Introduction to Environmental Science
EVPP 110
Fall 2002
Instructor: Largen
Lecture #1
What is environmental science?
definition
"the interdisciplinary study of humanity’s relationship with other organisms and the non-living physical environment"
interdisciplinary because it
- uses & combines info from many disciplines
- natural sciences: biology (ecology), geology, chemistry, physics
- applied sciences: geography, agriculture, engineering
- social sciences: economics, cultural anthropology, policy, politics, ethics, sociology
What environmental science is not
we need to differentiate between
environmental science
- "science" aspect is emphasized
environmental studies
- "studying", becoming aware of current environmental issues, environmental ethics, environmentalism
Why is environmental science important?
Human domination of earth's ecosystems (from Vitousek et al., 1998. Science: 277: 494-499)
"
to !
of land surface has been transformed by human action
atmospheric CO2 concentration has increased by ~30% since the beginning of the Industrial Revolution
more atmospheric nitrogen is fixed by humanity than all natural terrestrial sources combined
more than !
of accessible freshwater is put to use by humanity
1/4 of bird species that ever lived on earth have been driven to extinction
2/3 of major marine fisheries are fully exploited, overexploited or depleted
Why is environmental science important?
Sustainability
Human population issues
Challenges and complexity
Why is environmental science important?
Sustainability
environmental sustainability
- "the ability of the environment to function indefinitely without going into a decline from the stresses imposed by human society on natural systems that maintain life"
- enables humanity’s present needs to be met without endangering the welfare of future generations
- applies at many levels
- individual, community, regional, national, global
Why is environmental science important?
Sustainability
most experts believe environmental sustainability is not currently being achieved because
- non-renewable resources (such as fossil fuels) are being used as if supplies were unlimited
- renewable resources (such as fresh water) are being used faster than they can be replenished naturally
- pollutants & toxins are being released into the environment as if environment’s capacity to absorb them was unlimited
- human numbers continue to grow despite earth’s finite ability to support us
Why is environmental science important?
Human population issues
human population surpassed 6 billion in 1999
- placing unsustainable stresses on the environment
- consuming more food and water
- using more energy and raw materials
- producing more waste and pollution
- World Bank estimates that 1.3 billion people live in poverty
- unable to meet their basic needs for food, shelter, clothing
Why is environmental science important?
Challenges and complexity
issues may seem simple
- why don’t we just stop over-consumption, population growth and pollution?
Solutions are challenging & complex because of
- multifaceted interactions between ecological, social, cultural and economic factors
- inadequate scientific understanding of how
- the dynamic environment works
- how different human choices affect the environment
Intro to Some Current "Hot" Environmental Issues
Current "hot" environmental issues
Endocrine disrupters
Commercial fisheries
Declining bird populations
Ozone depletion
Global warming
Intro to Some Current "Hot" Environmental Issues
Endocrine disrupters
chemicals that may interfere with actions of hormones
- chemical messengers in organisms
- regulate growth, reproduction, other activities
appear to alter reproductive development in both genders in many species
- >50% drop in sperm count from 1940-1990 in men (60 studies, 15,000 men, many nations)
- juvenile alligator density in Lake Apopka (FL) declined 10 fold in 14 years following chemical spill
Intro to Some Current "Hot" Environmental Issues
Endocrine disrupters
river otters exposed to synthetic chemical pollutants were found to have abnormally small penises
female seagulls in southern CA exhibited behavioral aberrations
they paired with other females during mating season instead of paring with males
many widely used chemicals fall into this category
US EPA plans to test thousands of chemicals for their potential to disrupt endocrine system
- results will help determine exposure levels, effects, limits
Intro to Some Current "Hot" Environmental Issues
Commercial fisheries
several have been fished to commercial extinction
- = fish are harvested faster than they can replace themselves
- increased world demand
- high-tech methods increase catches
Georges Bank closed in 1994
- 16,500 sq km area off New England in North Atlantic
- once one of world’s richest fishing grounds
Grand Banks cod fishery (off Newfoundland) closed in 1990s
Peruvian anchovy fishery collapsed in 1970s
Intro to Some Current "Hot" Environmental Issues
Commercial fisheries
corrective measures
- national level
- 1997 Magnuson Fishery Conservation & Management Act
- requires National Marine Fisheries Service and 8 regional councils to devise quotas and other strategies to help fisheries recover
- international level
- 1995 UN Fish Stocks Agreement
- first international treaty to regulate marine fishing
Intro to Some Current "Hot" Environmental Issues
Declining bird populations
population declines seen across North America seen over past 2 decades
- particularly among songbirds of forests, shrub lands, grasslands
- many songbirds are tropical migrants
- winter in Central America, South America, Caribbean
- summer, migrate to North America to breed
- changing environments in both habitats
- burning of tropical rainforests for cropland
- fragmentation of temperate forest for development
Intro to Some Current "Hot" Environmental Issues
Ozone depletion
evidenced as a large ozone "hole" over Antarctica
- "hole" is area where ozone concentration is lowest of any place in the world
- occur in layer of atmosphere called stratosphere
- layer between 10-45km above earth
caused by chlorofluorocarbons (CFCs)
- previously widely used as cooling agents, still used some
- now banned or under phase out by most countries
- but existing CFCs can survive in atmosphere for 120+ years
Intro to Some Current "Hot" Environmental Issues
Global warming
caused by "greenhouse" gases
- allow solar radiation to pass through to earth
- don’t allow heat to radiate into space
chief among these gases is carbon dioxide
- CO2 levels have dramatically increased over past 2 centuries due mainly to
- burning of fossil fuels
- clearing & burning of forests
could cause increase in mean temperature (to levels higher than in past 100,000 years)