climate change Flashcards
1
Q
what is climate change
A
Climate change is very long term shifts in weather patterns. The most important variable is changes in temperature.
2
Q
evidence of climate change:
A
- sea levels rise
- ice melting
- increased frequency of flooding + drought
- temperature increase in atmosphere + oceans
- decline in some species
- migration of biodiversity poleward
3
Q
how many cm has average global sea level risen in the last 100 years
A
between 10 and 20cm
4
Q
what are the 2 reasons why sea levels have risen?
A
- when temperatures rise the freshwater stored in the ice sheets melt. This water is stored in the form of glaciers and ice caps. This water will then flow into the sea.
- when the ocean water warms it expands. This is called thermal expansion
5
Q
3 natural causes of climate change:
A
- solar activity
- orbital changes
- volcanic activity
6
Q
what is a sunspot?
A
a dark patch that appears from time to time on the surface of the sun. Sunspots are areas of more intense energy (solar flare)
7
Q
what are 3 types of orbital changes?
A
- axial tilt
- precession
- eccentricity
8
Q
what is axial tilt?
A
- earth spins on its axis causing night and day
- over a period of 41,000 years the tilt of the earth moves back and forth between 21.5 and 24.5 degrees
9
Q
what is precession?
A
- the ‘wobble’ of the earth
- one complete wobble takes about 26,000 years
- the earths ‘wobble’ can give areas (such as Norway) long days and long nights at certain times of year
10
Q
what is eccentricity?
A
- path of the earth as it orbits the sun
- earths orbit can change from circular to elliptical (rugby ball shaped)
- complete cycle occurs every 100,000 years
11
Q
if the earths orbit is closer to the sun what will this mean for tis climate?
A
increased temperatures
12
Q
what is a short term impact of volcanic activity (climate change)
A
volcanic ash can block out the sun, reducing temperatures on earth
13
Q
what is a long term impact of volcanic activity (climate change)
A
- fine droplets form as a result of the conversion of sulphur dioxide to sulphuric acid
- this acid acts like tiny mirror reflecting radiation from the sun
14
Q
sources of greenhouse gas emissions
A
- fossil fuels
- deforestation
- agriculture
15
Q
why is combustion of fossil fuels happening?
A
- population growth
-> more energy demand
-> more fossil fuels burnt and released into atmosphere
16
Q
what is the link between burning fossil fuels and increased temp?
A
produce CO2 adds to the enhanced greenhouse affect
17
Q
why is changing agriculture happening?
A
- increased population
-> more food needed to feed the growing population
18
Q
what is the link between changing agriculture and increased temp?
A
produces 20% of the greenhouse gas emissions especially methane from cattle/paddy fields
19
Q
why is deforestation happening?
A
- agriculture - crops/livestock
- logging - wood/paper
- roads - access
- urbanisation
20
Q
what is the link between deforestation and increased temp?
A
deforestation - trees can’t absorb CO2 -> more CO2 in atmosphere
21
Q
quaternary definition
A
a period of time stretching from 2.6 million years ago to today
22
Q
glacial period definition
A
a period lasting approximately 100,000 years in which global climate is colder. thick ice sheets accumulate over much of the continental areas
23
Q
interglacial period definition
A
a subsequent period of warmer global climate lasting 10,000 years where ice sheets retreat to the poles
24
Q
what can be used as evidence for climate change (long term)
A
- glacial retreat
- sea levels rise
25
long term climate change evidence (thousands to millions of years)
- ice cores
- pollen analysis
26
ice cores:
1) ice sheets are made up of layers of ice
2) scientists drill into ice sheets to get long cores of ice
3) by analysing the gases trapped in the layers of ice, they can tell what temperature each year was
4) the remains of organisms found in cores taken from ocean sediments can also be analysed. these can extend the temperature record back atleast 5 million years
27
pollen analysis:
1) pollen from plants get preserved in sediment, eg. at the bottom of lakes or in peat bogs
2) scientists can identify and date preserved pollen to show which species were living at that time
3) scientists know the conditions that plants live in now, so preserved pollen from similar plants shows that climate conditions were similar
28
medium term evidence for climate change
- historical records
- tree rings
29
historical records:
- proxy records are used to reconstruct climate before the start of instrumental records
-> these include paintings, poems, record books, diaries and journals which record weather at the time
- these records may indicate past climates
- evidence points to a colder period (the little ice age) and a warmer period (the medieval war period) in the historical past
30
tree rings:
1) as a tree grows it forms a new ring each year - the tree rings are thicker in warm, wet conditions
2) scientists take cores and count the rings to find the age of a tree. the thickness of each ting shows what the climate was like
3) tree rings are a reliable source of evidence of climate change for the past 10,000 years
31
short term evidence of climate change
- temperature records
- sea level rise
32
temperature records:
since the 1850s, global temperatures have been measured accurately using thermometers. this gives a reliable but short-term record of temperature change
33
how does cement production increase climate change
cement is made from limestone, which contains carbon
when cement is produced, lots of CO2 is released into the atmosphere
34
what effect do rising temps have on environment
- warmer temps are causing glaciers to shrink and ice sheets to melt. melting land ice, like the greenland and antarctic ice sheets, means that water stored on land is returning to the oceans, causing sea levels to rise
- sea ice is also shrinking, leading to loss of polar habitats
- rising sea levels means low-lying and coastal areas, like miami, will flood more regularly. coastal erosion will increase with sea level rise and some coastal areas will be submerged so habitats will be lost
- other species are declining due to warming, eg. coral reefs, like the great barrier reef, are suffering from bleaching (rising sea temps make coral expel the algae that live in them, causing them to starve and die)
- precipitation patterns are changing - global warming is affecting how much rain areas get
- the distribution and quantity of some species could change and biodiversity could decrease:
-> some species now live at higher latitudes (further away from the equator) due to warming temperatures
-> some habitats are being damaged or destroyed because of climate change - species that are adapted to these areas may become extinct, eg. climate change may limit bamboo growth, leading to the decline in numbers of giant pandas that rely on bamboo as a food source
35
what effects do rising temps and climate change have on people
- in some places, deaths due to heat have increased - but deaths due to cold have decreased
- some areas could become so hot and dry that they’re difficult or impossible to inhabit. low-lying coastal areas, eg. the maldives, could be lost to the sea or flood so often that they also become uninhabitable. this may lead to migration and overcrowding in other areas
- some areas are struggling to supply enough water for their residents due to problems with water availability caused by changing rainfall patterns. this can lead to political tensions, especially where rivers cross borders
- climate change is affecting farming in different ways around the world:
-> globally, some crops have suffered from climate change (eg. warming has caused smaller yields in argentinas wheat crops)
-> but some farmers in high-latitude countries are finding that their crops benefit from the warmer conditions and produce higher yields
- lower crop yields could increase malnutrition, ill health and death from starvation, particularly in lower latitudes
- climate change means the weather is getting more extreme. this means more money has to be spent on predicting extreme weather events, reducing their impacts and rebuilding after they take place
36
mitigation strategies to reduce causes of climate change
- planting trees
- carbon capture
- alternative energy production
- international agreements
37
plant trees to reduce causes of climate change:
planting trees increases the amount of CO2 that is absorbed from the atmosphere through photosynthesis
38
carbon capture to reduce causes of climate change:
- carbon capture and storage (CCS) is designed to reduce emissions from power stations burning fossil fuels
- CCS involves capturing CO2 and transporting it to safe places when it can be stored, eg. deep underground
39
alternative energy production to reduce causes of climate change:
- replacing fossil fuels with nuclear or renewable energy can help reduce greenhouse gas emissions
- in the uk, more offshore wind farms are being built
40
international agreements to reduce causes of climate change:
- the paris agreement aims to reduce greenhouse gas emissions and limit global warming -> it encourages developed countries to help developing countries put mitigation strategies in place
- each country has submitted a pledge which indicated how much they will try to reduce their greenhouse gas emissions by
41
adaptation techniques to respond to the effects of climate change
- changing agricultural system
- managing water supply
- coping with rising sea levels
42
changing agricultural systems to respond to the effects of climate change:
changing rainfalls patterns and higher temps will affect the productivity of existing systems.
- it may be necessary to plant new crop types that are more suited to the new climate conditions in an area
- in some regions, biotechnology is being used to create new crop varieties which are more resistant to extreme weather events
43
managing water supply to respond to the effects of climate change:
dry areas are predicted to get drier, leading to more water shortages - so people need to use water resources more efficiently
- water meters can be installed in homes to discourage excessive water use
- rainwater and waste water can be collected and recycled
44
coping with rising sea levels to respond to the effects of climate change:
at current rates, sea levels are predicted to rise about 65cm in 2100 - this would flood many islands and coastal areas
- better flood warning systems are being put in place, and physical defences such as flood barriers are being built
- in areas that can’t afford expensive flood defences, eg. bangladesh, people are building raised flood shelters and building houses on embankments
