The Strategic Arms Reduction Treaty (SORT) of 2002 calls for the US and Russia to each limit their operationally deployed warheads to 1700-2200 by December 2012. The treaty has many unusual features: warheads, rather than delivery systems are limited; verification measures are
not specified; permanent arms reductions are not required; warheads need not be destroyed; either side may quickly
withdraw; and the treaty expires on the same day that arsenal limits are reached. Nevertheless, should the limits envisioned in
SORT be achieved and the excess warheads destroyed, only about 6% of the 70,000 warheads existing in 1986 would remain.
Given such a large reduction, one might assume a concomitant large reduction in the number of potential fatalities from a
nuclear war and in the likelihood of environmental consequences that threaten the bulk of humanity. Unfortunately, that
assumption is incorrect. Indeed, we estimate that the direct effects of using the 2012 arsenals would lead to hundreds of
millions of fatalities. The indirect effects would likely eliminate the majority of the human population.
Nuclear winter revisited with a modern climate model and current nuclear arsenals: Still catastrophic consequences
Alan Robock,1 Luke Oman,1,2 and Georgiy L. Stenchikov1
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Twenty years ago, the results of climate model simulations of the response to smoke
and dust from a massive nuclear exchange between the superpowers could be summarized
as "nuclear winter", with rapid temperature, precipitation, and insolation drops at the
surface that would threaten global agriculture for at least a year. The global nuclear arsenal
has fallen by a factor of three since then, but there has been an expansion of the number of
nuclear weapons states, with additional states trying to develop nuclear arsenals. We use a
modern climate model to reexamine the climate response to a range of nuclear wars,
producing 50 and 150 Tg of smoke, using moderate and large portions of the current
global arsenal, and find that there would be significant climatic responses to all the
scenarios. This is the first time that an atmosphere-ocean general circulation model has
been used for such a simulation and the first time that 10-year simulations have been
conducted. The response to the 150 Tg scenario can still be characterized as "nuclear
winter", but both produce global catastrophic consequences. The changes are more
long-lasting than previously thought, however, because the new model, National
Aeronautics and Space Administration Goddard Institute for Space Studies ModelE, is
able to represent the atmosphere up to 80 km, and simulates plume rise to the middle and
upper stratosphere, producing a long aerosol lifetime. The indirect effects of nuclear
weapons would have devastating consequences for the planet, and continued nuclear
arsenal reductions will be needed before the threat of nuclear winter is removed
from the Earth.
A regional war involving 100 Hiroshima-size weapons would pose a worldwide threat due to the ozone destruction and climate change. A superpower confrontation with a few thousands weapons would be castastrophic.
The Atmospheric and Climatic Consequences of Nuclear War
It is the Halloween preceding 1984, and I deeply wish that what I am about to tell you were only a ghost story, only something invented to frighten children for a day. But, unfortunately, it is not just a story. Our recent research[1,2] has uncovered the surprising fact that nuclear war may carry in its wake a climatic catastrophe, which we call "nuclear winter," unprecedented during the tenure of humans on Earth.
Environmental Consequences of Nuclear War | Volume II - Ecological and Agricultural Effects