continents warrants an explanation and the representation of related processes in climate models. Here, the seasonality of SAT trends over North America is shown to result from land surface–hydroclimate interactions and, to an extent, also from the secular change in low-level atmospheric circulation and related thermal advection. It is argued that the winter dormancy and summer vigor of the hydrologic cycle over middle- to high-latitude continents permit different responses to the additional incident radiative energy from increasing greenhouse gas concentrations. The seasonal cycle of climate, despite its monotony, provides an expanded phase space for the exposition of the dynamical and thermodynamical processes generating secular warming, and an exceptional cost-effective opportunity for benchmarking climate projection models.

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