From Cosmic Explosions To Terrestrial Fires?

Multiple lines of evidence point to one or more moderately nearby supernovae, with the strongest signal ~2.6 Ma. We build on previous work to argue for the likelihood of cosmic ray ionization of the atmosphere and electron cascades leading to more frequent lightning, and therefore an increase in nitrate deposition and in wildfires.

The potential exists for a large increase in the pre-human nitrate flux onto the surface, which has previously been argued to lead to CO2 drawdown and cooling of the climate. Evidence for increased wildfires exists in an increase in soot and carbon deposits over the relevant period. The wildfires would have contributed to the transition from forest to savanna in northeast Africa, long argued to have been a factor in the evolution of hominin bipedalism.

Adrian L. Melott (Kansas), Brian C. Thomas (Washburn)
(Submitted on 4 Mar 2019)

Comments: 20 pages, 3 figures. To be published in the Journal of Geology
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); High Energy Astrophysical Phenomena (astro-ph.HE); Atmospheric and Oceanic Physics (physics.ao-ph); Geophysics (physics.geo-ph); Populations and Evolution (q-bio.PE)
Cite as: arXiv:1903.01501 [astro-ph.EP] (or arXiv:1903.01501v1 [astro-ph.EP] for this version)
Submission history
From: Adrian Melott
[v1] Mon, 4 Mar 2019 19:35:49 UTC (217 KB)
https://arxiv.org/abs/1903.01501
Astrobiology