It started with a flash brighter than a thousand suns...

The anthropocene started with a flash brighter than a thousand suns, but will it come to be defined by a sun made one thousandth less bright?

In ancient Greek mythology, the age of man opened with the Titan Prometheus stealing fire from the Olympian Gods to give to man. Prometheus's act brought humanity many great things: technology, civilization and progress, but it also brought them great trouble¹, and Prometheus himself was punished terribly for his crime².

In modern geology, the age of man, the Anthropocene, is defined by the mark our titanic powers are leaving on the environment. Modern geologists have located the transition in the mid-20th Century with The Great Acceleration of our impacts (Figure 1). The precise starting point is defined at the moment our modern Titans, the great powers of the world, stole atomic fire, leaving an indelible trace of radioactive ash around the world.

Figure 1. A selection of socio-economic and Earth system trends that show The Great Acceleration. Dashed vertical lines shows the year 1950. Figures 1 and 3 from Steffen et al. (2015).

It started with a flash brighter than a thousand suns…

When he witnessed the successful Trinity atomic bomb test (Figure 2), Robert Oppenheimer famously recalled a line from the Hindu epic the Bhagavid Gita:

“If the radiance of a thousand suns were to burst at once into the sky,
that would be like the splendor of the mighty one.”

Year later, when the terrible implications of the atomic age were clear to all, he swapped this line for another:

“Now, I am become Death, the destroyer of worlds.”

Figure 2. The expanding fireball and shockwave of the Trinity explosion, seen .025 seconds after detonation on July 16, 1945, US Department of Defence. (link)

For the Anthropocene to be more than a prelude to a dark Thanotocene (age of death), it cannot continue as it started. Our modern Titans must hold back from unleashing the nuclear fire they have mastered and the great acceleration of our impacts on the natural world must come to a stop. We must rein our powers in, using them in a measured way, conscious of the limits of the natural world and our dependence on it.

… Will it be defined by a sun a thousandth less bright?

If Stratospheric Aerosol Injection (SAI) geoengineering were deployed to halt global warming, within a few years the sun would be one thousandth less bright than it was. Doing this would likely greatly reduce the extremes of heat, rainfall, and many other impacts of climate change. And, if we do a decent job of cutting greenhouse gas emissions, we might never need to dim the sun by more than 1% to keep global temperatures below 1.5 Celcius.

When historians, centuries in the future, reflect on how the Anthropocene shaped up, they may not see the atomic bomb as the defining technology of the age. They may think of SAI instead: A deliberate, global, technological intervention to manage the consequences of our yet-to-be-constrained impacts on the environment.

Will it come to be seen as emblematic of our desire to escape the consequences of our actions, to chase perpetual, destructive growth on a finite planet to our ultimate undoing?

Or will it represent the kind of careful, coordinated management of the environment that a crowded world needed to transition safely to a more sustainable path?

Taking up Atlas’s burden

The great powers of the world, the modern Titans, ushered in the Anthropocene when they raised up their flashing, nuclear swords, and they will bring it to an abrupt and terrible end if they ever bring their swords down on each other.

I’m not so much of an optimist to hope that the great powers will lay down their arms anytime soon. However, I believe that despite their differences, they have a strong, mutual interest in stabilizing our rapidly changing environment. If the evidence of SAI’s potential to reduce climate risks continues to grow, then we may see these Titans working together to raise up a persistent aerosol layer, a shield of light, to hold back the heat of the sun.

Like Atlas, the Titan who held up the Heavens, the great powers will not be able to let their burden down, unless and until we drive CO2 concentrations back to safe levels. This then would be an epic undertaking, potentially spanning centuries, but if we want the Anthropocene to last, we’ll need to think and act on such titanic scales.

FIN

1. Zeus fashioned Pandora, the first woman, who opened the box containing all the evils of the world.

2. He was tied to a rock where a vulture endlessly pecked out his liver for all eternity.