DE (W6)

• external climate variation is caused by solar forcing and continental drift
• solar forcing (Milankovitch cycles) is determined by the Earth's movement around the sun: the changing eccentricity (degree of ellipticity) of the earth's orbit around the sun, the changing tilt of the earth's axis and the precession (axis wobble) of the earth
• sea level is influenced by many things including: winds, currents, glaciers (subsidence, isostatic adjustment), tectonics, thermal expansion of the oceans
• impacts of sea level rise include flooding/submergence, ecosystem change, erosion, salinisation
• global sea level changes occur over centuries to Millenia
• sea levels are measured through: tidal gauges and GPS satellits
• past sea levels (paleowater depth) can be determined through proxy organisms such as coral reef fossils that grew differently depending on depth
• transgression is the rapid rise in sea level
• radioactive dating of deposits and pristine samples of shells can help determine an absolute age of a sea level event
• coral in reefs enter different growth modes depending on their depth: give up mode, catch up and keep up
• Isostasy is the rising or settling of a portion of the Earth's lithosphere that occurs when weight (eg. glaciers) are removed or added.