Climate Change

Question 1

Evidence for Climate Change: Ice Cores

Answer 1

Scientists take long samples of ice out of ice sheet + analyse gases that are in there by inspecting bubbles, deeper ice in ice sheet, older it is, trapped air contains record of carbon dioxide + methane levels at time, more carbon dioxide there is, then warmer it was + vice versa

Question 2

Evidence for Climate Change: Tree Rings

Answer 2

Scientists look at tree rings to determine what climate was like before, small rings means growth was slow + vice versa, counting rings determines age of tree, trees grow wider rings when season is long + vice versa

Question 3

Evidence for Climate Change: Fossils

Answer 3

Palaeontologists can identify similarities between fossil remains + animals that are living today, if fossils found are different to animals that live today, then it’s likely that climate was different in past

Question 4

Evidence for Climate Change: Old Paintings and Diary Entries

Answer 4

Old Paintings can visually show us what climate was like + diary entries can describe what climate was like

Question 5

Evidence for Climate Change: Yearly Events ‘Natures Calendar’

Answer 5

Seasonal shift, when season lasts for either shorter or longer than it should have is evidence of climate change

Question 6

Evidence for Climate Change: Landforms

Answer 6

Depending on landscape, landforms are created e.g valley means that there was river there before, glaciers that existed in very cold climates also carve out landscapes, leaving behind U-shaped valleys

Question 7

Natural causes of climate change: Milankovitch Cycles

Answer 7

Eccentricity, Obliquity + Precession

Question 8

Eccentricity

Answer 8

Describes path of Earth as it orbits Sun - not fixed, every 100,000 years it changes to either circle or oval shape of orbit

Question 9

Obliquity

Answer 9

Tilt of Earth, Earth spins on its axis, causing night + day, angle changes every 41,000 years, tilt axis is between 24.5º - 22.5º, average angle is 23.5º, larger angle, more Northern Hemisphere is turned towards sun + vice versa

Question 10

Precession

Answer 10

Describes natural ‘wobble’ rather than spinning top, accounts for certain regions of world e.g Northern Hemisphere, experiencing very long days + very long nights at certain times of year, happens every 26,000 years

Question 11

Natural causes of climate change: Sunspots

Answer 11

Dark patch that appears from time to time on surface of Sun, ‘Sunspot Cycle’, when sunspot activity is at its maximum, Sun gives off more heat, large explosions occur on surface of Sun, resulting in solar flares, when sunspot activity is at its minimum, solar output is reduced, leading to lower temperatures

Question 12

Sunspot Cycle

Answer 12

Number of sunspots increase from minimum to maximum over 11 years

Question 13

Natural causes of climate change: Volcanic Activity

Answer 13

Violent volcanic eruptions blast huge quantities of ash, gases + liquids into atmosphere, volcanic ash can block out Sun, reducing temperatures on Earth, normally short-term impact, fine droplets that from from conversion of sulphur dioxide to sulphuric acid act like tiny mirrors reflecting radiation from Sun, last lot longer + can affect climate for many years

Question 14

Volcanic Winter

Answer 14

Cooling of lower atmosphere + reduction of surface temperatures

Question 15

Human causes of Climate change: Greenhouse effect

Answer 15

Atmosphere allows most of heat from Sun (short-wave radiation) to pass straight through it to warm up Earth’s surface, when Earth gives off heat in form of long-wave radiation, some gases e.g CO2 + methane are also able to absorb it, keeps Earth warm, without this ‘blanketing’ effect it would be far too cold for life to exist on Earth

Question 16

Greenhouse gas

Answer 16

Gas that is able to absorb long-wave radiation e.g carbon dioxide or methane

Question 17

Human causes of Climate change: Carbon Dioxide

Answer 17

Accounts for estimated 60% of enhanced greenhouse effect, sources: deforestation + burning wood, burning fossil fuels in industry + power stations to produce electricity e.g oil, coal + gas, car exhausts,

Question 18

Human causes of Climate change: Methane

Answer 18

Very effective in absorbing heat, accounts for 20% of enhanced greenhouse effect, sources: rice farming, burning biomass for energy, farm livestock e.g cows, decaying organic matter in landfill sites + compost tips

Question 19

Human causes of Climate change: Nitrous Oxides

Answer 19

Very small concentrations in atmosphere, but are up to 300 times more effective in capturing heat than carbon dioxide, sources: sewage treatment, power stations producing electricity, car exhausts, agricultural fertilisers

Question 20

Greenhouse Effect

Answer 20

When atmosphere traps heat from Sun, which keeps Earth warm, more heat leaves atmosphere than in enhanced greenhouse effect

Question 21

Enhanced Greenhouse Effect

Answer 21

Same as greenhouse effect just more heat is trapped in atmosphere as there are more greenhouse gases produced by humans in atmosphere, so less of Sun’s energy is leaving Earth’s atmosphere, increasing average atmospheric temperature, caused by humans

Question 22

Climate Change

Answer 22

Long-term change in Earth’s climate, especially change due to increase in average atmosphere temperature, causes natural events to be more extreme

Question 23

Changes in agricultural systems: Low-latitudes (Adaptation)

Answer 23

Scientists think that greatest change to agriculture will occur in low-latitudes, Southern Africa’s maize crop could fall by 30% by 2030 + production of rice in South Asia could fall by 10%

Question 24

Changes in agricultural systems: Mid-latitudes (Adaptation)

Answer 24

Warmer climate in Europe + North America could lead to increase in production of certain crops e.g wheat, in UK, Mediterranean crops e.g vines + olives may thrive in future

Question 25

Changes in agricultural systems: Example - Crop irrigation in The Gambia (Adaptation)

Answer 25

Adaption methods: Educating farmers in water havesting techniques, new irrigation systems, shade trees can be planted to protect seedlings from strong sunshine, new cropping patterns can be introduced e.g changing planting/sowing dates

Question 26

Managing water supply: Impact of Climate Change (Adaptation)

Answer 26

Causes more severe + frequent droughts + floods, unreliable rainfall + periods of water shortage require careful management, future climate change will affect current patterns of water supply, impacting quantity + quality of water, most vulnerable, particularly in rural areas of poorer countries, who are likely to be most affected

Question 27

Managing water supply in the Himalayas (Adaptation)

Answer 27

Millions of people in Asia depend on rivers fed by snow + glacial melt for their domestic + agricultural water supply, in Himalayas, most of 16,000 glaciers are receding rapidly due to global warming, which threatens long-term security of water supply in region, so they create artificial glaciers that freeze through system of diversion canals + embankments, when ‘glacier’ melts in spring, it will provide water for local villages

Question 28

Reducing the risk of rising sea-levels: Impact of Climate Change (Adaptation)

Answer 28

Average sea levels have risen by 20cm since 1900, by 2100, sea levels are expected to rise by further 20-82cm, which will flood important agricultural land in countries e.g Bangladesh, India + Vietnam, as sea levels rise, rates of coastal erosion will increase, fresh water supplies will become contaminated by saltwater + coastal areas will be prone to damage from storm surges

Question 29

Reducing the risk of rising sea-levels (Adaptation)

Answer 29

Building houses that are raised off ground on stilts, restoration of coastal mangrove forests as their tangled roots trap sediment + offer protection from storm waves, construction of sea walls, 3m sea wall is being constructed around capital city of Maldives - Male - with sandbags used elsewhere, construction of artificial islands up to 3m high so that people most at risk could be relocated

Question 30

Adaption

Answer 30

Changing behaviours/actions to cope with effects of something - e.g climate change - e.g building coastal flood defence

Question 31

Mitigation

Answer 31

Reduction of harmful effects of climate change + management of causes of climate change e.g changing cars to be electric to reduce carbon emissions being emitted

Question 32

Alternative energy production (Mitigation)

Answer 32

Way of producing energy without releasing carbon emissions, they don’t emit large amounts of carbon dioxide, some are renewable + will last in future, nuclear power use uranium to generate electricity, e.g hydroelectricity, nuclear + solar power, wind + tides, negatives: not all countries have right conditions, very expensive

Question 33

Planting trees (Mitigation)

Answer 33

Trees act as carbon sinks, removing carbon dioxide from atmosphere by photosynthesis, they release moisture into atmosphere, which has cooling effect by producing more clouds, reducing incoming solar radiation, plantation forests can absorb carbon dioxide at faster rate than natural forests + can do so effectively for up to 50 years

Question 34

Carbon sinc

Answer 34

Anything that absorbs more carbon from atmosphere than it releases e.g plants, sea, soil

Question 35

Carbon capture and storage - CCS (Mitigation)

Answer 35

Uses technology to capture carbon dioxide produced from use of fossil fuels in electricity generation + industrial processes, once captured, carbon gas is compressed + transported by pipeline to injection well, it’s injected as liquid into ground to be stored in suitable geological reservoirs, e.g Petra Nova Plant, Texas, USA, negatives: very expensive, could leak

Question 36

International agreements (Mitigation)

Answer 36

Climate change is global issue + requires global solutions, carbon emissions spread across world + affect everyone, Agreements: Kyoto Protocol, 2005, over 170 countries aimed to reduce carbon emissions by average of 5.2% below their 1990 levels by 2012, Copenhagen Accord, 2009, pledged to reduce emissions with financial support for developing nations to help them cope with impacts of climate change, Paris Agreement, 2015, 195 countries were legally bound to peak greenhouse gas emissions as soon as possible, to keep global temperature increase below 2ºC + limited to 1.5ºC above pre-industrial levels + to review progress every 5 years