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Lecture 6

ENVIRSC 2EI3 Lecture Notes - Lecture 6: World Meteorological Organization, Malaria, Coastal Erosion

5 pages26 viewsFall 2016

Environmental Science
Course Code
Luc Bernier

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Module #6: Climate Change
Unit #1: What is climate?
Weather and Climate
Weather: atmospheric conditions over a short time period (day or week)
Climate: Composite of the variety of day-to-day weather
Climate Change
Long-term shift or alteration in the climate of a specific location, region, or
the planet
Global Warming
o Changes in the average surface temperature
What Causes Climate?
Surface of the Earth is: unequally heated by the sun
Incoming solar energy: directly from the sun hitting the earth’s surface
Outgoing IR energy: emitted from the earth’s surface
Greenhouse gases: absorb or trap short wave radiation and re-radiate as long
radiation resulting in heat
Long term temperature changes are associated with shifts in the amount of
energy we receive by earth from the sun
o Axial wobble
o Variation of the tilt
Climate Indicators
Impact of earth’s climate can be traced in glacial ice or in marine sediments
Cycles of glaciation can be traced
Natural disruptions may influence climate
o Ex: El Nino
Represents the marked warming lf the waters of eastern and
central portions of the Pacific
Impacts can cause droughts in some parts of the world and
flooding in others
Unit #2: Evidence and Explanations
What is the evidence of Climate Change?
Since 19th century, average global temperature has increased by: 0.6 +/- 0.2
degrees Celsius
Increase in temperature in the Northern Hemisphere during 20th century
was the largest than any century in the past 1000 years
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Paleoclimate Indicators: past climate indicators based on ice cores, tree rings
and coral reef data
Greenhouse Gases
Continued to rise over the past decades
Carbon dioxide and Methane concentrations are higher now than ever before
Reduction in permafrost and snow cover
Since 1996, permafrost = warming
Lost more mass than have gained
o Due to increases in global temperature
Movement of glaciers due to warm temperatures
Climate Models
Consider some or all five components in order to predict future climates
o Radiation
o Dynamics
o Surface processes
o Chemistry
o Time step and resolution
General Circulation Models (GCM’s): most common and take the 3D nature of
Earth into account
o Combined land, atmospheric and ocean models
The intergovernmental Panel on Climate Change (IPCC)
Established in 1988 by the World Meteorological Organization and United
Nations Environmental Program
o Created to assess the scientific, technical and socioeconomic
information related to the understanding of the risks from human
induced change of climate
Scientific Explanations of Climate Change
Strong consensus that increase in greenhouse gases (GHG) is from human
o Impacts from forestry and agriculture (methane emissions)
Changes in Radiative Forcing
Having more greenhouse gases = more energy trapped within the Earth’s
Results from Climate Models
Can only replicate current climate conditions when past human increases of
greenhouse emissions are included
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