Rapidly expanding nuclear arsenals in Pakistan and India portend regional and global catastrophe

Abstract

Pakistan and India may have 400 to 500 nuclear weapons by 2025 with yields from tested 12- to 45-kt values to a few hundred kilotons. If India uses 100 strategic weapons to attack urban centers and Pakistan uses 150, fatalities could reach 50 to 125 million people, and nuclear-ignited fires could release 16 to 36 Tg of black carbon in smoke, depending on yield. The smoke will rise into the upper troposphere, be self-lofted into the stratosphere, and spread globally within weeks. Surface sunlight will decline by 20 to 35%, cooling the global surface by 2° to 5°C and reducing precipitation by 15 to 30%, with larger regional impacts. Recovery takes more than 10 years. Net primary productivity declines 15 to 30% on land and 5 to 15% in oceans threatening mass starvation and additional worldwide collateral fatalities.

A regional nuclear conflict would compromise global food security

“…Climatic responses to large soot injections over South Asia have been studied systematically (8,(13)(14)(15)(16)(17). The impacts of such low-likelihood but severe events require careful investigation to inform the public and policy makers in view of nuclear proliferation and conflict.…”

“…1) due to ocean thermal inertia and sea ice expansion (15). The CF2 simulations treat smoke as fractal particles and allow coagulation, which results in larger particles with a shorter lifetime and thus faster recovery compared to CF1 (13).…”

“…Territorial disputes over the Kashmir region between India and Pakistan provide an increasingly high level of instability (10,11), and escalatory retaliation could result in the use of nuclear weapons (12). This study highlights the indirect food system consequences of a possible, limited nuclear war based on a previously published India-Pakistan scenario, assuming 5 Tg of soot injection derived from a direct relationship between population density and target-specific fuel load (7,13).…”

The Potential Impact of Nuclear Conflict on Ocean Acidification

“…The atmosphere component of CESM in our simulations is the Whole Atmosphere Community Climate Model (WACCM; Marsh et al, ) with nominal 2° resolution, 66 vertical levels, and a model top at 145 km; it uses the Rapid Radiative Transfer Model for GCMs (RRTMG; Iacono et al, ) for the radiative transfer. The Community Aerosol and Radiation Model for Atmospheres (Bardeen et al, ) is coupled with WACCM to simulate the injection, lofting, advection, and removal of soot aerosols in the troposphere and stratosphere, and their subsequent impact on climate (Coupe et al, ; Toon et al, ). The ocean component of CESM is the Parallel Ocean Program version 2 (Danabasoglu et al, ) with nominal 1° resolution and 60 vertical levels.…”

“…These fires inject smoke into the upper troposphere, where rapid lofting can spread the sunlight-absorbing soot particles into the stratosphere (Turco et al, 1983). Recent research implies that even a small nuclear conflict may have impacts on the global climate system, affecting the state and circulation of the atmosphere (Robock et al, 2007), increasing the sea ice extent in both hemispheres (Mills et al, 2014), and reducing plant productivity and crop yields in regions far from the conflict location (Özdogan et al, 2013;Toon et al, 2019;Xia & Robock, 2013).…”