Gobal Environmental Change Flashcards
(76 cards)
1
Q
What does global change mean? What aspects does it encompass?
A
- Planetary changes in the earth system
o Lands
o Oceans
o Atmosphere
o Polar regions
o Life (including human society) - Encompasses: population, climate, economy, resource use, energy development, transport, communication, land use and land cover, urbanisation, globalisation, atmospheric circulation, carbon cycle, nitrogen cycle, water cycle, sea ice loss, sea-level rise, food webs, biological diversity, pollution, health, over fishing
2
Q
What causes global change?
A
- Solar variation
- Plate tectonics
- Volcanism
- Proliferation and abatement of life
- Meteorite impact
- Resource depletion
- Changes in earths orbit
3
Q
What is the main modern day driver of global change?
A
- Growing human population
- Demand for energy, food, goods, services and information and its disposal of waste products
4
Q
In the past 250yrs, what has global change caused?
A
- Climate change
- Species extinction (also fish stock collapse)
- Desertification and ocean acidification
- Ozone depletion and pollution
5
Q
What is pollution? What can it take form as? What are the 2 main classes? Pollution statistic?
A
- Introduction of contaminants into natural environment that cause adverse change
- Can take the form of chemical substances or energy, such as noise, light or heat
- Pollutants can be foreign substances and energies or naturally occurring
- Classed as point (single location like a sewage pipe) or non-point sources (stormwater, agricultural runoff)
- In 2015, pollution killed 9 million people globally
6
Q
What is the 1979 Halgate definition of pollution?
A
- “the introduction by humans into the environment of substances or energy liable to cause hazards to human health, harm to living resources and ecological systems, damage to structures or amenity, or interferences with legitimate uses of the environment”
7
Q
How do we measure pollution’s toxicity?
A
- Effect of a chemical will depend on the amount or concentration in the animal or plant, or certain sensitive parts of it
8
Q
What is lethal concentration (LC50)?
A
- Concentration of the chemical in the air or water that will kill 50% of the test animals with a single exposure
9
Q
What is lethal dose (LD)50?
A
- The single dose of a chemical that when fed to a group of test animals or applied dermally, will kill 50% of the animals
10
Q
What are the 3 different effects pollutants may be?
A
- Additive: effects of each may simply be added together to indicate an overall effect
- Antagonist: one pollutant may cancel out or reduce the impact of another
- Synergistic: pollutants may combine in such a way that the environmental effects are greater than would be expected additively
11
Q
What are the 4 sources of pollution?
A
- Point source: eg a sewage outlet
- Multi-source: eg chimney stacks
- Seeping: eg fertiliser runoff
- Spreading: eg volatiles in air flows
12
Q
What are the characteristics of acute pollution? Amoco Cadiz case study?
A
- Occurs when a large amount of waste matter enters the environment
- Usually from a point source, after a one off accidental event
- Commonly has a toxic affect on biota
- After event ecosystem begins to recover and return to resemble original situation
o Eg Amoco Cadiz ran aground near Brittany 1978, split in 3, releasing 1.6 million barrels (220,000 tonnes) of oil into the ocean
13
Q
What compounds make up crude oil? Sea empress case study?
A
- Aliphatic hydrocarbons (eg hexane and octane)
- Aromatic hydrocarbons (eg benzene and toluene)
- Polar compounds (eg ethanol)
- Sulphur compounds (eg benzothiopenes)
o Eg sea empress ran aground occurred at Milford Haven, Pembrokeshire on 15th February 1996. About 65,000 tonnes of crude oil spilt into the sea
14
Q
What are the biotic effects of oil?
A
- Around 90% of sunlight is intercepted
- Division of algal cells is inhibited at oil levels as low as 0.01ppm
- Food chains are modified (directly and indirectly)
15
Q
Describe global variation in oil spillage.
A
Major tanker accidents and oil slick regions usually follow the lines of very large and ultra large carrier routes, particularly in the Atlantic Ocean.
16
Q
What are the characteristics of chronic pollution?
A
- Low level input into the environment
- Occurs either more or less continuously or as frequent pulses
- Environment is constantly under stress, albeit light stress
- Ecosystem does not have opportunity to recover and often there is a cumulative effect
17
Q
Describe pesticides as a form of chronic pollution?
A
- Highly toxic chemical substances deliberately introduced into an ecosystem to kill or reduce population size or growth of particular pests or weeds
- Saved many lives: major players in increases in food and other organic products over past 50years
- Benefits considerable: reduction inn impact of weeds and pests, improved harvests, fewer storage losses, control of human/livestock/crop diseases
18
Q
What are the 6 different types of pesticides?
A
- Direct contact
- Secondary contact
- Ingested
- Repellent
- Fumigant
- Lure and kill
19
Q
DDT and peregrine falcon case study regarding chronic pollution?
A
- DDT: dichlordiphenyltrichloroethane
- By early 1960s UK and USA were commonly using DDT as a generalist pesticide
- 1961 British Trust for Ornithology (BTO) found that breeding numbers of peregrine falcons (Falco peregrinus) were falling dramatically
- Measured by index of thickness in peregrine falcon eggs
- High residue levels of DDE (the stable metabolite of DDT) found in the fatty tissues of peregrine carcasses and in eggs
20
Q
What are the 3 major classes of pesticides?
A
- organochlorine
- chlorophenoxy
- organophosphates
21
Q
What is organochlorine?
A
- Organochlorine: DDT, aldrin, diealdrin and heptachlor
o Broad spectrum toxins
o Remain in the environment for a long time
22
Q
What is chlorophenoxy?
A
- Chlorophenoxy: herbicides such as 2,4-D (2,4-dichlorophenoxyacetic acid)
o Chemisty resembles that of plant auxins
o Broken down in soil in a matter of days
23
Q
What are organophosphates?
A
- Organophosphates: malathion, parathion and carbamates
o Highly toxic to humans
o Biodegradable and non-persistent, readily broken down
24
Q
What is biomagnification and concentration factor (CF)? What is the link between the 2?
A
- Biomagnification: occurs when an element or chemical compound moves from one compartment to another and occurs at a higher concentration in the second
- Concentration factor (CF): concentration of the pollutant in the consumer divided by concentration of pollutant in the diet
- Biomagnification occurs when CF>1
25
Case study example of biomagnification?
Pollution: biomagnification
- Eg Clear Lake, Northern California USA
o Late 1940s, plagued by gnats
o September 1954 – organochlorine applied at 0.02ppm (1/50 million)
o December 1954 – over 100 western grebes dead
26
Describe plastic as a form of pollution. How does it affect marine animals? Humans?
- Accumulation of plastic products in the environment adversely affecting wildlife, habitat or humans
- Prominence correlated with plastics being inexpensive and durable
- Slow to degrade
- Affects land waterways and oceans
o Marine animals: entanglement, direct ingestion, or through exposure to chemicals causing interruptions in biological functions
o Humans: disruption of thyroid hormone levels
o UK: >5 million tonnes of recycled plastic consumed annually, only 24% recycled
27
What are microplastics? Primary/secondary?
- Small particles usually <5 mm in diameter
- Come from a variety of sources: cosmetics, clothing and industrial processes
- Primary microplastics: manufactured, direct result of human material and product use
- Secondary microplastics: fragments derived from the breakdown of larger plastic debris
- Both types persist in the environment at high levels, particularly aquatic and marine ecosystems
- Can be ingested and incorporated into and accumulated in the bodies and tissues of many organisms
28
General overview - global change 1
- Pollution
o How to quantify
o What type of effects
o Where from
- Acute pollution
o Oil spills
- Chronic pollution
o Pesticides
o Plastics
o Bioaccumulation
29
What is species extinction? What is the current extinction we are facing?
- >90% all species ever existed now extinct
- Estimate: 100-150 species of plant, insect, bird and mammal become extinct every 24 hrs
- 100-1000 times the ‘natural’ or ‘background’ rate
- Potentially greater than earth has experienced since vanishing of dinosaurs nearly 65m years ago
- Holocene extinction – 6th extinction or Anthropocene extinction: ongoing extinction event of species, mainly due to human activity
30
What are the main causes of extinction?
- Habitat fragmentation
- Agriculture
- Human over population
- Deforestation
- Poaching and hunting
31
What is biodiversity? What’s its definition?
- Contraction of biological diversity
- Attempt to capture complexity of life
- 12 formal published definitions
o The variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part: this includes diversity within species, between species and of ecosystems
32
What is genetic diversity? What is genetic variability?
- Genetic diversity: total number if genetic characteristics in the genetic makeup of a species
- Genetic variability: tendency of genetic characteristics to vary
33
What is species diversity? What are its 2 components?
Species diversity: number of different species
- Consists of 2 components: species richness and species evenness
o Species richness: count of species
o Species eveness: quantities how equal the abundances of the species are
34
What is the SIMPSONS diversity index? ***GO OVER THIS***
Simpsons Reciprocal Diversity index (1/D)
D = index
S = total number of species
Pi =proportion of individuals (n/N) in the i^th species
35
What is ecosystem (ecological) diversity?
- Ecosystem (ecological) diversity: variation in ecosystems found in region or variation in ecosystems over the whole planet
o Can take into account the variation in complexity of a biological community, number of trophic levels and other ecological processes
o Is the largest scale of biodiversity and within each ecosystem, there is considerable species and genetic diversity
36
What are the levels of diversity?
- Total species diversity in a landscape (gamma diversity) is determined by 2 different things, the mean species diversity in sites or habitats at a more local scale (alpha diversity) and the differentiation among those habitats (beta diversity)
37
What is endemism?
- Endemism: a term used to describe the usually limited geographical distribution of a taxonomic group, usually at a family, genus or species level
38
What are biodiversity hotspots?
- Areas of high species richness and a high level of endemism are generally areas of high conservation value, and are often referred to as biodiversity hotspots
- Around the world, 36 areas are considered to be biodiversity hotspots
- These sites support nearly 60% of the worlds plant, bird, mammal, reptile and amphibian species, with a very high share of those species as endemics
39
What are the values of biodiversity?
Direct use value:
- Derived from direct role of biological resources in consumption and production
Indirect use value:
- Derives from the many functions biodiversity performs in providing services critical to human well-being
Non-use value
40
How is food a direct use? Plants vs animals?
Direct use: food
- Biodiversity provides food for humans in forms that include meat, vegetables, fruits and nuts, and adjuncts to food in the form of food dyes, favourings and preservatives
o Plants: 80% of the food supply of the human population is obtained, directly or indirectly from just 20 kinds of plants
o Animals: more difficult to enumerate – wide range of species consumed but consumption concentrated on a small proportion of species
41
How is medicine direct use? How many chemical substances come directly from plants?
- Significant proportion of drugs derived directly or indirectly from biological sources
- 119 pure chemical substances extracted from plant species
- 35% all prescriptions for chemicals based on plant products
- Only about 5,000 predominantly temperate, species of higher plants thoroughly investigated as potential sources of new drugs
42
How is biocontrol direct use?
- Use of natural enemies to control species regarded as pests increasingly widespread
- 30% of weed control and 40% of insect control programmes are based on biocontrol
- In Africa – control of cassava mealybug saved £350 million per annum
43
How is industrial materials direct use?
- World wide export of tree export estimated to be about £4.5 billion and more than 3.8 million cubic meters are harvested annually worldwide, for fuel, timber and pulp
44
How sustainable is the total global fish harvest?
o 2015 140 million tonnes
o 66% of the worlds marine fish stocks, estimated at being fished at or beyond their maximum level of productivity
45
How sustainable is fuel wood?
o 1.3 billion people in developing countries consuming fuel-wood faster than it is being replenished
o If present trends continue, further 1 billion will face chronic fuel-wood shortages by 2050
46
What are the 3 definitions of ecotourism?
- Tourism directed towards exotic natural environments intended to support conservation efforts and observe wildlife
- The practice of travelling to beautiful natural places for pleasure in a way that does not damage the environment
- Responsible travel to natural areas that conserve the environment and improves the well-being of local people
47
What is ecotourism reliant on? Revenue?
- By definition is founded on biodiversity
- 250 million people take part in international ecotourism per annum
- Revenue - £80-250 billion per annum to national incomes
48
What are ‘ecosystem processes’?
- The physical, chemical and biological actions or events that link organisms and their environment
- Ecosystem processes includes decomposition, primary productivity, nutrient cycling and fluxes of nutrients and energy
49
What are ecosystem services? What are the 4 categories?
- Ecosystem services are defined as the benefits provided by ecosystems to humans
- Grouped into 4 categories
o Provisioning: such as the production of food and water
o Regulating: such as the control of climate and disease
o Supporting: such as nutrient cycles and crop pollination
o Cultural: such as spiritual and recreational benefits
- Ecosystem services are defined as the benefits provided by ecosystems to humans
- Grouped into 4 categories
o Provisioning: such as the production of food and water
o Regulating: such as the control of climate and disease
o Supporting: such as nutrient cycles and crop pollination
o Cultural: such as spiritual and recreational benefits
50
Revenue of ecosystem services?
- Recent attempt by economists and ecologists – short term economic services globally estimated at £25 trillion (almost twice the global gross national product GNP)
51
What is the ecotron experiment?
- Ecotrons provide a controlled environment where researchers can manipulate factors like water, light, temperature, humidity, Co2 and UV-B radiation
- They allow for creation of model systems with various organisms (plants, herbivores etc) and ecosystems, enabling the study of interactions between different species and their responses to environmental changes
52
What is the BIODEPTH experiment?
- Bio-diversity and Ecological Processes in Terretrial Herbaceous ecosystems experiment was a large scale, long term study that investigated the relationship between biodiversity and ecosystem functioning in grasslands.
- The experiment aimed to determine how different numbers of plant species affected various ecosystem processes, including productivity., nutrient cycling and decomposition
53
What is meant by non-use biodiversity?
- A Non-use value (feel good or warm glow) is a value associated that does not concern our use, either direct or indirect, of the experiment, its resources or services
- The current generation places value on ensuring the availability of biodiversity and ecosystem functioning to future generations
54
What is meant by the term climate change?
- Climate change: a large scale, long-term shift in the planets weather patterns or average temperatures
- Earth has had tropical climates and ice ages many times in its 4.5 billion years
- Since last Ice age (ended 11,000 years ago), earths climate has been relatively stable (14*c). In recent years, the average temperature has been increasing
55
What are the 3 natural causes of climate change?
- Solar activity
o Eg some evidence Little Ice age (1450-1850) coincided with periods of reduced sunspot activity
- Earths orbit – MilanKovitch cycles
o 3 long term changes in earths orbit and axial tilt that influence solar radiation reaching earth (Orbital eccentricity, axial tilt/obliquitiy, precession)
- Continental drift
56
What are the recent causes of climate change?
- El Nino event
- Volcanic eruptions
- Greenhouse effect (reabsorption of heat)
57
What is the history of climate change research?
- 1827 – Jean-Baptiste-Joseph Fourier first recognised existence of green house effect
- 1860 – John Tyndall – measured absorption of infrared radiation by carbon dioxide (CO2)
- 1896 – Svante Arrhenius – calculated effect of increasing concentration of greenhouse gases
- 1940 – G S Callender – first to calculate the warming die to increasing CO2 from burning fossil fuels
- 1957 – Roger Revelle and Hans Seuss – first expression of concern about climate change
58
How do carbon dioxide concentrations relate to climate change?
- Increase of atmospheric carbon dioxide (CO2) since 1000 (from ice cores in the Antarctica)
- Pre-industrial global average concentration of CO2 was 260-280 ppm
- 1990 CO2 level, about 350 ppm, 2024 – 427ppm
- IPCC predicts CO2 levels about 600 ppm by 2060
59
What are the greenhouse gases? What is the main one ?
- Greenhouse gases: CO2, CH4, H2O and CFCs
- Co2 is the major contributor to the green house affect
- CO2 less effective absorber than other gases
- Concern reCH4 – about 25 times as effective
60
What human activities produce methane?
- Coal
- Waste
- Leaks
- Livestock and rice paddies
61
How is climate change affecting wales?
- Sea levels at Holyhead increased over past 50 years
- Wheat crops at Aberystwyth flower 1-2 weeks earlier
- Blackcap arriving earlier on Skokholm islands
62
What are the consequences of climate change?
- Sea level rise
- Effects on species
- Distribution of species
- Effects on agriculture
- Patterns in disease
- Human migration
63
What is the IPCC predictions for sea level rise?
- IPCC predictions:
o Average sea level rise of 12cm by 2030
o 50cm by 2100
- 50% of humanity inhabits the coastal zones around the world. Lowest lying are some of the most fertile
64
How will sea level rise affect the Netherlands?
- Over 50% land below present sea level
- 400km of dykes and coastal dunes provides protection
- Estimated cost of protection against 1m sea level rise: £10,000 million
65
How will sea level rise affect Bangladesh?
- About 30% of land below 2m contour above sea level
- Estimates of sea-level rise in this area are 1m by 2050 and nearly 2m by 2100
- 120 million people located in the delta region (Ganges and Brahmaputra)
66
How will sea level rise affect low lying islands?
- 0.5 million people in archipelagos of small islands and coral atolls
- 0.5m sea level rise in this would reduce habitable area and remove 50% of ground water
67
How will sea level rise affect freshwater?
- Climate change will affect ground water supplies and reserves in many different ways
- Demands of increasing population
- Political – many of the worlds major sources of water are shared
68
What are the direct affects of Co2 in plants? C3 vs C4?
- Photosynthetic pathways respond in different ways to elevated CO2
o C3 plants generally respond positively to increased CO2 by increasing photosynthesis
- Plants commonly respond to elevated CO2 concentrations by increasing the ratio of carbon to nitrogen (C:N)
- C3 plants benefit from higher CO2 levels but do not acclimate
- High CO2 causes partial closing of the stomata reducing transpiration and making plants more efficient in water usage
- Doubling of CO2 levels increases growth in C3 plants by about 40% and in C4 plants by about 20%
- Nutrient supply may constrain carbon fixation
69
Types of C3 plants?
- Barley
- Oats
- Wheat
- Sugar beets
- Kentucky bluegrass
- Bent grass
70
What are the types of C4 plants?
- Corn
- Sorghum
- Millet
- Crabgrass
- Bermuda grass
71
What are the indirect effect of CO2 on plants?
- Leaves of plants in higher CO2 may be thicker, have more starch and more carbon based defences against herbivores
- Insects that eat plants usually limited by nitrogen supply – may need to consume more, they may develop slower
72
How have the distribution of insects changed in relation to climate change?
- 20th century changes in the range of Speckled Wood butterfly (Pararge aegeria) in Great Britain, shifting populations numbers towards the midlands
- A northward-shifting species, silver Washed Fritallary (Argynnis paphia) stable at its southern boundary and extending at its northern edge (primarily seen in Sweden and Finland)
73
What are the effects of climate change on agriculture?
- Negative effects of climate change partially compensated by increased productivity due to fertilisation effect of elevated CO2. About 5% reduction in global cereal production
- Increase disparity in cereal production between developed and less developed countries – developed increased by 5%, less developed declined by 10%
- Low temperature constrains on crop production will be lifted in many regions – but some crops require cold to intitiate germination
- Theoretically: 1*c increase in mean annual temperature will move northern boundaries 150-200km north
- Pole-ward expansion of the northern boundaries of most crops
74
What are the effects of climate change on human health?
- Health dependent on good environment
- Factors that impact health:
o Pollution
o Inadequate water supplies
o Poor soil
- Factors exacerbated with climate change
- Difficult predicting impact of climate change on health; many factors effect health
- Main direct effect: heat stress in the extreme high temperatures that will be more frequent and widespread
o St Louis in 1998 – 5*c above average in August, 50% increase in death rate
o Paris, 2003- 3000 deaths
75
How has climate change been associated with potential disease?
- Increased spreading of diseases is a potential concern
- Some tropical diseases could spread into mid-latitude
- Spread of malaria by mosquitoes: optimal temperature range 15-32*c with 50-60% humidity
- IPCC predict malaria incidence could increase from 45% to 60% of world population by 2050
76
What countries have high rates of environmental refugees?
- Bangladesh – 15 million
- China and India – 30 million
- Egypt – 14 million
