volcano climate effects III

Question 1

how do volcanic eruptions have short-term impacts on global average temperatures?

Question 2

what gas / chemical element has the greatest impact on climate during shorter time scales?

Answer 2

sulfur

Question 3

what are the short-term effects of volcanoes on the climate?

Answer 3

very large eruptions inject aerosols and ash into stratosphere (no weather to remove)
- duration of eruption can matter: shorter in the troposphere, if eruption continues for weeks, months or the year, it is constantly replenishing that in the troposphere, making it have similar impacts
- sulfur is hydrophilic (loves water), which forms reflective aerosols (high albedo: 1), which scatter and absorb incoming solar radiation
- ash has more mass, short resonance time, not a lot emitted into stratosphere

Question 4

what are SAGE satellites?

Answer 4

measure optical depth (how easily light penetrated through stratosphere to get to the surface)
- increase optical depth = harder for incoming radiation to get through

Question 5

where is optical depth greatest?

Answer 5

in the tropics

Question 6

why did optical depth of the atmosphere thicken?

Answer 6

sulfate aerosols and gas

Question 7

do larger eruptions have greater impacts? what variable effect how catastrophic an eruption is

Answer 7

not necessarily !
1. time of year
2. location (hemisphere vs equator)
3. weather patterns
4. volatile content
5. eruption style and length

Question 8

most large eruptions are _______, but _______ eruptions have a much higher sulfur content?

Answer 8

felsic; mafic

Question 9

what are the long term effects of super eruptions?

Answer 9

NO LONG TERM CHANGE because it is still a single injection and residence time of sulphate aerosols are limited

Question 10

what are the hypothesized effects of super eruptions?

Answer 10

• speeding the onset of glaciation
• bottleneck effect in human lineage
• massive tropical ozone depletion

Question 11

how can we tell how much sulfur is injected into the atmosphere?

Answer 11

ice cores: deposited and conserved

Question 12

are volcanoes the smallest or largest contributor to short-term natural climate variability?

Answer 12

largest!

Question 13

what will happen if you have multiple closely spaced together eruptions?

Answer 13

• more persistent climate perturbation because cooling may be extended, learning to amplification by climate feedback
• little ice age

Question 14

how is a little ice age created (steps)?

Answer 14

• triggered / intensified by multiple eruptions
• sulfate records show many eruptions prior and into ice age
• sea ice is less likely to melt
• reflectivity of northern latitudes stays high
• grow more sea ice the following year
• increase albedo, reflect more solar radiation back into atmosphere, cooler temp

Question 15

in hunga tonga- honga ha’apai, what made that eruption so catastrophic?

Answer 15

evaporated enormous amounts of water, despite having a small sulfur content
increased water vapor content into the stratosphere
estimated to raise global average temperature

Question 16

water vapor is an effective..?

Answer 16

greenhouse gas!

Question 17

what are large igneous provinces (LIPS)?

Answer 17

• large volumes of (mostly) mafic magmas were generated and extruded onto the landscape
• form independently of plate setting
• found on continents, in ocean, along margins between the two, within plate boundaries or at plate boundaries
• generally caused by hot spots / mantle plumes

Question 18

what specific places are large igneous provinces?

Answer 18

continental flood basalts
volcanic rifted margins
oceanic plates
ocean basin flood basalts

Question 19

what are the long-term climate effects of volcanoes?

Answer 19

• emit CO2
• CO2 pumped into atmosphere consistently for a long time
• global warming

Question 20

when the atmosphere is cooling, ________ gas is produced. when the atmosphere is warming, ______ gas is produced

Answer 20

sulfate; CO2

Question 21

persistent eruptions on LIPS may lead to what climate issues?

Answer 21

1. ocean acidification (CO2)
2. ocean anoxia (caused by acidification, eruptions lead to fertilization, which leads to plumes, which leads to anoxia)
3. acid raid (sulfur)
4. gas and light block impact on terrestrial ecosystems (photosynthetic shutdowns)

Question 22

out of the big 5 mass extinction events, what do most of them have in common?

Answer 22

LIPS volcanic eruption

Question 23

peak extinction events are associated with what characteristics?

Answer 23

• specific eruption pulses
• shorter overall duration
• siberian traps had the greatest impact (burnt through large coal deposits, and burnt large amounts of fossil fuels)

Question 24

what features of major extinction events do LIPS explain?

Answer 24

1. loss of carbonate deposits in the ocean (acidification)
2. negative carbon isotopic excursions (thermogenic greenhouse gas: methane) and persistent instability
3. spikes in metal deposits
4. other isotopic excursions (sulfur, mercury, nitrogen)

Question 25

what is the major reason for long-term climate change?

Answer 25

carbon cycling

Question 26

how does carbon cycling occur?

Answer 26

1. dissolution of CO2 in rain, becomes slightly acidic
2. calcium + magnesium silicates do not re-form on land, most material in ocean
3. calcium ions utilized by shell produces that bind CO2 to something more solid
4. ongoing exchange of CO2 between ocean and atmosphere

silicate weathering on land + carbonate precipitation in the sea = natural carbon sequestration

Question 27

what would happen if there was no return of CO2 to the atmosphere in carbon cycling?

Answer 27

take an extremely long time to deplete “short-term” cycle of carbon

carbon dioxide moves through ocean, biosphere, atmosphere, by a certain proportion of carbon atoms are sucked out and put into rock record (sequestered)

Question 28

what is the carbonate-silicate geochemical cycle?

Answer 28

plate tectonics keep the earth alive

Question 29

what is carbonate metamorphism?

Answer 29

reverse of silica weathering, carbonate precipitation and ocean-atmosphere exchange

releasing carbon, erupted through volcanoes

Question 30

what are the steps of the carbonate-silicate geochemical cycle?

Answer 30

1. carbon bearing rocks subducted
2. undergo metamorphism
3. sufficiently high temperature reached
4. subducted mantle-derived CO2 return to ocean and atmosphere through mid-ocean ridges and volcanoes

Question 31

how did we get out of snowball earth?

Answer 31

weathering was taken out of equation (not much CO2 out of atmosphere), but volcanoes still erupting and returning CO2 into the atmosphere