scholarly journals Method-uncertainty is essential for reliable confidence statements of precipitation projections

2020 ◽  
pp. 1-45
Author(s):  
Peter Uhe ◽  
Dann Mitchell ◽  
Paul D. Bates ◽  
Myles R. Allen ◽  
Richard A. Betts ◽  
...  

AbstractPrecipitation events cause disruption around the world and will be altered by climate change. However, different climate modeling approaches can result in different future precipitation projections. The corresponding ‘method-uncertainty’ is rarely explicitly calculated in climate impact studies and major reports, but can substantially change estimated precipitation changes. A comparison across five commonly-used modeling activities shows that for changes in mean precipitation, less than half the regions analyzed had significant changes between the present climate and 1.5°C global warming for the majority of modeling activities. This increases to just over half the regions for changes between present climate and 2°C global warming. There is much higher confidence in changes in maximum 1-day precipitation than in mean precipitation, indicating the robust influence of thermodynamics in the climate change effect on extremes. We also find that none of the modeling activities capture the full range of estimates from the other methods in all regions. Our results serve as an uncertainty map to help interpret which regions require a multi-method approach. Our analysis highlights the risk of over-reliance on any single modeling activity and the need for confidence statements in major synthesis reports to reflect this ‘method-uncertainty’. Considering multiple sources of climate projections should reduce the risks of policymakers being unprepared for impacts of warmer climates compared to using single-method projections to make decisions.

Author(s):  
Gerard Wedderburn-Bisshop ◽  
Lauren Rickards

Human consumption of livestock remains a marginal issue in climate change debates, partly due to the IPCC's arbitrary adoption of 100-year global warming potential framework to compare different emissions, blinding us to the significance of shorter-term emissions, namely methane. Together with the gas it reacts to form - tropospheric ozone - methane has been responsible for 37% of global warming since 1750, yet its atmospheric life is just 10 years. Neglecting its role means overlooking powerful mitigation opportunities. The chapter discusses the role of livestock, the largest anthropogenic methane source, and the need to include reduced meat consumption in climate change responses. Looking beyond the conventional focus on the consumer, we point to some underlying challenges in addressing the meat-climate relationship, including the climate science community's reluctance to adopt a short-term focus in its climate projections. Policy options are presented.


2022 ◽  
pp. 1027-1048
Author(s):  
Gerard Wedderburn-Bisshop ◽  
Lauren Rickards

Human consumption of livestock remains a marginal issue in climate change debates, partly due to the IPCC's arbitrary adoption of 100-year global warming potential framework to compare different emissions, blinding us to the significance of shorter-term emissions, namely methane. Together with the gas it reacts to form - tropospheric ozone - methane has been responsible for 37% of global warming since 1750, yet its atmospheric life is just 10 years. Neglecting its role means overlooking powerful mitigation opportunities. The chapter discusses the role of livestock, the largest anthropogenic methane source, and the need to include reduced meat consumption in climate change responses. Looking beyond the conventional focus on the consumer, we point to some underlying challenges in addressing the meat-climate relationship, including the climate science community's reluctance to adopt a short-term focus in its climate projections. Policy options are presented.


2020 ◽  
Vol 45 (1) ◽  
pp. 411-444 ◽  
Author(s):  
Valéry Masson ◽  
Aude Lemonsu ◽  
Julia Hidalgo ◽  
James Voogt

Cities are particularly vulnerable to extreme weather episodes, which are expected to increase with climate change. Cities also influence their own local climate, for example, through the relative warming known as the urban heat island (UHI) effect. This review discusses urban climate features (even in complex terrain) and processes. We then present state-of-the-art methodologies on the generalization of a common urban neighborhood classification for UHI studies, as well as recent developments in observation systems and crowdsourcing approaches. We discuss new modeling paradigms pertinent to climate impact studies, with a focus on building energetics and urban vegetation. In combination with regional climate modeling, new methods benefit the variety of climate scenarios and models to provide pertinent information at urban scale. Finally, this article presents how recent research in urban climatology contributes to the global agenda on cities and climate change.


2015 ◽  
Vol 28 (18) ◽  
pp. 7327-7346 ◽  
Author(s):  
Xiuquan Wang ◽  
Guohe Huang ◽  
Jinliang Liu ◽  
Zhong Li ◽  
Shan Zhao

Abstract In this study, high-resolution climate projections over Ontario, Canada, are developed through an ensemble modeling approach to provide reliable and ready-to-use climate scenarios for assessing plausible effects of future climatic changes at local scales. The Providing Regional Climates for Impacts Studies (PRECIS) regional modeling system is adopted to conduct ensemble simulations in a continuous run from 1950 to 2099, driven by the boundary conditions from a HadCM3-based perturbed physics ensemble. Simulations of temperature and precipitation for the baseline period are first compared to the observed values to validate the performance of the ensemble in capturing the current climatology over Ontario. Future projections for the 2030s, 2050s, and 2080s are then analyzed to help understand plausible changes in its local climate in response to global warming. The analysis indicates that there is likely to be an obvious warming trend with time over the entire province. The increase in average temperature is likely to be varying within [2.6, 2.7]°C in the 2030s, [4.0, 4.7]°C in the 2050s, and [5.9, 7.4]°C in the 2080s. Likewise, the annual total precipitation is projected to increase by [4.5, 7.1]% in the 2030s, [4.6, 10.2]% in the 2050s, and [3.2, 17.5]% in the 2080s. Furthermore, projections of rainfall intensity–duration–frequency (IDF) curves are developed to help understand the effects of global warming on extreme precipitation events. The results suggest that there is likely to be an overall increase in the intensity of rainfall storms. Finally, a data portal named Ontario Climate Change Data Portal (CCDP) is developed to ensure decision-makers and impact researchers have easy and intuitive access to the refined regional climate change scenarios.


2021 ◽  
Vol 21 (1) ◽  
pp. 53-71
Author(s):  
Shunya Koseki ◽  
Priscilla A. Mooney ◽  
William Cabos ◽  
Miguel Ángel Gaertner ◽  
Alba de la Vara ◽  
...  

Abstract. This study focuses on a single Mediterranean hurricane (hereafter medicane), to investigate its response to global warming during the middle of the 21st century and assesses the effects of a warmer ocean and a warmer atmosphere on its development. Our investigation uses the state-of-the-art regional climate model WRF to produce the six-member, multi-physics ensembles. Results show that our model setup simulates a realistic cyclone track and the transition from an initial disturbance to a tropical-like cyclone with a deep warm core. However, the simulated transition occurs earlier than for the observed medicane. The response of the medicane to future climate change is investigated with a pseudo global warming (PGW) approach. This is the first application of the PGW framework to medicanes. The PGW approach adds a climate change delta (defined as difference between future and present climate) to WRF's boundary conditions which is obtained for all prognostic variables using the mean change in an ensemble of CMIP5 simulations. A PGW simulation where the climate change delta is added to all prognostic variables (PGWALL) shows that most of the medicane characteristics moderately intensify, e.g. surface wind speed, uptake of water vapour, and precipitation. However, the minimum sea level pressure (SLP) is almost identical to that under present climate conditions. Two additional PGW simulations were undertaken; One simulation adds the projected change in sea surface and skin temperature only (PGWSST) while the second simulation adds the PGW changes to only atmospheric variables (PGWATMS); i.e. we use present-day sea surface temperatures. These simulations show opposing responses of the medicane. In PGWSST, the medicane is more intense than PGWALL as indicated by lower SLP values, the stronger surface wind, and the more intense evaporation and precipitation. In contrast, the medicane in PGWATMS still transitions into a tropical-like cyclone with a deep warm core, but the PGWATMS medicane weakens considerably (SLP, surface wind, and rainfall decrease). This difference can be explained by an increase in water vapour driven by the warmer ocean surface (favourable for cumulus convection). The warmer and drier atmosphere in PGWATMS tends to inhibit condensation (unfavourable for cumulus convection). The warmer ocean and warmer atmosphere have counteracting effects which leads to only a modest enhancement of the medicane by global warming. The novel approach in this study provides new insights into the different roles of warming of the ocean and atmosphere in medicane development.


2021 ◽  
Author(s):  
Christiana Photiadou ◽  
Peter Berg ◽  
Denica Bozhinova ◽  
Anna Eronn ◽  
Fulco Ludwig ◽  
...  

<p>The Operational Water Service of C3S (developed by the Swedish Meteorological and Hydrological Institute (SMHI)) aims to help a broad range of water managers with water allocation, flood management, ecological status and industrial water use, to adapt their strategies in order to adapt to climate variability and change. The aim is to speed up the workflow in climate-change adaptation by using seasonal hydrological forecasts and climate-impact indicators. This is done by offering an interactive web application with refined data, guidance and practical showcases to water managers across Europe. Policy makers will find a comprehensive overview for Europe with key messages and consultants can use the service for developing climate impact assessments and adaptation strategies.</p><p>The development of the current operational climate service for water management is based on the experience from two previous proof-of-concepts and will also be aligned with the hydrological model system of the Copernicus Emergency Management Service (CEMS).  The service is uses data from the Climate Data Store and the operational hydrological seasonal forecasting system runs entirely in the European Centre for Medium range Weather Forecasts (ECMWF) technical environment, although developed by SMHI.</p><p>The operational Water Service of C3S will be launched during the spring of 2021, and a series of activities and user interactions will be organised to ensure that the applications developed for the service fulfil the users’ needs. Here, we present the development process of the operational service and key outcomes from co-design interactions and resulting applications. The key issues identified by the user community were: i) clear visualisation and graphical representation of skill in seasonal forecasts and confidence in climate projections, ii) need of detailed documentation and process transparency in hydrological models and production of data, iii) user guidance and tutorials are needed for better understanding of the applications, and iv) workflows and scripts for indicator production in new applications for developers of information systems.</p>


Author(s):  
Andrew Hugh MacDougall ◽  
Joeri Rogelj ◽  
Patrick Withey

Abstract Global agriculture is the second largest contributor to anthropogenic climate change after the burning of fossil fuels. However the potential to mitigate the agricultural climate change contribution is limited and needs to account for the imperative to supply food for the global population. Advances in microbial biomass cultivation technology have recently opened a pathway to growing substantial amounts of food for humans or livestock on a small fraction of the land presently used for agriculture. Here we investigate the potential climate change impacts of the end of agriculture as the primary human food production system. We find that replacing agricultural primary production with electrically powered microbial primary production before a low-carbon energy transition has been completed could redirect renewable energy away from replacing fossil fuels, potentially leading to higher total CO2 emissions. If deployed after a transition to renewable energy, the technology could alleviate agriculturally driven climate change. These diverging pathways originate from the reversibility of agricultural driven global warming and the irreversibility of fossil fuel CO2 driven warming. The range of reduced warming from the replacement of agriculture ranges from -0.22 [-0.29 to -0.04] ºC for Shared Socioeconomic Pathway (SSP)1-1.9 to -0.85 [-0.99 to -0.39]ºC for SSP4-6.0. For limited temperature target overshoot scenarios, replacement of agriculture could eliminate or reduce the need for active atmospheric CO2 removal to achieve the necessary peak and decline in global warming.


Author(s):  
Joshua J. Lawler ◽  
Julia Michalak

This chapter explores the relative uncertainty associated with popular approaches to conservation planning in the face of climate change. Concern about uncertainties inherent in climate-change projections and associated ecological impacts have led many in the conservation community to avoid climate modeling, and instead favor forecast-free approaches that involve increasing connectivity and protecting “nature’s stage” (geophysical settings) to produce climate-smart conservation plans. A comparison of each of these approaches reveals that the uncertainties associated with connectivity modeling and mapping geophysical settings can be as large, if not larger than, the uncertainties associated with climate-change projections. Whereas the uncertainties of climate forecasts are widely appreciated, the same cannot be said for the approaches that avoid climate forecasts. It is not the case that there is one best approach. The answer to uncertainty is to seek robust conservation plans that work regardless of which approach is taken.


2012 ◽  
Vol 25 (20) ◽  
pp. 7100-7121 ◽  
Author(s):  
Carol F. McSweeney ◽  
Richard G. Jones ◽  
Ben B. B. Booth

Abstract Climate model ensembles, such as the Coupled Model Intercomparison Project, phase 3 (CMIP3), are used to characterize broadscale ranges of projected regional climate change and their impacts. The 17-member Hadley Centre perturbed physics GCM ensemble [Quantifying Uncertainty in Model Predictions (“QUMP”)] extends this capability by including data enabling dynamical downscaling of these ranges, and similar data are now being made available from the CMIP phase 5 (CMIP5) GCMs. These raise new opportunities to provide and apply high-resolution regional climate projections. This study highlights the importance of employing a well-considered sampling strategy from available ensembles to provide scientifically credible information on regional climate change while minimizing the computational complexity of ensemble downscaling. A subset of the QUMP ensemble is selected for a downscaling program in Vietnam using the Providing Regional Climates for Impacts Studies (PRECIS) regional climate modeling system. Multiannual mean fields from each GCM are assessed with a focus on the Asian summer monsoon, given its importance to proposed applications of the projections. First, the study examines whether any model should be eliminated because significant deficiencies in its simulation may render its future climate projections unrealistic. No evidence is found to eliminate any of the 17 GCMs on these grounds. Second, the range of their future projections is explored and five models that best represent the full range of future climates are identified. The subset characterizes the range of both global and regional responses, and patterns of rainfall response, the wettest and driest projections for Vietnam, and different projected Asian summer monsoon changes. How these ranges of responses compare with those in the CMIP3 ensemble are also assessed, finding differences in both the signal and the spread of results in Southeast Asia.


2010 ◽  
Vol 7 (5) ◽  
pp. 6823-6850 ◽  
Author(s):  
H. Xu ◽  
R. G. Taylor ◽  
Y. Xu

Abstract. Quantitative evaluations of the impacts of climate change on water resources are primarily constrained by uncertainty in climate projections from GCMs. In this study we assess uncertainty in the impacts of climate change on river discharge in two catchments of the River Yangtze and Yellow Basins that feature contrasting climate regimes (humid and semi-arid). Specifically we quantify uncertainty associated with GCM structure from a subset of CMIP3 AR4 GCMs (HadCM3, HadGEM1, CCSM3.0, IPSL, ECHAM5, CSIRO, CGCM3.1), SRES emissions scenarios (A1B, A2, B1, B2) and prescribed increases in global mean air temperature (1 °C to 6 °C). Climate projections, applied to semi-distributed hydrological models (SWAT 2005) in both catchments, indicate trends toward warmer and wetter conditions. For prescribed warming scenarios of 1 °C to 6 °C, linear increases in mean annual river discharge, relative to baseline (1961–1990), for the River Xiangxi and River Huangfuchuan are +9% and 11% per +1 °C, respectively. Intra-annual changes include increases in flood (Q05) discharges for both rivers as well as a shift in the timing of flood discharges from summer to autumn and a rise (24 to 93%) in dry season (Q95) discharge for the River Xiangxi. Differences in projections of mean annual river discharge between SRES emission scenarios using HadCM3 are comparatively minor for the River Xiangxi (13% to 17% rise from baseline) but substantial (73% to 121%) for the River Huangfuchuan. With one minor exception of a slight (−2%) decrease in river discharge projected using HadGEM1 for the River Xiangxi, mean annual river discharge is projected to increase in both catchments under both the SRES A1B emission scenario and 2° rise in global mean air temperature using all AR4 GCMs on the CMIP3 subset. For the River Xiangxi, there is great uncertainty associated with GCM structure in the magnitude of the rise in flood (Q05) discharges (−1% to 41% under SRES A1B and −3% to 41% under 2° global warming) and dry season (Q95) discharges (2% to 55% under SRES A1B and 2% to 39% under 2° global warming). For the River Huangfuchuan, all GCMs project a rise in the Q05 flow but there is substantial uncertainty in the magnitude of this rise (7% to 70% under SRES A1B and 2% to 57% under 2° global warming). Greatest differences in the projected hydrologic changes are associated with GCMs in both catchments than emission scenarios and climate sensitivity. Critically, estimated uncertainty in projections of mean annual flows is less than that calculated for extreme (Q05, Q95) flows. This research suggest that the common approach of reporting of climate change impacts on river in terms of mean annual flows may mask the magnitude of uncertainty in flows of most importance to water managers.


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