climate change - natural hazards Flashcards
causes, adaptations, mitigation
climate change definition
a long-term shift in the average weather patterns of the Earth, such as changes in temperature, precipitation, wind, and ocean currents
global warming definition
the gradual increase in the average surface temperature of the Earth
Ice cores
-geological, long-term
-drill into ice sheets, analyse gases trapped within, oxygen isotopes are used to estimate temperature: higher ratio of O-18 to O-16 when warmer
-800,000 years back
sediment core/pollen analysis
-long-term, geological
-core trap information: organisms, sediment, pollen
-types give data on past temperatures, oxygen levels + nutrients
historical records
-medium-term, imprecise
-paintings, diaries, newspaper, culture can tell us climate in the past e.g. painting of the Thames frozen over
tree rings
-medium-term, indirect
-dendrochronology
-thicker ring = warm, wet
-thin ring = cold, dry
-ring per year of growth
retreating glaciers
-medium-term
-warming, melting glaciers
-measure how fast ice melts, provide visible changes
weather records
-short-term, instrumental
-measured data from weather stations provides lots of information: wind, rain, temp etc
-only goes back to 1850s
polar ice melt
-short-term
-can take data from satellites
ecosystem changes
-short/long-term
-extinctions/migrations/adaptations of organisms due to climate
3 natural causes of climate change
orbital changes (Milankovitch Cycle), solar output, volcanic activity
what is solar output + how does it contribute to CC
-sunspots are magnetic storms on the sun’s surface
-no. + size of sunspots show cyclical patterns
-minimal change over last 50yrs
-during low amplitude, sun’s output of radiation is reduced, cold earth
what is eccentricity + how does it contribute to CC
-change in shape of orbit (circular to elliptical) over 100,000 yrs
-elliptical = ice age
what is precession + how does it contribute to CC
-as the earth rotates it wobbles over 26,000 yrs
-impacts the seasonal contrasts between hemispheres + timing of seasons.
what is obliquity + how does it contribute to CC
-variation in earth’s tilt (22.5°-24.5°)
-When the angle increases the summers become warmer and the winters become colder
how do volcanic eruptions contribute to CC
-eruptions eject sulfur dioxide, can stay in atmosphere for 3yrs
-reacts w/water vapor, forming volcanic aerosol that’s optically dense layer that reflects sunlight + reduces sun’s heat energy entering earth’s atmosphere
3 human causes of climate change
fossil fuels, agriculture, deforestation
what is the greenhouse effect
CO2, methane + water vapour trap infrared heat from the sun. this is natural + without it, it would be 33°C colder
how do fossil fuels contribute to CC
-accounts for >1/2 of gg emissions
-burning releases CO2 enhancing gh effect
how does agriculture contribute to CC
-accounts for 20% of gg emissions
-methane produced by cattle, microbes in paddy fields
how does deforestation contribute to CC
-accounts for 10% of gg emissions
-during photosynthesis trees sequester carbon
-when trees are slash + burnt CO2 is released + there are less trees to absorb it
4 impacts of climate change in UK
-sea levels could rise, flood low lying areas, e.g. east England
-droughts + floods are more likely as extreme weather increases
-increased need for water in hot summers pressures water supplies
-Industry impacted e.g. Scottish ski resorts have to close due to no snow
4 Impacts of climate change globally
-sea level rise will affect 80mil people
-tropical storms will increase in magnitude
-species in affected areas (Arctic) become extinct
-diseases such as malaria increase, an additional 280 mil people may be affected
mitigation definition
actions to limit the magnitude/rate of global warming + its effects
