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

(Sarmiento and Gruber, 2002) Global Carbon Cycle

CO 2 source/sink equation 3.3 = -2.3 – IPCC 2000 best guess sink sink source source

(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 CO 2 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 CO 2

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 CO 2 in the ocean surface and the atmosphere Ocean chemistry Ocean productivity (nutrients) Climate connection –Ocean temperatures: solubility –Ocean circulation (currents)

Terrestrial exchange of CO 2 Photosynthesis – uptake of CO 2 Plant and soil respiration – release of CO 2 Disturbance – release and then uptake Climate connection –Light, temperature, humidity, soil moisture –Concentration of CO 2 –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

(from UK Hadley Centre Carbon website) One example

UK Hadley Centre +280 ppm (710 vs 970 ppm) and +3.0 o C (4.8 vs. 7.8 o C) over non- coupled run IPSL CO 2 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 (CGC 3 M) Earth Systems Model of Intermediate Complexity (EMICs) Fluxnet Canada CO 2 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