Carbon and Communities

New Findings for the New England Landscape

Presented by Steve M. Raciti

Steve M. Raciti, Timothy Fahey, Charles Driscoll, Frederick J. Carranti, David Foster, Philip S. Gwyther, Brian Hall, Steven Hamburg, Jennifer C. Jenkins, Julian Jenkins, Christopher Neill, Scott Ollinger, Brandon W. Peery, Erin Quigley, Ruth Sherman, R. Quinn Thomas, Matt Vadeboncoeur, David Weinstein, Geoff Wilson, Peter Woodbury

2

Carbon as a Pollutant• CO2: most important

greenhouse gas– 85% of U.S. emissions

(based on warming potential)– 77% of global emissions

• Potential impacts– Rising mean global

temperature– Sea level rise– Extreme weather events– Species extinctions– Droughts, floods

Natural Carbon fluxes are large, but they are in relative balance.

Anthropogenic activities have changed this balance, largely through fossil fuel combustion and land use change.

The Carbon Budget• Assembling C budgets for Northeastern Counties

– Collaboration• Hubbard Brook Science Links Program• Hubbard Brook, Harvard Forest, Plum Island, & Baltimore LTERs

• Carbon Budget = Emissions – Sequestration– Emissions: Carbon losses to the atmosphere– Sequestration: Removal of carbon from the atmosphere

• Useful for decision-makers and conservationists– What are our emissions sources?– How can we reduce them?– Can we hope to balance the budget?– What role can forest conservation play in that balancing?

County Area (km2)

Pop. density (#/km2)

Character

Coos, NH 4,740 7 Rural, forestedGrafton, NH 4,532 18 Rural, forestedTompkins, NY 1,273 76 Rural, small city, mixed ag and forestChittenden, VT 1,605 91 Rural, small city, forested

Worcester, MA 4,090 184 Suburban/exurban, medium city, forested

Baltimore County, MD 1,573 501 Suburban, mixed agriculture and forested

Essex, MA 1,297 567 Suburban, forestedMiddlesex, MA 2,133 688 Suburban, forestedBaltimore City, MD 206.7 3,055 Urban

County-level Carbon Budgets

Variation in- Climate - Topography- Population density- Land-use and Land Cover

0500

100015002000250030003500400045005000

kg C

/pe

rson

/yea

r

Per Capita CO2 EmissionsIndustrialCommercialResidentialTransport

Increasing Population Density

Net C Flux = Emissions - Sequestration

R2 = 0.99

More people = more emissions. Regardless of differences in per capita emissions among counties.

Boring data?

Gets more interesting at the lower part of our graph…

Does not include emissions from manufacture of imported goods or air travel.

Net C Flux = Emissions - Sequestration

Net zero Emissions31 persons/km2

Northeast Population134 persons/km2

Conclusion:

- Forest and soil C sinks are large. Protecting these sinks by conserving forests and minimizing conversion to development would be a good idea if we want to slow climate change.

Does not include emissions from manufacture of imported goods or air travel.

However

- These forest C sinks will slow down over time.

- We’ll need to reduce emissions, while maintaining the C stored in forest trees and soils.

Note that maximum potential biomass may be under and over-predicted by the model and future changes in climate may increase or decrease carbon storage potential. There is increasing evidence that even old growth forests can continue to sequester carbon in biomass and soils, but at slower rates than younger forests.

0%

50%

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150%

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300%

350%

Miti

gatio

n Po

tenti

al (%

of e

mis

sion

s)"Zero Cost" Mitigation Opportunities

Wind

Fuelwood Harvesting

Space and Water Heating

Lighting

Computers and Appliances

1,050%

------------- Increasing population density ------------->

Fortunately…

-We can significantly reduce CO2 emissions at little long term cost.

-“Zero cost” = pays for itself via energy savings or revenue over the life of the strategy.

- Rural areas will supply a large share of carbon offsets and alternative energy opportunities.

Energy efficiency technologies in urban and suburban areas.

Alternative energy in rural areas.

0%

20%

40%

60%

80%

100%

120%

140%

160%

180%

200%

Miti

gatio

n Po

tenti

al (%

of e

mis

sion

s)"Non-zero Cost" Mitigation Opportunities

Forest Preservation

Photovoltaics

Afforestation

Biofuel Crops

440%

------------- Increasing population density ------------->

Forest Preservation is the largest C mitigation opportunity for rural counties in the region (among the opportunities we evaluated).

Carbon markets could provide financial incentives to forest land owners, but there are several challenges to overcome.

Note: Forest Preservation provides important additional non-carbon ecosystem services that enhance the benefits of this option.

Potential Forest C Offset Markets• Regional Greenhouse Gas Initiative (RGGI): Offsets must be “real,

additional, verifiable, enforceable and permanent”

– Additional: Cannot replace a management activity that would have happened anyway.

– Verifiable: Data collection at regular intervals.

– Permanent: Sequestered carbon should not be re-emitted to the atmosphere within the foreseeable future.

– Enforceable: Contracts or other legal instruments should ensure compliance and exclusive ownership.

• Emerging Option: allocate a portion of emission allowances to fund domestic conservation easements through state, regional or national programs.

The Ecology of Forest Carbon• Aboveground biomass (wood)

and Soil Organic Matter are the largest pools.

• Aboveground– Easiest to measure – Tree diameter + allometric

equations

• Root biomass– Can be estimated based on

aboveground biomass

• Soil organic matter– C sequestration is more

difficult to measure due to high spatial variability.

Fahey et al. 2010

Challenges• Measurement and projection of forest C

at small scales can be costly.– We need an inexpensive, standardized

system that discourages dishonest accounting

• For easement option– we need a defensible method for

allocating potential conservation easement funding based on estimated carbon benefit.

Forest Product Substitution

• Can provide immediate emissions reductions– Substitute wood for other building materials– Displace fossil fuel energy with biomass

energy (heating systems or power plants)

• Again, we need standardized accounting approaches

Conclusions

• Forests already offset a large portion of emissions in the Northeast

• Development threatens to change rural areas from net C sinks to net carbon sources

• Carbon markets could provide financial incentives to forest land owners, but we need inexpensive, standardized approaches for C accounting or a defensible easement-based approach

• Land trusts can play an important role in retaining carbon storage by accelerating forest conservation and reducing forest loss in New England

Forestry Rural Suburban Urban0

50

100

150

200

250

300

93 96

71

3025

187

1,896 11,069

Forest Carbon Storage & Emissions

Forest SequestrationEmissions

(g C

/m2/

yr)

11,000

2,000 1,900

11,000

Slide 24

Courtesy: Hubbard Brook Research FoundationRaciti et al. In prep.

Forests absorb large amounts of carbon relative to emissions in rural areas, but not in urban areas.