Storm Track Changes in the Middle East and North Africa Under Stratospheric Aerosol Geoengineering

K Karami,S Tilmes,H Muri,S V Mousavi

doi:10.1029/2020gl086954

Abstract

AbstractAs a potential approach to prevent dangerous climate change, stratospheric aerosol geoengineering (SAG) aims to reflect some incoming solar radiation into space and reduce temperatures. Previous modeling studies suggest that storm tracks will shift poleward due to the increases in the greenhouse gas concentrations. As a consequence of this, the Middle East, North Africa, and Mediterranean regions will most likely experience a strong precipitation decrease, increasing the pressure on the region's vulnerable environment. Our results from an Earth system model indicate that SAG can partially offset the poleward shift of the storm tracks, thus potentially soothing the environmental and water stresses of the region. However, other climatic side effects may occur, hence still motivating ambitious mitigation action to reduce emissions and impacts of global warming. The results presented may have practical implications for ongoing climate policy debates in the region.

Highlights

Slow progresses in decoupling anthropogenic emissions from economic growth is the main reason for continued increase in the global atmospheric greenhouse gas concentrations (Fuss et al, 2014; Rozenberg, David, Narloch, & Hallegatte, 2015; Sanderson, Tebaldi, & O'Neill, 2016)
These features of the Middle East and North Africa (MENA) region's storm‐tracks is comparable to the reanalysis data of the National Centers for Environmental Prediction (NCEP, figures not shown), suggesting that a realistic storm‐tracks climatology is provided in the Geoengineering Large Ensemble (GLENS) simulations deeming the model suitable for the purpose of our study
We analyzed the differences of the amplitudes of the Rossby wave packets that are representatives of the storm‐tracks in RCP8.5 and stratospheric aerosol geoengineering (SAG) simulations with control simulation (CTL) simulation

Summary

Introduction

Slow progresses in decoupling anthropogenic emissions from economic growth is the main reason for continued increase in the global atmospheric greenhouse gas concentrations (Fuss et al, 2014; Rozenberg, David, Narloch, & Hallegatte, 2015; Sanderson, Tebaldi, & O'Neill, 2016). As a theoretical approach to limit global warming, solar radiation management (SRM) aims to reflect a small percentage of incoming solar radiation to space, reducing global mean temperatures (Crutzen, 2006; Rasch et al, 2008). By introducing reflective sulfate aerosols into the stratosphere though deliberate injections of sulfur, SAG would reduce some amount of incoming solar radiation reaching the Earth's surface and mimic the cooling effect of volcanic eruptions. SRM is not to be considered as an alternative to emission reductions, it is the only known approach that could quickly (within a few years) slow, stop, or even reverse the increasing global temperatures. The risks of stratospheric aerosol geoengineering are uncertain, . It remains unclear if the risks of breaking the 2°C target exceed or fall short of the risks from stratospheric aerosol geoengineering (Parker & Irvine et al, 2018; Rahman et al, 2018)

Objectives

Results

Conclusion