In Science magazine:
A nuclear war would disrupt the global climate so badly that billions of
people could starve to death, according to what experts are calling the
most expansive modeling to date of so-called nuclear winter. Although
the exact effects remain uncertain, the findings underscore the dangers
of nuclear war and offer vital insights about how to prepare for other
global disasters, researchers say....
Scientists have long known massive explosions can throw enough dust,
ash, and soot into the air to affect the global climate. In 1815, Mount
Tambora in what’s now Indonesia unleashed the largest known volcanic
eruption in history. In the following months, its ash rose and spread
worldwide, blocking enough sunlight to produce “the year without a summer”—a cold spell in 1816 that resulted in massive crop failures and famine across the globe.
For decades, scientists have warned a similar catastrophe could
follow a nuclear war, as fires ignited by hundreds or thousands of
nuclear explosions would release millions of tons of soot, blocking
sunlight and inducing global environmental effects. Worries about
climate effects of nuclear warfare emerged soon after World War II, and
studies took off during the Cold War.
Over the past decade, two pioneers of nuclear winter studies, Alan
Robock and Brian Toon, have assembled a cross-disciplinary team of
scientists to take the calculations further. They turned to the same
climate models that underlie global warming studies—but used the models
to simulate global cooling instead. “Now, we have the computational
capacity to simulate these kinds of things in a sophisticated way,” says
Jonas Jägermeyr, a climate change scientist, crop modeler, and team
member at NASA and Columbia University.
So, how bad could it be? Pretty bad!
A few years after a nuclear war between the United States, its allies, and Russia, the global average calories produced would drop by about 90%—leaving
an estimated 5 billion dead from the famine, the researchers report. A
worst-case war between India and Pakistan could drop calorie production
to 50% and cause 2 billion deaths. The team tried to simulate the impact
of food-saving emergency strategies, such as converting livestock feed
and household waste to food. But in the larger war scenarios, those
efforts did little to save lives.
Baum urges caution in interpreting the estimates. Although the
climate models are “excellent,” he says, there’s too much uncertainty in
how humanity would react to such a global catastrophe to get an
accurate read on the death toll. Still, the study “makes a very worthy
contribution” to envisioning these scenarios, he adds.
It's interesting that some people are putting effort into envisaging how emergency food production might work, though:
The nightmarish prospects have already inspired others to look for ways
to fight the hypothetical famine. David Denkenberger, who co-founded the
nonprofit Alliance to Feed the Earth in Disasters, is exploring ideas
including scaling up “resilient foods” such as seaweed, repurposing
paper factories to produce sugar, converting natural gas into protein
with bacteria, and relocating crops to account for an altered climate.
He and his research associate Morgan Rivers think those approaches could
dramatically increase the amount of food available to humans. “Even if [a substitute] doesn’t taste as good as sweet corn, it’s better than starving,” he says.
I don't know - maybe Soylent Green would actually happen in these circumstances? All very unpleasant to contemplate.
As
