Science of Sustainability midterm

EVR 3021

Ecosystem:

the interacting system made up of all the living and nonliving objects in a specified volume of space

Absolute inference:

an inference that is not scientifically based, and relies mostly on opinion.

example: people who smoke will develop lung cancer

Statistical Inference:

an inference that is scientifically based, and relies on statistics to influence judgement.

example: people who smoke are more likely to develop lung cancer

Advantages of the definition of an ecosystem:

• use of mass balances (stocks and flows)

• holistic “black box” approach

• flexibility in choosing spatial and temporal boundaries

• emphasis on close ties between living and nonliving components

What is the ecosystem “black box” approach?

get insights on what’s happening on a scale without knowing everything thats happening on another scale. knowing whats happening in the context of that black box without focusing on an entire area or a too-narrow scope.

how are humans considered in regards to the definition of ecosystem?

humans are considered a part of the ecosystem, not a witness of it

first law of thermodynamics:

energy can not be created or destroyed. it can only be converted/change form

second law of thermodynamics:

irreversibiliities during real processes do not allow you to recover the original quality of energy you put into a system

Structure of an Ecosystem:

components (materials): bacteria, plants, animals, air, water, nutrients

organization: pathways of matter and energy, distribution of organisms or nutrient (e.g., patchiness)

size location

Function of an Ecosystem:

consuming energy and transforming materials

more useful energy (solar radiation, chemical potential energy)

less useful energy (heat)

open vs. closed system

material function (source or sink)

External Forces: dynamics of ecosystems

nutrient inputs

increased temperatures

Internal Forces: dynamics of ecosystems

age of a tree stand

succession

does NOT have impacts from outside factors

reduction & oxidation:

reduction reduces the charge, gaining electrons

oxidation loses electrons and raises the atom charge

example: Na → NA⁺ +e

primary production:

storage of energy through the formation of organic matter form inorganic compounds

NPP

net primary production

the difference between GPP and autotrophic respiration

What is the formula for NPP?

GPP - Ra

Ra

respiration of autotrophs, organisms that produce food needed for metabolism, growth, and reproduction

NEP

net ecosystem production

what is the formula for NEP?

GPP - Re

OR

GPP - (Ra - Rh)

Re (respiration of ecosystems)

(Ra + Rh)

The sum of autotrophic respiration and heterotrophic respiration

Rh

respiration of heterotrophs, or organisms that do not have the ability to produce their own food

Redox reactions of carbon: aerobic (oxic) respiration:

the process by which most living organisms, including humans, extract energy from glucose and other organic molecules

CH2O + O2 → CO2 + H2O + energy

Redox reactions of carbon: anaerobic respiration

occurs in oxygen-deficient environments and is used by some microorganisms

occurs AFTER aerobic respiration

types: lactic acid fermentation & alcoholic fermentation

GPP

Gross primary productivity

includes all CO2 fixed into organic matter regardless of respiratory loses

Chemosynthesis

exploitation of available chemical energy to convert inorganic carbon compounds into organic matter

heterotrophic ecosystems

includes lakes, estuaries, and cities

negative NEP

respires MORE carbon than they produce

dCorg = NEP + I + CM - Ex - Oxnb

I = imported carbon

CM = movement of consumers (animal migration)

Ex = exported carbon

Oxnb = non-biological oxidation of organic carbon

what is the average oxidation number of carbon in CO2?

+4

what is the average oxidation number of carbon in methane (CH4)?

-4

what is the average oxidation number of carbon in nitrous oxide (N2O)?

-2

what are bottom-up controls (variables) that impact production?

light (aquatic ecosystems, thick forest canopy)

nutrients (macronutrients, micronutrients)

precipitation

what are top-down controls (variables) that impact production?

herbivory

what are the fates of primary production?

consumed by herbivores

converted to detritus (i.e. leaf litter)

stored in biomass, soil, or sediments

lost through non-biological mechanisms (fire, UV exposure)

exported

climate change detection:

understanding that climate change is happening

climate change attribution:

understanding the drivers behind climate change. (why is it happening?)

e.g., inflow, outflow, albedo

inflow:

energy coming in from the sun

outflow:

energy radiating out

albedo:

reflectance

energy that enters the system but is reflected out immediately

groundcover (e.g., snow)

cloudcover

what are the 5 pieces of evidence that show Earth is warming?

1. sea level rise

2. increasing global surface temps

3. increasing ocean temps

4. declining in polar ice sheets

5. declining glacial

what role do ice cores play in our understanding of climate change?

looking at air bubbles in ice cores help us analyze and understand carbon levels in the atmosphere from centuries prior, helping us understand how much levels have risen since then.

what are the key drivers of climate change?

inflow (solar radiation): Milankovitch cycles, sunspots

Albedo (radiation reflected): groundcover (snow), clouds

Long-wave radiation exiting Earth system (GHGs)

main driver of contemporary climate change?

industrialization, carbon emissions

What are the three main GHGs?

• carbon dioxide (traps most heat)

• methane

• Nitrous oxide (traps heat)

Carbon Sink: Land

Photosynthesis (stored carbon from biomass, soils, & freshwater sediments), exported to the sea, increased flow from atmospheric stock (CO2 fertilization, nitrogen fertilization)

Weathering (MOST work pulling CO2 out of atmosphere is done by photosynthesis)

Carbon Sink: Ocean

only 10% is done biologically (photosynthesis)

other 90% is done by a diffusion pump

Ocean: carbon sink or source?

USED to be a source, now is a sink

which of the following flows of carbon into atmosphere is the largest?

Volcanos

Emissions from fossil fuels and cement production

Net land use change

Freshwater outgassing

Emissions from fossil fuels and cement production

Which of the following BEST describes the comparison between the flow of carbon into the atmosphere from fossil fuel emissions and the flow of carbon from volcanos? 

The magnitude of the flow of carbon into the atmosphere from fossil fuels about 10 times the magnitude of the flow from volcanos.

It’s about 250 times the magnitude of the flow from volcanos.

It’s about the same as the magnitude of the flow from volcanos.

It’s about about 80 times the magnitude of the flow from volcanos.

80 times

True False. Earth's life systems (e.g., forests) are pulling more carbon dioxide out of the atmosphere today (through photosynthesis) than they did in pre-industrial times.

true

true false. as the ocean warms, it’s ability to hold carbon dioxide in solution will increase

false

Which of the following BEST completes the sentence below?

 

At a constant temperature, an increase in the partial pressure of carbon dioxide in the atmosphere would _______.

have no impact on the concentration of carbon dioxide in the ocean water.

cause an increase in the concentration of carbon dioxide in the ocean water.

cause an decrease in the concentration of carbon dioxide in the ocean water.

cause an increase in the concentration of carbon dioxide in the ocean water.

Which of the following was the primary forcing(s) behind previous shifts between glacial and interglacial periods? In other words, which of these initiated those shifts?

Changes in albedo

Sunspot activity

Milankovitch cycles

Greenhouse gases in the atmosphere

Milankovitch cycles

Which of the following is the primary forcing(s) behind the temperature increases experienced in the last 100 years? In other words, which of these initiated that shift?

Milankovitch cycles

Changes in albedo

Sunspot activity

Greenhouse gases in the atmosphere

Greenhouse gases in the atmosphere

Sunspot activity

The impact of this driver has been cyclical, but it has not increased enough recently to explain the global temperature increases of the last several decades.

Which of the following surfaces would reflect the most solar energy back out to space?

water (e.g., ocean)

snow

rocks

green (e.g., grasslands or forests)

snow

Ocean acidification

from an increase of carbon. harms ecosystems, animals, and coral

climate justice:

finding solutions to the climate crisis that not only reduce emisions or protect the natural world, but do so in a way that creates a fairer, mroe just and more equal world in the process

mitigation:

measures taken to reduce emissions & stabilizing levels of atmospheric GHGs

examples: renewable energy, afforestation

adaptation:

measures taken to adjust to current or expected changes in climate

examples: shifting to different crops, raising roads to accomodate rising sea levels

transformative:

describing measures taken that address not only climate change, but other issues through co-benefits

command and control:

the government sets specific conditions, such as required equipment and maximum allowable flowrate out of a smokestack

cap and trade:

the gov. sets a total allowable level of pollutant for an industry and allows individual actors to buy and sell their individual allowances within that limit

carbon tax

the gov. adds an additional fee based on the amount of carbon emissions are produced, which raises the price of carbon intensive activities

clean energy standards

the gov. requires a specific proportion of energy production in a state or country to come from low- or zero-carbon sources

Which of the following BEST completes this sentence?

 

All the policies listed in the previous question are examples of climate _______ .

adaptation

mitigation

impacts

externality

mitigation

Which of the following energy sources produces the most carbon emissions per kWh?

Wind

Coal

Hydroelectric

Petroleum

Solar

Coal

Which of the following characteristics are true of nuclear energy?

High levels of carbon emissions

High land footprint (takes up a lot of space)

High toxicity of solid waste produced

High initial costs and high operating costs

High levels of air pollution

High toxicity of solid waste produced

High initial costs and high operating costs

Which of the following is the energy source that will resolve all our issues regarding climate change?

Biomass

Solar

Nuclear

Wind

No single source can address all the issues by itself.

No single source can address all the issues by itself.

On a global level, what percentage of our energy came from fossil fuels?

1973: 87.0%  and 2019: 80.9%

reinforcing loop:

reinforces the impact of whatever feedback loop it is.

balancing loop:

balances out the impact in the feedback loop

positives of petroleum

high energy density

consistent

reliable

easy to store/transport

established technology

negatives of petroleum

fossil fuels

air pollution

GHGs

water pollution

positives of coal

high energy density

stores easy

cheap

nonvolatile

U.S. has lots of it

negatives of coal

fossil fuel

GHGs

air pollution

mining impacts

positives of natural gas:

U.S. has lots of it

it’s not coal lmfao

negatives of natural gas

fossil fuel

leaks in pipeline

positives of nuclear energy

no air pollution

low GHGs

small land footprint

negatives of nuclear energy

high operating costs

high capital costs

potential for catastrophe (e.g., chernobyl)

nuclear waste

some people have a NIMBY mindset (not in my backyard)

postives of hydroelectric energy

low carbon emissions

negatives of hydroelectric energy

habitat loss

displacement of people

emissions concern

limited room for expansion

positives of wind energy

renewable

low GHGs

negatives of wind energy

large land footprint

not always reliable

solid waste

positives of solar power

renewable

low GHGs

negatives of solar power

large land footprint

toxic substances

mindset towards “each person doing a little”

each person doing a little will only lead to a little change

facing climate change from an equity standpoint:

richer countries have a moral obligation to do more to help lift the impacts of climate change