Climate Change Flashcards
Evidence for Climate Change: Ice Cores
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
Evidence for Climate Change: Tree Rings
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
Evidence for Climate Change: Fossils
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
Evidence for Climate Change: Old Paintings and Diary Entries
Old Paintings can visually show us what climate was like + diary entries can describe what climate was like
Evidence for Climate Change: Yearly Events ‘Natures Calendar’
Seasonal shift, when season lasts for either shorter or longer than it should have is evidence of climate change
Evidence for Climate Change: Landforms
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
Natural causes of climate change: Milankovitch Cycles
Eccentricity, Obliquity + Precession
Eccentricity
Describes path of Earth as it orbits Sun - not fixed, every 100,000 years it changes to either circle or oval shape of orbit
Obliquity
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
Precession
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
Natural causes of climate change: Sunspots
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
Sunspot Cycle
Number of sunspots increase from minimum to maximum over 11 years
Natural causes of climate change: Volcanic Activity
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
Volcanic Winter
Cooling of lower atmosphere + reduction of surface temperatures
Human causes of Climate change: Greenhouse effect
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
Greenhouse gas
Gas that is able to absorb long-wave radiation e.g carbon dioxide or methane
Human causes of Climate change: Carbon Dioxide
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,
Human causes of Climate change: Methane
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
Human causes of Climate change: Nitrous Oxides
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
Greenhouse Effect
When atmosphere traps heat from Sun, which keeps Earth warm, more heat leaves atmosphere than in enhanced greenhouse effect
Enhanced Greenhouse Effect
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
Climate Change
Long-term change in Earth’s climate, especially change due to increase in average atmosphere temperature, causes natural events to be more extreme
Changes in agricultural systems: Low-latitudes (Adaptation)
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%
Changes in agricultural systems: Mid-latitudes (Adaptation)
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
Changes in agricultural systems: Example - Crop irrigation in The Gambia (Adaptation)
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
Managing water supply: Impact of Climate Change (Adaptation)
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
Managing water supply in the Himalayas (Adaptation)
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
Reducing the risk of rising sea-levels: Impact of Climate Change (Adaptation)
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
Reducing the risk of rising sea-levels (Adaptation)
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
Adaption
Changing behaviours/actions to cope with effects of something - e.g climate change - e.g building coastal flood defence
Mitigation
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
Alternative energy production (Mitigation)
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
Planting trees (Mitigation)
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
Carbon sinc
Anything that absorbs more carbon from atmosphere than it releases e.g plants, sea, soil
Carbon capture and storage - CCS (Mitigation)
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
International agreements (Mitigation)
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
