uwo geo 2152 - climate system

• • Montreal Protocol (1987)
  • A highly successful worldwide agreement among countries to reduce CFC concentrations
  • Ultraviolet radiation breaks up CFC molecules causing the release of chlorine
  • Chlorine rapidly destroys ozone
  • A CFC molecule can remain in the atmosphere for many decades
• • Though CFCs have declined since 1970, there is little decline recognized in the atmosphere
  • Why?
  • Because of the residence time of CFCs
  • Decreased amounts of the stratospheric ozone have resulted in increased cases of skin cancer
  • Skin cancer rates have doubled since the 1950s
• acid precipitation: precipitation that combines with pollutants that turn the precipitation acidic
• main sources of acid precipitation: sulfur oxides, nitrogen oxides
• effects of acid precipitation: it slows tree growth, reduces fish population in lakes, and erodes materials
• the pH scale:

  • a measure of acidity
  • Scale Range: from 0 to 14; 7 is neutral and below 7 is acidic
  • Precipitation is naturally acidic (~5.5)
• • Canada - US Air Quality Agreement
  • Force factories and industries to reduce pollution
  • Acid precipitation is most common in Eastern North America
  • Nitrogen oxides and sulfur oxides react with water molecules to form nitric and sulfuric acid
  • Aquatic life cannot survive when pH < 4.8
• positive feedback:

  •  a process in a system that encourages the continuation of the original process
  • Example specific to climate change:
  • Less snow/ice decreases the reflectivity of solar radiation (because snow is highly reflective)
  • Therefore, after snow/ice melts, more solar radiation is absorbed rather than reflected
  • This process leads to continually warmer conditions
• climate models: Estimating by how much the Earth will warm in the future
• how do climate models work?

  • By solving a series of mathematical equations
  • What do the variables in the equations represent?
  • Greenhouse gases, solar radiation, other climatological components
  • To best estimate observed temperatures, a climate model must incorporate many different variables
• kyoto protocol (1997):

  • a global agreement aiming to slow climate change
  • Objective: to reduce greenhouse gas emissions to 5% below 1990 levels by 2010
  • Australia and US did not sign
• • As sea level rises, erosion in affecting areas farther inland; are eroding at 10m annually
  • North American cities at greatest risk include Vancouver, Miami, New Orleans, and New York
• impacts on humans from climate change:

  •  affects food production, tourism, and human health
  • The most serious impact of climate change to humans is the spread of malaria
• impacts of climate change on biodiversity:

  • Bleaching of corals
  • Loss of flora and fauna
  • Extinction risk for polar bears
• deaths from climate change primarily occur due to an increase in malaria and malnutrition in less developed countries
• relationship between humans and nature:

  1. Humans are simply one component of the natural world
  2. Humans are separate from nature
• our relationship with nature dictates our actions:

  1. Living in harmony with nature (sustainable development)
  2. Exploiting nature for economic gain (ignore the true costs of resource extraction)
• the realities of natural resources:

  1. Many natural resources are finite
  2. Using resources creates waste products

  • Problem: developed countries have created societies and economies in which these two realities are neglected
  • There is resistance to changing the way resources are extracted
• precautionary principle: when there is a risk involved to either humans are the environment, we should still act even if there is come uncertainty about the risk. There is a social responsibility to protect people and the environment from harm
• examples of precautionary principle use: insurance policies and preventative maintenance
• wind farms are viable in areas with constant, moderate winds - it is a renewable and pollution free source of energy
• issues preventing growth of wind farms:

  • Habitat disruption
  • Appearance (NIMBYism)
  • noise
• wind atlas: ontario created this to identify the best locations for wind turbines
• the largest hydroelectric energy project is the Three Gorges Dam on the Yangtze River in China
• implications of large hydroelectric projects:

  1. Loss of land to flooding
  2. Displaced population
  3. leaching
  4. Destruction of habitats - Small generators on smaller rivers are desirable full can be very costly