Transcript 20 March 2012 Ankur R Desai Ecometeorology Lab CCR-SAGE Symposium Or… Why Climate Scientists will never hug Ecologists again Or why CCR and SAGE need each.

20 March 2012
Ankur R Desai
Ecometeorology Lab
CCR-SAGE
Symposium
Or… Why Climate Scientists will
never hug Ecologists again
Or why CCR and SAGE need each other more than ever…
Arrhenius, S., 1896. On the influence of carbonic acid in the air
upon the temperature of the ground.
if the quantity of carbonic acid increases in geometric
progression, the augmentation of the temperature
will increase nearly in arithmetic progression
Double CO2 ->
5-6 C increase
Callendar, G.S., 1938. The artificial production of carbon dioxide
and its influence on climate. QJRMS, 64, 233-240.
If only were it so simple…
The Beat Goes On…
Data: NOAA/ESRL
Image: They Might Be Giants
Biology drives Physics
Houghton et al. (2007)
And we fail at modeling it…
Feedbacks are ubiquitous and unconstrained
Friedlingstein et al., 2006
Why?
xkcd.com
Light
Schaefer et al., submitted
Farquhar vs LUE
Long et al., 2006
C3 vs C4
Temperature and Humidity
Yi et al., 2011
n
FOCUS | REVIEW ARTICLE
NATURE GEOSCIENCE DOI: 10.1038/ NGEO844
Box 1 | Conceptual scheme depicting the mechanisms that explain the nitrogen-induced response of below-ground carbon cycling
and its variation.
Figure 1 | E ect of experimental nitrogen addition on various forest
carbon pools and fluxes as calculated by meta-analysis. Positive values
indicate that nitrogen addition had a positive e ect, negative values
indicate a decrease. Error bars indicate the 95% confidence interval. Data
are the weighted means for n data points (right axis). Parameters listed
are carbon inputs (lef t axis): litter fall (LF) and fine-root production (FRP);
carbon pools: t otal tree biomass (TB), microbial biomass (Cmic) and soil
carbon content (Soil C); and carbon losses: litter decomposition (LD),
heterotrophic respiration (Rh), root respiration (Rr) and soil carbon dioxide
e ux (SCE). Exact numbers can be found in Supplementary Table S1.
Reduced
soil respiration
Nitrogen deposition
Neutral to positive
e ect on
photosynthesis
Enhanced formation of
recalcitrant compounds
Reduced
nitrogen limitation
Reduced
saprotrophic
respiration
Allocation
shift
(–)
Recalcitrant
Recalcitrant
SOC
SOC
(+)
Labile
Liable
SOC
SOC
Saprotrophic
microbes
Wood
growth
Microbial community shifts and/
or decomposing-enzyme shifts
Reduced
priming
Rhizospheric
microbes
Reduced
rhizospheric
respiration
Reduced
SOC inputs
Reduced carbon tr ansfer
to rhizosphere
Increased carbon
limitation
studies lasting longer than two years. Given that forest litter con-
trenching technique31 — both of which physically sepa
from root inputs.
Our statistical meta-analysis revealed that the avera
of heterotrophic respiration to nitrogen addition is
pronounced than that of leaf-litter decomposition alon
over 36 nitrogen-manipulation studies in forest
heterotrophic respiration declined by 15% when n
added (Fig. 1). Variation between experiments was
responses ranging from a reduction of 57% to a stimula
(Fig. 2). Forests exposed to elevated atmospheric nitr
sition are also observed to have lower heterotrophic
than forests receiving background levels of nitrogen
(wet deposition <5.5 kg N ha–1 yr –1; Fig. 3a). For fore
annual biomass production of around 600 g C m–2 yr –1
tion amounts to roughly 100 g C m–2 yr –1 (Fig. 3a).
slopes of the two regressions in Fig. 3a further sugges
gen deposition has a stronger negative e ect at highly
sites, where nitrogen is unlikely to be the most limiti
than at less productive sites, where nitrogen immo
likely to be higher, and the negative e ect on heterotr
ration is only marginal. It can be concluded that both
addition of high amounts of fertilizer, and the chronic
of small amounts of nitrogen, induce a decline in he
soil respiration in most, but not all, forest ecosystems.
[N]
Reductionsin soil carbon dioxide e ux. Soil carbon d
(SCE) is an important indicator of below-ground carbo
Although heterotrophic respiration constitutes a substa
SCE, two important carbon uxes, related to the prese
in soils, di erentiate SCE from heterotrophic respirat
major component of SCE is autotrophic in nature (root,
and rhizosphere respiration),
coupling
variat
Janssens
ettemporal
al., 2010
to variations in below-ground carbon allocation and
Indirect Climate 1: Phenology
Richardson et al., 2012
Indirect Climate 2: Water
Sulman et al., 2012
Forest Succession
Image: P. Curtis, Figure: Amiro et al., 2010
Pests
Amiro et al., 2010
600
NEP (g C m-2 y-1)
400
200
0
Mountain Pine Beetle
Forest Tent Caterpillar
Gypsy Moth
-200
-2
-1
0
1
2
3
Time since disturbance (years)
4
5
People!
Gower et al., submitted
What else?
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Microbes, fungi, earthworms
Herbivores (deer)
Shading, resource competition
Genetic variation
Dispersal, recruitment, adaptation/evolution
Fire, extreme events, feedbacks
Acclimation
Riverine export
Ahhhh!
It Matters…
Friedlingstein et al., 2006
What to do?
4th Paradigm: Confronting science with intensive data
NSF Advances in Biological Informatics
M. Dietze, A. Desai, D. LeBauer, R. Kooper
www.pecanproject.org