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Global Change
Lessons from History
Global Change
• Changes in geologic history
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Climate
Soils
Oceans
Atmosphere
• Climate Change
• Global Warming
Rate of Δ
• Non-linear changes
• All causes of Δ are not equal
• All changes are not equal
Millenium Ecosystem Assessment
www.milleniumassessment.org
-released in 2004
-1300 scientists commissioned by UN to
comprehensively analyze the state of the global
environment
-assessed the state of 25 major “ecosystem services”
(food production, forests, fisheries, climate
regulation, etc.) that Nature provides for life on Earth
-conclusion: 16 out of 25 are being
used unsustainably. 16 of 25!
MEA Summary:
“At
the heart of this assessment is a stark
warning. Human activity is putting such strain
on the natural functions of Earth that the
ability of the planet’s ecosystems to sustain
future generations can no longer be taken for
granted.”
Anthropogenic Change
• Burning of fossil fuels
• CO2
• particulate matter
• Agricultural
• CO2
• Methane
• NOx
• CFC  HCFC
• Deforestation
• CO2
• particulate matter
World deforestation rates and forest cover
statistics, 2000-2005
• the Food and Agriculture Organization of the United Nations
(FAO) released its 2005 Global Forest Resources Assessment, a
regular report on the status world's forest resources. Overall,
FAO concludes that net deforestation rates have fallen since
the 1990-2000 period, but
-some 13 million hectares of the world's forests are still lost
each year, including 6 million hectares of primary forests.
• Primary forests -- forests with no visible signs of past or present
human activities -- are considered the most biologically diverse
ecosystems on the planet.
Read more: http://news.mongabay.com/2005/1115forests.html#ixzz1ewPyQ05z
The impact of humans on continental erosion and
sedimentation
• erosion as a result of human activity, primarily through agricultural
practices, has resulted in a sharp increase in net rates of continental
denudation;
• data on thicknesses and ages of alluvial sediment that has been
deposited immediately downslope from eroding croplands over the
history of human agriculture show that:
• Accumulation of post settlement alluvium on higher-order tributary
channels and floodplains is the most important geomorphic process in
terms of the erosion and deposition of sediment that is currently shaping
the landscape of Earth. It far exceeds even the impact of Pleistocene
continental glaciers or the current impact of alpine erosion by glacial
and/or fluvial processes.
Melting of arctic ice arctic arctic ide
Intergovernmental Panel on Climate Change
(IPCC)
• The Intergovernmental Panel on Climate Change
(IPCC) is a scientific intergovernmental body[1][2] which
provides:
• comprehensive assessments of current worldwide about the
risk of climate change based upon
• scientific,
• technical and
• socio-economic information
• its potential consequences on
• environmental and
• socio-economic
• possible options for
• adapting to these consequences, or
• mitigating the effects
IPCC 2007
“Warming of the climate system is unequivocal,
as is now evident from observations of
increases in global average air and ocean
temperatures, widespread melting of snow and
ice and rising global average sea level.”
Responsible Scientists
• “Human-caused climate change is not a belief, a hoax, or a conspiracy.
It is a physical reality. Fossil fuels powered the Industrial Revolution.
But the burning of oil, coal, and gas also caused most of the historical
increase in atmospheric levels of heat-trapping greenhouse gases.
This increase in greenhouse gases is changing Earth’s climate.”
Global CO2 emissions rising faster than worst-case
scenarios (Nov 2011)
Keeling Curve
Correlation ≠ Causation
• Does increasing CO2 cause a rise in temperature?
• Does increasing temperature cause a rise in CO2 levels in the
atmosphere?
• Scientists correlate other GHG with CO2 levels.
Feedback Loops
• Negative Feedback Loops
• Work to maintain a ‘set point’,
• as in organisms = blood sugar, body temp, etc
• CO2  absorption by plants
• Positive Feedback Loops
• Reinforces movement in same direction
• Warming, melting, lower albedo, melting, anaerobic decay, CH4….
Not all GHGs created equally!!!
Consequences to Environment
• Polar Ice caps
• NW passage, increase drilling, (+ feedback)
• Glaciers
• Reservoirs
Consequences to Environment
• Permafrost
• Sea Level Rise
• Salt water intrusion
• Erosion
• 100M people w/in 1meter
Consequences to Environment
• Weather Changes
• Heat waves/cold spells
• Precipitation
• Storm Intensity
• Ocean Currents
Changes to Life
• Increased growing season
• Ranges move N & S
• Migration and fractured habitats
• Rates of Δ-v- migration
• Δ in human disease
• Relocation of 1B people?