ocean final

decadal variability

wet and dry times seem to cluster over decades; wet and dry conditions shape civilization

connections between history and climate change?

decline and fall of many civilizations coincide with periods of climate change; correlations between climate change and frequency of wars

Asymptotically stable (decadal variability term)

force
system away from initial
condition and the system
returns to initial state

Unstable decadal variability

force away and
system moves to a different
state. This usually implies
multiple possible stable
equilibria, with forcing that is
strong enough to push into a
different equilibrium state

what does decadal variability cause

complex interplay between ocean and atmosphere, including pacific decadal oscillation (PDO) and atlantic multidecadal oscillation (AMO)

pacific decadal oscillation (PDO)

defined by how much ocean temperatures deviate from the average;
there are warm or Cold Phases (Warm = warmer than
average off California; Cold = colder than
average off California); PDO switches phases approx. 20-30 years;
every few decades

how does PDO affect fishing

PDO warm= good salmon fishing off Alaska

PDO cold= poor salmon fishing off Alaska

how/ why does PDO affect fish distribution?

Position of North Pacific High Pressure(s) affects the
path of the winds
Path of winds drives motion of water
Motion of water drives upwelling (of cold water)
Upwelling brings nutrients (N, P) up to surface ocean
Phytoplankton can obtain nutrients and plants grow
Zooplankton eat phytoplankton => more Zooplankton = more Salmon

true or false- Phase of PDO influences rainfall patterns

true

true or false- changes in ocean affects continental climate

true; thus PDO affects continental climate

what is the affect of hydrogen pressure over the pacific

A persistent H pressure system over the N. Pacific Ocean
can create an Oceanic Heat Wave
A ’blob’ of warm water can develop

signs of a persistent H pressure system

Sinking Air, clear skies, extra heating, ocean warms
Warm water is less dense
creates more stratified ocean,
stratification inhibits ocean mixing, fewer nutrients
get into upper ocean
Entire ecosystem suffers

what do sunspots (literally spots on sun) mean

sunspots= more solar energy; the fewer sunspots means a colder climate

what is driving decadal variability

solar insolation + sun spots

areas affected by PDO

Affects currents and water temperature off coasts of
Alaska, Washington, Oregon, California

el nino southern oscillation (ENSO)

ocean atmosphere phenomenon in the tropical pacific; leading cause of inter annual climate variability w/ global consequences

why is it called el nino

peruvian fishermen; el nino is a periodic ocean warming that usually happens around xmas, and is problematic because of huge reductions of anchovy fishery and seabird populations

side effect of el nino

cloudy sky in peru

what else does enso describe besides atmosphere

shifts in wind and ocean currents in the equatorial pacific ocean; as the wind is blowing it moves water from west to east and the pressure moves as well

southern oscillation

atmospheric pressure seesaw between darwin, Australia, and tahiti

what causes el nino

occurs when trade winds diminish and the warm water moves from west to east along the equatorial pacific and along with it low pressure rainfall and winds

what are normal ocean conditions in equatorial pacific

trade winds blow equatorial currents carry water westward; in west pacific a warm water pool is formed and its pushed up against indonesia into indian ocean

what happens to thermocline (place where temp in ocean changes from warm to cold) during el nino

the thermocline deepens in east pacific

shallower thermocline

nutrients are closer to ocean and there is more fish; but since el nino causes a deep thermocline fishing is harder

what is la nina

opposite of el nino; strong trade winds, Very cold waters in the eastern Pacific, warm waters pushed far to the West

2 climate states associated with ENSO

el nino and la nina

why care about ENSO

Fisheries change in the eastern Pacific, Warm waters along South and Central
American coastlines change coastal ecosystems up and down the Americas, ENSO Changes weather patterns around the globe

why is el nino’s impact global

due to Teleconnections: Teleconnections are correlations between weather events that occur at different places on the Earth, so what happens at the equator doesn’t stay
at the equator

why study oceans of the past

allows us to predict change in the future; and the ocean and climate are coupled- the changes in the climate coincide with the growth or collapse w civilizations or extinction of animals, etc.

length of PDO vs el nino

PDO- decadal

el nino- 3-10 years

climate- LONG TERM environmental conditions

paleocoeanograpy - study of past ocean

past climate archives

• ice cores- layers of ice record temp

• glaciers- leave behind evidence of where they’ve been

• tree rings- record climate, wide rings mean good rainfall and conditions

little ice age in n. europe (~1500-1800 AD)

Crops failed
Ecosystems changed
Famine/Malnutrition
Wineries failed
Sea Ice Plague
Social Unrest
Flooding/Storms
Glacial growth (failure of civilization on Greenland)
Art and Literature were influenced
Historical Records tell this story

longest archive of paleoclimate

ocean sediments: sediments represent slices of time (pages of book); the oldest layer is at the bottom, with successively younger layers above.

how are sediments collected

sediment cores (tubes) placed down into the ocean to collect sediments

proxy

the way we stay ancient ocean conditions; a measurable quantity that substitutes for something no longer measurable eg: this fossil is a proxy
for ocean temperature

how is foraminifera a good ocean proxy?

• some elements have the same number of protons, but a different number of neutrons (isotope) (ex O16 v. O18)

• water is held together by hydrogen bonds, and 16OH bonds are easier to break than 18OH bonds and H16O evaporates more easy as well)

• There’s more O18 when its colder because when there is more ice more O16 captured as snow and so the ocean is ore likely to be saturated in O18

• FORAMS (caCO3) record ocean water and the concentration of O18 v. O16 because forams incorporate the O from H2O, so the more O18 in the ocean the more O18 in the shells

  • can roughly tell what the temp was like then

sediment cores

fossil organisms record info about seawater when they form their shells; gives info abt ice ages

how long has fluctuation of earths climate occurred

at least 500 million years, happening in warm or cold phases and affecting sea level and the oxygen makeup of forams

what happened during the last ice age (~20,000 years ago)

average Global temperature was 8-10°C colder (about 15-20° F colder); Glaciers extended over most of Canada, Alaska, Greenland, Antarctica,
Scandinavia, and northern Siberia; Permanent ocean ice extended farther out
into the ocean surrounding Antarctica

sea level during ice age

Sea level was about 105 meters lower
than today—
• Russia and Alaska were connected
• There were no continental shelves
• In Southern California, the Channel
Islands were almost connected to
mainland

true or false:During the last Ice Age, ocean water vapor became trapped as Snow and Ice

true

asymmetrical pattern of temp maps

the climate gets warm quickly but gets cold slowly; increases in regular cycles of 2 degrees celcius warmer and 8 degrees celsius colder (temperature ceilings and floors)

what keeps climate fluctuating on regular cycles?

solar insolation- milankovich cycles: the earths movement around the sun causes a variation in orbit and thus variation in solar energy because of the eras wobble, tilt and eccentricity

true or false- earth is sensitive to the amount of solar insolation received

true

main driver of climate change

solar insolation

largest heat reservoir

the ocean

water pollution

any chemical, biological, or physical change in water quality that has an effect on living organisms; such as gas (co2), liquid (agricultural runoff), or solid (metals)

gulf of mexico dead zone

• anoxia= no oxygen, hypoxia= little oxygen

• mississippi river covers a lot of major agricultural area and drains into 41% of USA, including the gulf of mexico

• nitrogen fertilizer from agricultural runoff drains into the gulf, resulting in nitrate in the ocean

• fertilizer causes phytoplankton blooms, and when they die the oxygen dissolves which makes a deadzone

sewage pollution

treated sewage is dumped into the ocean; outfall pipes lie on the bottom of the ocean and DDT can exit out the pipe, causing biomagnification

harmful algae blooms pollution

diatom produces domoic acid (neurotoxin); causing sea lions and brown pelicans to get sick

plastic pollution

plastics float when they break up into small pieces and marine organisms ingest the plastic; plastics can also absorb toxic chemicals that organisms will consume; and plastic is particularly concentrated in subtropical gyres

oil pollution

oil spills contaminates the environment, harming wildlife, disrupting ecosystems, and posing risks to human health

how is the ocean profitable

billions of dollars can be made off ocean; half made off of ocean tourism, other avenues include fisheries, high tech, ships and ports

emerging ocean economies

offshore wind energy, marine and seabed mining, biotechnology, marine robotics

what makes blue economy different from land economy

sea is larger than land, more 3d, fluid and interconnected, and has lack of ownership

number one blue economy sector?

marine robotics, ex: robotics can clean ship hulls

EEZ (exclusive economic zone)

area of sea in which a sovereign state has special rights regarding the use of marine resources; stretches from shoreline to 200 nautical miles from the coast

how do people take advantage of EEZ’s

they suck up sediment from seabed, transport it through broken pipes and deposit it on reefs killing corals in process), ultimately creating manmade islands to have ownership of EEZ and using the island for a military installation

marine mining

• countries are switching to clean energy, and so demands for copper lithium nickel cobalt and rare earth elements (REEs) are soaring

  • rivers can carry REEs into the ocean, and they settles into openings of manganese nodules

how are REEs/ chemicals extracted from manganese nodules

manganese nodules are collected and broken up to extract the chemicals on the boat, then directly after the manganese nodules particles are dumped in the ocean, which causes dirty/ cloudy ocean

impacts of marine mining

sediments released can choke filter feeding species and fish swimming in the water column; mining also introduces noise vibrations and light pollution that interrupt animal habitats

argument for ocean windmills and turbines instead of land windmills

• Ocean Wind is more constant than on land, less gusty

• Fewer complaints about visual eyesore

• Denmark gets very high fraction energy from wind

• Ocean wind energy was on a huge uptick, until
  government change in 2024-25

marine microbes

bacteria can be a rich source of potential drugs, helping chemo, anticancer and bone repair

true or false- unloading shipping containers requires specialized ports/large amts of trucks/warehouses

true

how do ships remain efficient when traveling

travels in a curved path, moving with the gyres

fuel usage on ships

container ships burn 200-350 tons of fuel per day; the faster the travel the more fuel burned

why is it difficult to decarbonize shipping

shipping accounts for 3% of global co2 emissions

which hemisphere is warming faster

n hemisphere is warming faster than s hemisphere because there is more land and rock to warm up

consequences of warming the northern high latitudes

opens up shipping through arctic ocean

why is greenland valuable to trump

about 31 REEs present

geologic basins in artic

more drilling for oil, consequences of warming world

movement of permafrost boundary

frozen tundra is melting 12.5km a year, caribou cannot keep up and ecosystem is harmed

what happens as tundra melts

as tundra melts more nutrients get into the arctic rivers and ocean, and phytoplankton growth is on the increase in the arctic as a result

anthropocene

era of human influence on planet, started 240 years ago

evidence of anthropocene

• loss of ice on sea/land

• fish off maine and northeast navigated towards canada as oceans warm

• retreating glaciers

• ice in arctic and antic is melting bc air and ocean water is getting warmer——> sea level is rising

what does a warming ocean mean

warmer ocean= more stratified ocean; and the less mixing, the less oxygen in deeper water, which makes more dead zones and thus fewer fish

warmer ocean, acidic ocean, less oxygen in ocean

2090 projections

hot ocean, lower oxygen= breathless, more acidic= coral bleaching

warmer ocean also means more intense weather

hurricane formation depends on warm water

true or false- co2 acts like a blanket

true

evidence that lack of carbonate is a problem

pteropods use carbonate to form shells usually, but their shells are dissolving which threatened the pteropod population; which is really bad because salmon depend on pteropods for food

how much co2 does the ocean intake

of the ~6 units of CO2 that enter the atmosphere every year from burning fossil fuels, the ocean takes up 2 units

impact of increasing co2 levels in the atmosphere

global heating and ocean acidification

co2 turning into 2HCO3

because of ocean acidification co2 becomes bicarbonate instead of carbonate, so organisms can’t build shells

true or false- number of extinct animals rapidly climbing since 1960

true, scientists worry we are approaching our 6th major mass extinction

rate of extinction

mammals tend to go extinct the most because of hunting (along w/ birds); but ocean species are now disappearing faster than those on land

consequences of overfishing

we are losing whales in the ocean, and alongside whale populations krill populations are declining because they need whale poop to fertilize phytoplankton for krill to eat to grow.

jellyfish population exploding

their predators are being overfished, and there is a theory that plastics floating in ocean allows for jellyfish polyps to attach for larvae growth

7 wedges/ approaches to lessen co2 levels and move from business as usual to stabilization

transportation efficiency, biofuels, nuclear power, wind power, solar power, carbon (finding a way to get rid of CO2), reforestation

CO2 sequestration is on the rise

wants to put more co2 in the ocean where it has a better chance to balance

marine carbon dioxide removal (marine CDR) (WAYS TO SEQUESTER CARBON)

• ecosystem restoration

  • restocking whale, seaweed, and mangrove pop.

• ocean fertilization

  • iron, nitrogen or phosphorus fertilization; artificial upwelling

• modification of ocean chemistry

  • ocean alkalinity enhancing, seawater CO2 stripping

• storage of carbon captured on land

  • liquid CO2 on seabed, crop waste and micro algae deposition

ocean alkalinity enhancement- 4 approaches

• add silicate materials to ocean and land to suck up CO2

• add a strong base (lime) to suck up co2

• electrochemical hydrolysis (break water apart)- separate H from the OH and then let the OH suck up the CO2

• accelerated weathering of limestone (AWL) (professors line of work-might be important)

  • neutralizing of CO2 emitted by ships

  • CO2 + calcite +seawater = clean gas + slightly saltier seawater

  • neutralizes ocean, like TUMS medicine

  • via AWL we are acerbating the addition of HCO3 +Ca to the ocean