Lecture 31 - Human Impacts

Question 1

Drivers of anthropocentric change

Answer 1

1. acceleration of global population growth

2. the ecological footprint of each human being on the limited resources of the earth

Question 2

Population growth rate

Answer 2

1.2% or about 80 billion per year

Question 3

Ecological footprint

Answer 3

a measure of the resources required to support a person in terms of land area. The ecological footprints in Europe and Asia are generally lower than those in North America

Question 4

Countries with the greatest overall ecological footprints

Answer 4

China, the United States, and India followed by Russia, Brazil, and Indonesia.

Question 5

Biocapacity

Answer 5

The ability for a community or country to provide resources

Question 6

Ecological footprints ____ biocapacity

Answer 6

exceeds

Question 7

Biocapacity includes what factors:

Answer 7

forests, grazing and crop lands, finishing regions, and built-up regions.

Question 8

We need ___ earths to support humanity today

Answer 8

1.75

Question 9

We need ___ earths if everyone lived like Canadians

Answer 9

3

Question 10

Desertification

Answer 10

the expansion of dessert into previously productive lands. This can be caused by land degradation due to overgrazing or over-irrigation (resulting in soil salinization).

Question 11

Soils form on timescales of ____ years, while global soil loss is occurring at about ___ per decade.

Answer 11

1000 of years

7%

Question 12

How to minimize soil erosion

Answer 12

employing proper crop rotation (allowing fields to be fallow periodically), preventing soil pollution, terracing on sloped land, and optimizing: irrigation, pesticide, herbicide, and fertilizer applications.

Question 13

How waste disposal has led to contamination

Answer 13

landfill leak and waste disposal has led to widespread soil and water contamination by both inorganic (metals) and organic substances that are toxic to ecosystems and human health

Question 14

The main mechanism by which all contaminants touch the rest of the world

Answer 14

atmospheric transportation

Question 15

POP

Answer 15

persistent organic pollutant

Question 16

issues with POP

Answer 16

POPs can be transported long distances and accumulate in the arctic due to global circulation patterns. Deposition begins on vegetation and is biomagnified up the food chain, reaching potentially harmful concentrations in mammals such as whales and polar bears.

Question 17

Cause of large ozone hole found in 1985

Answer 17

A class of compounds called chlorofluorocarbons (CFCs) were widely used for refrigeration and propellants. They were later found to cause the breakdown of ozone in the atmosphere.