BIOC58H3 Lecture Notes - Lecture 4: Mountain Pine Beetle, Pinus Contorta, Bark Beetle
Document Summary
Lecture 4 lessons of the past: terrestrial responses. Part 1 ecosystem responses to anthropogenic change ii. Increase in forest fires = increase in co2 released (more widespread: amount of co2 released by drought estimated to equal the annual. Co2 production of entire usa: cloud forests, lifting cloud base hypothesis. If amazon dries out enough that loses forest in an area, could cascade through entire system: decreases in forest cover over large areas and increased co2 from decomposition > global climate affected, deforestation = area becomes drier. Increased temperatures have caused bark beetle population explosion and drought in pinyon pine forests: more than 90% of trees have died in some areas. Increase chance of forest fire: permafrost melting, lakes draining (areas that are wetter/drier, forests shifting north, positive feedback loop with global warming. Polar and marine systems: arctic oceans, southern oceans, between 1978 and 2011, 20% decrease in arctic ice cover. Part 2 past terrestrial response to climate change.
