GLOBAL CHANGE BIOLOGY Dr Tyler Evans Email tylerevanscsueastbayedu Phone 5108853475 Office Hours MW 10301200 or by appointment Website http evanslabcsuebweeblycom PREVIOUS LECTURE ID: 356645
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BIOL 3999: Issues in Biological Science
GLOBAL CHANGE BIOLOGY
Dr. Tyler Evans
Email:
tyler.evans@csueastbay.edu
Phone: 510-885-3475
Office Hours: M,W 10:30-12:00 or by appointment
Website: http
://evanslabcsueb.weebly.com
/Slide2
PREVIOUS LECTURE
How human systems influence Earth systems
socio-economic development
p
roduction and consumption
r
esource use
ecosystems
climate
g
eochemical cycles
HUMAN SYSTEMS
EARTH SYSTEMS
Global
Change
BiologySlide3
HOW ARE HUMANS INFLUENCING EARTH SYSTEMS?
ALTERING CLIMATE
CLIMATE: refers to the behavior of the atmosphere over a longer period of time, and usually for a large area.WEATHER: refers to the conditions of the atmosphere over a short period of time, such as hours or days, and typically for a local areaSlide4
HOW IS CLIMATE ALTERED?
The power of a process to alter the climate is estimated by its
RADIATIVE FORCING, the change in the Earth's energy balance due to that process.RADIATIVE FORCES may be:POSITIVEe.g. increases in solar output
NEGATIVE
e.g. volcanic eruptions
Balance between positive and negative
radiative
forcing determines climateSlide5
RADIATIVE FORCING CAN BE CAUSED BY HUMAN ACTIVITIES
c
arbon dioxide emitted from the burning of fossil fuel is presently the largest single climate forcing agent, accounting for more than half of the total positive forcing since 1750.Slide6
Prior to the industrial revolution, the carbon cycle was approximately in balance.
SOURCES (add CO
2
)
respiration
SINKS (removes CO
2)p
hotosynthesisoceans
CO2CO2
Carbon dioxide is naturally present in the atmosphere as part of the Earth's carbon cycle (the natural circulation of carbon among the atmosphere, oceans, soil, plants, and animals).Slide7
Since that time humans have become a source of CO2 by releasing the carbon stored in fossil fuels
Currently, inputs of CO2 outpace the ability of the carbon cycle to remove it from the atmosphere
SOURCES (add CO2)respiration
f
ossil fuels
SINKS (removes CO2)photosynthesisoceans
CO2
CO2Slide8
A USEFUL ANALOGYSlide9
CO2 IS ACCUMULATING IN THE ATMOSPHERE
393 ppm in 2013
315 ppm in 1958Slide10
CO2 IS ACCUMULATING IN THE ATMOSPHERE
n
amed fore Charles David Keeling who collected data
b
ased on atmospheric data collected at Mauna Loa, HI
record starts in 1958 and still continues todaylongest continuous record of atmospheric CO2KEELING CURVESlide11
SEASONALITY IN KEELING CURVE
r
eflects seasonal differences in photosynthesis (SINK)
d
eciduous plants shed leaves in winter and respiration outpaces photosynthesis
in summer, photosynthesis outpaces respiration
respiration
photosynthesisSlide12
DOESN’T FULLY EXPLAIN SEASONALITY
w
hen it is winter in Northern hemisphere (i.e. respiration), it is summer in Southern Hemisphere (i.e. photosynthesis). so shouldn’t these differences cancel each other out?
m
ajor difference in percent land cover between Northern and Southern hemispheres
most land in Southern hemisphere is in tropics where very little seasonal variationthis difference is greatest at temperate latitudes, where deciduous forests dominatephotosynthesis in the Northern hemisphere growing season is greater than the amount of CO2 respired during winter in the southern hemisphere
equatorSlide13
HOW DOES CO2 AFFECT CLIMATE?
CO2 is a GREENHOUSE GAS
and contributes to the GREENHOUSE EFFECT
the Sun emits energy that travels to Earth. Because the Sun is very hot, the energy is emitted in high-energy, short wavelengths that penetrate the Earth's atmosphere.Slide14
HOW DOES CO2 AFFECT CLIMATE?
CO2 is a GREENHOUSE GAS
and contributes to the GREENHOUSE EFFECTabout 30% of the Sun's energy is reflected directly back into space by the atmosphere, clouds, and surface of the Earth. The rest of the Sun's energy is absorbed into the Earth's system.Slide15
HOW DOES CO2 AFFECT CLIMATE?
CO2 is a
GREENHOUSE GAS
and contributes to the
GREENHOUSE EFFECT
Because the Earth is cooler than the Sun, the energy is emitted in the form of infrared radiation, at wavelengths longer than the incoming solar energy.Slide16
HOW DOES CO2 AFFECT CLIMATE?
CO2 is a
GREENHOUSE GAS
and contributes to the
GREENHOUSE EFFECT
greenhouse gases in the atmosphere absorb much of the long-wave energy emitted from the Earth's surface, preventing it from immediately escaping from the Earth's system. The greenhouse gases then re-emit this energy, warming the Earth's surface and atmosphere.Slide17
HOW DOES CO2 AFFECT CLIMATE?
CO2 is a GREENHOUSE GAS
and contributes to the GREENHOUSE EFFECT
t
he increase in the concentration of CO2 has amplified the natural greenhouse effect by trapping more of the energy emitted by the Earth. This change causes Earth's surface temperature to increase among other changes.
greenhouse gases have a POSITIVE RADIATIVE FORCE because they absorb energy radiating from Earth’s surface, rather than allowing it to be directly transmitted into space. Slide18
CO2 IS NOT THE ONLY GREENHOUSE GAS THAT AFFECTS CLIMATE
s
everal other greenhouse gases produced by human activities:
METHANE (CH4)
a colorless, odorless non-toxic gas consisting of molecules made up of four hydrogen atoms and one carbon atom.
NITROUS OXIDE(N2O)
is a colorless, non-flammable gas with a sweetish odor, made up of two nitrogen atoms and one oxygen atom
SULFUR HEXAFLUORIDE (SF6)
Human made gas containing one sulfur atom and six fluoride atoms
human sources of greenhouse gases far exceed natural sourcesSlide19
METHANE
methane (CH4) is the second most prevalent greenhouse gas emitted in the United States from human activities.
methane is emitted by natural sources such as wetlands, however over 60% of total CH4 emissions come from human activities.INDUSTRYAGRICULTURE
LANDFILLS
p
rimary source of methane is natural gas
e
nteric fermentation
b
i-product of decaying organic matterSlide20
NITROUS OXIDE
is a colorless, non-flammable gas with a sweetish odor
nitrous oxide is naturally produced in the oceans and in rainforestsglobally, about 40% of total N2O emissions come from human activities:FERTILIZER
NYLON
NITRIC ACID
CARSBURNING ORGANIC MATTER
i
mprove plant
production
a
lso used in fertilizers
formed in catalytic converters
Component of nylonSlide21
SULFUR HEXAFLUORIDE
fluorinated gases have no natural sources and only come from human-related activities
ALUMINIUMSEMICONDUCTORS
t
hese compounds were produced as an alternative to chlorofluorocarbons (CFCs), which were responsible for depleting the ozone layer
i
ronically, these compounds are potent greenhouse gases with long atmospheric lifetimes Slide22
GREENHOUSE GASES THROUGH TIME
CARBON DIOXIDESlide23
GREENHOUSE GASES THROUGH TIME
METHANESlide24
GREENHOUSE GASES THROUGH TIME
NITROUS OXIDESlide25
GREENHOUSE GASES THROUGH TIME
SULFUR
HEXAFLUORIDE
AND RELATED COMPUNDS Slide26
NOT ALL GREENHOUSE GASES ARE CREATED EQUAL…Slide27
ATMOPSHERIC CONCENTRATIONS OF ALL THESE GREENHOUSE GASES ARE INCREASING
2008
economic
crisisSlide28
2008 Global CO2 Emissions
from fossil fuel combustion
and some industrial processes (million metric tons of CO2)
h
alf of emissions are coming from two countries
not corrected for population (i.e. per capita)Slide29
WILL THE TREND OF INCREASING GREEENHOUSE GASES CONTINUE?Slide30
FUTURE GREENHOUSE GAS EMISSION SCENARIOS
Predictions focus on carbon dioxide:
other greenhouse gases track the pattern of CO2CO2 is by far the largest source of greenhouse gases
A CO2 PROBLEM
U.S.A (84%)
WORLD (77%)Slide31
FUTURE CO2 EMISSIONS SCENARIOS
g
oal of developing future emission scenarios is not to predict the futureunderstand what futures are possible and where major points of uncertainty lieinform how present-day decisions will influence a range of possible futuresto develop future emission scenarios and how this will impact climate scientists use MODELS: a mathematical representation of the interactions between human activities and key components of the Earth systems.
FUTURE CLIMATE MODELS
t
o construct climate models, scientists divide each of the Earth's components spatially into a set of boxes. Simple models may have only a few boxes. The most complex models may have more than a hundred thousand.Slide32
CLIMATE MODELS HAVE TWO COMPONENTS:
1.) Earth System Modelsexplore future changes in physical and biogeochemical responses to changing atmospheric composition and
radiative forcinguse mathematical equations based on well-understood principles to depict the behavior of Earth processes in each box.the movement of energy, air, and water are represented as horizontal and vertical exchanges between the boxes. In this way, models represent interactions between different parts of the climate system and the world.Slide33
2.) Integrated Assessment Models
driving forces and responses by humans through changes in technology, economies, lifestyle and policy
explore alternative socio-economic conditions that would result in such future atmospheric composition changes
Integrated assessment models contain three main factors:
CLIMATE MODELS HAVE TWO COMPONENTS:
a. POPULATIONb. URBANIZATIONc. ECONOMIC DEVELOPMENT
m
ore people = more CO2
m
ore urban areas = more CO2
bigger economy = more CO2Slide34
EFFECT OF POPULATION SIZE ON CO2 EMISSIONSSlide35
EFFECT OF ECONOMY ON CO2 EMISSIONSSlide36
INTERNATIONAL PANEL ON CLIMATE CHANGE (IPCC)
international body for the assessment of climate change established by the United Nations and World
Meterological Organization in 1998goal is to provide the world with a clear scientific view on the current state of knowledge in climate change and its potential environmental and socio-economic impacts.
t
housands of scientists from all over the world contribute to the work of the IPCC on a voluntary basis and reflect a range of views and expertiseSlide37
FUTURE CO2 EMISSION SCENARIOS
v
ery rapid economic growth
p
ursue wealth over environment
changes in economic structures
reductions in energy useclean and resource-efficient technologies.Slide38
LECTURE SUMMARY
climate is altered by changes in
radiative forcingcarbon dioxide emitted from the burning of fossil fuel is presently the largest single climate forcing agentinputs of CO2 outpace the ability of the carbon cycle to remove it from the atmosphere
accumulation of CO2 in atmosphere exhibits a distinct seasonal trend
CO2 and other human emissions act as greenhouse gases and contribute to the greenhouse effect.
greenhouse gas emission are tightly linked with economic developmentgreenhouse gases emissions are expected to increase over the next centurySlide39
NEXT LECTURE:
CO2 AND TEMPERATURESlide40
http://www.esrl.noaa.gov/gmd/ccgg/trends/mlo.html
NOAA Earth System Research Laboratory
MORE INFORMATIONhttp://www.ipcc.ch/TRENDS IN CO2 EMISSIONS
IPCC AND EMISSION SCEANRIOS
GREENHOUSE GASES
http://www.epa.gov/climatechange/ghgemissions/Environmental Protection Agency