scholarly journals Sensitivity of simulated climate to latitudinal distribution of solar insolation reduction in solar radiation management

2014 ◽  
Vol 14 (15) ◽  
pp. 7769-7779 ◽  
Author(s):  
A. Modak ◽  
G. Bala
Keyword(s):  
Climate Change ◽  
Radiative Forcing ◽  
Solar Radiation Management ◽  
Sulfate Aerosols ◽  
Latitudinal Distribution ◽  
Solar Insolation ◽  
Global Mean Temperature ◽  
Mean Climate ◽  
Radiation Management ◽  
Global Mean

Abstract. Solar radiation management (SRM) geoengineering has been proposed as a potential option to counteract climate change. We perform a set of idealized geoengineering simulations using Community Atmosphere Model version 3.1 developed at the National Center for Atmospheric Research to investigate the global hydrological implications of varying the latitudinal distribution of solar insolation reduction in SRM methods. To reduce the solar insolation we have prescribed sulfate aerosols in the stratosphere. The radiative forcing in the geoengineering simulations is the net forcing from a doubling of CO2 and the prescribed stratospheric aerosols. We find that for a fixed total mass of sulfate aerosols (12.6 Mt of SO4), relative to a uniform distribution which nearly offsets changes in global mean temperature from a doubling of CO2, global mean radiative forcing is larger when aerosol concentration is maximum at the poles leading to a warmer global mean climate and consequently an intensified hydrological cycle. Opposite changes are simulated when aerosol concentration is maximized in the tropics. We obtain a range of 1 K in global mean temperature and 3% in precipitation changes by varying the distribution pattern in our simulations: this range is about 50% of the climate change from a doubling of CO2. Hence, our study demonstrates that a range of global mean climate states, determined by the global mean radiative forcing, are possible for a fixed total amount of aerosols but with differing latitudinal distribution. However, it is important to note that this is an idealized study and thus not all important realistic climate processes are modeled.

scholarly journals Sensitivity of simulated climate to latitudinal distribution of solar insolation reduction in SRM geoengineering methods

2013 ◽  
Vol 13 (10) ◽  
pp. 25387-25415 ◽  
Author(s):  
A. Modak ◽  
G. Bala
Keyword(s):  
Climate Change ◽  
Radiative Forcing ◽  
Aerosol Concentration ◽  
Solar Radiation Management ◽  
Latitudinal Distribution ◽  
Solar Insolation ◽  
Global Mean Temperature ◽  
Mean Temperature ◽  
Mean Climate ◽  
Global Mean

Abstract. Solar radiation management (SRM) geoengineering has been proposed as a potential option to counteract climate change. We perform a set of idealized geoengineering simulations to understand the global hydrological implications of varying the latitudinal distribution of solar insolation reduction in SRM methods. We find that for a fixed total mass of sulfate aerosols (12.6 Mt of SO4), relative to a uniform distribution which mitigates changes in global mean temperature, global mean radiative forcing is larger when aerosol concentration is maximum at the poles leading to a warmer global mean climate and consequently an intensified hydrological cycle. Opposite changes are simulated when aerosol concentration is maximized in the tropics. We obtain a range of 1 K in global mean temperature and 3% in precipitation changes by varying the distribution pattern: this range is about 50% of the climate change from a doubling of CO2. Hence, our study demonstrates that a range of global mean climate states, determined by the global mean radiative forcing, are possible for a fixed total amount of aerosols but with differing latitudinal distribution, highlighting the need for a careful evaluation of SRM proposals.

scholarly journals Estimates of Uncertainty in Predictions of Global Mean Surface Temperature

2007 ◽  
Vol 20 (5) ◽  
pp. 843-855 ◽  
Author(s):  
J. A. Kettleborough ◽  
B. B. B. Booth ◽  
P. A. Stott ◽  
M. R. Allen
Keyword(s):  
Twentieth Century ◽  
Energy Balance ◽  
Temperature Change ◽  
Radiative Forcing ◽  
Balance Model ◽  
Future Climate Change ◽  
Model Parameters ◽  
Global Mean Temperature ◽  
Mean Temperature ◽  
Global Mean

Abstract A method for estimating uncertainty in future climate change is discussed in detail and applied to predictions of global mean temperature change. The method uses optimal fingerprinting to make estimates of uncertainty in model simulations of twentieth-century warming. These estimates are then projected forward in time using a linear, compact relationship between twentieth-century warming and twenty-first-century warming. This relationship is established from a large ensemble of energy balance models. By varying the energy balance model parameters an estimate is made of the error associated with using the linear relationship in forecasts of twentieth-century global mean temperature. Including this error has very little impact on the forecasts. There is a 50% chance that the global mean temperature change between 1995 and 2035 will be greater than 1.5 K for the Special Report on Emissions Scenarios (SRES) A1FI scenario. Under SRES B2 the same threshold is not exceeded until 2055. These results should be relatively robust to model developments for a given radiative forcing history.

Situating and Abandoning Geoengineering: A Typology of Five Responses to Dangerous Climate Change

2013 ◽  
Vol 46 (01) ◽  
pp. 23-27 ◽  
Author(s):  
Clare Heyward
Keyword(s):  
Climate Change ◽  
Large Scale ◽  
Solar Radiation Management ◽  
Diverse Range ◽  
Political Issues ◽  
Government Organizations ◽  
Mitigation And Adaptation ◽  
Potential Strategy ◽  
Dangerous Climate Change ◽  
Radiation Management

Geoengineering, the “deliberate, large-scale manipulation of the planetary environment in order to counteract anthropogenic climate change” (Shepherd et al. 2009, 1), is attracting increasing interest. As well as the Royal Society, various scientific and government organizations have produced reports on the potential and challenge of geoengineering as a potential strategy, alongside mitigation and adaptation, to avoid the vast human and environmental costs that climate change is thought to bring (Blackstock et al. 2009; GAO 2010; Long et al. 2011; Rickels et al. 2011). “Geoengineering” covers a diverse range of proposals conventionally divided into carbon dioxide removal (CDR) proposals and solar radiation management (SRM) proposals. This article argues that “geoengineering” should not be regarded as a third category of response to climate change, but should be disaggregated. Technically, CDR and SRM are quite different and discussing them together under the rubric of geoengineering can give the impression that all the technologies in the two categories of response always raise similar challenges and political issues when this is not necessarily the case. However, CDR and SRM should not be completely subsumed into the preexisting categories of mitigation and adaptation. Instead, they can be regarded as two parts of a five-part continuum of responses to climate change. To make this case, the first section of this article discusses whether geoengineering is distinctive, and the second situates CDR and SRM in relation to other responses to climate change.

The Paris Agreement and the Future of the Climate Regime

2019 ◽  
pp. 189-205 ◽  
Author(s):  
Annalisa Savaresi
Keyword(s):  
Climate Change ◽  
International Law ◽  
Paris Agreement ◽  
Global Mean Temperature ◽  
The Future ◽  
International Climate ◽  
The One ◽  
Global Mean ◽  
Important Objective ◽  
Climate Change Governance

This chapter discusses how international law has responded to climate change, focusing on the challenges that have faced implementation of existing climate treaties, and on the suitability of the Paris Agreement to address these. Expectations of this new treaty could scarcely be greater: the Paris Agreement is meant to provide a framework to improve international cooperation on climate change, and to keep the world within the global mean temperature-change goal identified by scientists as safe. Yet, whether and how this important objective will be reached largely depends, on the one hand, on the supporting political will and, on the other, on the redesign of the international architecture for climate governance. This chapter specifically reflects on international law-making and on the approach to climate change governance embedded in the Paris Agreement, drawing inferences from the past, to make predictions on what the future may hold for international climate change law.

scholarly journals Impact of methane and black carbon mitigation on forcing and temperature: a multi-model scenario analysis

2020 ◽  
Vol 163 (3) ◽  
pp. 1427-1442 ◽  
Author(s):  
Steven J Smith ◽  
Jean Chateau ◽  
Kalyn Dorheim ◽  
Laurent Drouet ◽  
Olivier Durand-Lasserve ◽  
...  
Keyword(s):  
Black Carbon ◽  
Radiative Forcing ◽  
Climate Model ◽  
Economic Structure ◽  
Time Frame ◽  
Focused Attention ◽  
Carbon Mitigation ◽  
Global Mean Temperature ◽  
Model Parameter Uncertainty ◽  
Global Mean

AbstractThe relatively short atmospheric lifetimes of methane (CH4) and black carbon (BC) have focused attention on the potential for reducing anthropogenic climate change by reducing Short-Lived Climate Forcer (SLCF) emissions. This paper examines radiative forcing and global mean temperature results from the Energy Modeling Forum (EMF)-30 multi-model suite of scenarios addressing CH4 and BC mitigation, the two major short-lived climate forcers. Central estimates of temperature reductions in 2040 from an idealized scenario focused on reductions in methane and black carbon emissions ranged from 0.18–0.26 °C across the nine participating models. Reductions in methane emissions drive 60% or more of these temperature reductions by 2040, although the methane impact also depends on auxiliary reductions that depend on the economic structure of the model. Climate model parameter uncertainty has a large impact on results, with SLCF reductions resulting in as much as 0.3–0.7 °C by 2040. We find that the substantial overlap between a SLCF-focused policy and a stringent and comprehensive climate policy that reduces greenhouse gas emissions means that additional SLCF emission reductions result in, at most, a small additional benefit of ~ 0.1 °C in the 2030–2040 time frame.

Why Is Climate Sensitivity So Unpredictable?

Science ◽  
2007 ◽  
Vol 318 (5850) ◽  
pp. 629-632 ◽  
Author(s):  
Gerard H. Roe ◽  
Marcia B. Baker
Keyword(s):  
Climate Change ◽  
Atmospheric Carbon Dioxide ◽  
Probability Distributions ◽  
Analytic Form ◽  
Future Climate Change ◽  
Large Temperature ◽  
Global Mean Temperature ◽  
Simple Analytic Form ◽  
Global Mean

Uncertainties in projections of future climate change have not lessened substantially in past decades. Both models and observations yield broad probability distributions for long-term increases in global mean temperature expected from the doubling of atmospheric carbon dioxide, with small but finite probabilities of very large increases. We show that the shape of these probability distributions is an inevitable and general consequence of the nature of the climate system, and we derive a simple analytic form for the shape that fits recent published distributions very well. We show that the breadth of the distribution and, in particular, the probability of large temperature increases are relatively insensitive to decreases in uncertainties associated with the underlying climate processes.

scholarly journals An Assessment of Global Macroeconomic Impacts Caused by Sea Level Rise Using the Framework of Shared Socioeconomic Pathways and Representative Concentration Pathways

2020 ◽  
Vol 12 (9) ◽  
pp. 3737
Author(s):  
Osamu Nishiura ◽  
Makoto Tamura ◽  
Shinichiro Fujimori ◽  
Kiyoshi Takahashi ◽  
Junya Takakura ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Low Income ◽  
Temperature Increase ◽  
General Circulation ◽  
Economic Losses ◽  
Global Mean Temperature ◽  
Mean Temperature ◽  
Global Mean

Coastal areas provide important services and functions for social and economic activities. Damage due to sea level rise (SLR) is one of the serious problems anticipated and caused by climate change. In this study, we assess the global economic impact of inundation due to SLR by using a computable general equilibrium (CGE) model that incorporates detailed coastal damage information. The scenario analysis considers multiple general circulation models, socioeconomic assumptions, and stringency of climate change mitigation measures. We found that the global household consumption loss proportion will be 0.045%, with a range of 0.027−0.066%, in 2100. Socioeconomic assumptions cause a difference in the loss proportion of up to 0.035% without greenhouse gas (GHG) emissions mitigation, the so-called baseline scenarios. The range of the loss proportion among GHG emission scenarios is smaller than the differences among the socioeconomic assumptions. We also observed large regional variations and, in particular, the consumption losses in low-income countries are, relatively speaking, larger than those in high-income countries. These results indicate that, even if we succeed in stabilizing the global mean temperature increase below 2 °C, economic losses caused by SLR will inevitably happen to some extent, which may imply that keeping the global mean temperature increase below 1.5 °C would be worthwhile to consider.

scholarly journals Anthropocenic Limitations to Climate Engineering

Humanities ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 186 ◽  
Author(s):  
Jeroen Oomen
Keyword(s):  
Climate Change ◽  
Solar Radiation ◽  
Solar Radiation Management ◽  
Climate Engineering ◽  
Engineering Research ◽  
Future Experimentation ◽  
Fundamental Objection ◽  
Climatic System ◽  
Radiation Management ◽  
And Control

The development of climate engineering research has historically depended on mostly western, holistic perceptions of climate and climate change. Determinations of climate and climate change as a global system have played a defining role in the development of climate engineering. As a result, climate engineering research in general, and solar radiation management (SRM) in particular, is primarily engaged in research of quantified, whole-Earth solutions. I argue that in the potential act of solar radiation management, a view of climate change that relies on the holistic western science of the climatic system is enshrined. This view, dependent on a deliberative intentionality that seems connected to anthropocenic notions of responsibility and control, profoundly influences the assumptions and research methods connected to climate engineering. While this may not necessarily be to the detriment of climate engineering proposals—in fact, it may be the only workable conception of SRM—it is a conceptual limit to the enterprise that has to be acknowledged. Additionally, in terms of governance, reliability, and cultural acceptance, this limit could be a fundamental objection to future experimentation (or implementation).

A new approach for assessing climate change impacts in ecotron experiments

2019 ◽  
Author(s):  
Inne Vanderkelen ◽  
Jakob Zschleischler ◽  
Lukas Gudmundsson ◽  
Klaus Keuler ◽  
Francois Rineau ◽  
...  
Keyword(s):  
Climate Change ◽  
Regional Climate Model ◽  
Climate Model ◽  
Global Climate Model ◽  
Regional Climate ◽  
Climate Change Impacts ◽  
New Approach ◽  
Global Mean Temperature ◽  
Mean Temperature ◽  
Global Mean

Abstract. Ecotron facilities allow accurate control of many environmental variables coupled with extensive monitoring of ecosystem processes. They therefore require multivariate perturbation of climate variables, close to what is observed in the field and projections for the future, preserving the co-variances between variables and the projected changes in variability. Here we present a new experimental design for studying climate change impacts on terrestrial ecosystems and apply it to the UHasselt Ecotron Experiment. The new methodology consists of generating climate forcing along a gradient representative of increasingly high global mean temperature anomalies and uses data derived from the best available regional climate model (RCM) projection. We first identified the best performing regional climate model (RCM) simulation for the ecotron site from the Coordinated Regional Downscaling Experiment in the European Domain (EURO-CORDEX) ensemble with a 0.11° (12.5 km) resolution based on two criteria: (i) highest skill of the simulations compared to observations from a nearby weather station and (ii) representativeness of the multi-model mean in future projections. Our results reveal that no single RCM simulation has the best score for all possible combinations of the four meteorological variables and evaluation metrics considered. Out of the six best performing simulations, we selected the simulation with the lowest bias for precipitation (CCLM4-8-17/EC-EARTH), as this variable is key to ecosystem functioning and model simulations deviated the most for this variable, with values ranging up to double the observed values. The time window is subsequently selected from the RCM projection for each ecotron unit based on the global mean temperature of the driving Global Climate Model (GCM). The ecotron units are forced with 3-hourly output from the RCM projections of the five-year period spanning the year in which the global mean temperature crosses the predefined values. With the new approach, Ecotron facilities become able to assess ecosystem responses on changing climatic conditions, while accounting for the co-variation between climatic variables and their projection in variability, well representing possible compound events. The gradient approach will allow to identify possible threshold and tipping points.

Representing transient precipitation change of Solar Radiation Management and Carbon Dioxide Removal with fast and slow precipitation components

2020 ◽  
Author(s):  
Anton Laakso ◽  
Peter Snyder ◽  
Stefan Liess ◽  
Antti-Ilari Partanen ◽  
Dylan Millet
Keyword(s):  
Carbon Dioxide ◽  
Solar Radiation ◽  
Climate Warming ◽  
Carbon Dioxide Removal ◽  
Precipitation Change ◽  
Solar Radiation Management ◽  
Temperature Dependent ◽  
Radiation Management ◽  
Global Precipitation ◽  
Global Mean

<p>Solar Radiation Management (SRM) and Carbon Dioxide Removal (CDR) have been proposed to mitigate global warming in the event of insufficient greenhouse gas emission reductions. We have studied temperature and precipitation responses to CDR and SRM with the RCP4.5 scenario using the MPI-ESM and CESM Earth System Models (ESMs). The two SRM scenarios were designed to meet different climate targets to keep either global mean 1) surface temperature or 2) precipitation at the 2010-2020 level via stratospheric sulfur injections. This was done in two-fold method, where global aerosol fields were first simulated with aerosol-climate model ECHAM-HAMMOZ, which were then used as prescribed fields in ESM simulations. In the CDR scenario the annual CO<sub>2</sub> increase based on RCP4.5 was counteracted by a 1% annual removal of the atmospheric CO<sub>2</sub> concentration which decreased the global mean temperature back to the 2010-2020 level at the end of this century. </p><p>Results showed that applying SRM to offset 21st century climate warming in the RCP4.5 scenario led to a 1.42%  (MPI-ESM) or 0.73% (CESM) reduction in global mean precipitation, whereas CDR increased global precipitation by 0.5% in both ESMs for 2080-2100 relative to 2010-2020. To study this further we separated global precipitation responses to a temperature-dependent and a fast temperature-independent components. These were quantified by a regression method. In this method the climate variable (e.g. precipitation) is regressed against the temperature change due to the instantaneous forcing. Temperature-dependent slow response and temperature independent fast response are given by the fitted regression line. We showed that in all simulated geoengineering scenarios, the simulated global mean precipitation change can be represented as the sum of these response components. This component analysis shows that the fast temperature-independent component of atmospheric CO<sub>2</sub> concentration explains the global mean precipitation change in both SRM and CDR scenarios. Results showed relatively large differences in the individual precipitation components between two ESMs. This component analysis method can be generalized to evaluate and analyze precipitation, or other climate responses, basically in any emission scenario and in any ESM in a conceptually easy way. </p><p>Based on the SRM simulations, a total of or 292-318 Tg(S) (MPI-ESM) or 163-199 Tg(S) (CESM) of injected sulfur from 2020 to 2100 was required to offset global mean warming based on the RCP4.5 scenario. The distinct effects of SRM in the two ESM simulations mainly reflected differing shortwave absorption responses to water vapor. To prevent a global mean precipitation increase, only 95-114 Tg(S) was needed. Simultaneously this prevent the global mean climate warming from exceeding 2 degrees above preindustrial temperatures in both models. </p>

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