The Biosphere: Climatic Cause and Effect

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The Biosphere Climatic Cause and Effect
Climate and Global Change Geoscience Workshop
2002
The Biosphere Climatic Cause and Effect
Dr. Peter HarleyBiosphere-Atmosphere
Interactions GroupAtmospheric Chemistry
DivisionNational Center for Atmospheric Research
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The Biosphere Climatic Cause and Effect
AcknowledgementsThanks for providing
slides! Gordon Bonan, CGD, NCAR Alex Guenther,
ACD, NCAR Joanie Kleypas, CGD, NCAR Russ
Monson, EPOB, CU David Schimel, CGD,
NCAR Christine Wiedinmyer, ACD, NCAR
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IPCC Impacts of Climate Change
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The Biosphere Climatic Cause and Effect
Climate Biosphere
Effects of Increasing CO2 on Biosphere (partial
list) Changes in plant physiology Changes in
higher trophic levels Damage to coral reef
ecosystems Effects of Environmental Warming
(partial list) Changes in phenology (timing of
growth/reproduction) Changes in geographic range
of organisms Changes in community
structure Damage to coral reef ecosystems
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GAIA A New Look at Life on Earth
. . . the physical and chemical condition of the
surface of the Earth, of the atmosphere, and of
the oceans has been and is actively made fit and
comfortable by the presence of life itself. This
is in contrast to the conventional wisdom which
held that life adapted to the planetary
conditions as it and they evolved their separate
ways. James Lovelock, 1979
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GAIA forming and regulating atmosphere?
An awesome thought came to me. The Earths
atmosphere was an extraordinary and unstable
mixture of gases, yet I knew that it was constant
in composition over quite long periods of time.
Could it be that life on Earth not only made the
atmosphere, but also regulated it keeping it at
a constant composition, and at a level favorable
for organisms? James Lovelock, 1991
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Earths Improbable Atmosphere
Oxidizing Reducing Inert
If life on Earth ceased, all the elements in the
crust, oceans and atmosphere would react together
until a state close to chemical equilibrium was
reached. The planet would become a hot,
waterless, and inhospitable place.
(290oC) James Lovelock, 1979
Mars Venus Dead Earth Earth
O2 CO2 CH4 H2 N2 Ar
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Atmospheric Composition (simplified)

• Major gases
• 21 Oxygen (O2) and 79 Nitrogen
• Trace gases
• Stable
• Carbon dioxide, nitrous oxide, methane, hydrogen
• Global radiation balance, oxidant sinks
• Reactive
• Isoprene, dimethyl sulfide, oxides of nitrogen,
  ozone
• Photochemical oxidant production, oxidant sinks,
  secondary particle formation, global radiation
  balance, air pollution

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Lovelocks GAIA Contribution
Whether or not you accept the extreme versions of
the GAIA hypothesis, the publication of GAIA, A
New Look at Life on Earth (1979) has influenced
the way in which scientists and the general
public view the Earth. It is still being hotly
debated 25 years later. Raised consciousness!
Holistic view of the Earth. Earth from
space. Focused attention on the role of the
Biosphere in Atmospheric processes Promoted
interdisciplinary research (now strongly
supported by NCAR) Stimulated research to
prove/disprove GAIAN regulatory
mechanisms Fostered a systems approach to Earth
Science in which the Earth is viewed as a complex
system, with biogeochemical cycling between
Geosphere, Hydrosphere, Biosphere and Atmosphere
with important interactions and feedbacks between
them
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Denver Post July 2, 2002
   
NCAR teams for climate model
Boulder lab allies with scientists nationwide to
predict trends
By Diedtra HendersonDenver Post Science Writer
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Satellite-Derived Plant Geography
Newest generation of Land Surface Models classify
all vegetation as falling into one of six broad
categories.
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Community Land Model
Biogeophysics
Sensible Heat Flux
Latent Heat Flux
Photosynthesis
Diffuse Solar Radiation
Longwave Radiation
Direct Solar Radiation
Reflected Solar Radiation
Emitted Long- wave Radiation
Absorbed Solar Radiation
Soil Heat Flux
Heat Transfer
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Community Land Model Dynamic Vegetation
Ecosystem Carbon Balance
Vegetation Dynamics
Photosynthesis
Growth Respiration
?g CO2?g-1?s-1
Autotrophic Respiration
?g CO2?g-1?s-1
Litterfall
Heterotrophic Respiration
?g CO2?g-1?s-1
Nutrient Uptake
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Land Surface Model Vegetation Dynamics
The model can predict for each grid cell the
change in vegetation over time. This example is
for a single grid cell in Canada, following a
forest fire in year 0.
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The Biosphere Climatic Cause and Effect
Radiative Effects
Clouds and Precipitation
Absorption at surface Radiatively-active gases
Effects of Biosphere on Climate (partial
list) Vegetation affects albedo CH4 from
wetlands, rice paddies, termites, flatulence
- Role of terrestrial biosphere in global CO2
budget - Role of marine phytoplankton
emissions on aerosols/clouds - Role of VOC
emissions in O3 formation Evapotranspiration and
rainfall
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Global Radiation Balance (Simplified)
Transmitted to space (12)
Incoming solar radiation (100)
Reflected by atmosphere (25)
Absorbed by atmosphere and re-radiated back to
earth (88)
Absorbed by atmosphere (25)
Reflected by surface (5)
Emitted thermal radiation (100)
Absorbed by surface (45)
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Radiative Forcing Potentials
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The Biosphere Climatic Cause and Effect
Radiative Effects
Clouds and Precipitation
Absorption at surface Radiatively-Active Gases
Effects of Biosphere on Climate (partial
list) Vegetation affects albedo CH4 from
wetlands, rice paddies, termites, flatulence
- Role of terrestrial biosphere in global CO2
budget - Role of marine phytoplankton
emissions on aerosols/clouds - Role of VOC
emissions in O3 formation Evapotranspiration and
rainfall
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Mauna Loa Observatory CO2 Data
In addition to documenting the large increase in
atmospheric CO2 over the last several decades,
these data clearly identify the signature of the
terrestrial biosphere in the annual CO2
fluctuations.
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Carbon Cycle
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Global Carbon Budget
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Carbon Budget Terrestrial Sink
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Mauna Loa CO2 Data Amplitude Changes
Keeling, CD et al., Increased activity of
northern vegetation inferred from atmospheric CO2
measurements. Nature 382146 (1996).
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Global CO2 Flux Network
Global distribution of
Fluxnet
sites
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Above-Canopy Towers for Measuring Ecosystem CO2
Exchange
Towers are instrumented to measure instantaneous
fluxes of CO2 to or from the forest ecosystem,
using a technique called Eddy Covariance or Eddy
Correlation. Summed over time, these
measurements can give us daily, weekly or annual
Carbon balances, to answer the question Is
the forest a source of CO2 to the atmosphere or a
sink which removes CO2 from the atmosphere? What
environmental factors control how much Carbon is
removed?
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What is Eddy Correlation?
What is eddy correlation?
A measurement technique for surface atmosphere
exchange
that makes use of turbulence and concentration
measurements
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3-D Sonic Anemometer
Measures wind speed in 3 dimensions very rapidly
(9 Hz). CO2 close to the anemometer is measured
simultaneously. By noting how the CO2
concentration varies with the vertical wind
speed, it is possible to calculate the CO2 flux
into or out of the forest (Trust me!)
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Eddy Covariance Technique
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Two Years of CO2 Exchange Niwot Ridge, CO

• Interannual variation in the amount of carbon
  sequestration

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Ancillary Measurements Understanding CO2
Uptake/Release
Automated Dendrometer
Photosynthesis
Soil Carbon Litter
Soil Respiration
Bole Respiration
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Spring-time Initiation of CO2 Uptake

• Control over springtime initiation of NEE by soil
  temperature

• Concomitant initiation of tree bole expansion

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Terrestrial Carbon Sink Why and How Long?

• Human activities (fossil fuel use and land-use)
  perturb the carbon cycle -- increasing the
  atmospheric concentration of carbon dioxide
• The current terrestrial carbon sink is caused by
  land management practices, higher carbon dioxide,
  nitrogen deposition and possibly recent changes
  in climate
• This uptake by the terrestrial biosphere will not
  continue indefinitely. The question is when will
  this slow down, stop or even become a source?
• Land management results in the sequestration of
  carbon in three main pools -- above and below
  ground biomass and soils

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Terrestrial Biosphere predicted to take up C but
will level off or reverse next century
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The Biosphere Climatic Cause and Effect
Radiative Effects
Clouds and Precipitation
Absorption at surface Radiatively-Active Gases
Effects of Biosphere on Climate (partial
list) Vegetation affects albedo CH4 from
wetlands, rice paddies, termites, flatulence
- Role of terrestrial biosphere in global CO2
budget - Role of marine phytoplankton
emissions on aerosols/clouds - Role of VOC
emissions in O3 formation Evapotranspiration and
rainfall
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Marine Aerosols from Algal Emissions can affect
Climate
ODowd et al., Marine aerosol formation from
biogenic iodine emissions, Nature 417, 632 -
636 (2002)
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Phytoplankton and DMS
Charlson et al. (1987) described a multi-stage
negative feedback phenomenon that links biology
with climate change. The process begins with
an initial impetus for warming that stimulates
primary production in marine phytoplankton. This
enhanced process leads to the production of more
copious quantities of dimethylsulphonio
-propionate, which leads in turn to the evolution
of greater amounts of dimethyl sulphide, or DMS,
in the surface waters of the world's oceans.
Larger quantities of DMS diffuse into the
atmosphere, where the gas is oxidized, leading to
the creation of greater amounts of acidic
aerosols that function as cloud condensation
nuclei or CCN. This leads to the creation of
more and brighter clouds that reflect more
incoming solar radiation back to space, thereby
providing a cooling influence that counters the
initial impetus for warming. Negative feedbacks
like this is how GAIA is supposed to work.
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GAIA Gone Mad Dont Worry, Be Happy!
As time marches on, and more and more studies of
this nature are conducted, it becomes ever more
clear that earth's biosphere has a number of very
effective ways of combating extreme temperature
changes and in view of their efficacy, it would
seem we have little to worry about in the way of
CO2-induced global warming.
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Aerosol Formation from CH2I2
ODowd et al., Marine aerosol formation from
biogenic iodine emissions, Nature 417, 632 -
636 (2002)
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The Biosphere Climatic Cause and Effect
Radiative Effects
Clouds and Precipitation
Absorption at surface Radiatively-Active Gases
Effects of Biosphere on Climate (partial
list) Vegetation affects albedo CH4 from
wetlands, rice paddies, termites, flatulence
- Role of terrestrial biosphere in global CO2
budget - Role of marine phytoplankton
emissions on aerosols/clouds - Role of VOC
emissions in O3 formation Evapotranspiration and
rainfall
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Volatile Organic Compounds emitted from Vegetation
R. Fall 1999
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Global Biogenic VOC Emissions
Vegetation foliage and other biogenic sources
1 x 1015 g C y-1 Fossil fuel combustion and
other anthropogenic sources 1 x 1014 g C y-1
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Tropospheric O3 Chemistry (Greatly Simplified!!)
In the presence of sunlight and Nitrogen Oxides
(NOx), VOC contribute to tropospheric O3
formation. Additionally, because they react
readily with OH radical (the major atmospheric
scrubber), VOC can also indirectly affect the
concentrations of other atmospheric constituents,
like CH4. O3 and CH4 are both radiatively active.
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Biosphere VOC Interactions

Atmospheric
Radiative
Physical
Constituents
balance


Environment



Trace gas
temp, light
Trace gas Emission
deposition




Biosphere

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BVOC Emission Modeling Environmental Conditions
BVOC Emission
Solar radiation
Temperature
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Modeling Changes in Atmospheric Chemistry
Resulting from Land Use Change

• Goal
• Investigate the changes in global chemistry and
  climate that result from changes in land use and
  biogenic isoprene emissions
• Land use changes occurring globally
• Many of the forested areas of the world,
  particularly in the U.S. and the Amazon, are
  seeing significant land use changes
• Forest replaced by pasture, urban landscapes and
  agriculture
• Changes in land use can affect the biogenic
  emissions from these areas
• Atmospheric chemistry and climate can be altered
  as a result of the changes in biogenic emissions.

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Effect of Forest Removal on Isoprene Emission
Effects on July isoprene emissions if forest is
replaced by pasture (Brazil) or suburbs
(Southeastern U.S.)
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Effect of Forest Removal on O3 Levels
Effects on July O3 concentrations if forest is
replaced by pasture (Brazil) or suburbs
(Southeastern U.S.)
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IPCC Impacts of Climate Change
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Climate Change is not Uniform over the Earth
Although globally averaged temperatures have
increased by 0.6 oC over the past century,
changes in both temperature and precipitation are
very non-uniform. As a result, regional impacts
on organisms, ecosystems and the Biosphere in
general can be substantial, and are already being
documented. Walther et al., Ecological
responses to recent climate change, Nature
416389 (2002)
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Threshold Concept
Ecological systems have many interacting
non-linear processes and are thus subject to
abrupt changes and threshold effects arising from
relatively small changes in driving variables,
such as climate. For example Temperature
increase beyond a threshold, which varies by crop
and variety, can affect key development stages of
some crops and result in severe losses in crop
yields.
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The Biosphere Climatic Cause and Effect
Effects of Increasing CO2 on Biosphere (partial
list) Changes in plant physiology Changes in
higher trophic levels Damage to coral reef
ecosystems Effects of Environmental Warming
(partial list) Changes in phenology (timing of
growth/reproduction) Changes in geographical
range of organisms Changes in community
structure Damage to coral reef ecosystems
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Effects of Increasing CO2 on Coral Reefs (Direct
and Indirect)
Increased Atmospheric CO2
Climatic Changes
Increased Atmospheric Temperature
Altered storm frequency/ intensity
Increased dust (Fe fertilization)
Increased SST
Reduced CO32-
Sea level rise
Reduced Calcification
Increased Bleaching
Differential Impacts
Increased Breakage Erosion
Reduced Light
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Carbonate Chemistry
CO2
photosynthesis respiration
CO2aq (CO2 H2O)
Carbonic acid
H2CO3
Proportion of HCO3 and CO32 adjusts to balance
alkalinity CO32 ALK ?CO2
HCO3 H
Alkalinity
bicarbonate
Na
Mg2
Ca2
K
CO32 H
carbonate
CaCO3
calcification
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Coral Bleaching
Coral reefs flourish mainly in the tropical
latitudes, extending at most to 30 north or
south of the Equator. Every coral species, as
well as numerous other reef inhabitants,
maintains a special symbiotic relationship with
microscopic algae called zooxanthallae, which
provide their hosts with oxygen and organic
compounds they produce through photosynthesis.
When stressed, many reef species expel their
zooxanthallae en masse. The polyps of the coral
are left without pigmentation and appear nearly
transparent on the animal's white skeleton. This
phenomenon is normally referred to as coral
bleaching.
Severe bleaching events have dramatic long-term
effects on the coral. The ability of the coral to
feed itself in the absence of zooxanthallae may
be very important to its survival during and
after a bleaching event. Recovery rates differ
with species, and the time to full recovery of
symbiotic algae varies from 2 months to as much
as one year. When the level of environmental
stress is high and sustained, the coral may die.
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Coral Bleaching expected to Increase
Bleaching prior to the 1980s was attributed to
local phenomena such as storm events,
sedimentation, rapid salinity changes, pollution,
or thermal shock. Numerous laboratory studies
have shown a direct relationship between
bleaching and water temperature stress. Elevated
water temperatures have been implicated in most
of the major bleaching events of the 1980s and
1990s
Brain coral
Branched coral
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The Biosphere Climatic Cause and Effect
Climate Biosphere
Effects of Increasing CO2 on Biosphere (partial
list) Changes in plant physiology Changes in
higher trophic levels Damage to coral reef
ecosystems Effects of Environmental Warming
(partial list) Changes in phenology (timing of
growth/reproduction) Changes in geographical
range of organisms Changes in community
structure Damage to coral reef ecosystems
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British Plants Flowering Earlier
The average first flowering date of 385
British plant species has advanced by 4.5 days
during the past decade compared with the
previous four decades 16 of species flowered
significantly earlier in the 1990s than
previously, with an average advancement of 15
days. Ten species (3) flowered significantly
later in the 1990s than previously. These data
reveal the strongest biological signal yet of
climatic change. A. H. Fitter R. S. R.
Fitter, Rapid Changes in Flowering Time in
British Plants, Science 296 1689-1691 (2002)
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Anomalies of phenological phases in Germany
correlate well with anomalies of mean spring air
temperature
Spring arrival in birds, island of Helgoland,
North Sea
Hatching in flycatchers (Ficedula
hypoleuca), Northern Germany
Mean onset of leaf unfolding of
Aesculus hippocastanum and Betula pendula.
Walther et al., Nature 416389-395 (2002)
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Climate Effects on Species Composition
Shift from indigenous deciduous to exotic
evergreen vegetation in southern Switzerland. The
shrub layer is dominated by the growing number of
spreading exotic evergreen broad-leaved species
that appear to profit from milder winter
conditions, indicated by the decreasing number of
days with frost per year. Walther et al.,
Nature 416389-395 (2002)
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Recent Range Shifts due to Warming
Walther et al., Ecological responses to recent
climate change, Nature 416389 (2002)
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Predicted Change in Bobolink Range
US Environmental Protection Agency web site
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Biosphere-Climate Interactions Conclusions
- Biogeochemical cycling of carbon, nitrogen,
sulfur and many other elements are largely
controlled by the Biosphere (Schimel). - Since
many of these compounds (e.g., CO2, CH4, N2O) are
radiatively active, they play a significant role
in climate. - Atmospheric concentrations of
other radiatively active gases (O3, CH4) are
indirectly controlled by tropospheric chemistry,
and are strongly influenced by biogenic volatile
emissions. - Biogenic emissions (DMS,
monoterpenes, organic particles) play a
significant role in aerosol formation and growth,
with effects on radiation absorption and cloud
formation. - Observable changes in organisms
(range, physiology, mortality) and ecosystems
(structure, range, functioning) may be the best
way to infer early effects of global change.
Many changes (some good, some maybe not so good)
already observable.
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Thanks for your kind attention!
To truly begin to understand that Earth System,
in all its wonderful complexity, will require a
combination of reductionist science and holistic
approaches.
Interdisciplinary approaches involving
Geosciences, Biology, Chemistry, Hydrology,
Marine Sciences, Cybernetics, etc. will be
required.
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LI-6400 Photosynthesis System
LI-COR, Inc., Lincoln, NE