ANTH 4185 Lecture Notes - Lecture 1: Water Cycle, Presentation Of A Group, Ozone Depletion
8 Sep 2017
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Document Summary
Anth-ahcl-ersc 4185 human impact on ancient environments 08/09/17. Human impact on ancient environments is sometimes referred to as global change archaeology. Ecosystem changes and extinctions equal a loss of biodiversity. High risk: biogeochemical flows anthropogenic changed (industrial and agriculture) E. g. target crops only take up a small percent of nitrogen and phosphorus we are well into the danger zone. Increased risk: climate change natural climate cycling, anthropogenic forcing"s (greenhouse gas emissions, loss of carbon sinks) positive feedbacks equal rapid earth system changed. Increased risk: land system change impacts of land-use conversions (especially agriculture), impacts on: biodiversity, biogeochemical and water cycles, carbon sinks. Below threshold/safe: stratospheric ozone depletion release of ozone-depleting chemicals into the atmosphere (aerosols), increased uv radiation. Below threshold/safe: ocean acidification dissolving of atmospheric co in oceans (25% of emissions) converted to carbonic acids increases ph, chemical changes, species loss (e. g. poor shell growth) Below threshold/safe: freshwater use the hydrological cycle and access to freshwater.
