Presentation to the Standing
Senate Committee on
Agriculture and Forestry
February 18, 2003
Nigel Roulet
Professor of Geography
Associate Member of the McGill School of Environment
McGill University
Montreal, Quebec
Introductory Remarks
• Assumed invitation was based on our
ISUMA: Canadian J. of Policy Research
article
– Responsible for the climate – carbon cycle
sections of paper
– Will talk to this issue
• Read the previous testimony
– Impressive amount of information
– Impressive questions/comments
– A little less sure that we know as much as we
think we know than some of the other witnesses
• Uncertainty large but circumstantial evidence is
convincing
Global Carbon Cycle
(Sarmiento and Gruber, 2002)
CO2 source/sink equation
CO2 _ C  Foceans  Fland  F ff  Flanduse
3.3 = -2.3 – 2.3 + 6.3 + 1.6
sink
sink
source source
IPCC 2000 best guess
(Sarmiento and Gruber, 2002)
Why should your committee be
concerned about the global carbon
cycle?
Impacts & adaptation
• Study of impacts and adaptation has to assume a
range of probable future conditions (uncertainty)
• Changes in climate will, through feedbacks, alter
the stores and rates of exchange in the global
carbon cycle further altering CO2 concentrations
• What will be the size and direction of change in
the carbon cycle?
Global Perspective
• Current atmosphere – ocean/terrestrial
exchange: ≈ 150 Gt C/yr
• Current anthropogenic emissions: ≈ 8 Gt C/yr
– 50% stays in atmosphere; 50% goes into
terrestrial biosphere and oceans
• Comparisons for reference
– A 5% change in ‘natural’ exchanges equals the
size of current anthropogenic emissions
– Any decrease/increase in ocean and/or terrestrial
uptake results in an increase/decrease in
atmospheric CO2
Perspective: Canada
• Terrestrial biosphere
– 10% of all living and soil carbon
• Boreal and temperature forest
• Arctic tundra
• Wetlands (peatlands)
– Terrestrial exchange is more than 10 times
that of Canada’s emissions
– Currently a net sink?
• Surrounded by three oceans
– Generally net sinks
Should we expect changes in the
atmosphere – ocean/terrestrial
exchange with climate change
and/or variability?
YES
Past records indicate change.
Many processes directly related to climate.
Ocean uptake of carbon
• Difference in concentration of CO2 in
the ocean surface and the atmosphere
• Ocean chemistry
• Ocean productivity (nutrients)
• Climate connection
– Ocean temperatures: solubility
– Ocean circulation (currents)
Terrestrial exchange of CO2
• Photosynthesis – uptake of CO2
• Plant and soil respiration – release of
CO2
• Disturbance – release and then uptake
• Climate connection
– Light, temperature, humidity, soil moisture
– Concentration of CO2
– Drought, extreme weather
– Nutrients
Can we estimate the climate –
carbon cycle feedback?
Until very recently climate projections have
ignored this feedback (most still do)
but
Most climate modelling groups are developing
crude terrestrial and ocean carbon models to
couple to climate models
One example
(from UK Hadley Centre Carbon website)
UK Hadley Centre
+280 ppm (710 vs 970
ppm) and +3.0oC (4.8
vs. 7.8oC) over noncoupled run
IPSL
CO2 concentration
was +19% higher
than non-coupled run
(3 times smaller than
UK Hadley Centre
result)
(Sarmiento and Gruber,
2002)
What is happening in Canada to
address this issue?
• Several initiatives (examples)
– collaborations/partnerships
• Canadian Global Coupled Climate Carbon
Model Network (CGC3M)
• Earth Systems Model of Intermediate
Complexity (EMICs)
• Fluxnet Canada
• CO2 and GHG measurement programs
• North American Carbon Project
• BIOCAP Canada
Canada’s Uniqueness
• Canada has large ‘natural’ carbon
stores and exchanges
• Canada’s ecosystems are locate in the
north and therefore may experience
greater climate change
• Canada has considerable expertise
What is needed?
• Continued and strengthen effort in the science of
coupled climate – carbon research
– Long-term studies (multi-year to decadal)
• “Monitoring” is a bad word
• Funding agencies not well adapted for long-term support
– Increased commitment to world class modelling community
• government and university collaborations (ideal model)
• Need to move in the direction of more integrated
assessment modelling (earth system models coupled to
socio-economic models)
• Need a significant investment in developing the next
generations of ‘earth system’ and ‘social’ scientists who
will continue to develop this field
– capacity