First Nuclear Bomb Set Off The Anthropocene

  • When, precisely, did the 12,000-year-old, Holocene epoch transition into the Anthropocene, an epoch of catastrophic human-led change that threatens Earth’s future?
  • Did it begin several millennia ago with agriculture and altered carbon dioxide levels?
  •  Was it spurred by the Industrial Revolution in the early 1800s with the increasing use of fossil fuels?
  • Two recent scientific papers say the Anthropocene could be pinned down to a precise moment on 16, July 1945
  • On this very day the world's first nuclear bomb exploded in Alamogordo, New Mexico.
  • The atomic bomb represents an instantaneous shift into another geological epoch, much the way the Cretaceous-Paleogene boundary is placed at the moment a meteorite impacted the Yucatan Peninsula
  • The Alamogordo explosion, followed soon by the Hiroshima and Nagasaki bombs in August 1945 and other bombs “detonated at the average rate of one every 9.6 days until 1988” produced markers across the globe in the form of radionuclides, found in all continents and in polar ice on both poles.
  • Physical and chemical markers  especially in deposits in rock strata and their fossil contents  are vital tools in defining epochal boundaries as they signal substantial changes in the Earth system.
  • The Alamogordo explosion also signalled the beginning of the “Great Acceleration”
  • This is the phase of massive economic growth and environmental changes post World War II, also associated widely with the beginning of the Anthropocene.
  • In another paper in Anthropocene Review scientists describe unprecedented global shifts
  • The scientists observed that the mid-20{+t}{+h}century Great Acceleration spurred: global average surface temperature increased by nearly 0.9°C; atmospheric concentrations of the three greenhouse gases – carbon dioxide, nitrous oxide and methane – reached levels well above the maximum observed at any time during the preceding Holocene and biodiversity loss may be approaching mass extinction rates.
  • The first atomic bomb “provide a unique signal of the start of the Great Acceleration” with the release of radioactive isotopes that spread worldwide and entered the sedimentary record, says the paper.
  • A third paper in Science that coincided with these studies, says that in this phase, the Earth crossed four out of nine “planetary boundaries”: (i) climate change(ii) loss of biosphere integrity(iii) land-system change(iv) altered biogeochemical cycles (phosphorus and nitrogen).
  • Will Steffen, professor at the Stockholm Resilience Centre, Stockholm University and the lead author of the second two papers said in an email : These transgressions mean that the risk of destabilising the global environment is increasing with obvious risks for human well-being.
  • Will Steffen  also noted: We need new technologies to de-couple economic growth from environmental impact. And we need to solve global equity issues, stabilising or reducing consumption in the wealthy countries to allow further development elsewhere to bring people out of poverty.