LECTURE 32- Anthropogenic Global Issues

what is the current extinction rate compared to background extinction rate

The current extinction rate is 100 to 1,000 times the “background” extinction rate

what is the anthropocene

increased consumption and demand for energy, land and water that is driving a new geological epoch.

• First time where one species (homo sapiens) have had such a powerful impact on the planet

what year had exponential human population growth

1700s

what was the human population in 8,000BC

5 million

how long did it take for the population to reach 1 billion

50,000 years

how much did the population grow during the 20th century

 1.65 billion to 6 billion (1999)

what year did the population reach 7 billion

october 2011

what is the current population

8.29 billion

how long did it take for the population to reach 2 billion

130 years

how long did it take for the population to reach 3 billion

30 years

how long did it take for the population to reach 4 billion

15 years

how long did it take for the population to reach 5 billion

13 years

what is the predicted population sizes for 2037 and 2060

UN predicts world population to reach 9 billion in 2037, and 10 billion in 2060

the is the relationship between human biomass and the biomass of wild mammaks

The mass of humans is 7 times higher than that of all wild mammals combined

what percentage of global biomass is from humans

36%

what percentage of global biomass is from livestock

54%

what percentage of global biomass is from wild mammals

4%

what percentage of global biomass is from wild birds

<1%

what makes up most of global biomass

plants (450 Gt C)

what makes up most of animal biomass

arthropods (followed by fish)

what environment does most biomass occur in

terrestrial system (mainly because of trees)

what makes up most of biomass in terrestrial systems

plants and fungi

what makes up most of animal biomass

marine systems

what did intense whaling result in

fivefold decrease in marine mammal global biomass

what happened to megafauna during the quaternary period

50% of large mammal species went extinct (Biomass of wild animals was 7 times higher than it is today)

what happened to the total biomass of mammals

the total mass of mammals has increased approximately fourfold due to the vast increase of the biomass of humanity and its associated livestock

when did the great acceleration begin

1950s

what is the great acceleration

• period of exploding human population and economic growth

• Drove unprecedented planetary change through increased demand for energy, land and water

what is the free services nature offers worth

 $125 trillion and $179 trillion per year  (USD)

what services from nature do we get for free

• Clean air

• Protection from solar radiation

• Photosynthesis that grows plants

• Nutrient cycling

• Clean water

how much have wildlife population sizes dropped between 1970 and 2020

73%

how are some ways nature is measured

• Global living planet index (looks at data from monitored populations through time)

• Red list index (lists critically endangered species)

• Biodiversity intactness 

• Rate of extinctions

what are the top human activities that threaten species

• Habitat loss and degradation

• Excessive use of wildlife (overfishing and overhunting)

the countries have the most pronounced wildlife declines

• Latin america and caribbean: 95%

• Africa: 76%

• Asia-pacific: 60%

what is habitat loss and degradation driven by

food production

what are five global decline tipping points

1. coral reef die-off

2. amazon rainforest

3. collapse of subpolar gyre (greenland)

4. ice sheets melting

5. large-scale thawing of permafrost

what are the 5 main threats to biodiversity

• Habitat loss and degradation

• Overexploitation

• Climate change

• Pollution

• Invasive species

how do threats impact domestic species

More than 9% of all domesticated animals used for food and agriculture have become extinct by 2016

why is biodiversity fundamental to food security

The variety of life allows food to be produced in different environments and helps provide diverse and balanced diets

what percentage of species were harmed from overexploitation or agricultural activity

75%