climate chpt 2 Flashcards
1
Q
Define natural variability.
A
Variations in earth’s climate caused by natural processes
2
Q
What are the natural causes of climate variability over time ?
A
- changes in the earth’s orbit and angle of tilt
3
Q
How does the angle of tilt affect natural variability of earth’s climate ?
A
- earth’s axis varies back an forth between 21.5 and 24.5 degrees
- occurs over a cycle of 41000 years
- when tilt decease, hemispheres lean further away from sun -> warmer winters and cooler summers
- enable build up of large ice sheets at higher latitudes, cooling the earth
4
Q
How does earth’s orbit around sun affect climate variability ?
A
- earth’s orbit stretches between an elliptical and circular shape
2 occurs over cycle of 100000 - when earth’s orbit is most elliptic, the distance of earth from sun at furthest departure is further than the distance from sun at earth’s closest approach
- at furthest departure, less solar radiation than at closest approach
5
Q
How do sunspot occurrences affect earth;s climate variability over time ?
A
- sunspots have lower temperatures
- areas around sunspot radiate more energy
- leads to more solar radiation emmited from sun, causing higher temp
- periods of max sunspot activity is linked to periods of high annual temp on earth
- rises and falls within cycle of 11 years
(sunspots are generally linked to higher amounts of solar radiation emitted from sun)
6
Q
How do sunspot occurrences affect earth’s climate variability over time ?
A
- sunspots have lower temperatures
- areas around sunspot radiate more energy
- leads to more solar radiation emmited from sun, causing higher temp
- periods of max sunspot activity is linked to periods of high annual temp on earth
- rises and falls within cycle of 11 years
(sunspots are generally linked to higher amounts of solar radiation emitted from sun)
7
Q
How do large scale volcanic explosions lead to variabilities in earth’s climate ?
A
- when volcano erupts, produces large amounts of ash, dust, co2 an sulfur dioxide into atmosphere
- dust and ash spread over lower atmosphere areas of the earth
- particles absorb and radiate heat back to space in form of longwave radiation
- temporarily offsets greenhouse effects and lowers temperatures until these particles become large enough to drop onto earth’s surface
eg mount pinatubo’s eruption in 1991 led to a drop in average global temperature of about 0.6 degrees celsius over 15months after the eruption
8
Q
What is the greenhouse effect ?
A
- shortwave radiation travels from sun to earth’s surface
- shortwave radiation mostly absorbed by earth;s urface
- some shortwave radiation reflected back to space by clouds
- longwave radiation from earth escapes into space
- some longwave radiation trapped by greenhouse gases and is reemitted into the atmosphere, keeping earth warm
9
Q
What is the enhanced greenhouse effect ?
A
less heat escapes from earth to space as more greenhouse gases traps longwave radiation and re emits it back to earth’s atmosphere
10
Q
What are some anthropogenic factors that lead to the enhance greenhouse effect ?
A
- burning of fossil fuels
- changing land use for UDAI (urbanisation, deforestation, agriculture and industrialisation)
11
Q
How do burning of fossil fuel lead to enhance greenhouse effect ?
A
- fossil fuels eg coals, oils and natural gas contain high carbon content
- upon burning, carbon is released into the atmosphere in the forms of co2 and other greenhouse gases
- fossil fuels are burnt to create energy for UDAi
12
Q
How UDAI lead to enhanced greenhouse effects ?
A
- urbanisation
burning of fossil fuels to power machinery such as vehicle as well as household activities eg heaters, cooling and lighting - Deforestation
forests are large carbon sinks
bun trees -> carbon released back into the atmosphere as co2 because when trees photosynthesise, they store carbon
soil exposed to sunlight -> increases soil temp and rate of carbon oxidation - agriculture
livestock rearing and natural decomposition processes release methane, a common natural gas that has high carbon content
nitrogen in chemical fertilisers also convert into nitrous oxide, a greenhouse gas - industrialisation
fossil fuels burnt to power factories and machineries
up to 43% of greenhouse gas emissions annually
13
Q
How might climate change impact natural systems ?
A
1.increases in atmospheric and ocean surface temperatures
2. changes to ocean circulations
3. changes to precipitation on land
14
Q
How does increase in atmospheric and ocean temps impact natural systems ?
A
since start of industrial revolution, earth’s atmospheric temp has been increasing
heat trapped by greenhouse gases are absorbed by oceans
avg temp of oceans increasing (over 1 degree in last century)
uneven increase in temperature (some part os ocean warm up quicker than others that might still be cool)
15
Q
How does changes to ocean circulation impact natural systems ?
A
- warm surface water blown by wind from equator to poles
- water cools, becomes denser and sinks
- cool water spreads along bottom of ocean, forming cool subsurface flows
- cool water eventually rises back to surface of ocean
(ocean circulation) - climate change slows it down as increased atmospheric temperatures heats up water at poles, making it less dense and reducing the rate of sinking
- ocean current in Atlantic ocean slowed by 15%
16
Q
How do changes in precipitation impact natural systems ?
A
- droughts (decrease ppt)
warmer air increases rate of evaporation, quickly drying out water bodies and plants
lack of moisture reduce occurrence of rain
dry climate area become even drier
eg sahel region in africa (deserts in the subtropics) - floods (excess ppt)
warmer air leads to increased water vapour in atmosphere esp where water bodies are present
warmer air can hold more water vapour
warmer air causes increased evaporation
ppt and excessive rainfall occurrences increase
eg southeast asia
17
Q
How might climate change impact aquatic ecosystems ?
A
- threats to coral reefs
2.ocean acidification - disruptions in marine food webs
18
Q
Elaborate on threats to coral reefs.
A
- increased temp in oceans causes algae that live in coral to leave them
- algae are the coral’s main source of food and what gives the coral its colour
- without algae, coral loses their major source of food and turns white, making them vulnerable to diseases -> death
- without corals, many species lose their food source and habitat, causing these species to deteriorate
- these species are part of food web, hence affecting entire ecosystem
19
Q
How does ocean acidification impact aquatic ecosystems ?
A
- more greenhouse gases eg co2 absorbed by oceans as oceans are natural carbon sinks
- oceans ph decrease and become more acidic
- phytoplanktons absorb co2 to photosynthesise
- excessive co2 leads to carbonic acid forming in water, making oceans acidic
- carbonic acid dissolves calcium carbonate which is needed by aquatic organisms eg mussels, oysters and corals in order to form their shell
- coral reefs to erode faster than new ones can form
- as coral skeletons shrink, species than depend on them for food and habitat and shelter from predators are negatively affected and might even go extinct
eg
great barrier reef in aus has dropped to 30% of what it was in the 1960s bc of ocean acidification
20
Q
How does disruptions of marine food webs impact aquatic ecosystems ?
A
1 slowing down of ocean circulations
- increase in ocean surface temperatures
changes in geographic distribution of aquatic species
changes in composition of aquatic ecosystems
21
Q
How is slowing down of ocean circulations related to disruptions of marine food webs ?
A
ocean circulations transport heat from the tropics from the poles
this allows exchange of nutrients btwn deep and surface waters
slowing down of ocean circulations reduces sinking of water at poles
warm surface water therefore mix less with cooler, deeper waters
separates phytoplankton from nutrients below, reducing number of phytoplanktons
species higher up in the food chain that feed on phytoplanktons are negatively affected and suffer from lack of food
22
Q
How is increase in ocean surface temperatures related to disruptions in marine food webs ?
A
- changes in geographic distribution of aquatic species
due to warming temps, species migrate to areas where temps are more favourable
aquatic species generally prefer cooler, deeper waters so they migrate polewards
drop in biodiversity in equatorial regions
increase in biodiversity in poleward regions - changes in composition of aquatic ecosystems
as geographic distribution changes, mix of prey, predators and competitors in ecosystem change
disrupts existing food webs
some epcies will flourish and some will not
population of species that cant adapt will decrease
23
Q
How does climate change impact terrestrial ecosystems ?
A
- threats to flora and fauna
- changes in compositions of terrestrial ecosystems
24
Q
How do threats to flora and fauna impact terrestrial ecosystems ?
A
- droughts
plants are vulnerable to droughts as they are unable to move to get water
droughts causes plants to wither and die
weakened plants also vulnerable to diseases
droughts force animals to leave their habitats to search fr water
spread of diseases eg botulism
eg droughts in california USA btwn 2012 and 216 dried up many wetlands, many insects fishes and plants died, causing migratory birds to die as well - excessive rainfall
floods -> drowning and destruction of habitat - changes in geographic distribution
species migrate t higher altitudes an latitudes where temp is colder
mix of diff predator and prey
disrupts existing food webs and new terrestrial communities develop
some species will decline as they cannot find suitable habitats to migrate to eg mountain species have nowhere to go if mountains get warm
competition or food -> species that cannot adapt will die
25
How does climate change impact humans directly ?
1. heat waves
2. droughts
3. floods
4. tropical cyclones
5. wildfires
26
How does climate change indirectly impact humans ?
1. affects provisioning ecosystems including food production
2. affect regulating ecosystems including disease regulation
3. alters cultural ecosystems including melting of artic ice degradation of natural lanscapes
27
Why are impacts of climate change on human systems uneven ?
1. Places have varying climate variables eg temp and precipitation
2. central aus which is drier is more susceptible to droughts
3. india experiences intense precipitation during monsoon season, more susceptible to intense flooding
4. countries have different levels of economic dvlpment
5. LDCs take longer to recover due to lack of financial resources - > prolongs economic losses as compared to developed countries
28
How do provisioning ecosystem services indirectly impact humans ?
1. impacts on fish production
geographically distribution of fishes change as fishes migrate polewards to cooler waters
affects economic livelihood of fishermen
affects food security of places as fish supplies dwindles
eg in tonle sp lake in cambodia, fishing is a main economic activity -> esp for people living close to the lakes
increased temps has caused unpredictable rainfall in area -> leads to declining water levels and reduces availability of fishes
threatens economic livelihoods and food security of cambodians
BUT
places at higher latitudes and altitudes get more variety of fish as more migrate there
eg fishermen in portugal have begun to catch new species of fish that were previously in warmer regions
2. impacts on crop yields
more severe and frequent weather events
making it harder for crops to live eg 2020 drought in thailand
shortened monsoon season made it harder for farmers to grow crops
severely affected thailand as its agriculture sector uses 70% of nation’s water supply
lesser food -> increased food prices -> cannot afford -> malnourishment and lack of food
29
How does regulating ecosystem services indirectly impact human systems ?
1. warmer temp leads to increase in mosquitos
2. mosquitos are able to moe to areas at higher altitudes and latitudes as temperatures become warmer
3. more areas of world are now impacted by vector borne diseases
4. more people get sick
loss of lives
reduced economic productivity a people cannot work
increased in healthcare costs
eg bhutan in 2018 never had any mossies as they were too cold
in 2019, bhutan suffered country’s first national dengue epidemic where many parts of countries experienced diseases
30
How does cultural ecosystem services indirectly impact human systems ?
1.melting of artic ice
changes everyday cultural practices of artic indigenous people
eg storing of food in ice cellars disrupted due to melting ice -> disrupts cultural ecosystem services
reduce in number of sled dogs -> travel and hunting rate decreased
2. degradation of natural landscapes
affects tourism industry as some countries rely on their scenic beauty to attract tourists
eg
sea level rising in the maldives -> many islands become inhabitable as they are low lying
corals, a popular tourist attraction, are also impacted by increasing temps and coral bleachng
reduction in tourism revenue as fewer tourists can visit
cultural, regulating and provisioning ecosystems are linked
when fishermen in tonle sap experienced reduced catch -> had top switch to diff jobs as it affected their economic livelihoods
also affects their traditional, cultural way of life
