scholarly journals An integrated assessment modelling framework for uncertainty studies in global and regional climate change: the MIT IGSM-CAM (version 1.0)

2013 ◽  
Vol 6 (1) ◽  
pp. 2213-2248 ◽  
Author(s):  
E. Monier ◽  
J. R. Scott ◽  
A. P. Sokolov ◽  
C. E. Forest ◽  
C. A. Schlosser
Keyword(s):  
Climate Change ◽  
21St Century ◽  
Integrated Assessment ◽  
Regional Climate ◽  
Regional Climate Change ◽  
System Model ◽  
Climate Parameters ◽  
Modelling Framework ◽  
Integrated Assessment Modelling ◽  
Emissions Scenarios

Abstract. This paper describes an integrated assessment modelling framework for uncertainty studies in global and regional climate change. In this framework, the Massachusetts Institute of Technology (MIT) Integrated Global System Model (IGSM), an integrated assessment model that couples an earth system model of intermediate complexity to a human activity model, is linked to the National Center for Atmospheric Research (NCAR) Community Atmosphere Model (CAM). Since the MIT IGSM-CAM framework (version 1.0) incorporates a human activity model, it is possible to analyse uncertainties in emissions resulting from both uncertainties in the economic model parameters and uncertainty in future climate policies. Another major feature is the flexibility to vary key climate parameters controlling the climate system response: climate sensitivity, net aerosol forcing and ocean heat uptake rate. Thus, the IGSM-CAM is a computationally efficient framework to explore the uncertainty in future global and regional climate change associated with uncertainty in the climate response and projected emissions. This study presents 21st century simulations based on two emissions scenarios (unconstrained scenario and stabilization scenario at 660 ppm CO2-equivalent) and three sets of climate parameters. The chosen climate parameters provide a good approximation for the median, and the 5th and 95th percentiles of the probability distribution of 21st century global climate change. As such, this study presents new estimates of the 90% probability interval of regional climate change for different emissions scenarios. These results underscore the large uncertainty in regional climate change resulting from uncertainty in climate parameters and emissions, especially when it comes to changes in precipitation.

scholarly journals An integrated assessment modeling framework for uncertainty studies in global and regional climate change: the MIT IGSM-CAM (version 1.0)

2013 ◽  
Vol 6 (6) ◽  
pp. 2063-2085 ◽  
Author(s):  
E. Monier ◽  
J. R. Scott ◽  
A. P. Sokolov ◽  
C. E. Forest ◽  
C. A. Schlosser
Keyword(s):  
Climate Change ◽  
Climate Model ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Climate System ◽  
System Model ◽  
System Response ◽  
Continental Scale ◽  
Climate Parameters ◽  
Precipitation Changes

Abstract. This paper describes a computationally efficient framework for uncertainty studies in global and regional climate change. In this framework, the Massachusetts Institute of Technology (MIT) Integrated Global System Model (IGSM), an integrated assessment model that couples an Earth system model of intermediate complexity to a human activity model, is linked to the National Center for Atmospheric Research (NCAR) Community Atmosphere Model (CAM). Since the MIT IGSM-CAM framework (version 1.0) incorporates a human activity model, it is possible to analyze uncertainties in emissions resulting from both uncertainties in the underlying socio-economic characteristics of the economic model and in the choice of climate-related policies. Another major feature is the flexibility to vary key climate parameters controlling the climate system response to changes in greenhouse gases and aerosols concentrations, e.g., climate sensitivity, ocean heat uptake rate, and strength of the aerosol forcing. The IGSM-CAM is not only able to realistically simulate the present-day mean climate and the observed trends at the global and continental scale, but it also simulates ENSO variability with realistic time scales, seasonality and patterns of SST anomalies, albeit with stronger magnitudes than observed. The IGSM-CAM shares the same general strengths and limitations as the Coupled Model Intercomparison Project Phase 3 (CMIP3) models in simulating present-day annual mean surface temperature and precipitation. Over land, the IGSM-CAM shows similar biases to the NCAR Community Climate System Model (CCSM) version 3, which shares the same atmospheric model. This study also presents 21st century simulations based on two emissions scenarios (unconstrained scenario and stabilization scenario at 660 ppm CO2-equivalent) similar to, respectively, the Representative Concentration Pathways RCP8.5 and RCP4.5 scenarios, and three sets of climate parameters. Results of the simulations with the chosen climate parameters provide a good approximation for the median, and the 5th and 95th percentiles of the probability distribution of 21st century changes in global mean surface air temperature from previous work with the IGSM. Because the IGSM-CAM framework only considers one particular climate model, it cannot be used to assess the structural modeling uncertainty arising from differences in the parameterization suites of climate models. However, comparison of the IGSM-CAM projections with simulations of 31 CMIP5 models under the RCP4.5 and RCP8.5 scenarios show that the range of warming at the continental scale shows very good agreement between the two ensemble simulations, except over Antarctica, where the IGSM-CAM overestimates the warming. This demonstrates that by sampling the climate system response, the IGSM-CAM, even though it relies on one single climate model, can essentially reproduce the range of future continental warming simulated by more than 30 different models. Precipitation changes projected in the IGSM-CAM simulations and the CMIP5 multi-model ensemble both display a large uncertainty at the continental scale. The two ensemble simulations show good agreement over Asia and Europe. However, the ranges of precipitation changes do not overlap – but display similar size – over Africa and South America, two continents where models generally show little agreement in the sign of precipitation changes and where CCSM3 tends to be an outlier. Overall, the IGSM-CAM provides an efficient and consistent framework to explore the large uncertainty in future projections of global and regional climate change associated with uncertainty in the climate response and projected emissions.

scholarly journals Responsibility of major emitters for country-level warming and extreme hot years

2022 ◽  
Vol 3 (1) ◽  
Author(s):  
Lea Beusch ◽  
Alexander Nauels ◽  
Lukas Gudmundsson ◽  
Johannes Gütschow ◽  
Carl-Friedrich Schleussner ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Policy ◽  
Regional Climate ◽  
Regional Climate Change ◽  
System Model ◽  
Regional Warming ◽  
Country Level ◽  
The Us ◽  
Per Capita ◽  
Second Year

AbstractThe contributions of single greenhouse gas emitters to country-level climate change are generally not disentangled, despite their relevance for climate policy and litigation. Here, we quantify the contributions of the five largest emitters (China, US, EU-27, India, and Russia) to projected 2030 country-level warming and extreme hot years with respect to pre-industrial climate using an innovative suite of Earth System Model emulators. We find that under current pledges, their cumulated 1991–2030 emissions are expected to result in extreme hot years every second year by 2030 in twice as many countries (92%) as without their influence (46%). If all world nations shared the same fossil CO2 per capita emissions as projected for the US from 2016–2030, global warming in 2030 would be 0.4 °C higher than under actual current pledges, and 75% of all countries would exceed 2 °C of regional warming instead of 11%. Our results highlight the responsibility of individual emitters in driving regional climate change and provide additional angles for the climate policy discourse.

scholarly journals Climate change implications for the glaciers of the Hindu Kush, Karakoram and Himalayan region

2014 ◽  
Vol 8 (3) ◽  
pp. 941-958 ◽  
Author(s):  
A. J. Wiltshire
Keyword(s):  
Climate Change ◽  
Mass Balance ◽  
21St Century ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Glacier Mass Balance ◽  
Climate Modelling ◽  
Degree Days ◽  
Projected Change ◽  
Hindu Kush

Abstract. The Hindu Kush, Karakoram, and Himalaya (HKH) region has a negative average glacial mass balance for the present day despite anomalous possible gains in the Karakoram. However, changes in climate over the 21st century may influence the mass balance across the HKH. This study uses regional climate modelling to analyse the implications of unmitigated climate change on precipitation, snowfall, air temperature and accumulated positive degree days for the Hindu Kush (HK), Karakoram (KK), Jammu–Kashmir (JK), Himachal Pradesh and West Nepal regions (HP), and East Nepal and Bhutan (NB). The analysis focuses on the climate drivers of change rather than the glaciological response. Presented is a complex regional pattern of climate change, with a possible increase in snowfall over the western HKH and decreases in the east. Accumulated degree days are less spatially variable than precipitation and show an increase in potential ablation in all regions combined with increases in the length of the seasonal melt period. From the projected change in regional climate the possible implications for future glacier mass balance are inferred. Overall, within the modelling framework used here the eastern Himalayan glaciers (Nepal–Bhutan) are the most vulnerable to climate change due to the decreased snowfall and increased ablation associated with warming. The eastern glaciers are therefore projected to decline over the 21st Century despite increasing precipitation. The western glaciers (Hindu Kush, Karakoram) are expected to decline at a slower rate over the 21st century in response to unmitigated climate compared to the glaciers of the east. Importantly, regional climate change is highly uncertain, especially in important cryospheric drivers such as snowfall timing and amounts, which are poorly constrained by observations. Data are available from the author on request.

scholarly journals Climate Change Hotspots Identification in China through the CMIP5 Global Climate Model Ensemble

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Huanghe Gu ◽  
Zhongbo Yu ◽  
Jigan Wang ◽  
Qin Ju ◽  
Chuanguo Yang ◽  
...  
Keyword(s):  
Climate Change ◽  
21St Century ◽  
Climate Model ◽  
Greenhouse Gas Emission ◽  
Global Climate Model ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Seasonal Temperature ◽  
Climate Variables ◽  
Model Ensemble

China is one of the countries vulnerable to adverse climate changes. The potential climate change hotspots in China throughout the 21st century are identified in this study by using a multimodel, multiscenario climate model ensemble that includes Phase Five of the Coupled Model Intercomparison Project (CMIP5) atmosphere-ocean general circulation models. Both high (RCP8.5) and low (RCP4.5) greenhouse gas emission trajectories are tested, and both the mean and extreme seasonal temperature and precipitation are considered in identifying regional climate change hotspots. Tarim basin and Tibetan Plateau in West China are identified as persistent regional climate change hotspots in both the RCP4.5 and RCP8.5 scenarios. The aggregate impacts of climate change increase throughout the 21st century and are more significant in RCP8.5 than in RCP4.5. Extreme hot event and mean temperature are two climate variables that greatly contribute to the hotspots calculation in all regions. The contribution of other climate variables exhibits a notable subregional variability. South China is identified as another hotspot based on the change of extreme dry event, especially in SON and DJF, which indicates that such event will frequently occur in the future. Our results can contribute to the designing of national and cross-national adaptation and mitigation policies.

scholarly journals Estimating regional climate change uncertainty in Japan at the end of the 21st century with mixture distribution

2017 ◽  
Vol 11 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Shunya Wakamatsu ◽  
Kenji Oshio ◽  
Koji Ishihara ◽  
Hirokazu Murai ◽  
Takuya Nakashima ◽  
...  
Keyword(s):  
Climate Change ◽  
21St Century ◽  
Regional Climate ◽  
Mixture Distribution ◽  
Regional Climate Change ◽  
Climate Change Uncertainty
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