Climate Change (from 4th form revision booklet)

what is evidence of climate change since 1914? (3 bullet points)

• increase in average surface air temp by 1°C over last 100 years

• warmest ocean temps since 1850

• 19cm rise in sea levels since 1900

other than weather data, what other evidence can can we use that there have bene climate changes? (4 bullet points)

• tree rings (short term climate change) + ice cores (long term climate change) → spanning 800,000 years

• ocean sediments → spanning over quaternary period

• help estimate past temps by comparing oxygen, carbon dioxide, and methane in ice cores

• melting ice sheets overtime

what is a quaternary period?

period of time stretching from 2.6 million years ago

name 3 possible natural causes of climate change

• orbital changes

• solar output

• volcanic activity

name 3 possible human causes of climate change

• fossil fuels

• agriculture

• deforestation

how is orbital changes a cause of climate change?

sun’s energy on earth’s surface changes as Earth’s orbit is elliptical, its axis is tilted on angle + Earth isn’t spherical

how is solar output a cause of climate change?

• sunspots increase from a minimum to maximum every 11 years

• fewer sunspots observed during coldest period 1645-1715

• solar output barely changed in last 50 years

how is volcanic activity a cause of climate change?

volcanic aerosols reflect sunlight away, reducing global temps temporarily

how is fossil fuels a cause of climate change?

burning fossil fuels release carbon dioxide - this accounts for 50% of greenhouse gases

how is agriculture a cause of climate change?

• accounts for 20% of greenhouse gases

• larger populations + demand for meat and rice will increase its contribution

how is deforestation a cause of climate change?

logging + clearing land for agriculture/roads increase amount of carbon dioxide in atmosphere as less photosynthesis occurs

in what ways are environmental effects of climate change likely to affect people?

• environmental effects could lead to extreme weather → e.g. increase in droughts

• this means that crop production fails

• increased food prices

• hard to afford basic meals

• could lead to famine

what are the social impacts of climate change? (4 bullet points)

• increased risk of diseases → skin cancers/heat strokes as temps increase

• decrease winter-related deaths bc milder winters

• crop yield affected - maize will decrease by 12% in South America

• less ice in Arctic ocean increases shipping + extraction of gas + oil reserves

what are the environmental impacts of climate change? (4 bullet points)

• lower rainfall causes food shortages for orangutans in Indonesia

• sea-level rise increases flooding + coastal erosion, so defences under increasing strain

• warmer rivers affect marine wildlife → food supply decreases for Ganges river dolphins

• increased drought in areas like Mediterranean region

what is the difference between mitigation + adaption?

• mitigation strats respond to causes of climate change

• adaption strats address the impacts of climate change

name 4 mitigation strategies

• alternative energy production

• carbon capture

• planting trees

• international agreements

explain the mitigation strategy, alternative energy production (5 bullet points)

• e.g. wind, solar, geothermal

• reduces greenhouse gases (compared to fossil fuels)

• lasts longer

• expensive (getting cheaper)

• can’t be relied upon for electricity (if no wind/sun)

explain the mitigation strategy, carbon capture (5 bullet points)

• takes carbon dioxide from emission sources + stores safely in ground

• impermeable “cap rock” stops it escaping

• expensive

• unclear if carbon dioxide remain captured long term

• doesn’t promote renewable energy

explain the mitigation strategy, planting trees (5 bullet points)

• removes carbon dioxide in air by photosynthesis

• increase carbon forest storage by 28%

• oxygen produced bc photosynthesis, trees provide habitats

• land may be limited

• biodiversity reduced if only 1 species planted

explain the mitigation strategy, international agreements (5 bullet points)

• encourage countries to take responsibility for CO₂ emissions

• targets more likely met if legally binding (Paris 2015 agreement)

• financial support provided for LICs

• some countries = considered mor responsible

• may not be achieved

name 3 adaptation strategies

• changes in agricultural systems

• reducing risk

• managing water supplies

explain the adaptation strategy, changes in agricultural systems (4 bullet points)

• deal with changing rainfall + temp patterns

• weather become more extreme

• production move location to suit climate

• adaptations more accessible to rich HIC farmer → least likely affected

explain the adaptation strategy, reducing risk (2 bullet points)

• reducing risk from rising sea levels involve constructing defences, raising properties on stilts, relocating people at risk

• economic, social, environmental implications of these strats

explain the adaptation strategy, managing water supplies (3 bullet points)

• ensures populations can face challenge of changing rainfall patterns

• in London involves reducing demand + increasing supply

• adding to water supplies being under strain, security may be threatened in areas of deficit → especially where less politically stable