Unit Three Flashcards
What is exponential growth?
Increase in number or size, at a constant rate. Eg. Pandemic at first no one was sick, then everyone at once
What is carrying capacity?
the number of people, other living organisms, or crops that a region can support without environmental degradation
What is the rule of 70?
number of years to double = 70/annual growth rate
What led to fast growth?
1) moved from hunting to farming (agrarian)
2) Developed sewer system (food separate from waste)
3) Medicine and vaccines
Stage one of fast growth…
HUNTING AND GATHERING
- Food was not reliable
- Populations fluctuate like the hare/lynx graph. When game or plants were abundant, population increased; if food was scarce population
- Large area of land necessary to support small number of people - earth carrying capacity low
- In order for population to increase a increase in reliable and abundant food source necessary
Stage two of fast growth…
AGRICULTRE REVOLUTION
- Resulted in food surplus*
- Increased carrying capacity and provided people with time
- Only reason we are sitting here is because we are based upon the agrarian calendar
- Don’t have to keep moving can stay in one spot → civilizations form
What did agriculture revolution lead to?
Less fear of starvation
Other activities due to time
Better life expectancy
Improved health
Introduce trade
Beijing writing
Job specialization
What are the two population growth patterns?
1) J Curve
Unlimited environment
No limits to growth
2) S Curve
Pressure on growth (competition, predators) causing rates to slow
Stage 3 of fast growth…
CARRYING CAPACITY
- estimate of # of people who can live in an area and be supported (depends on ecological footprint and recourse consumption)
How do we continue to grow carrying capacity?
things like GMOs and golden rice provide food to people and allow them to thrive
What is overshoot?
Longer the consumption of over the carrying capacity
Degrades carrying capacity
Thomas Malthusian
Malthusian growth model, an exponential formula used to project population growth. The theory states that food production will not be able to keep up with growth in the human population, resulting in disease, famine, war, and calamity.
The ideas that malthus had are very interesting because of the threats that climate change is posing to us. Yes we have increased technology, medicine, etc. but will that come to a cost. Maybe Malthus is right and we are to early to see it.
Population is affected by what 4 factors?
Birth
Death
Immigration (moving permanently to a new country)
Emigration (moving permanently from one’s native country)
Birth and immigration have a positive effect on a population
Death and emigration have a negative effect on a population
Final population formula
Final population = starting pop + births - deaths + imigrantions - emigration
Birth rate formula
Birth rate = births / population x 1000
death rate formula
Death rate = deaths/population x1000
immigration rate
Imigration rate = immigrants/population x1000
immigration rate
Emigration rate = emigrants/population x1000
Natural increase rate
Natural increase = birth rate - death rate
Net migration rate
Net migration rate = immigration rate - emigration rate
Population growth rate
Population growth rate = natural increase rate + net migration rate
doubling rate
Doubling time = 70/population growth rate
What is causing huge fertility decrease?
caused by woman success going to school and getting jobs, want less children
what is dependancy ratio?
Measure used to indicate the ratio of people in the “dependant” ages (under 15 and over 65) per 100 people in “economically productive” ages
Dependancy ratio formula
% age under 15 + % of age over 65/ population age 15-64% *100
what is a population pyramid?
A diagramic representation of the age and sex composition of a population
Allows you to analyze trends in birth and death rates, fertility rates, infant mortality rates
Tells about past and present
Unstable population pyramids?
PYRAMID SHAPE - Dips in
High birth and death rate
Low life expectancy
Brings countries medical system or political system into question
- Lack of contraceptives
- Lack of medical
Expanding population pyramid?
STRONG PYRAMID SHAPE
High births
Death rates a bit lower, life expectancy starting to improve
Suggests a decent medical system
Expect the country’s population to increase rapidly
Lots of young, not many elderly
Stable population pyramid?
YOUNGER YEARS TO EARLY ADULT AROUND SAME THEN GOES INTO PYRAMID FORM
Slow growth
Low birth and death
High life expectancy
Birth rate > death rate
Suggest a food medical system: availability of contraceptives and medical treatment
Income and standard of living increasing
Stationary/slow growth pyramid?
POPULATION DOESN’T DECREASE UNTIL LATER ON
Most developed countries
All ages groups are similar
Birth and earth rates low
Life expectancy high
Less and less babies
No growth
Birth rate = death rate
Declining pyramid?
UPSIDE DOWN TRIANGLE
No country has reached this staged yet, therefore this pyramid represents a prediction of future trends
Low birth and death rate
High life expectancy
Death rate > birth rate
Canada heading this way
Death rate goes up since there is more old then young, causing more deaths then births
What is demographic transition model?
- Theory that every country goes through these different stages of growth and development and will affect their population growth in each stage
- The transitions from high birth rates and death rates to low birth rates and death rates as a country develops
What happens in stage 2 of transition model?
Stage 2 → death rate drops, birth increases → expansion (demographic trap if countries can’t get out of it- lack of education for females, gender inequality, young marriage age) Highest Growth occurs
What happens in stage 4 of transition model?
In Stage 4 → life gets better (family planning, health, improving
More developed the higher the stage
What led to the large increase in GHG?
industrialization and clear cutting forest
What is the concentration of GHG in the earths atmosphere directly linked to?
average global temp.
What is the green house effect?
good thing only reason we are here, the problem is that humans are enhance the effect and causing heat to be trapped faster increase our global temperature
- Most heat is absorbed by greenhouse gasses and reflected in all directions, warming the earth
- Sunlight reaches the earth
- Some energy is reflected back into space
- Some is absorbed and re-radiated as heat
Main green house gases
water (H2O), CO2 (most human caused), and methane (CH4) - These two correlate with human activity (industrialization)
Why is earth called the goldi locks planet
not too hot, not too cold, perfect distance from the sun
Only planet able to sustain life that we know of
What are carbon sinks?
Any reservoir, natural or otherwise that accumulates and stores carbon for an indefinite period and thereby lowers the concentration of CO2
- Two most important carbon sinks are vegetation and the ocean
Since when have global temperatures been continuing to rise?
Industrial revolution
what is the most abundant GHG?
CO2 - product of burning fuels
Carbon VS Methane
Carbon dioxide is the most significant anthropogenic GhG, but not because of its effectiveness to absorb heat (global warming potential or GWP of 1)
Methan (GWP of 62) is powerful of GhG when organic material breaks down in absence of O2
60-80% of global methane comes from human activity
what is methane caused by?
Decomposing garbage
Waste production of extraction/processing of fossil fuels
Digestive tracts of domestic animals
How do we measure CO2?
Ancient air bubbles trapped in ice enable us to step back in time and see what Earth’s atmosphere, and climate, were like in the distant past.
They tell us that levels of carbon dioxide (CO2) in the atmosphere are higher than they have been at any time in the past 400,000 years.
Where do GHG come from?
Majority comes from energy requirements (industry, businesses, cars, transportation, etc)
Next biggest chunk - agriculture (to feed us, deforestation, agriculture , crop burning)
Where are we seeing impacts of warming?
everywhere but especially in Northern hemisphere and Arctic being impacted most
What is causing warming oceans
Absorb most of excess head form GHG emissions leading to rising ocean temps
Rising temps cause coral bleaching and loss of breeding grounds for marine fishes and mammals
Threatens food security, increasing the prevalence of disease and causing more extreme weather
What is albedo?
= Amount of solar radiation reflected by surface
Surface that are light have high albedo and reflect heat
Darker surfaces absorb heat
Positive feedback loop?
The affect of something than enhances the result of global warming
Causes sea ice to melt, exposes more ocean which have a low albedo and absorb more heat, cause it to melt more ice and continues the cycle
The permafrost in the northern hemisphere, exists tundra vegetation and in that is frozen tons of carbon and methane and viruses etc. over time the permafrost melts which releases more CO2 and methane which causes more warming and causes more permafrost to melt and continues on
Negative feedback loop?
Decreases the effect
Response to some kind of stimulus
In tropical areas vegetation will grow larger as heat increases and pull CO2 out of the air
But unfortunately can’t keep up
Climate feedback loop
Can either amplify or diminish the effect climate is forcing
Climate tipping points?
ocean circulation, ice loss, rapid release of methane
How is ocean circulation a tipping point?
As Arctic sea ice and Greenland ice sheet melt (fresh water) ocean circulation in the Atlantic may divert the gulf stream
This would significantly change regional weather patterns
Could lead to cooling in the western europe
Highlights the importance of ocean circulation in maintaining regional climates
Once you switch ocean currents there is no going back and there are dramatic effects
How is ice loss a tipping point?
Due to strong albedo of ice and the positive feedback loop.
If enough ice melts the earths surface will absorb more and more heat and we may hit a point of no return
Shrinking ice sheets contribute to sea level rise
Can impact costal communities
How is rapid release of methane a tipping point?
Deposits of frozen methane, potent GHG and CO2 lie beneath permafrost in arctic regions
A quarter of the northern hemisphere is covered by permafrost
As the environment warms and permafrost thaws the deposits can be released into the atmosphere and present risk of enhanced warming
What is causing rising sea levels?
- added water from melting ice sheets
- expansion of water as it warms
What is polar vortex?
Area of low pressure and cold air over the Earth’s North and South poles
Gets speed and temperature from difference in temperatures
As polar regions start to warm, the stream will lose its power as the difference between warm and cold is less
Stream starts to wobble a lot
Tragedy of the commons
This is a situation where individuals acting independently and rationally according to their own self-interest behave contrary to the best interests of the whole by depleting some
common resource.
Carbon footprint and meat
We waste a ton of food from consuming and producing food
Majority of food should come from plants
Beef produces huge amounts of methane and GHG emissions
Deforestation for farming
Meat is a big cause for deforestation
In tropical areas, agriculture consumes the land
Corporations and local farmers take over forest and clear trees to supply the high demand of crops such as soybeans and palm oil
How can we lower GHG emissions
improve diet, healthy calories, high yields, plant rich diet, half food waste, lower emission intensity at farm
