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Ecology and the Environment > Lecture 25 + 26 > Flashcards

Lecture 25 + 26 Flashcards

1
Q

In the first half of the 20th century, by what percentage did the global population change?

A

There was a 40% increase in the global population

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2
Q

In which year did the world’s population of people living in cities match the number of people living in rural environments?

A

2010
- the trend of increasing urbanization is predicted to continue

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3
Q

Relative to more developed countries, how does the trend in the amount of calories consumed per person per day in developing countries compare?

A

The trend is similar and both consume on average per day nearly the same amount of calories

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4
Q

Currently, a major concern with regard to limited resources as the global population grows is overconsumption. How has the global incidence of obesity changed since the 1980s?

A

It has doubled

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5
Q

True or false: There is ongoing evolution of agriculture pests (herbivores) such that the pests are more resistant to pesticides.

A

True

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6
Q

Things changed along population, technology, and affluence axes from 1900 to 1950, but change has accelerated massively since

A

Per capita GDP: $1,100 in 1900, $2,200 in 1950, $7,900 in 2011
- per capita energy over time, increased significantly

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7
Q

New York City

A
  • 13th largest city in the world by population (~ 8 million)
  • Largest in the US, 3rd largest in all of the Americas (after Sao Paulo and Mexico City)
  • Most densely populated city in all of the Americas
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8
Q

Total energy consumption per capita, 2005

A
  1. usa
    -> texas, california, new york
    -> new york: nyc: 88.5 MBTUs compared to 209 MBTUs state average
  2. germany
  3. china
  4. india

Per capita greenhouse gas emissions in New York City (2007) = 1.9 metric tons C of CO2 equivalents per year

Average for US = 6.7 metric tons C of CO2 equivalents per year

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9
Q

Urbanization is supported by

A

intensification of agriculture in rural areas
- 570 million farms in the world today

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10
Q

72% of farms < 1 hectare and control 8% of cropland

A
  • primarily produce food for own family
  • goal of farmers is to minimize risk of crop failure, maximize stability, and predictability of harvest
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11
Q

1% of farms > 50 hectares, control 65% of cropland

A
  • produce food for market (increasingly, a global market)
  • goal of farmers is to maximize productivity, maximize profit, and minimize labour (since labour is often the largest cost)

Global intensification of agriculture is all in the large farms.

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12
Q

Large, intensive farms

A
  • very low diversity (both in terms of numbers and genetics of crops)
  • low nutrient retention
  • high inputs (fertilizer, pesticides, etc.)
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13
Q

Small, subsistence farms

A
  • moderate to high diversity of crops
  • moderate to high nutrient retention
  • low inputs
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14
Q

Intensification of agriculture

A
  • Increased global production of cereal crops (wheat, rice, corn, etc.)
  • Increased global use of nitrogen and phosphorus fertilizer, and increased area of irrigated land
  • Increased global production and import of pesticides
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15
Q

Natural ecosystems: max to min diversity

A

tropical rain forest > temperate forest > natural grasslands > boreal forests > coastal salt marshes > geothermal pools

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16
Q

Agroecosystems max to min diversity

A

shifting cultivation in tropical forests > polycultures > home gardens > wheat varieties > hybrid corn > clonal crops

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17
Q

Monocultures Aggravate Pest Problems

A
  • With intensification, the great bulk of food resources are now grown as dense populations of single species called MONOCULTURES (often even the same genetic strain)
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18
Q

Monocultures encourage both

A

oubreaks of insect pests and weed problems

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19
Q

The best available information indicates a heavy toll by pests on global agricultural production, with losses of somewhat more than

A

25% for soybean and wheat, over 30% for corn, 37% for rice, and 40% for potatotes

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20
Q

Chemical Approaches to Pest Control

A
  • Intensification often relies on heavy use of chemical pesticides, chemicals used to control pests (both insects and weeds)
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21
Q

Pesticides are most polluting when they are

A

unselective and persistent, and when they biomagnify in food chains
- Following their development in World War II, widespread use of unselective pesticides (such as DDT) in 1950s & 1960s

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22
Q

DDT and the Peregrine Falcon

A
  • Until the 1940s, about 4,000 nesting pairs of peregrine falcon in North America.
  • Between 1955 and 1965, very sharp decline in populations, leading almost to extinction (listed as endangered in 1969). Went locally extinct in eastern US.
  • Some excellent science showed the decline was due to very high breakage of eggs.
  • The cause was DDT in parent birds.
  • Following ban of DDT for agricultural use in US in 1972, falcons recovered.
  • Today, 2,000 to 3,000 nesting pairs; removed from threatened & endangered list in 1999
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23
Q

Silent Spring by noted ecologist Rachel Carson was published in 1962

A

Was very important in banning DDT, and in starting the environmental movement of the 1960s and 1970s

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24
Q

Crop breeders have been able to genetically modify crops to make them more resistant to herbicides. Has this changed the amount of herbicides that farmers use?
A) Yes they use less herbicide
B) Yes they use more herbicide
C) No the amount does not change

A

B) Yes they use more herbicide

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25
Q

Pests evolve so as to become resistant to pesticides, often quite quickly!

A
  • The first case of DDT resistance was reported as early as 1946 (houseflies).
  • Resistance to various pesticides has occurred for every family of arthropod pest (including flies, beetles, moths, wasps, fleas, lice, moths, and mites) as well as in weeds and fungal plant pathogens
  • more and more insects have evolved resistance to pesticides over the past half century
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26
Q

Note that chemical pesticides can aggravate pest problems, for instance by killing off insect predators that normally would help control pest insects

A
  • Also, pesticides kill important pollinators, such as bees, and other beneficial organisms that may help with soil health
  • There are better ways to control pests: various biological controls, and integrated pest management
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27
Q

Integrated pest management

A

combines physical control (keeping pests away from crops), cultural control (rotating crops), biological and chemical control, and the use of resistant crop varieties

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28
Q

65% of all plant species require pollination by animals

A
  • 75% of agricultural crop species require animal pollination
  • The value for pollination by insects for agricultural crops is estimated as $190 billion/year
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29
Q

Bacteria evolve so as to become resistant to antibiotics, very, very quickly!!

A

Routine use of antibiotics in animal agriculture leads to resistance to the antibiotics by bacteria, including human pathogens.

A MAJOR threat to human health. And costs hospitals $20 billion/yr

30
Q

Global land area constraints to agriculture:

A
  • How much land is required now for agriculture?
  • How much will be in the future?
  • What are the global consequences of this?
31
Q

Cropland per person has

A

fallen by 50% since 1961

32
Q

Precautionary principle

A

When in doubt, do not take the risk
- Analysis of trends to date indicate agricultural productivity may be reaching its limits
- And climate change, water shortages, and air pollution (particularly ozone, created by reaction of nitrogen gases with methane and other hydrocarbons in atmosphere, and floods, droughts, and excessive heat) are increasingly affecting agricultural production

33
Q

While for most crops, yields per area continue to increase, the rate of this increase is

A

slowing, suggesting a limit to further yields

34
Q

Potential yield for corn and canola oil

A

high potential in india, mexico, brazil for corn

high potential in Canada, china, india for canola oil

35
Q

Estimated agricultural land lost by 2050

A

low end: 195 (millions of hectares)
high end: 355 (millions of hectares)
Compare to total global crop land area of 1,600 million hectares in 2015

36
Q

Dust storms as part of agricultural degradation

A

(over-plowing marginal land, plus drought)
United States, 1935
China, 2011

Plus global population will continue to grow (estimated 9.1 billion people in 2050, a 20% increase from the 8.1 billion in 2023)
- And people may eat more per person (including meat, which requires a lot of crop production)?

37
Q

870 million people still lack sufficient caloric intake (12% of global population)

A

But 1.4 billion suffer from being overweight or obese (20% of global population)

38
Q

In 1952, meat consumption in the US was at the level of

A

43 kg per person per year
- one quarter pound per person per day

39
Q

Global trends in total meat consumption since 1970, and projections to 2050

A

The demand is increasing. Global meat production tripled from 47 million to 139 million tons per year between 1980 and 2002.

Although the pace of growth is slowing down, current meat production is expected to double by 2050 to meet rising demand.

40
Q

Estimated “need” for new farmland globally by 2050 given current trends (“Business as Usual”)

A

low end (millions of hectares): 390
high end (millions of hectares): 1,280
Compare to total global crop land area of 1,600 million hectares in 2015

41
Q

Assessing Global Land Use: Balancing Consumption with Sustainable Supply

A

A cautious global target is to halt the expansion of global cropland into grasslands, savannahs and forests by 2020.

At that point, 1,640 million hectares of cropland = 0.2 hectares per person

42
Q

Are we on the right track?
- 12% net expansion since 1960

A

“Business as Usual” projection; steep linear increase, far above the dotted horizontal line of “safe operating space” at around 1675 Mha

43
Q

The path forward recommended by the UN: stop further deforestation and other land conversion to agriculture by 2020, corresponding to 0.2 hectares of agricultural land per person in 2030

A

More than sufficient for everyone in the world to consume meat at the 1952 US level, if good agricultural practices are followed, agricultural productivity in developing countries increases reasonably, we greatly reduce use of liquid biofuels, and global climate change is not too disruptive.

Explicit call for managing consumption of food.

44
Q

Global increase in ethanol biofuel driven by US, and based on corn

A

Increasing especially in the past 20 years

45
Q

Is the use of corn biofuels (ethanol) carbon neutral?

A

Very far from neutral
- Greenhouse gas emissions from corn-ethanol usually (but not always) less than from fossil fuels – but NOT carbon neutral (lot of emissions associated with growing the corn, distilling the ethanol, etc.
- And this figure DOES NOT include CO2 emissions from indirect land-use consequences…

46
Q

80% of deforestation in the Amazon driven by beef ranching

A

Increased use of corn for biofuels in the US -> increased soybean production in Cerrado of Brazil -> Displacement of low-intensity livestock farming to the Amazon

“If the Amazon is to die, it will be beef that kills it.”

“And America will be an accomplice.”

47
Q

When the indirect land-use effects (deforestation, savannah conversion) are included, ethanol from corn has a greenhouse gas footprint that is far worse than any fossil fuel

A

This is due to CO2 release from the land disturbance (negative rates of net ecosystem production)

48
Q

True or false: In the United States people living in cities use less energy per capita than people living in the suburbs and rural areas.

A

True. There are efficiencies built into living in a city.

49
Q

Which of the following pairs of items are more closely associated with subsistence farming relative to intensive commercial farming. (Choose one option for each pair.)
1. small farm
1. large farm
2. small global total land cover
2. large global total land cover
3. less mechanized
3. more mechanized
4. farming for profit
4. farming for food
5. low diversity
5. high diversity
6. low nutrient inputs
6. high nutrient inputs
7. low nutrient retention
7. high nutrient retention
8. more common in low GDP nations
8. more common in high GDP nations
9. more total farms
9. less total farms

A
  1. small farm
  2. small global total land cover
  3. less mechanized
  4. farming for food
  5. high diversity
  6. low nutrient inputs
  7. high nutrient retention
  8. more common in low GDP nations
  9. more total farms
50
Q

Growing organic crops _________ the environment because _________.

A

Benefits; it reduces the amount of nitrogen in agricultural runoff

51
Q

Under what conditions would a pesticide be most polluting?

A
  • unselective and persistent
  • if it biomagnifies in the food chain
52
Q

Which of the following are associated with intensified agriculture?
- monocultures
- biomagnification of pesticides
- increased disease transmission
- a reduction in feedlots

A
  • monocultures
  • biomagnification of pesticides
  • increased disease transmission
53
Q

An increase in the percentage of meat consumption and intensification of animal agriculture is most closely related to what?

A

A countries’ wealth

54
Q

True or false: New agricultural technologies alone will likely enable humanity to feed the growing global population.

A

False: The gains in agricultural production as time goes on are slowing. More farm land (and the mechanisms to distribute food) will be needed to feed the world’s population which is both growing and consuming more food per capita.

55
Q

Why isn’t ethanol living up to its promise as a carbon-neutral biofuel? (You may select one or more answers).
- When ethanol is burned plants do not reabsorb the same carbon molecules that were produced during production.
- There is energy associated with the production and distribution of of ethanol that is not always fully accounted for
- The use of ethanol has resulted in changing patterns of land use
- There is efficiency in scale, and very little corn is used to produce ethanol in the United States
- The corn used for ethanol would have a lower “nitrogen footprint” if it was fed to cattle for meat production.

A
  • There is energy associated with the production and distribution of of ethanol that is not always fully accounted for
  • The use of ethanol has resulted in changing patterns of land use
56
Q

Albert Einstein

A

nuclear weapons

57
Q

Rachel Carson (ecologist)

A

DDT, pesticides

58
Q

Carl Sagan

A

nuclear winter

59
Q

George Woodwell (ecologist)

A

pesticides, nuclear exposure, global change

60
Q

Gene Likens (ecologist)

A

acid rain

61
Q

Dave Schindler (ecologist)

A

eutrophication, acid rain

62
Q

Stephen Schneider

A

global change

63
Q

Jim Hansen

A

global change

64
Q

Michael Mann

A

global change

65
Q

Science based advocacy

A

Being objective in the research and development of the science, and then communicating the importance of the scientific conclusion to the public and policy makers
- highly ethical, widely practiced by great scientists, and expected by scientific professional societies

66
Q

Advocacy based science

A

Using selective scientific
information to support a pre-determined position
- not ethical, according to the ethics of science (but using information selectively is considered ethical and normal by lawyers, and therefore many NGOs)

67
Q

Howarth’s very most recent policy interaction:

A
  • Liquified natural gas (LNG) export from US was banned until 2016
  • US became largest LNG exporter globally in 2022
  • Industry wanted to greatly increase further, but that required approval from Biden by end of December 2023
68
Q

LNG greenhouse gas emissions are greater than for either coal or natural gas produced and used domestically in the US

A

Length of cruise and type of tanker matters, but even for most modern tankers and shortest cruises with no holding time, LNG climate footprint is significant.
- “Howarth’s study was a factor in the Biden administration’s decision to pause making the required determination required for approval of new LNG export projects and launching a US Department of Energy Study on the climate impact of LNG exports”

69
Q

How can a scientist try to protect themselves?

A
  • Important to be true to the science
  • Important role in publishing as a scientist (peer-reviewed articles, including syntheses), and not just blogs, letters to the editor, etc.
70
Q

The importance of networking, and mutual support:

A
  • professional societies and scientific peers
  • advisors, former advisors, important colleagues (George Woodwell, Gene Likens, Dave Schindler, John Teal, John Farrington, Michael Mann)
  • NAS committees, etc.
  • international committees and efforts

Also, important to get the OBJECTIVE science out there, through publication

71
Q

Working with different segments of society:

A
  • the press (totally different set of ethics and traditions; although you can be friendly, remember they are not your friends; they are doing their job, which is quite different from that of a scientist; they are generally trained to always see 2 sides, and only 2 sides; story telling is central to them)
  • lawyers (totally different set of ethics; they are trained to emphasize one side)
  • NGO’s, for-profit corporations, and politicians (do not always understand science, or the difference in ethics between science and law)

Ecology and the Environment (13 decks)

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