[Aqualist] FW: Earth Sciences Seminar Friday 31st October, Prof Prosenjit Ghosh,

[John Tibby]

Hi All,
A fascinating sounding lecture at Adelaide later this week.
Cheers,
John


From: Andrew Merdith <andrew.merdith at adelaide.edu.au>
Sent: Tuesday, 28 October 2025 2:55 PM
To: SPCES - All Earth Sciences Staff <earthsciencesstaff.pces at dl.adelaide.edu.au>; SPCES - Earth Sciences Academic Staff <earthsciencesacademics.pces at dl.adelaide.edu.au>; SPCES - Earth Sciences Titleholders <earthsciencestitleholders.pces at dl.adelaide.edu.au>; SPCES - Earth Sciences Honours Students <earthscienceshonours.pces at dl.adelaide.edu.au>; earthscienceshdr.pces at list.adelaide.edu.au
Subject: Earth Sciences Seminar Friday 31st October, Prof Prosenjit Ghosh,

Hi everyone,

This week will be our last seminar for the semester (woo!). We have our visiting international fellow, Professor Prosenjit Ghosh from the Indian Institute of Science, Bangalore, presenting some of his recent work on wildfires, titled 'Wildfire-alkalinity and CO2 drawdown in greenhouse world'! Please see attached flyer for abstract and biography. The seminar will be on the Mawson Lecture Theatre at 1100, we will head somewhere for lunch after so please let me know if you would like to come!

The talk will be zoomed and recorded, link below.

Thanks
Andrew

Event: Earth Science Seminar
Speaker: Prof. Prosenjit Ghosh
Date: Friday 31st October 2025
Time: 11am-12pm
Venue: Mawson Lecture Theatre / Zoom: https://adelaide.zoom.us/j/83220371102?pwd=L2I0dzlxbmVVMThmb0J3aGhwNnRwQT09  (Passcode: Mawson)

Wildfire-alkalinity and CO2 drawdown in greenhouse world
Abstract: The Plio-Pleistocene transition (1.5–3 million years ago, Ma) is marked by a ⁓140 ppm drop in
atmospheric CO2 levels, leading to a long-term global cooling. Excess production of organic carbon (OC) from
terrestrial vegetation, followed by its transport and burial, was responsible for the decline in CO2 level. The role
of wildfire triggering as a system response to the high atmospheric CO2 is proposed for the first time as a viable
mechanism to explain vegetational shift, erosion, burial of OC as charcoal and alkalinity buildup. All these led to
a drastic drawdown of atmospheric CO2. Here, we quantified the impact of Fire-Induced EPects (FIE) on the OC
burial rates at both regional and global scales during the interval from 4 to 1.5 Ma. Nicobar Fan serves as an ideal
depocenter for terrestrial carbon. The multi-proxy approach reveals a notable intensification of wildfire activity
during the Plio-Pleistocene transition, accompanied by respective 2.9 and 2.4-fold rises in the rate of continental
erosion and OC burial fluxes compared to the early Pliocene. On a global scale, we constructed a global wildfire
stack using 19 wildfire proxy records sourced from continental and marine sediments. We calculated the global
OC burial rate using sediment OC content and Mass Accumulation Rate data from 23 ODP/IODP sites worldwide.
Global data showed a 4.8-fold surge in wildfire activity and a 1.5-fold increase in global OC burial rates, from 2.29
± 0.48 Mt C a-1 in the early Pliocene to 3.52 ± 0.80 Mt C a-1 at the Plio-Pleistocene transition. Our research
highlights the pivotal role of FIE in atmospheric CO2 drawdown, a topic that has been seldom discussed in
previous studies.