EESA11 Environmental Pollution Thursday, January 10, 2019Week 1: Introduction + Understanding Pollution1.Humans are massively changing the Earth -Between one-third and one-half of the land surface has been transformed by human action.-We are the major reason for all of these troubles…oIn the 50’s-60’s this is when we saw the impact of humans on the environment.oLots of jobs, lots of studies came from the study of environmental pollution/studies. -Some plants but not all can fix nitrogen… (nitrogen fixation) oNitrogen through the roots into the atmosphere. -The carbon dioxide concentration in the atmosphere has increased by nearly 30% since the beginning of the industrial revolution. -More than halfof all accessible surface fresh water is put to use by humanity. -More atmospheric nitrogen is now fixed by humanity than by all-natural terrestrial sources combined. -About one-quarter of the bird species on Earth have been driven to extinction. -All trace to a single cause, the growing scale of the human enterprise. The rates, scales, kinds, and combinations of changes occurring now are fundamentally different from those at any other time in history; we are changing earth more rapidly than we are understanding it. (Vitousek et al. 1997) 2.Biosphere 2: The Experiment (i)Objective-To test if and how people could live and work in a closed biosphere, while carrying out scientific experiments. -It was designed to explore the web of interactions within life systems in a structure with different areas based on various biological biomes. -To explore the possible use of closed biospheres in space colonization. (ii)Key issues -Oxygen levels began falling at a steady pace of 0.5% per month. This trend continued to the point where the atmosphere inside resembled that of a community at an elevation of over 1200 m. -Atmospheric carbon dioxide spiked erratically, while nitrous oxide rose to levels that could impair brain function. (air) -Water became polluted. -Several plant and animal species became extinct.
(iii)A pessimistic conclusion -Earth is a closed system too, a larger version of biosphere 2!(iv)Ten lessons from biosphere 2-#1 Ecology can be a science: no one had ever tried to do ecology in what is essentially a giant test tube, with full control of every variable. Biosphere made complex natural systems more like chemistry and physics – something researchers could experiment on instead of just observe. -#2 Coral reefs are salvageable: marine biologist Gaie Alling oversaw the artificial reef- the largest ever constructed – in the projects million-gallon ocean. -#3 Complexity is no obstacle: the system balanced itself remarkably well. -#4 Massive spacecraft WILL hold their air: largest sealed structures ever built, and overall air leakage rate was less than 10% per year.