Feb 5 Lec 9 .docx

3 Pages

School of Environment
Course Code
Jacob Hirsh

This preview shows page 1. Sign up to view the full 3 pages of the document.
ENV 200 Feb 5, 2013 Ozone  Pollutant in troposphere: -Ground level ozone (bad) -Results from secondary reactions (doesn’t come out of cars directly) of air pollutants and contributes to smog formation in urban center -NOx (nitrogen & oxygen) +VOCs (volatile organic compounds) produce O3 in the presence of sunlight -Adversely affect crop and forest vegetation, human respiratory health  Ozone: Naturally produced component in the stratosphere -Shields Earth’s surface from UV radiation, and therefore essential -In 1976 thinning of ozone over Antarctica and hit record low levels in 2000 Effects of Ozone depletion  More UV radiation reaches Earth  Damage to ecosystems  Human health problems -More cataracts, skin cancer, weakened immunity  Breaks down plant material, hinder processes Causes of Ozone thinning  CFC’s (Chlorofluorocarbons), halons, industrial solvents (refrigeration systems)  First used in 1960s  These chemicals were cheap and easy to produce  Were eventually banned Recovery of the Ozone Layer  1987 Montreal Protocol- phase ouf CFC’s  By 2007, 191 countries participating  Industry substitutes such as hydro fluorocarbons do not attack ozone but are potent greenhouse gases  Most countries have phased out CCFC’s  Long residence time (est~70-100 yrs)  “The single most successful international agreement to date” Unprecedented ozone hole opens over Canadian Arctic  Arctic ozone hole covering 2 million km squared reported in spring 2011 (Nature)  The hole initially formed over the Arctic, then spread across northern Canada, northern Europe and Central Russia to northern Asia  A cooling trend in the stratosphere?, is thought to be tied to increasing greenhouse gases like carbon dioxide, and could create more ozone holes Sidebar  Environment Canada not being allowed to discuss the discovery with the media  Co-author is one of several Environment Canada ozone scientists who have received letters of warning of possible “discontinuance of job function” as part of the downsizing underway  Censor what employees can tell public, massive layoffs (ozone monitoring) Climate Change: Weather and Climate Weather  Atmospheric conditions at a specific place and time  Rapid changes Climate  Average long-term weather conditions  Changes over hundreds/thousands of years  Important factors: temperature and precipitation How do we currently understand the climate paradigm?  Earth’s climate system is “inherently chaotic, sensitively balanced, and threshold-laden”  The latest peer-reviewed paleoclimatic studi
More Less
Unlock Document

Only page 1 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.