World Climate Research Programme Research Articles

Climate Symposium 2014: Findings and Recommendations

Here, the Climate Symposium 2014, organized by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) and the World Climate Research Programme (WCRP), with support from the European Commission (EC), European Space Agency (ESA), and other agencies, took place in Darmstadt, Germany, from 13 to 17 October 2014. Around 500 participants from 49 countries attended the event and represented over 200 organizations. Another 500 individuals participated remotely via “live streaming.”

Incorporating Potential Severity into Vulnerability Assessment of Water Supply Systems under Climate Change Conditions

AbstractIn response to climate change, vulnerability assessment of water resources systems is typically performed based on quantifying the severity of the failure. This paper introduces an approach to assess vulnerability that incorporates a set of new factors. The method is demonstrated with a case study of a reservoir system in Salt Lake City using an integrated modeling framework composed of a hydrologic model and a systems model driven by temperature and precipitation data for a 30-year historical (1981–2010) period. The climate of the selected future (2036–2065) simulation periods were represented by five combinations of warm or hot, wet or dry, and central tendency projections derived from the World Climate Research Programme’s (WCRP’s) Coupled Model Intercomparison Project Phase 5. The results of the analysis illustrate that basing vulnerability on severity alone may lead to an incorrect quantification of the system vulnerability. In this study, a typical vulnerability metric (severity) incorrectly...

Future Directions for the World Climate Research Programme

The worldwide climate research community has talent, dedication, and a clear sense of knowledge gaps. It needs to close those gaps and convey its messages effectively to user communities.

A global portrait of hydrological changes at the 2050 horizon for the province of Québec

This paper presents the methodology and results of a vast study on climate change impacts on hydrology for the province of Québec for the 2050 horizon. A climate ensemble was first built with simulations from the World Climate Research Programme (WCRP)'s Coupled Model Intercomparison Project phase 3 (CMIP3) multi-model dataset, the North American Regional Climate Change Assessment Program (NARCCAP) and the Canadian Regional Climate Model (CRCM) operational runs. Direct outputs and post-processed data from the climate simulations were used as input to the calibrated HSAMI hydrological model in order to produce a large ensemble of hydrological projections for 305 Québec watersheds. Simulations results indicate that increases in mean annual streamflow are projected for the whole province, with greater changes (up to 14%) in the north. The intra-annual distribution of streamflow also changes, with higher winter flows and lower summer flows as well as apparently earlier spring floods. The maximum height of the snow cover and the number of days with snow on the ground are likely to diminish for the 2050 horizon for the southern half of the province, while the northern half will see more snow, but a shorter snow season as well.

Projections of climate change in the Mediterranean Basin by using downscaled global climate model outputs

AbstractThe Mediterranean Basin is one of the regions that shall be affected most by the impacts of the future climate changes on hydrology and water resources. In this study, projected future changes in mean air temperature and precipitation climatology and inter‐annual variability over the Mediterranean region were studied. For performing this aim, the future changes in annual and seasonal averages for the future period of 2070–2100 with respect to the period from 1970 to 2000 were investigated. Global climate model outputs of the World Climate Research Program's Coupled Model Intercomparison Project Phase 3 multi‐model dataset were used in this work. Intergovernmental Panel on Climate Change SRES A2, A1B and B1 emission scenarios' outputs were used in future climate model projections. Future surface mean air temperatures of the larger Mediterranean basin increase mostly in summer and least in winter, and precipitation amounts decrease in all seasons at almost all parts of the basin. Future climate signals for air temperature and total precipitation values are much larger than the inter‐model standard deviation. Inter‐annual temperature variability increases evidently in summer season and decreases in the northern part of the domain in the winter season, while precipitation variability increases in almost all parts of domain. Probability distribution functions are found to be shifted and flattened for future period compared to the reference period. This indicates that the occurrence of frequency and intensity of high temperatures and heavy precipitation events will likely increase in the future period.

Narratives of the past for Future Earth: The historiography of global environmental change research

This paper analyses the auto-historiography of global environmental change research. It traces how participating researchers make sense of and rationalise research strategies through narratives of the history of global change and Earth System science. Our study draws on personal and programme accounts of Earth System science’s background related to the international global environmental change research programmes International Geosphere-Biosphere Programme (IGBP), the International Human Dimensions Programme on Global Environmental Change (IHDP), the World Climate Research Programme (WCRP), and Future Earth, from 1983 to 2013. The study finds three core narratives: the science history narrative motivates the future development of the programme by building on the successes of earlier international projects. The Earth System departs from an enhanced understanding of environmental change over time. Finally, the Anthropocene narrative underpins arguments for a science-based management of human–environment systems. We argue that including reflexive analytical perspectives in the history writing of Future Earth contributes to making environmental change research relevant and useful for democratic decision-making.

On inclusion of water resource management in Earth system models – Part 1: Problem definition and representation of water demand

Abstract. Human activities have caused various changes to the Earth system, and hence the interconnections between human activities and the Earth system should be recognized and reflected in models that simulate Earth system processes. One key anthropogenic activity is water resource management, which determines the dynamics of human–water interactions in time and space and controls human livelihoods and economy, including energy and food production. There are immediate needs to include water resource management in Earth system models. First, the extent of human water requirements is increasing rapidly at the global scale and it is crucial to analyze the possible imbalance between water demands and supply under various scenarios of climate change and across various temporal and spatial scales. Second, recent observations show that human–water interactions, manifested through water resource management, can substantially alter the terrestrial water cycle, affect land–atmospheric feedbacks and may further interact with climate and contribute to sea-level change. Due to the importance of water resource management in determining the future of the global water and climate cycles, the World Climate Research Program's Global Energy and Water Exchanges project (WRCP-GEWEX) has recently identified gaps in describing human–water interactions as one of the grand challenges in Earth system modeling (GEWEX, 2012). Here, we divide water resource management into two interdependent elements, related firstly to water demand and secondly to water supply and allocation. In this paper, we survey the current literature on how various components of water demand have been included in large-scale models, in particular land surface and global hydrological models. Issues of water supply and allocation are addressed in a companion paper. The available algorithms to represent the dominant demands are classified based on the demand type, mode of simulation and underlying modeling assumptions. We discuss the pros and cons of available algorithms, address various sources of uncertainty and highlight limitations in current applications. We conclude that current capability of large-scale models to represent human water demands is rather limited, particularly with respect to future projections and coupled land–atmospheric simulations. To fill these gaps, the available models, algorithms and data for representing various water demands should be systematically tested, intercompared and improved. In particular, human water demands should be considered in conjunction with water supply and allocation, particularly in the face of water scarcity and unknown future climate.

A review of seasonal climate prediction research in China

The ultimate goal of climate research is to produce climate predictions on various time scales. In China, efforts to predict the climate started in the 1930s. Experimental operational climate forecasts have been performed since the late 1950s, based on historical analog circulation patterns. However, due to the inherent complexity of climate variability, the forecasts produced at that time were fairly inaccurate. Only from the late 1980s has seasonal climate prediction experienced substantial progress, when the Tropical Ocean and Global Atmosphere project of the World Climate Research program (WCRP) was launched. This paper, following a brief description of the history of seasonal climate prediction research, provides an overview of these studies in China. Processes and factors associated with the climate variability and predictability are discussed based on the literature published by Chinese scientists. These studies in China mirror aspects of the climate research effort made in other parts of the world over the past several decades, and are particularly associated with monsoon research in East Asia. As the climate warms, climate extremes, their frequency, and intensity are projected to change, with a large possibility that they will increase. Thus, seasonal climate prediction is even more important for China in order to effectively mitigate disasters produced by climate extremes, such as frequent floods, droughts, and the heavy frozen rain events of South China.

Evaluation of CMIP climate model hydrological output for the Mississippi River Basin using GRACE satellite observations

Summary We use measurements of terrestrial water storage (TWS) inferred from Gravity Recovery and Climate Experiment (GRACE) satellite observations to evaluate the hydrological output composite-averaged over the Mississippi River Basin (MSRB) and over the ten-year period 2003–2012 from a subset of GCMs from the World Climate Research Programme’s Coupled Model Intercomparison Project Phase 5 (CMIP5) and Phase 3 (CMIP3). We then investigate mid-20th to 21st century hydrological trends over the MSRB projected by the CMIP5 models. Improvements were found in CMIP5 simulations of the annual cycle of composite TWS, estimated as the sum of modeled depth-integrated soil moisture and snow water, over those of CMIP3 when compared with the GRACE composite TWS cycle. These improvements coincide with higher horizontal resolution and changes in hydrological parameterizations applied in most of the CMIP5 GCMs compared to earlier CMIP3 versions. Simulated values of composite hydrological budget terms among CMIP5 models, however, are not improved overall, with some models exhibiting increased precipitation and others decreased runoff from CMIP3 to CMIP5 to values outside long-term observed ranges. Since the effect of both increased precipitation and decreased runoff is to increase infiltration and soil water retention, the composite TWS annual cycles from these CMIP5 models, whose earlier CMIP3 simulations in some cases highly underestimated TWS annual cycle amplitudes compared to GRACE, now better agree with GRACE. In spite of the improved prediction of the composite TWS annual cycle, multi-decadal hydrological trends for the MSRB produced by the CMIP5 models vary. A consensus for future decreasing soil moisture is found among models, but with varied responses in magnitude as well as in direction of annual precipitation, evapotranspiration and runoff trends. Overall, GRACE data appear highly useful for evaluating GCM hydrological predictions over large river basins, and a longer time period of these data as more retrievals become available should help to evaluate GCM hydrological output on a multi-decadal time scale.

Using records from submarine, aircraft and satellites to evaluate climate model simulations of Arctic sea ice thickness

Abstract. Arctic sea ice thickness distributions from models participating in the World Climate Research Programme Coupled Model Intercomparison Project Phase 5 (CMIP5) are evaluated against observations from submarines, aircraft and satellites. While it is encouraging that the mean thickness distributions from the models are in general agreement with observations, the spatial patterns of sea ice thickness are poorly represented in most models. The poor spatial representation of thickness patterns is associated with a failure of models to represent details of the mean atmospheric circulation pattern that governs the transport and spatial distribution of sea ice. The climate models as a whole also tend to underestimate the rate of ice volume loss from 1979 to 2013, though the multimodel ensemble mean trend remains within the uncertainty of that from the Pan-Arctic Ice Ocean Modeling and Assimilation System. Although large uncertainties in observational products complicate model evaluations, these results raise concerns regarding the ability of CMIP5 models to realistically represent the processes driving the decline of Arctic sea ice and to project the timing of when a seasonally ice-free Arctic may become a reality.

Satellite Observations for CMIP5: The Genesis of Obs4MIPs

The objective of the Observations for Model Intercomparison Projects (Obs4MIPs) is to provide observational data to the climate science community, which is analogous (in terms of variables, temporal and spatial frequency, and periods) to output from the 5th phase of the World Climate Research Programme's (WCRP) Coupled Model Intercomparison Project (CMIP5) climate model simulations. The essential aspect of the Obs4MIPs methodology is that it strictly follows the CMIP5 protocol document when selecting the observational datasets. Obs4MIPs also provides documentation that describes aspects of the observational data (e.g., data origin, instrument overview, uncertainty estimates) that are of particular relevance to scientists involved in climate model evaluation and analysis. In this paper, we focus on the activities related to the initial set of satellite observations, which are being carried out in close coordination with CMIP5 and directly engage NASA's observational (e.g., mission and instrument) science teams. Having launched Obs4MIPs with these datasets, a broader effort is also briefly discussed, striving to engage other agencies and experts who maintain datasets, including reanalysis, which can be directly used to evaluate climate models. Different strategies for using satellite observations to evaluate climate models are also briefly summarized.

Physical Mechanisms Related to Climate-Induced Drying of Two Semiarid Watersheds in the Southwestern United States

Abstract Water managers across the United States face the need to make informed policy decisions regarding long-term impacts of climate change on water resources. To provide a scientifically informed basis for this, the evolution of important components of the basin-scale water balance through the end of the twenty-first century is estimated. Bias-corrected and spatially downscaled climate projections, from phase 3 of the Coupled Model Intercomparison Project (CMIP3) of the World Climate Research Programme, were used to drive a spatially distributed Variable Infiltration Capacity (VIC) model of hydrologic processes in the Salt–Verde basin in the southwestern United States. From the suite of CMIP3 models, the authors select a five-model subset, including three that best reproduce the historical climatology for the study region, plus two others to represent wetter and drier than model average conditions, so as to represent the range of GCM prediction uncertainty. For each GCM, data for three emission scenarios (A1B, A2, and B1) were used to drive the hydrologic model into the future. The projections of this model ensemble indicate a statistically significant 25% decrease in streamflow by the end of the twenty-first century. The primary cause for this change is due to projected decreases in winter precipitation accompanied by significant (temperature driven) reductions in storage of snow and increased winter evaporation. The results show that water management in central Arizona is highly likely to be impacted by changes in regional climate.

Tropical Atlantic influence on Pacific variability and mean state in the twentieth century in observations and CMIP5

This paper investigates the influence of the tropical Atlantic on the tropical Pacific interannual variability and mean state in the twentieth century. It is demonstrated that observational datasets show a significant time-delayed impact of the tropical Atlantic on tropical Pacific sea surface temperatures, leading to an anticorrelation between the tropical Atlantic and the eastern Pacific if the Atlantic is leading by about 10 months. This result is robust across different sea surface temperature reconstructions. There is no robust correlation between the tropical Atlantic and the eastern Pacific when the Pacific is leading, although in recent decades a positive correlation between the two basins is more dominant. An analysis of the surface pressure response to the tropical Atlantic indicates an atmospheric bridge and a modification of the Walker circulation as the likely trigger for the teleconnection, and this result is consistent with recent observational and modelling results for the recent decades. 30 out of the analyzed 45 World Climate Research Program’s Coupled Model Intercomparison Project Phase 5 (CMIP5) models show statistically significant anticorrelations between individual tropical Atantic warm and cold events and the time-lagged eastern Pacific sea surface temperatues. 16 out of the 45 analyzed models fulfill the more stringent criterion of lead–lag correlations between the tropical Atlantic and Pacific similar to the observations. The atmospheric bridge mechanism seems also valid in the selected CMIP5 models. We have identified the tropical Atlantic warm bias present in nearly all models as one potential candidate for the overall weak time-delayed teleconnection between the tropical Atlantic and the Pacific, but also other mean state biases are important. In the selected models a stronger warming of the tropical Atlantic Ocean compared to the global sea surface temperature mean is associated with a La Nina-like mean state change in the tropical Pacific. However, the ensemble mean of these models still shows a weakly El Nino-like trend, which is associated with a relatively weak Atlantic warming compared to the global mean and the observations.

Introduction to the special issue: the phase I CORDEX RegCM4 hyper-matrix (CREMA) experiment

This special issue of Climatic Change gathers a series of papers detailing the first analysis of the Phase I CORDEX RegCM4 hyper-Matrix (or CREMA) experiment. CORDEX (COordinated Regional Downscaling Experiment) is a newly implemented modeling framework under the auspices of the World Climate Research Program (WCRP) whose goals are to: i) assess and improve different regional climate downscaling techniques; ii) produce a new generation of 21st century regional climate projections over regions worldwide; iii) foster the interactions between the climate science and end-user communities and in particular the involvement of scientists from developing countries (Giorgi et al. 2009; Jones et al. 2011). It is envisioned to achieve these objectives through the completion and analysis of large multi-model, multimethod simulations with different downscaling techniques (dynamical and empirical) using a common and intercomparable experiment framework. regional climate models (RCMs) are thus key components of the CORDEX initiative. During the last decades a number of RCMs systems have been developed (e.g. Giorgi 2006; Rummukainen 2010). One of these is the RegCM system developed and maintained at the Abdus Salam International Centre for Theoretical Physics (ICTP). This model has evolved through successive versions (Dickinson et al. 1989; Giorgi et al. 1993a, b; Giorgi and Mearns 1999; Pal et al. 2007) up to the most recent RegCM4 (Giorgi et al. 2012). Over the last 25 years the RegCM has been applied to a wide range of studies by a large user community coordinated through the Regional Climate research NETwork, or RegCNET (Giorgi et al. 2006). The Phase I CREMA experiment represents the first contribution of the RegCNET modeling community to the CORDEX effort. The Phase I CREMA experiment consists of a series of 34 scenario simulations completed with the RegCM4 over 5 CORDEX domains (see Table 1): Africa, Mediterranean, Central America, South America and South Asia. Each domain follows the CORDEX specifications (see Giorgi et al. 2009), with a horizontal grid spacing of 50 km, and all simulations cover the period 1970–2100. In the CREMA experiment we attempted to cover, albeit in a limited way, Climatic Change (2014) 125:1–5 DOI 10.1007/s10584-014-1166-4

Addressing Climate‐Related Challenges and Information Needs in Africa

The Africa Climate Conference 2013 (ACC‐2013), which was organized by the World Climate Research Programme, the African Climate Policy Center of the United Nations Economic Commission for Africa, and the University of Dar es Salaam, brought together more than 300 participants, including decision makers, representatives of research funding agencies, scientists from various disciplines, and practitioners from Africa and around the globe.

The Application of GIS Spatial Analysis Method in Biomass and Carbon Storage Jatropha Curcas

It has become the international geosphere biosphere program, the world climate research programme and one of the core tasks of global change human factors plan that the global carbon cycle and curb greenhouse gas concentrations continue to rise , therefore, the existing biomass and carbon storage quantity of ecosystem research has important practical significance. We analyzed Jatropha curcas L biomass in Yunnan Simao district, basing on GPS location positioning, combining ARCGIS spatial analysis technology, selecting ecological factor such as altitude, slope, land use. Studies have shown that the Jatropha curcas L biomass under different land use types have significant differences by using the background data of these factors, with the help of space analysis method, combining with the measured data validation, respectively, it is: the most IS plantation, the second is cultivated land, the third is weeds, and the least is shrubbery. The research results can provide based data for Jatropha curcas L biomass and carbon storage calculation, also provide information for the decision-making department industry.

Trends in daily temperature and precipitation extremes over Georgia, 1971–2010

Annual changes to climate extreme indices in Georgia (Southern Caucasus) from 1971 to 2010 are studied using homogenized daily minimum and maximum temperature and precipitation series. Fourteen extreme temperature and 11 extreme precipitation indices are selected from the list of core climate extreme indices recommended by the World Meteorological Organization – Commission for Climatology (WMO-CCL) and the research project on Climate Variability and Predictability (CLIVAR) of the World Climate Research Programme (WCRP). Trends in the extreme indices are studied for 10 minimum and 11 maximum temperature and 24 precipitation series for the period 1971–2010. Between 1971 and 2010 most of the temperature extremes show significant warming trends. In 2010 there are 13.3 fewer frost days than in 1971. Within the same time frame there are 13.6 more summer days and 7.0 more tropical nights. A large number of stations show significant warming trends for monthly minimum and maximum temperature as well as for cold and warm days and nights throughout the study area, whereas warm extremes and night-time based temperature indices show greater trends than cold extremes and daytime indices. Additionally, the warm spell duration indicator indicates a significant increase in the frequency of warm spells between 1971 and 2010. Cold spells show an insignificant increase with low spatial coherence. Maximum 1-day and 5-day precipitation, the number of very heavy precipitation days, very wet and extremely wet days as well as the simple daily intensity index all show an increase in Georgia, although all trends manifest a low spatial coherence. The contribution of very heavy and extremely heavy precipitation to total precipitation increased between 1971 and 2010, whereas the number of wet days decreases.

The Cryosphere in a Changing Climate

The World Climate Research Programme (WCRP) Joint Science Committee has announced a series of “Grand Challenges,” calls to scientists to focus their research on areas that are important in understanding the climate system. One such area is the cryosphere in a changing climate. A 2012 draft white paper on this topic (http://www.climate‐cryosphere.org/media‐gallery/618‐gc‐cryo) served as the basis for a WCRP workshop held in mid‐October 2013 in Tromsø, Norway. The workshop centered on four themes: predictions and projections of polar climate; cryosphere model biases and shortcomings; ice sheet models, dynamics, and sea level rise; and permafrost and carbon for Earth system models.

CMIP5 Climate Model Analyses: Climate Extremes in the United States

This is the fourth in a series of four articles on historical and projected climate extremes in the United States. Here, we examine the results of historical and future climate model experiments from the phase 5 of the Coupled Model Intercomparison Project (CMIP5) based on work presented at the World Climate Research Programme (WCRP) Workshop on CMIP5 Climate Model Analyses held in March 2012. Our analyses assess the ability of CMIP5 models to capture observed trends, and we also evaluate the projected future changes in extreme events over the contiguous Unites States. Consistent with the previous articles, here we focus on model-simulated historical trends and projections for temperature extremes, heavy precipitation, large-scale drivers of precipitation variability and drought, and extratropical storms. Comparing new CMIP5 model results with earlier CMIP3 simulations shows that in general CMIP5 simulations give similar patterns and magnitudes of future temperature and precipitation extremes in the Unite...

A possible explanation on the changes in the spatial structure of ENSO from CMIP3 to CMIP5

AbstractThis study examines changes in the structure of El Niño‐Southern Oscillation (ENSO) amplitude using the historical climate simulations of the World Climate Research Program Coupled Model Intercomparison Project (CMIP) phase‐3 and phase‐5 coupled general circulation models (CGCMs). The analysis focuses on the “so‐called” Bjerknes feedback. The Bjerknes feedback affects the sea surface temperature (SST) variability differently between the CMIP3 and CMIP5 models. In the CMIP5 models, the strength of the Bjerknes feedback is associated with the amplitude of ENSO, whereas the changes in the strength of Bjerknes feedback are not associated with changes in ENSO amplitude in CMIP3 CGCMs. The relationship between the Bjerknes feedback and the SST anomaly variance is suggested as a possible explanation for the eastward shift in the SST anomaly variance in CMIP5 relative to CMIP3.