Climate Change Flashcards
What are the characteristics of greenhouse and icehouse conditions?
Greenhouse
-High co2 levels in the atmosphere
-Temperature rise
-Transgressive eustatic sea level rise
-Thermal expansion
-Melting of ice, stored in oceans as water
-Submergent landforms
Icehouse
-Low co2
-Temperature fall
-Regressive eustatic change
-Thermal contraction
-Water stored as ice
-Emergent landforms
What are the 5 periods of differing climates?
- Mid-cretaceous - 100ma, greenhouse conditions
- Oligocene - 35ma, coolhouse, glaciation of Antarctica
- Quaternary - 2.6ma (Ice age) fluctuated temperatures
- Holocene - 11700 - Now, little ice age
- Anthropocene - Now, Period where man is influencing climate
What were the characteristics of the mid-cretaceous period?
Avg temperatures - 6-8 degrees more than today
-Co2 levels 5x higher than today
-No polar ice caps (continental drift) which affected currents in the ocean
What were the characteristics of the Oligocene period?
-Rapid transition from greenhouse to icehouse conditions
-Co2 levels dropped from 500ppm to 110 ppm
What caused the glaciation of Antarctica?
-Tectonic processes lead to Antarctica moving towards the south pole.
-The Antarctica circumpolar current isolated Antarctica from warmer currents so didn’t melt
-South Sandwich Islands. Submerged volcanos that distribute deep water currents isolating Antarctica from warmer currents.
What was the main feature of the Quaternary period?
The cyclic changes of climate. Long periods of cold, glacial periods lasting 100,000 years. And shorter periods of warmer interglacial periods
-1/3 of continental land mass was covered by snow/ice
-During the last glacial maximum 18,000 years ago, NW Europe was < 0 degrees
What were the characteristics of the Holocene?
-Steady warming, but periods of cooling
-Co2 levels were in dynamic equilibrium fluctuating around 280ppm.
-1-2 degrees higher than today, sea levels increased by 100m
-Major decline in ice cover
-Little ice age
What are the main characteristics of the anthropocene?
-The last 200 years since industrialisation
-Co2 levels no longer in dynamic equilibrium
-Human activity rather than natural causes
-C02 levels risen from 280ppm to 420ppm
Explain the natural greenhouse effect?
-Input of short wave solar radiation
-30% is reflected back into space (albedo effect)
-Remaining 70% is absorbed by the atmosphere, land and oceans, and re-emitted as longwave terrestrial radiation.
-Some of this terrestrial radiation leaves the atmosphere but most of it is absorbed by GHG
What is the global energy budget?
is the balance between incoming solar radiation and outgoing terrestrial radiation. It is the ditributor of this balance that causes climate change. 1/3 is reflected by clouds
1/5 is absorbed by water
2/3 is lost to space
Rest is absorbed by GHG
What are natural forcing’s and what are the two external forcing’s and the 4 internal forcing’s?
Forcing’s that affect the Earths energy budget induce climate change. They can be internal or external
External - Sunspots, Milankovitch cycles (orbital forcing’s)
Internal- Volcanic eruptions, continental drift, ocean circulation, greenhouse gases
Explain how eccentricity can alter the climate
-Shape of the Earths orbit, changes from circular to elliptical every 100,000 years
-Circular - Earths distance to the sun is the same all year, so equal solar input
-Elliptical - Not the same distance from the sun, so there are points of close and far - Different temperatures depending on how close or far away
Perihelion - Close
Aphelion - Away
Explain how obliquity and how it can alter the climate
-The Earth rotates on its axis between 22 degrees and 24.5 degrees. The tilt is what causes seasons and how long / intense they are on a 41,000 year cycle
-When the tilt is 22 degrees, seasonal temperatures are reduced. Summers are cooler and winters are warmer
-When the tilt is less than 22 degrees, winters are colder, summers are warmer.
is what causes interglacial periods.
Explain precession and how it can alter the climate
The Earth wobbles on its axis, in cycles of 26,000 years
-As it wobbles, the Earths axis position changes, which determines how much solar energy each hemisphere receives, and is reponsible for the timings of the seasons
-Long term
Explain how sunspots alter the climate.
-Sun Spots, solar flares and hot gassy ejections occur on the sun. These reach Earth and can change the climate
-Follow an 11 year cycle
-In the little ice age, there was little sun spot activity, which cooled the Earth
How does volcanic activity alter climate?
Volcanic eruptions trigger short term climate change (Months - Years)
-Mount Pinatubo erupted and released an ash cloud, with 20 million tonnes of SO2
-This increases the albedo effect and cools the Earth’s climate
How can plate tectonics and continental drift alter the climate?
Sea floor spreading, slab bull, ridge push, convection currents move plates from land maass
This caused more landmass in the Northern Hemisphere
How can plate tectonics and continental drift alter the climate?
Sea floor spreading, slab bull, ridge push, convection currents move plates from land maass
This caused more landmass in the Northern Hemisphere
How can plate tectonics and continental drift alter the climate?
Sea floor spreading, slab bull, ridge push, convection currents move plates from land maass
This caused more landmass in the Northern Hemisphere
How can plate tectonics and continental drift alter the climate?
Sea floor spreading, slab bull, ridge push, convection currents move plates from land mass
This caused more landmass in the Northern Hemisphere so will therefore absorb more solar radiation, and melt land ice faster, decreasing the albedo effect
Also caused Antarctica to move towards the South pole, which cooled it.
How does ocean circulation effects the Earths climate?
-Before 5ma ago, ocean currents were weak due to NA and SA not being connected so warm water could not reach the poles
-5ma, NA joined with SA which made currents stronger so they could reach the North Pole.
How do natural greenhouse gases change the climate of the Earth
Natural GHG causes icehouse and greenhouse conditions. We know this because of direct correlation between CO2 levels and temperature. They are added by decomposition and respiration. They are removed from dissolving with water vapour and photosynthesis.
What are the 6 methods used to construct past climates?
- Historical data
- Dendrochronology
- Ice cores
- Sea floor sediments
- Lake sediments - Varves
- Lake sediments - Pollen
How can historical data provide evidence for past climate change?
-Daniel Gabriel Fahrenheit developed the first thermometer 300 years ago. Climate records have been found dating back 140 years ago. Books from 1000 years ago also are used but is qualitative data and may be inaccurate due to less reliable measurement tools. It doesn’t date far back either.
How is dendrochronology used for evidence for past climate change?
Trees can live up to 100 years or longer. Thick rings show warm, wet conditions due to more photosynthesis from higher co2 so growth increased
Thin lines show cold, dry conditions due to less co2 in atmosphere. The number of rings show how old the tree is. However, they dont tell us much past 10k years ago and is PROXY DATA.
How can we use ice cores to provide past climate change?
Ice cores contain bubbles of atmospheric gas at the time the ice was deposited. This therefore allows us to asses the concentration of GHG. However, data may be inaccurate when collected further down a core as gasses will be compresses due to ice on top. Frequent melting and freezing will also leak gases out of the ice.
Oxygen 16 and 18 are also collected to show temperatures.
How can sea floor sediments provide evidence for past climate change?
Micro fossils called foraminifera accumulate on the sea floor. When taking sediment cores, the layers of different fossils show the climatic conditions at the time. Calcium carbonate levels could also show temperature, and co2 levels due to acidity.
How can pollen provide evidence for past climate change?
Pollen collected from lake sediments show the type of vegetation but also the climatic conditions as different flora lived in different conditions.
How are varves used to show past climatic conditions?
Varves are tiny layers of lake sediment compromising of light and dark bands. Light bands are coarse sediment indicate high energy environments (meltwater - hotter). Dark bands are finer sediments, indicating low energy environments (Slow water speed, winter). Correlate with the seasons.
What are the three reasons for global warming due to a rise in GHG?
Global energy demand increase
Population increase
Land use change
How much PPM has co2 emissions risen since the industrial revolution?
280ppm - 420ppm
Now in disequillibrium
How have AC’s changed their emissions since the industrial revolution?
AC’s were responsible up until the 1960’s where global shift meant LIDC’s emitted the most.
How is the enhanced greenhouse effect different to the natural greenhouse effect?
Less heat escapes when reflected from the surface, so there is more re-emitted heat
What are the 6 strong pieces of evidence that indicate global warming is human induced?
-Increasing in global temperatures
-Rising sea level rise
-Decreasing glacial stores
-Increase in water vapour
-Rising GHG emissions
-Decreasing snow and ice cover
How much has the temperature increased since the industrial period?
1 degree, last 7 years hottest on record.
What two points for climate deniers use to disprove temperature increase?
-May be unreliable due to variations in instruments to record data
-Also temperature anomalies are found. Although the Earth is warming, there are areas of cooling
What evidence is there for shrinking valley glaciers and ice sheets?
-NASA reported 400 billion tonnes of ice sheets lost since 1994 and thickness decreased by 12m
-Greenland and Antarctica contain 97% of the global ice
-Antarctica is losing 148 billion tonnes/yr due to calving
-Larsen B melted in 6 weeks
-13% per decade less ice
Explain calving of glaciers
Ice melts, which produces meltwater which penetrate the ice and increases the velocity of glacier flow. It runs under the glacier, melting it from underneath. This undercuts the glacier and causes it to fall into the water.
What evidence is there for sea level rise?
-Over the C19th, sea levels rose by 20cm
-In C20th, sea levels rise by 1-2.5mm/yr
-Expected to rise by 0.6m by the end of the century
-Due to 43% thermal expansion, 45% ice melt, 12% other (circulation etc)
What do climate deniers use to disprove sea level rise?
-Isostatic fall/rebound
-Land rising at 2mm/yr, so sea level rise isnt seen as large
-South East of the UK is falling at 0.5mm/yr, so the relative sea level rise will be higher
What do climate deniers use to disprove glacial melt?
Antarctica is melting at a slow rate
How is an increase of atmospheric water vapour used as evidence for human induced cc?
-Water vapour reflects most terrestrial radiation, therefore directly related to temperature
-Water vapour condenses, releases latent heat
-Positive feedback, more water vapour, warms planet, thermal expansion, more evaporation, more water vapour
-Negative feedback - Increased water vapour, more cloud, more albedo, less absorption of heat
How do climate deniers use feedback loops with water vapour?
The contrasting feedback loops show it could be natural. Causes rather than man made. Also could show there is not much known about them.
How is decreasing of snow and ice cover evidence for human induced cc?
Melting of ice and snow cover is due to the rise in global temperature. Mostly in the Northern hemisphere due to more landmass. This causes a reduce in the albedo effect, causing a positive feedback loop.
What do climate deniers use to disprove the evidence of melting of ice and snow cover?
In Antarctica, there is melting of sea ice and counteracting feedback loops.
What are the 4 reasons emissions peaked in the 1970s then fell in the UK?
- Shift away from coal to gas/oil
- Nuclear power
- Improvements in energy conservation (in homes such as double glazed windows)
- The Kyoto protocol - 1997
How was the kyoto protocol successful?
Forced countries to reduce emissions by 5%
Then set a target for 18% but only managed to do 12.5%
What were the issues with the Kyoto protocol?
1- Targets were easy to meet so had no real impact
2- Blame put on AC’s for their emission and global shift to LIDC’s and EDC’s so they were exempt
3- Not all countries ratified (agreed) to the protocol so didn’t cut any emissions
What was the Kyoto protocol?
Meeting of 41 countries that joined UNFCCC (United Nation Framework Convention on Climate Change), to consider what to do, which resulted in the protocol being made which included 192 countries to cut their emissions by 5% by 2000 and a further 18% by 2020.
Why did emissions rise from 2252-7269 tonnes of carbon from 1750-1850?
Because the UK was reliant on wood and water to power everything. Population low, SoL low (below 20 million) so wasn’t on a big rise.
Why did emission rise from 7269-114,559 tonnes in 1800-1900s?
Represents the start of industrialisation and the UK economy shifted from agriculture to a manufacturing powerhouse. Coal became main source of energy which led to increase in energy demand and population increased to 40 million.
Why was there a peak of 180 million tonnes in 1970 then fell?
- Global shift
- Move to oil and gas (20% less dirty)
- Miners striked
Why did emission rise from 20k - 210,422 in 1970 in China?
-700 million population
-Less than UK due to rural areas and largely driven by biofuels
-Global shift of industrial industry into China - used to be primary focused.
Why did emissions rise from 21 million tonnes to 10 billion tonnes in 2020 in China?
1- China controlled most exports, so government welcomed industrialisation
2- Caused rural-urban migration for employment so there was more energy demand
3- Raised incomes from $299/yr to $9620/yr - More disposable income so more emissions
4- Reliance on coal
5- No participation in Kyoto protocol
Which country produces the most emissions per capita?
UK. Although china has a 1.4 billion population, they have less disposable income so emissions are lower per capita than UK.
When did both China and the UK say they would become net zero by?
UK - 2050
China - 2060
Who is to blame for the emissions between UK and China?
China
-uses coal
-Didn’t partake in the Kyoto protocol
-Net zero by 2060
However,
-Use it for economy
-AC’s planted industrial buildings there due to global shift
Uk
-Global shift
-Per capita more emissions
-Use renewables
-Going net zero by 2050
-Ratified Kyoto protocol
What were 6 key events that influenced the debate over climate change?
1824 - Joseph Fourier - Idea of the greenhouse effect
1862 - Suggested glacial periods correlate to temperature and the greenhouse effect
1896 - Svente Aveteius - Observed CO2 levels, absorber of longwave radiation
1938 - Guy Callendar - linked fossil fuels and global warming, as well as oceans absorbing CO2
1957 - Hanss Svess and Roger Revelle - Proved global warming and oceans absorbing CO2.
1958 - Hawaii - Accurate measurements began at observatory. Furthest place from industrial areas and provided proof CO2 levels were rising. Now plotted on the keeling curve
What does the keeling curve show?
Shows the fluctuating increase in CO2 levels. It fluctuates due to seasons and correlates to photosynthesis. Winter = More CO2 Summer = Less CO2
What does the hockey stick curve show?
Shows global temperature over the last millennium compared to 1961-1990 average
What are 6 key points in the global warming debate?
1- Began in 1970. Some scientists believes the Earth was cooling, but technology has disproved this
2- IPCC - Free from bias and provide data
3- 97% of scientists believe CC is human induced
4 - Believed Sun spots + volcanic activity are the cause, not GHG - but disproved
5- If temperature is higher than 2 degrees, cc will be irreversible - Feedback loops will spiral
6- The effects will increase extreme weather, high sea levels, conflict, disease, flooding and migration
What are three arguments for anthropogenic global warming?
1- Was thought to be sun spot and volcanic activity but is till continuing to rise when there is less activity
2- CO2 levels are rising at a faster rate than natural global warming. 280-420ppm
3- Specific isotope of CO2 is rising connected to oil and coal
What are three arguments against anthropogenic global warming?
1- Over 1000 scientists believe there is not enough evidence, unreliable measurements to say it is human induced
2- The rise in temperature is part of the fluctuating trend of natural cc over the past 3000 years
3- Most human emitted emissions are re-absorbed by carbon sinks (However we are decreasing these carbon sinks so less is absorbed via agriculture and land use change)
What are the 7 ways the media’s misrepresentation changed public opinions?
1- Misinterpretation - Only read headlines etc
2 - People dont read scientific sources, only media which is inaccurate.
3- The public only trust certain players (Government)
4- Political bias in news reporting (Left/Right wing)
5- False balance such as the BBC (Two sides)
6- Statistics can be manipulated
7- Scientific language is misunderstood.
What are two other players that can manipulate the public opinion in climate change?
1- Energy companies - Exxon promoted climate denial for 30 years while knowing climate change was happening so they didn’t loose assets. They had biased employment and politicians, funded $31 million for this.
2- Environmental groups - Extinction rebellion eco protests, could alter the public opinion
What is the importance of the carbon cycle?
People - Food, farming, fossil fuels, plastics
Climate - Greenhouse effect, stopping snowball Earth
Flora - Farming, photosynthesis, producers, decomposition
Fauna - Energy, livestock, survival, consumers
