ocean prelim 3

avg surface temp now is how much above pre-industrial?

1.46 C

what is the widely accepted upper limit of warming

1.5 C above pre-industrial

how much colder were global avg temperatures during the ice age?

4 C

UN IPCC

the United Nations’ Intergovernmental Panel on Climate Change

what did the IPCC 6th assessment report conclude?

it is unequivocal that human influence has warmed the atmosphere, ocean, and land

greenhouse gas forcing

energy imbalance caused by human-emitted gases trapping heat that Earth radiates back, which then warms the planet

methane adds how much to greenhouse gas forcing?

50%

what is the primary cause of the increase in atmospheric methane since 2009?

natural gas extraction (methane) and its transport

Bob Howarth showed that global warming effect from burning natural gas for energy was as bad or worse than

burning coal

what level will the sea level reach with business as usual emissions?

1 meter above global average by the end of the century

What did IPCC AR6 say about the longevity of sea level rises?

rise for hundreds to thousands of years, and will remain elevated for thousands of years

three core strategies for adapting to sea-level rise

Retreat, Accomodate, Protect

when will the Arctic be largely ice-free in the summer if temperatures rise by 2C? if to 1.5C?

2C - first ice-free summer in 2035

1.5C - first in 2065

what significant changes are happening in Antarctica?

the West Antarctic Peninsula is one of the fastest warming areas on Earth, and the West Antarctic Ice Sheet is losing mass due to warmer ocean water near the coast

what significance do krill play in the Southern Ocean?

keystone species (large impact relative to abundance), serving as food for a broad array of predators

what will happen to krill in West Antarctica?

Antarctic krill are sea ice associated, and models project sea ice habitat will decline by up to 80%

what were the INDCs?

Intended Nationally Determined Contributions, pledges by nations responsible for 90% of global emissions

what was one of the key components of the Paris agreement with regards to reporting?

instititute a system of review of the emissions targets every five years

what did the NSA 2021 report conclude?

outlines that the pathway to net zero emissions would produce jobs and cleaner energy, but would require heavy political lifting

how much does carbon capture do compared to what needs to be done?

worldwide firms capture 45 million tons per year, but we need to be close to 1 billion

green hydrogen vs blue hydrogen and their relevance to energy

green - generated from electrolysis of water, which is good when separation is done with renewable energy

blue - generated from methane via natural gas fracking, which is bad even if renewable energy is used to separate

what has the international seabed authority approved since 1994?

over two dozen ocean floor mining exploration contracts since 1994

what elements of interest are in the deep sea?

lithium, cobalt, nickel

what type of country has contributed more to climate change today?

developed countries

how much will developing countries overtake developed countries?

2x cumulative emissions of developed countries over the next 100 years

what’s a more realistic target for limiting global warming?

3 C

how many losses over the decade from climate disasters?

1.4 trillion

how can small increases in mean global temperature cause large climate impacts? relate to the graph

a small shift in the mean temperature (blue horizontal arrow) drastically increases the probability of extreme hot weather and decreases cold weather (horizontal arrow)

what happens to drier and wetter regions during global warming?

• regions that are dry due to strong evaporation will get drier

• regions that are typically wet due to strong precipitation will get wetter (more heat —> more evaporation —> more moisture)

what did AR5 conclude regarding human activity?

it is very likely that human forcing has contributed to the intensity of daily temperature extremes

what did AR6 conclude regarding human activity?

its an established FACT that human emissions have led to an increased frequency of climate extremes

extreme weather attribution

science quantifying how much climate change increased the likelihood of specific events

how common were heatwaves pre-industrially, and how common are they now?

pre-industrial: every 50 years

at 1.5 C: every 6 years

at 2 C: every 4 years

what keeps the polar jet stream strong and stable under normal conditions?

a large temperature difference between cold Arctic/warm mid-latitude air creates a pressure gradient, keeping it contained at higher latitudes

what happens to the polar jet stream with climate change?

polar regions heat faster, so there’s less of a temperature gradient with warmer mid-latitude regions leading to a reduced pressure gradient

what happens as a result of a weaker pressure gradient for the jet stream?

jet stream meanders south, bringing polar air to low latitudes that last there for a long time

how did the heatwave affect primary production and zooplankton?

reduced primary production and shifted the zooplankton population to become smaller and less nutritious species

In addition to ice shelves being melted from warm air above, they are also being melted

from below by warm ocean waters

what part of the glacier melts fastest?

crevasses

Kyoto Protocol

1997 UN treaty that set legally binding targets for industrialized nations to reduce greenhouse gases

what did the Kyoto Now student organization push Cornell to do?

commit to Kyoto Protocol emission reductions

what plan was developed by president David Skorton?

a plan to become climate neutral, with a target date of 2050

what is the new target for Cornell Carbon Neutrality?

2035

what three elements does Cornell’s campus energy strategy consist of?

lake-source cooling, renewable energy, and district heating

what is Cornell’s main source of heat?

Earth-Source Heat, which uses deep earth source for warmth

what three sources of electricity does Cornell use?

wind, water, and solar

how much have we reduced CO2 emissions, and what was the primary cause?

reduced by 36% since 2008, primarily due to reduction in purchased electricity

what does the Cornell University Borehole Observatory do?

measures very hot rocks to test the feasibility of enhanced geothermal heating

how did the Cornell Climate Action plan get started?

students raising their voices in 2001

what is Hot Dry Rock? what would we need to do to it to obtain geothermal energy?

hot rock with high temperatures but low permeability, so we would need to fracture it to circulate water and extract heat

how does an enhanced geothermal system work?

injects cold water into fractured hot rock through one well, then pumps heated water back up through another

horizontal drilling

a technique where a well is drilled vertically first, then extended horizontally

what do hydraulic fracturing methods do?

insert high pressure fluid into natural rock fractures to make them larger

what is Cornell’s Earth Source Heat project?

replace campus heating with deep geothermal direct heat via deep rocks

what two layers of rock have promise for campus heating?

1. colder soft rock layer with well understood patterns, but hard to drill horizontally

2. hotter basement rock that is easier to drill horizontally, but has complicated fracturing

Earth Source Heat vs widely used Shallow Geoexchange System

similar carbon footprints if you only consider drilling, but constructing deep source heat is much less disruptive

point source pollution

singularly identifiable source of pollution, like a smoke stack

nonpoint source pollution

diffuse source of pollution, such as rainfall that carries human-made pollutants like oil

how large was the Deepwater Gulf spill?

over 180 million gallons of oil

what damage has the Gulf spill caused to fish populations? (PAH chemicals)

elevated levels of polycyclic aromatic hydrocarbons in every surveyed fish species, with some even disappearing

why do top predator fish have such high mercury levels?

mercury is not lost between trophic levels - it bioaccumulates, so a fish like tuna has 10^5 higher mercury concentration than its food base

what is the main concern of micro-plastics?

can acquire toxic organics on their surface, which is consumed by zooplankton and moved up the marine food chain

UN INC

Intergovernmental Negotiation Committee

what did the UN INC attempt to sign?

a plastic pollution treaty, but it has not yet been confirmed

what is the primary treatment to clean sewage outfall?

physical settling: solids sink to form sludge, and the rest of the liquid is discharged into environment

what is the secondary wastewater treatment?

biological: oxygen added so microbes consume dissolved organic matter, BUT this leaves nitrogen and phosphorus

what is tertiary wastewater treatment?

combination of primary and secondary with special nutrient removal, targeting nitrogen and phosphorus

how is a cumulative process employed by sewage treatment facilities?

all facilities in order, e.g. secondary requires that solids have already been removed

what is nutrient pollution (eutrophication) caused by

excess nitrogen and phosphorus in the air and water

what’s the issue with high nutrient loading?

increased nutrient loads simulates lots of algae growth, which eventually die and are consumed by microbes that also consume oxygen —> oxygen near the bottom of the ocean is very low, suffocating all aerobic organisms

what three factors have driven use of fertilizers?

human population increase, meat consumption, and industrial farming practices

what does high fertilizer use cause?

increase of coastal nitrogen pollution, since it provides extra nitrogen that runs off into coastal waters

how does meat production drive increased fertilizer use?

increases in grain production are needed to support an increase in global meat consumption, which is growing faster than population

what is a key takeaway from the modern farm/food nitrogen balance?

37% of fertilizer nitrogen is lost to water or the environment, and only a small share ends up in human food

what is particular about corn in regards to nitrogen?

increases in fertilizer to grow corn, but corn is a leaky crop for nitrogen

how do manure ponds outside concentrated animal farms contribute to pollution?

liquid manure is spread on fields, causing excess nitrogen to leach into waterways

the EPA reported that what percentage of US rivers are now unsuitable for aquatic life?

over 50%, largely due to nutrient pollution

what is the Gulf of Mexico “Dead Zone”?

summer area of low oxygen caused by nutrient runoff from rivers lik the Mississippi

what is beef’s overall water footprint, and what does that reflect?

around 4 million gallons per tons produced, which reflects the high freshwater demand of meat production

what fraction of earth’s groundwater basins are under threat due to meat production?

1/3

what greenhouse gases are produced from meat production, and how?

1. methane - digestion and manure decomposition

2. carbon dioxide - via deforestation for land and transportation

3. nitrous oxide - from crops subject to fertilizer

how could dietary changes affect our land usage and global CO2 emissions?

changing to plant-based diets could free up millions of square kms of land and reduce ~8 billion tons of emissions per year

why is overfishing caused?

shift to industrialized fishing operations run by large corporate companies

what percentage of top predator fish have declined since the 1960s?

90%

how many of the major world fisheries are currently overfished or maximally exploited?

maximally exploited - 50%

overfished - 43%

what is the issue with subsidizing global fisheries?

they receive 35 billion/yr, driving overfishing

trawlers

boats that drags large nets (trawls) to catch fish

how much sea life is discarded by trawlers? how much area does it affect?

as much as 70% of sea life is discarded, and trawling affects an area 150x greater than the global area of forest cleared

fish aggregating device

man-made floating object designed to attract fish

how often are FADs deployed, and how much tuna is caught using them?

100k FADs deployed each year, catching 50% of the world’s tuna

what two other species are threatened by FADs?

juveline yellowfin and bigeye

what is the marine debris problem caused by FADs?

tens of thousands of FADs are abandoned every year, leading to their plastic netting washing up on beaches

longline fishing

a very long line of thousands of baited hooks , intended to catch swordfish and tuna

what two other species are unintentionally caught by longlines?

seabirds (all 21 species face extinction) and sharks (slow reproductive rates)

what issues has shark fishing caused?

70% worldwide loss of sharks, leading to 1/3 of all sharks/rays being at risk of extinction

what efforts have been made to save sharks, and why are they ineffective?

governments have banned shark finning alone, but we need to ban shark fishing instead

why is aquaculture (fish farming) growing so rapidly? how much has it grown and is projected to grow?

wild fisheries are stagnant, so aquaculture now provides 50% of fish and projected to supply 60% by 2030

what are 5 key areas of serious global aquaculture concerns?

1. coastal eutrophication

2. fish feed supply

3. habitat destruction

4. disease

5. antibiotic use

fed aquaculture

finfish such as salmon that produce waste byproducts and require feed (other wild-caught fish)

unfed aquaculture

seaweed and shellfish that only require sunlight and plankton