9.5 global climate change

Impact on marine ecosystems from global climate change

Altered range of marine ecosystems: new habitats from by rising sea level flooding coastline

Altered ranges for organisms: warm water hold less O2 → fish have declined/ migrated

Historic climate change

Earths climate has varied over geologic time, due to variations in earths orbit around the sun

-varies in obliquity → northern latitude to high insolation @ different times

-varies in eccentricity → brings it closer to & further from sun @ different times

-leads to predictable variation in earths climate called Milankovitch Cycles

Earths historical climate, scientist measurements

Scientists have measured and estimated earths historical temperature and CO2 level using 3 evidences

1) foraminifera shells in ocean sediments

2) air bubbles in ice cores → contain ancient atmospheric gas

3) concentrations in annual ice (increased O = increased temp)

Effects of climate change

1) Rising temperature: habitat/species loss, drought, soil desiccation

2) rising sea level: due to glacial, polar ice melt + thermal expansion

3) melting permafrost: permanently frozen tundra soils that begin to thaw & release methane

Impact of coastal communities from climate change

1) property loss, damage, potential relocation

2) loss of barrier islands

Impact on atmospheric currents from climate change

1) widening & weakening of Hadley cell: temp differs between equator & poles → decrease, air expanding from equator travels further

2) wakes, destabilized jet stream: arctic warms faster → temp difference between equator & poles weaken

Impact on ocean circulation from climate change

Suppression of thermohaline circulation: global ocean current → redistributes heat from equator, salt, nitrites → mixing ocean waters → could slow/stop

Unequal global warming

Polar regions of earth are warming fast than other regions (polar amplification)

Melting permafrost: permanently frozen tundra soils that begin to thaw & release methane

Impact on polar ecosystems from global climate change

arctic sea ice loss → habitat loss