Dipesh: the way to make this work is not to have discussants and respondents
Now Jan Zalasiewicz will speak, the only non-social science/humanities scholar here
geologist at U of Leicester
The Earth after Us (2008)
he is part of the push to make the Anthropocene acceptable >> International Stratigraphy Association
this is as political as naming something “genocide” or “famine”
he will address us on the history of the term and the current status of the concept
International Stratigraphic Chart. There is a problem in the study of Earth. We have to deal with 4.5 billion years of complex history. No way to deal without resorting to some means of trickery.
We take dynasties of time and simply categorize them into successive units that we can handle. To give us labels that we can use. It simply tries to represent the major events and turning points in Earth history.
Where are we? Currently we are at the top of this mountain of time, divided hierarchically. We are in the phanerozoic eon in which creepy crawlies have been on the planet. There are three eras. We are in the Cenozoic era, in the Quaternary period when ice has been dominant on Earth.
The very last 11 and a bit thousand years (when the ice last retreated) is now called the Holocene epoch. Vietnam, Louisiana, etc made of Holocene deposits.
Now on top of this do we put another geological time interval? This idea has been around for quite some time
The first person who specifically developed such an idea was Buffon. Les epochs de la nature. First stratigraphic history of the Earth. 7 epochs. The last of these “Lorsque la puissance de l’homme a seconde celle de la Nature.”
Included ideas of global warming (a good thing, he thought, to postpone deep freeze)
Stoppani, Anthropozoic era; Vernadsky was also getting onto these ideas
But geologists said “nonsense.” Earth is very old and powerful. Colliding continents must be far more powerful than anything humans can introduce. Jokes about the Coke bottle layer in the strata.
This changed. Paul Crutzen, an atmospheric chemist. 2000: suggested Holocene had finished. Human impact on cryosphere, ocean, land. Anthropocene concept.
2002 Nature paper.
>> eventually term used without inverted comments in the literature, as if it were a real geological term
(even though it still isn’t)
we discussed it on the Stratigraphic Commission. We have the privilege of a free lunch with wine! We wrote a position paper on the term. 21 out of 22 serious non radical often commercial geologists said there is merit in the idea and it should be examined further. So evidence for and against is now being gathered
Philosophical Transactions of the Royal Society A: Mathematical and Physical Engineering Sciences 369.1938
last 200 years: human population rose above 1 billion then climbed very steeply
energy use climbed even more steeply
climate change: not significant yet...
sea level change: yet to budge...
4500 natural minerals probably doubled by humans
metals like to combine with other things in nature; aluminum is present in micrograms, vanadium and molybdenum not at all
growth of aluminum since 1950: we have produced 0.5 billion tons of aluminum, enough to cover whole USA in kitchen foil!
synthetic minerals; garnets for lasers; tungsten carbide; carbon fiber, graphene
mineraloids: ceramics, glasses
polymers, plastics; there is nothing quite like that in nature; 280 million tons a year, hardly any of which is recycled
it’s everywhere now, land and sea; almost all since 1950
by 2050 you can wrap Earth six times over in plastic wrap
rock: concrete; 2 billion tons a year produced.
bricks: one trillion bricks each year...
new strata: artificial hill in Cracow; holes in the ground (1km in Siberia)
holes filled with sediment
just about every major river has got one dam on it now
that is geology; it can be classified geologically
meters thick strata formed very rapidly, orders of magnitude faster than most geological processes
chemical signals: global warming at the moment is a small part of the Anthropocene yet may become dominant
fossil air in arctic ice: temperature fluctuation has gone up in lockstep with CO2
clearly we are changing that
Transport: since 1950, motor vehicles
it is surprisingly easy to change earth
>> it is fairly easy to change the composition
the climb is irregular; the Earth has a complicated plumbing system but the climb is for real
Antarctica is clearly losing mass now
5 meter sea level rise is trivial but for humans it would be uncomfortable
strata change: Triassic-Jurassic boundary in UK
bigger than climate change
the other CO2 problem: acidification
down 0.1 of a Ph point: 30% more hydrogen ions in the ocean
we don’t yet know
at 500ppm coral will stop growing and start shrinking probably mid-century
we need lots of it to keep ourselves alive; mid C19 turnips << fertilizers: bone meal; raiding skeletons from battlefields of Europe to grind up and put on fields
mummified cats ground up 1880 ground up and put on fields (wow)
dinosaur bones, feces (coprolites)
and we are still extracting phosphate; this appears to be near peak levels at the moment
we can take out of atmosphere; we have doubled the amount at Earth’s surface
1950: input of nitrogen in areas far from civilization
a global nitrogen signal
Cretaceous: sea also died << lack of circulation; gray layer in rock
since 1945 and more so 1956 (air bomb tests)
footprints; but also wasps’ nest; equivalent would be the building we are in at the moment!
we are creating trace fossils made of minerals and rocks, eminently traceable
Shanghai “trace fossil” that goes on and on and on...
we are converting the surface into a rural trace fossil (me: agrilogistics!)
diversity of “shelly” marine vertebrates can tell time
zoologists, botanists, ecologists use different numbers than geologists
golden toad of Costa Rica: discovered 1964, extinct by 1990s
do we have an era scale extinction event? not yet--but masses of things critically endangered
we are within a couple of centuries of it!
McDonaldization of life, spreading species across world
rabbits, cats, zebra mussel (took over USA)
New Zealand: 1790 native, 1570 invasive species
wet weight, dry weight, simple bulk
biomass: humans are roughly 32% of vertebrate biomass
other 65% is creatures we keep to eat
vertebrate wildlife <3 font="">3>
Nature: strong case
Q: what is the other side?