natural hazards - climate change Flashcards
how temperature has changed compared to today’s average
last 2.6 million years (quaternary) - temperatures fluctuated a lot but shows a gradual cooling
before that - less fluctuating, more constant, higher temperatures
this interglacial period is longer than usual
average global temperature has increased due to global warming
global effects of climate change
glaciers and ice caps melting
arctic sea ice less extensive - thinned, effects wildlife
low-lying island under threat from sea-level rise
sea level predicted to rise from 0.48m to 0.84m by 2100 - thermal expansion, increased water temp, melting ice
seasonal changes - tree flowering, bird migrating advancing up to two days per decade
effect of orbital changes on climate change
milankovitch cycles
eccentricity - path of orbit, circular to elliptical
axial tilt - angle of earth’s axis changes
precession - natural wobble
effect of solar orbit on climate change
number of sunspots increases from a minimum (lower temps on earth) to maximum (more heat) and then back
little ice age between 14th and 19th century
effect of volcanic activity on climate change
ash, carbon dioxide, sulphur dioxide, liquids into atmosphere
ash blocks out sun, short term surface temperature reduction
greenhouse effect
natural warming of atmosphere by absorption of heat radiated off earth’s surface - giant blanket, conditions to cold to live without it
heated in day, retained at night
allows most short-wave heat from sun in, some long wave escapes out greenhouse gases (co2, ch4, n2o) absorb it - conc increases in recent decades, enhanced greenhouse effect, global warming
effect of fossil fuels on climate change
formed by natural processes of decomposition of buried dead organisms, burned to create heat energy, ghg released
dominant cause of global warming
1/3 emissions from burning oil, 20% from natural gas
effect of agriculture on climate change
carbon dioxide - deforestation and drainage for land, soil disturbance releases carbon in soil, energy for heating and transportation
methane - livestock digestion (average 250-500 litres per day per herbivorus mammal), anaerobic decomposition of paddy rice
nitrous oxide - manure, fertilisers, soil disturbance
effect of deforestation on climate change
carbon stored during photosynthesis released as co2, less trees to absorb co2
in tropical region - about 20% annual ghg emissions
mitigation of climate change
actions to reduce or prevent emission of ghg such as alternative renewable energy production, new technologies (carbon capture), planting trees, international agreements
adaptation to climate change
actions by individuals, communities and national/international authorities to manage the unavoidable impacts of climate change, such as changing agricultural systems, managing water supply and reducing risk from rising sea levels
alternative energy production to mitigate climate change
hydro-electricity, nuclear power, solar, wind, tides
do not emit large amounts of co2, most renewable
50% of uk’s electricity is renewable, 65% target by 2030
carbon capture to mitigate climate change
capture co2 emissions, 90% that would otherwise enter atmosphere
captures, compressed, transported to injection wells, injected as liquid in underground aquifers, fossil fuel deposits
high costs
planting trees to mitigate climate change
carbon sinks
afforestation and reforestation
cost-effective
international agreements to mitigate climate change
paris agreements - limit global warming to well below 2 degrees C
COP26 in Glasgow - reduce rate of deforestation, cut methane emissions, phase down use of coal
