Solar radiation modification(SRM,also termed as geoengineering)has been proposed as a potential option to counteract anthropogenic warming.The underlying idea of SRM is to reduce the amount of sunlight reaching the at...Solar radiation modification(SRM,also termed as geoengineering)has been proposed as a potential option to counteract anthropogenic warming.The underlying idea of SRM is to reduce the amount of sunlight reaching the atmosphere and surface,thus offsetting some amount of global warming.Here,the authors use an Earth system model to investigate the impact of SRM on the global carbon cycle and ocean biogeochemistry.The authors simulate the temporal evolution of global climate and the carbon cycle from the pre-industrial period to the end of this century under three scenarios:the RCP4.5 CO_(2) emission pathway,the RCP8.5 CO_(2) emission pathway,and the RCP8.5 CO_(2) emission pathway with the implementation of SRM to maintain the global mean surface temperature at the level of RCP4.5.The simulations show that SRM,by altering global climate,also affects the global carbon cycle.Compared to the RCP8.5 simulation without SRM,by the year 2100,SRM reduces atmospheric CO_(2) by 65 ppm mainly as a result of increased CO_(2) uptake by the terrestrial biosphere.However,SRM-induced change in atmospheric CO_(2) and climate has a small effect in mitigating ocean acidification.By the year 2100,relative to RCP8.5,SRM causes a decrease in surface ocean hydrogen ion concentration([H^(+)])by 6% and attenuates the seasonal amplitude of[H^(+)]by about 10%.The simulations also show that SRM has a small effect on globally integrated ocean net primary productivity relative to the high-CO_(2) simulation without SRM.This study contributes to a comprehensive assessment of the effects of SRM on both the physical climate and the global carbon cycle.展开更多
Carbon dioxide removal and solar radiation modification(SRM)are two classes of proposed climate intervention methods.A thorough understanding of climate system response to these methods calls for a good understanding ...Carbon dioxide removal and solar radiation modification(SRM)are two classes of proposed climate intervention methods.A thorough understanding of climate system response to these methods calls for a good understanding of the carbon cycle response.In this study,we used an Earth system model to examine the response of global climate and carbon cycle to artificial ocean alkalinization(AOA),a method of CO_(2)removal,and reduction in solar irradiance that represents the overall effect of solar radiation modification.In our simulations,AOA is applied uniformly over the global ice-free ocean under the RCP8.5 scenario to bring down atmospheric CO_(2)to the level of RCP4.5,and SRM is applied uniformly over the globe under the RCP8.5 scenario to bring down global mean surface temperature to the level of RCP4.5.Our simulations show that with the same goal of temperature stabilization,AOA and SRM cause fundamentally different perturbations of the ocean and land carbon cycle.By the end of the 21st century,relative to the simulation of RCP8.5,AOA-induced changes in ocean carbonate chemistry enhances global oceanic CO_(2)uptake by 983 PgC and increases global mean surface ocean pH by 0.42.Meanwhile,AOA reduces land CO_(2)uptake by 79 PgC and reduces atmospheric CO_(2)concentration by 426×10^(−6).By contrast,relative to the simulation of RCP8.5,SRM has a minor effect on the oceanic CO_(2)uptake and ocean acidification.SRM-induced cooling enhances land CO_(2)uptake by 140 PgC and reduces atmospheric CO_(2)concentration by 63×10^(−6).A sudden termination of SRM causes a rate of temperature change that is much larger than that of RCP8.5.A sudden termination of AOA causes a rate of temperature change that is comparable to that of RCP8.5 and a rate of ocean acidification that is much larger than that of RCP8.5.展开更多
The present study proposes an improved method for generating better typical meteorological years( TMYs) used in building energy simulation in China. Modifications are made to the commonly used Sandia method,by optimiz...The present study proposes an improved method for generating better typical meteorological years( TMYs) used in building energy simulation in China. Modifications are made to the commonly used Sandia method,by optimizing the weightings of indices and thus giving more emphasis to dry bulb temperature and relative humidity and less to wind velocity. After analyzing the solar heat gain on the vertical envelop,an index of diffuse radiation rather than direct normal radiation is added for solar radiation. Using the improved method proposed,TMYs for 5 representative cities of 5 major climate zones in China are generated from the meteorological data recorded during the period 1981—2010. The results show that,compared with previous studies,the monthly diffuse solar radiation of typical meteorological months generated by the improved method are the"closest"to the 30-year average,and the comparison between annual diffuse radiation for the TMY and the 30-year annual average is improved,while little adverse effect is produced on global horizontal radiation comparisons,indicating that the improved method is more suitable to generate the TMY data than previous studies.展开更多
Solar Radiation Management (SRM) geoengineering is a proposed response to anthropogenic global warming (AGW)(National Academy of Sciences, 2015). There may be profound - even violent - disagreement on preferred temper...Solar Radiation Management (SRM) geoengineering is a proposed response to anthropogenic global warming (AGW)(National Academy of Sciences, 2015). There may be profound - even violent - disagreement on preferred temperature. SRM disruption risks dangerous temperature rise (termination shock). Concentrating on aircraft-delivered Stratospheric Aerosol Injection (SAI), we appraise threats to SRM and defense methodologies. Civil protest and minor cyberattacks are almost inevitable but are manageable (unless state-sponsored). Overt military attacks are more disruptive, but unlikely - although superpowers' symbolic overt attacks may deter SRM. Unattributable attacks are likely, and mandate use of widely-available weapons. Risks from unsophisticated weapons are therefore higher. An extended supply chain is more vulnerable than a secure airbase - necessitating supply-chain hardening. Recommendations to improve SRM resilience include heterogeneous operations from diverse, secure, well-stocked bases (possibly ocean islands or aircraft carriers);and avoidance of single-point-of failure risks (e.g. balloons). A distributed, civilianoperated system offers an alternative strategy. A multilateral, consensual SRM approach reduces likely attack triggers.展开更多
基金supported by the National Natural Science Foundation of China[grant number 41975103].
文摘Solar radiation modification(SRM,also termed as geoengineering)has been proposed as a potential option to counteract anthropogenic warming.The underlying idea of SRM is to reduce the amount of sunlight reaching the atmosphere and surface,thus offsetting some amount of global warming.Here,the authors use an Earth system model to investigate the impact of SRM on the global carbon cycle and ocean biogeochemistry.The authors simulate the temporal evolution of global climate and the carbon cycle from the pre-industrial period to the end of this century under three scenarios:the RCP4.5 CO_(2) emission pathway,the RCP8.5 CO_(2) emission pathway,and the RCP8.5 CO_(2) emission pathway with the implementation of SRM to maintain the global mean surface temperature at the level of RCP4.5.The simulations show that SRM,by altering global climate,also affects the global carbon cycle.Compared to the RCP8.5 simulation without SRM,by the year 2100,SRM reduces atmospheric CO_(2) by 65 ppm mainly as a result of increased CO_(2) uptake by the terrestrial biosphere.However,SRM-induced change in atmospheric CO_(2) and climate has a small effect in mitigating ocean acidification.By the year 2100,relative to RCP8.5,SRM causes a decrease in surface ocean hydrogen ion concentration([H^(+)])by 6% and attenuates the seasonal amplitude of[H^(+)]by about 10%.The simulations also show that SRM has a small effect on globally integrated ocean net primary productivity relative to the high-CO_(2) simulation without SRM.This study contributes to a comprehensive assessment of the effects of SRM on both the physical climate and the global carbon cycle.
基金Long Cao and Xiao-Yu Jin are supported by the National Natural Science Foundation of China(41975103,42275179)。
文摘Carbon dioxide removal and solar radiation modification(SRM)are two classes of proposed climate intervention methods.A thorough understanding of climate system response to these methods calls for a good understanding of the carbon cycle response.In this study,we used an Earth system model to examine the response of global climate and carbon cycle to artificial ocean alkalinization(AOA),a method of CO_(2)removal,and reduction in solar irradiance that represents the overall effect of solar radiation modification.In our simulations,AOA is applied uniformly over the global ice-free ocean under the RCP8.5 scenario to bring down atmospheric CO_(2)to the level of RCP4.5,and SRM is applied uniformly over the globe under the RCP8.5 scenario to bring down global mean surface temperature to the level of RCP4.5.Our simulations show that with the same goal of temperature stabilization,AOA and SRM cause fundamentally different perturbations of the ocean and land carbon cycle.By the end of the 21st century,relative to the simulation of RCP8.5,AOA-induced changes in ocean carbonate chemistry enhances global oceanic CO_(2)uptake by 983 PgC and increases global mean surface ocean pH by 0.42.Meanwhile,AOA reduces land CO_(2)uptake by 79 PgC and reduces atmospheric CO_(2)concentration by 426×10^(−6).By contrast,relative to the simulation of RCP8.5,SRM has a minor effect on the oceanic CO_(2)uptake and ocean acidification.SRM-induced cooling enhances land CO_(2)uptake by 140 PgC and reduces atmospheric CO_(2)concentration by 63×10^(−6).A sudden termination of SRM causes a rate of temperature change that is much larger than that of RCP8.5.A sudden termination of AOA causes a rate of temperature change that is comparable to that of RCP8.5 and a rate of ocean acidification that is much larger than that of RCP8.5.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51278349)Foundation of Fujian Provincial Education Department(Grant No.JA13185)
文摘The present study proposes an improved method for generating better typical meteorological years( TMYs) used in building energy simulation in China. Modifications are made to the commonly used Sandia method,by optimizing the weightings of indices and thus giving more emphasis to dry bulb temperature and relative humidity and less to wind velocity. After analyzing the solar heat gain on the vertical envelop,an index of diffuse radiation rather than direct normal radiation is added for solar radiation. Using the improved method proposed,TMYs for 5 representative cities of 5 major climate zones in China are generated from the meteorological data recorded during the period 1981—2010. The results show that,compared with previous studies,the monthly diffuse solar radiation of typical meteorological months generated by the improved method are the"closest"to the 30-year average,and the comparison between annual diffuse radiation for the TMY and the 30-year annual average is improved,while little adverse effect is produced on global horizontal radiation comparisons,indicating that the improved method is more suitable to generate the TMY data than previous studies.
文摘Solar Radiation Management (SRM) geoengineering is a proposed response to anthropogenic global warming (AGW)(National Academy of Sciences, 2015). There may be profound - even violent - disagreement on preferred temperature. SRM disruption risks dangerous temperature rise (termination shock). Concentrating on aircraft-delivered Stratospheric Aerosol Injection (SAI), we appraise threats to SRM and defense methodologies. Civil protest and minor cyberattacks are almost inevitable but are manageable (unless state-sponsored). Overt military attacks are more disruptive, but unlikely - although superpowers' symbolic overt attacks may deter SRM. Unattributable attacks are likely, and mandate use of widely-available weapons. Risks from unsophisticated weapons are therefore higher. An extended supply chain is more vulnerable than a secure airbase - necessitating supply-chain hardening. Recommendations to improve SRM resilience include heterogeneous operations from diverse, secure, well-stocked bases (possibly ocean islands or aircraft carriers);and avoidance of single-point-of failure risks (e.g. balloons). A distributed, civilianoperated system offers an alternative strategy. A multilateral, consensual SRM approach reduces likely attack triggers.
