Unit 2 : Causes of Global Climate Change

Question 1

Atmosphere

Answer 1

consists of mixture of soilds, liquids and gases – up to height of 80 m consists of nitrogen, oxygen, argon and other gases such as co2. most weather conditions occur in the troposphere – temperatures fall with height

Question 2

Atmospheric energy balance

Answer 2

open system : energy from both the Sun and Earth - Incoming solar radiation (insolation)
Solar energy drives all weather systems and climates – earth absorbs most of this energy in tropical regions whereas there is a loss of energy from temperate and polar regions

Question 3

Atmospheric Energy Budget

Answer 3

earths atmosphere constantly receives solar energy but there is still balance between inputs and outputs - recent imbalance (global warming) – linked to human activities such as land use changes and the use of fossil fuels
1) Radiation - emission of short waves and long waves - from the sun in the form of UV waves
2) convection - transfer of heat by a movement of a liquid or gas
3) conduction - transfer of heat by contact

Question 4

Radiation from sun

Answer 4

of short wave radiation that reaches the ground (46 units)
- 14 re-radiated as long wave radiation to the atmosphere and space
- 10 units pass to the atmosphere by conduction or lower atmosphere only
- 22 units transfered by latent heat – heat energy used by a substance change

Question 5

Structure of the earths atmosphere (short wave and long wave radiation)

Answer 5

Short wave radiation emitted by the Sun is re-radiated at long wave by earth – clouds and the atmosphere absorb some of the energy and re-radiate it back to earth
c02 traps the outgoing long wave radiation – heating the atmosphere (greenhouse effect)

Question 6

Incoming short wave radiation

Answer 6

main energy input and it varies according to latitude season and cloud cover. Amount of insolation received varies with the angle of the Sun or cloud type – less cloud cover there is = more radiation reached the earth

Question 7

Long wave radiation

Answer 7

from the earth back to the atmosphere : during cloudless night = large losses of long wave radiation from the Earth and very little return back to the atmosphere (net loss of energy)

Question 8

The greenhouse effect

Answer 8

process by which certain gases allow short wave radiation to pass through but trap outgoing long wave radiation - leading to warming of the atmosphere = it is a good thing as without it we wouldn’t be able to inhabit the planet

Number of greenhouse gases = Water vapour most common greenhouse gas, accounting for 95%

C02 = levels have risen from about 315 parts per million in 1950 to over 400 ppm in 2015 - increase due to human activity (fossil fuels) and due to deforestation

Methane = second largest contributor – presence in the atmosphere increasing – cattle convert up to 10% of the food they eat into methane - methane bogs trapped in permafrost will be released as they melt

Cfc’s = man-made chemicals that destroy ozone as absorb long wave radiation

Question 9

Variations in Solar radiation

Answer 9

earths temp changes for many reasons - solar output changes. Milankovitch cycles - variations in the earths orbit affect the seasonal and latitudinal distribution of solar radiation and are responsible for ice ages. On a shorter timescale - changes due to volcanic erruption decrease global temp. Changes in reflectivity (ice melty and replaced by green vegetation that does not reflect as much heat)

Question 10

Pollution and Global Dimming

Answer 10

from the 1950’s to early 1990’s = level of solar energy reaching the earths surface has dropped over Antartica the USA, The UK and Russia– all due to higher levels of pollution at the time - Natural particles in clean air provide condensation nuclei for water. Polluted air contains ash, soot and sulphur dioxide which provides many more sites for water to bind to - droplets formed tend to be much smaller than natural droplets - many small droplets reflect more light than fewer larger ones so polluted clouds reflect far more light back to space preventing insolation from. getting into the atmosphere

Question 11

Albedo Values

Answer 11

reflection from the earths surface is generally about 7% - Albedo values vary for different types of ground eg fresh snow albedo about 75-90% while forest about 5-15%

Question 12

Global dimming

Answer 12

following the 9/11 terrorist attacks on the USA - the banning of air travel across the USA average temp rose by 11*C in the absence of condensation trails – global dimming is the cooling of air temperature due to pollution - possible that it has been reducing what would be even faster global warming than is currently occurring

Question 13

Feedback loops

Answer 13

impacts of global warming may be greatest in tundra environments – regions of seasonal ice cover at edges of glaciers and ice sheets

effects will be most noticeable in terms of winter warming – melting of polar ice caps results in less ice and lowers planetary albedo- as ice is more reflective than water less ice leads to less reflection , increasing the amount of solar energy absorbed and increasing the temperature

Rotting vegetation trapped under permafrost in the tundra releases methane that is unable to escape due to the frozen subsurface – increased thawing of permafrost leads to an increase in the release of methane adding to greenhouse gases in the atmosphere and increasing global temperatures

Negative feedback loops:
- increased evaporation in low latitudes due to higher temperatures may lead to increased snowfall on the polar ice caps reducing the mean global temperatures - an increase in co2 in the atmosphere leads to increased plant growth - increased biomass and activity increases store of terrestrial carbon but reduces atmospheric conditions of c02

Question 14

enhanced greenhouse effect

Answer 14

impact of increasing levels of greenhouse gases in the atmosphere due to human activities - more frequently called global warming = changes in global pattern of rainfall and temp and the incidence of droughts, floods and storms

Question 15

Main contributors to greenhouse gas emissions

Answer 15

increase in greenhouse gas linked to industrialisation, trade and globalisation - as industrialisation has increased so has atmospheric c02

Question 16

Global warming

Answer 16

many far reaches affect on natural, social and economic environment - sea levels will rise causing flooding in low level areas
- storm activity will increase
- agricultural patterns will change
- less rainfall over the USA
40% of species will become extinct
- Human health = increased disease (eg malaria)

Question 17

Changes to the hydrosphere

Answer 17

potential impacts of global warming on hydrosphere = rise in sea levels causing flooding in low level areas
- floods from melting glaciers

steric effect = expansion of water as it gets warmer leading to slight rise in sea level

Question 18

Changes in Sea Ice

Answer 18

artic sea ice - declined dramatically since mid 1970’s (main reason due to global warming) - annual artic sea ice minimum usually occurs during sep each each and max during march - overall volume and thickness has been decreasing

As ice recedes- potential for wave formation increases (5 meter waves) - these waves also helped to break up the sea ice

sea ice decline - linked to increased primary productivity of plankton blooms - melting ice reduces time polar bears have to hunt = must spend more time on land

Question 19

Glaciers and ice caps

Answer 19

many himalayan glaciers are retreating - may have major impact on regions water supply - many of Asia’s major river systems stem from himalayas and provide water for drinking, irrigation and other uses

eg Gangorti glacier = one of largest in region and has been on retreat since 1780 - since 1990 = retreated more than 800 m

Question 20

Ice

Answer 20

periglacial areas have low temp and permafrost = in man regions the permafrost is beginning to thaw - slow rate of decomposition has allowed the large accumulation of carbon to develop in the form of dead organic matter - more nutrients will be released

warming will lead to increased methane emissions

Question 21

Oceans

Answer 21

contain about 50 times more carbon than the atmosphere - with climate change = causing changes - increased carbon in the atmosphere warms the earth and may make plants grow more and store more carbon but contrastingly ocean pH is decreasing - dropped by 0.1 - some of excess carbon dissolves in the ocean to become carbonic acid which reacts with carbonate to for bicarbonate. With less carbonate available shell building organisms such as lobsters and coral end up with thinner shells

Question 22

Biosphere

Answer 22

terrestrial plants have absorbed more than 25% of total co2 humans have released – for a doubling of co2 plant growth increases significantly, providing there are no other limiting factors

Question 23

biome changes

Answer 23

climate change in the geological past can show how biomes might move in future – latitudinal shift relative to the equator and altitudinal shift as biomes move up the slope - low lying biomes such as mangroves my be lost due to sea level change and high will be lost as they do not have anywhere to move to

species composition in ecosystems also likely to change – climate change in the past has allowed species to adapt gradually to new conditions – current changes are happening very rapidly = little time for organisms to adapt

reduction in biodiversity may also occur - some species (fewer options for migration and so are more vulnerable to extinction

Question 24

Animal Migrations

Answer 24

forced movement of some plants and animals outside of their normal range or preferred temperature - to survive they must move polewards or to higher elevation - corridors that allow animals to migrate eg appalachian moutains – also providing some shelter for refugees from climate change.

Question 25

Soil Erosion

Answer 25

global warming could lead to an increase in soil erosion, degradation, desertification and salinisation - warmer temp could double soil loss on moderate slopes -- higher when rainfall is high and vegetation is low

Question 26

Changes to agriculture

Answer 26

as global temp rise changes in agriculture patterns likely to rise -- rise of 3* C could lead to 35% drop in crop yields -- could lead to hunger rising Changing in crop growing location can be expected with latitudinal movements away from equator eg viticulture (growing of grapes to produce wines) will move polewards reduction in water sources will make it more difficult to cultivate crops they grow

Question 27

Impact of climate change on human health

Answer 27

effects of global warming are varied -- rise in temp could expose up to 60 million africans to malaria -- mosquitoes would be able to breed in areas previously too cool for them - other tropical diseases will spread as warmer conditions extend to higher latitudes may lead to increased human migration One benefit could be new sea routes as sea ice melts -- could open up new trade routes -- geopolitical issues to be resolved before either of sea routes is used for international shipping

Question 28

Disparities in exposure to climate change

Answer 28

Uncertainties about the nature and scale of climate change -- levels may very according to a person's location Vulnerability = degree to which people are susceptible or unable to cope with the negative impacts of climate change 1) degree to which they are exposed 2) degree to which they could be harmed by exposure to climate change 3) degree to which they could mitigate the potential harm by taking action to reduce exposure

Question 29

Populations that are more vulnerable to climate change

Answer 29

women, very young, elderly, those with disabilities, people with mobility problems, refugees and indigenous groups. Carers = burden of sickness from young or elderly

Question 30

Locations that are more at risk

Answer 30

low lying islands, river mouths, coastal areas and regions that derive their water supplies from mountain glaciers

Question 31

Problems for low lying areas

Answer 31

increased coastal erosion salt water intrusion into groundwater damage to coral reefs out- mitigation of people decline in economic activities and infrastructure

Question 32

Indigenous people

Answer 32

often live in vulnerable environments as well as face socio-economic problems such as low incomes and limited access to resources eg Inuit in Mackenzie Basin in Canada = rise in temp about 3.5*C since 1980 -- wildlife in the basin is major source of food clothing and income and this has all declined over recent years

Question 33

Flooding in Bangladesh

Answer 33

Most of the country forms a low lying delta -- since 1970's scale and intensity and duration of the floods have increased -- scientist predict that flooding will increasingly rise in the future -- densely populated coastline of Bangladesh is increasingly vulnerable to coastal floods - potential for flood likely to increase intensity of precipitation events by 14%-40% by the 2030's and 52%-135% by 2090's In 1988 -- Government of Bangladesh developed flood action plan with aim to prevent this -- sluice gates were build on rivers and also provide protection from flooding by tidal waves and storm surges -- government has built 5700 km of embankments and dug 5000 km of drainage channels frequent flooding in Padma River Islands makes the lives of the people extremely vulnerable -- since 1990 = frequency of extreme precipitation has increased

Question 34

Vulnerability in Ghana

Answer 34

population groups that are most vulnerable = poor, elderly, women, children, infirm, indigenous, minority groups and refugees -- impacts = decreased water availability, increased illness and fatality, out-migration and increasing poverty Climate change -- likely to lead to conditions outside the normal ranges of experiences for many countries -- In Ghana = types of adaptation include infrastructure development, eco-system based nature and capacity development

Question 35

Government led action

Answer 35

many obstacles to achieving a low carbon world, political obstacles found nationally and internationally -- fossil fuel industry is one of the most powerful lobby groups in the USA (coal, oil and gas interests have limit climate change regulations.

Question 36

Kyoto protocol

Answer 36

in 1997 -- 183 countries signed up to an agreement that called for the stabilisation of greenhouse gas emissions at safe levels the would avoid serious climate change -- agreement aimed to cut greenhouse gas emissions by 5% of their 1990 levels by 2012

Question 37

Paris Agreement

Answer 37

2015 UN climate change conference was held in Paris -- France was taken as an example of an HIC that has decarbonised it's energy production -- generates over 90% of power from nuclear, hydroelectric and wind energy. 174 countries signed the Paris agreement on the reduction of climate change -- key objective is to limit global warming to 2*C compared to pre industrial levels -- unliek kyoto = no countrs specific goals

Question 38

Adaptation Strategies

Answer 38

possibly to reduce human emissions of greenhouse gases -- technology exist and measures such as energy efficiency and fuel switching are all possible. Examples of adaptations = flood defences, vaccination programmes, desalination plants, planting of crops in previously unsuitable env

Question 39

What mitigation involves

Answer 39

reduction and or stabilisation of greenhouse gas emissions and their removal from the atmosphere - reducing energy consumption - using alternative sources of energy to fossil fuels - geo- engineering

Question 40

Carbon Trading

Answer 40

attempt to create a market in which permits issues by governments to emit carbon can be traded -- in europe = through the Emissions Trading System - governments set targets for the amount of co2 that industries can emit and plants that exceed forced to buy from others who don't

Question 41

Carbon offsetting schemes

Answer 41

designed to neutralize the effects of carbon dioxide human activities produced by investing in projects that cut emissions elsewhere -- some say it dis encourages a shift in behaviour

Question 42

Carbon Capture and Sequestration

Answer 42

currently when fossil fuels burned . c02 enters the atmosphere which it may reside for centuries - potential to capture the c02 before it is released into the atmosphere 1) Capture c02 at the sit where it is produced and store it underground in geologic deposit 2) allow co2 to enter atmosphere but then remove it using specially designed removal processes -- direct air capture

Question 43

Carbon Taxes

Answer 43

some countries introducing carbon taxes = taxes imposed relative to the proportion of carbon burnt - co2 imposes high costs on societies but those who emit the c02 do not pay the social cost that they impose -- users of fossil fuels could pay an extra "tax" equal to the societal cost of c02 emitted

Question 44

Geo - engineering

Answer 44

large scale engineering schemes that alter natural proceses -- eg sulphate aerosol particles in the air could be used to dim the incoming sunlight and thereby cool the planet -- giant space mirrors in space to deflect some of the incoming solar radiation

Question 45

Ocean fertilization

Answer 45

C02 absorption can be increased by fertilising the ocean with compounds of iron, nitrogen and phosphorus. This introduces nutrients to the upper oceans, increases marine food production and takes carbon dioxide from the atmosphere -- may trigger an algea bloom