Lecture 1: Anthropocene

Question 1

Anthropocene=

Answer 1

a proposed epoch dating from the start of significant human impact on Earth’s geology & ecosystems

Question 2

geologic time = ____ time
what is the geological time scale? (GTS) List in order

Answer 2

deep

Eons
Eras
Periods
Epochs
Ages (subunits of epochs)

Question 3

How old is the Earth? (aprox)

Answer 3

4.6 billion years old

Question 4

___ are the largest time unit in the GTS
____ are the smallest time unit in the GTS

Answer 4

eons
ages

Question 5

where are we now in the GTS?

Answer 5

eon: phanerozoic
era: Cenozoic
period: quaternary
epoch: holocene

Question 6

Why is it hard to define a new epoch right now?

Answer 6

Defining a period while in it has never been done before- this is problematic

Question 7

list a few reasons that support that we’ve entered a new epoch

Answer 7

• human pop growth rate explosion
• inc urbanization
• mass extinctions
• climate change
• damage to ozone layer
• anthropogenic materials (plastic, concrete)
• coastal wetland loss

Question 8

When did the Anthropocene start?

Answer 8

This is not solved yet!
Some proposed start dates are:
- some dates pre-industrial revolution
- 1760: industrial revolution
- 1945: nuclear weapon denotation
- 1950s: Beginning of the great acceleration; persistent industrial chemicals, plutonium from atomic weapon testing found in soil in 1951 could mark the Anthropocene

Question 9

What’s a recent alternative to adding the Anthropocene as an epoch?

Answer 9

Anthropocene as an ongoing event, not an epoch

geological event= major transformative episode in Earth’s history that varied spatially and and temporally (they are very important and change our planet)

Question 10

Who proposed the Anthropocene and made it popular? When?

Answer 10

Biologist Eugene Stoermer and Chemist Paul Crutzen
(in the Global Change Newsletter)
Year published= 2000

Question 11

Pleistocene epoch=

Answer 11

ice age

Question 12

When did Paul Crutzen suggest that the Anthropocene started?

Answer 12

In the late 18th century, when analysis of air trapped in polar ice showed the beginning of growing global concentrations of CO2 and methane

Question 13

In 1873, Italian geologist Antonio Stoppani suggested we were entering an:

Answer 13

Antropozoic era

Question 14

T/F
our socioeconomical trends show logarithmic growth of almost everything (population, urbanization, water use, paper production, fertilizer consumption, tourism)

Answer 14

False
These all show exponential growth :(

Question 15

What do graphs show about our earth system trends?
eg.
- surface temp
- atmospheric CO2 and methane
- tropical forest loss
- domesticated land

Answer 15

these are all growing exponentially

Question 16

T/F
urbanization is growing at a similar rate all around the world

Answer 16

true
people everywhere are moving to the cities for jobs

Question 17

What are some changes that are happening with Carbon?

Answer 17

overall levels of CO2 and CH4 are increasing; there are lots of fluctuations- not following trajectories of the past

Question 18

What are the 6 most important greenhouse gases? List them in order of potency, not abundance

Answer 18

1. CO2 (most abundant, least potent)
2. water vapor
3. methane (21x as potent as CO2)
4. N2O (laughing gas): 310 CO2
5. tropospheric ozone: 1000 CO2
6. CFCs: 4750 CO2

Question 19

___ are responsible for breaking down the ozone layer

Answer 19

CFCs (chloroflourocarbons)

Question 20

the layers inside ice cores indicate ____
The bubbles=
larger chunks=

Answer 20

seasons (summer= light, winter= dark)

bubbles= gasses from the atmosphere at a certain time

larger chunks= sediments

Question 21

T/F
the anthropogenic imbalance of the C cycle is superseded by that of the global N cycle

Answer 21

true!

Anthropogenic flux for C= +13%
Anthropogenic flux for N= +108%? (much more of a change)

Question 22

nitrogen leaves a clear trace in the geological record. Describe trends of soil nitrogen (nitrate NO3) N15, and N14

Answer 22

soil N (NO3)= doubled in the past century b/c of fertilizer

N15 is retained in animal tissued: decrease in N15= increase in N14 (more anthropogenic emissions)

Question 23

What are 2 reasons causing N14 to increase?

Answer 23

1. Fossil fuel emissions: NOx (nitric acid etc) emitted into the atmosphere
2. The Haber- Bosch Process
   - Artificial N fixation

Question 24

Describe the Haber-Bosch Process

Answer 24

this is artificial nitrogen fixation. It combines N gas and H gas using a metal catalyst under high heat and pressure to form NH3

NH3 gets into the N cycle b/c animals in the soil immobilize it, then die and break down

Question 25

___ is the main source of anthropogenic nitrogen fixation

Answer 25

fertilizer production (Haber Bosch process)

Question 26

What could be one of the causes of the more powerful/ frequent storms we have been experiencing recently?

Answer 26

anomalies in temp of ocean surface

Question 27

What is the Montreal Protocol?

Answer 27

the banning of CFCs to decrease damage to our ozone layer
- it is helping

Question 28

____ ___ provide habitat, water purification, etc, and they are being destroyed by urbanization and global warming.

Answer 28

coastal wetlands

Question 29

The collapse of fisheries is connected to the loss of ___

Answer 29

wetlands

also overfishing is out of control!

Question 30

What has been appearing in our oceans/ sediments?

Answer 30

anthropogenic materials
- aluminum
- concrete
- plastics
- synthetic fibers

Question 31

Explain the spikes in radioactive materials in the 1960s

Answer 31

these spikes were not natural; used for fuel of atomic weapons

the huge spike in 1964= date of atomic bomb testing

this increase in radioactive materials is evidence of anthropogenic change

Question 32

How do we define the Anthropocene?

Answer 32

= profound change in geological conditions and processes due to humans

• must be scientifically justified
• can’t agree: on a spatial and temporal marker for the onset of the Anthropocene
• agree: changes are occurring- just don’t know how to categorize it

Question 33

what are 3 alternatives for the Anthropocene?

Answer 33

1. Add the Anthropocene as a new epoch after the Holocene
2. Replace the epoch Holocene with Anthropocene (not popular)- downgrade holocene to age
3. the anthropocene as a new age/ stage within Holocene epoch

*know what these look like on the GTS scale

Question 34

Summary of proposed start dates/ events for the Anthropocene (9)

Answer 34

1. Megafauna extinction- 50,000- 10,000 yr BP
2. Origin of farming- 11,000 yr BP
3. Extensive farming- 8,000yr BP to present
4. Rice production- 6500yr BP to present
5. anthropogenic soils- 3000-500ys BP
6. New-Old world collision- 1492-1800
7. industrial revolution- 1760- present
8. Nuclear weapon denotation- 1945- present
9. persistent industrial chemicals- 1950 to present

Question 35

what was the proposed formal definition of the Anthropocene in 2017 by the “working group on the Anthropocene”?

Answer 35

Anthropocene as a new epoch
- starting mid 20th century (~1945- plutonium fallout)

Question 36

In ___ Gibbard et al. proposed that the anthropocene is:

Answer 36

2022
an ongoing event, not an epoch
- this is informal, but still a geological definition (but does not appear in the GTS)

Question 37

geological event=

Answer 37

major transformative episode in earth history that vary spatially and temporally
- very important; they change our planet
- Gibbard et al. suggested that the anthropocene is an ongoing geological event

Question 38

give 2 examples of ongoing geological events

Answer 38

1. great oxidation event (an increase of oxygen in atmosphere 2.4-2.0 Ga)
2. forestation of continents in the middle-late Devonian
   (land was colonized by plants- very important, but didn’t happen at the same time everywhere)