Geophysical Fluid Dynamics Laboratory ReviewJune 30 - July 2, 2009

Geophysical Fluid Dynamics Laboratory Review

Geophysical Fluid Dynamics Laboratory Review

June 30 - July 2, 2009June 30 - July 2, 2009

Geophysical Fluid Dynamics Laboratory ReviewJune 30 - July 2, 2009

Land Ecosystems and Biogeochemical Cycling Land Ecosystems and Biogeochemical Cycling

Presented by

Lori T. SentmanElena Shevliakova

Presented by

Lori T. SentmanElena Shevliakova

3

5 vegetation types

5 vegetation C pools(Cl, Csw, Cw, Cr, Clv)

2 soil C pools(Cfs and Css)

4 land-use types

Up to 15 tiles of different ages per grid-cell

Natural mortality and fire

Shevliakova et al., 2009

Vegetation structure in the LM3 land model Vegetation structure in the LM3 land model

4

mo

del

po

ten

tial

,cu

rren

t cl

imat

eo

bse

rvat

ion

-bas

ed e

stim

ates

Vegetation C, Kg/m2 Soil C, Kg/m2

LM3V generates present-day distributions of vegetation and soil CLM3V generates present-day distributions of vegetation and soil C

5

Simulated historical wood harvests compare well with the FAO-based estimates

The model’s estimate of the 90s land use flux, 1.1-1.3 PgC/a, is about half of previous estimates and implies asmaller “missing sink”

Sage-Hyde land-use scenario

Hyde land-use scenario

Shevliakova et al., 2009

North

South

OBS, NHLM3V, NHOBS, SHLM3V, SH

LM3V simulates the land-use sinks & sources, including forestryLM3V simulates the land-use sinks & sources, including forestry

6

GFDL Slab-Ocean Climate Model (SM2.1-LM3V)Atmospheric CO2 concentration: 572 ppm in both experiments

No fertilization, photosynthesis at 286 ppm Fertilization, photosynthesis at 572 ppm

- 460Pg +201Pg

Shevliakova et al., subm.

The difference in the resulting land carbon storage suggests that the magnitude of the CO2 fertilization uncertainty can be as large as that associated with clouds or oceanic heat uptake

Equilibrium changes in land C from preindustrial levels

Uncertainty about CO2 fertilization is the key factor for future land C uptake

Uncertainty about CO2 fertilization is the key factor for future land C uptake

7

Lan

d C

arb

on

, GtC

CO2 fertilization: Carbon storage increases in 21st century and then declines

No CO2 fertilization: Catastrophic loss of land carbon

Photosynthesis at 286

Photosynthesis at atmospheric concentrations

Historical CO2 SRES A1B CO2 concentrations

1600

1800

2000

2200

2400

1900 2000 2100 2200 2300

Transient changes in land C storage depend on CO2 fertilization (ESM2.1)Transient changes in land C storage

depend on CO2 fertilization (ESM2.1)

8

• The GFDL ESM land component, LM3– represents a range of biosphere-climate interactions and feedbacks– captures effects of both climate change and land use on vegetation

dynamics and structure– simulates historic and future distribution of Carbon sources and sinks

• A version of LM3 simulates coupled Carbon-Nitrogen dynamics in plants and soils – poster by Gerber, Keel et al.

• Considerable uncertainty about the magnitude of climate effects on biosphere and its feedbacks

SummarySummary

Geophysical Fluid Dynamics Laboratory ReviewJune 30 - July 2, 2009

Geophysical Fluid Dynamics Laboratory Review

Geophysical Fluid Dynamics Laboratory Review

June 30 - July 2, 2009June 30 - July 2, 2009