National Assessment of Ecological C Sequestration and Greenhouse Gas Fluxes – the USGS LandCarbon Project

Zhiliang Zhu, Project Chief, zzhu@usgs.gov

National Assessment of Ecological C Sequestration and Greenhouse Gas Fluxes – the USGS LandCarbon Project

Zhiliang Zhu, Project Chief, zzhu@usgs.gov

• What is the role of carbon in global change research? What do we know about carbon dynamics nationally and globally?

• The USGS assessment: what are our objectives and approach?

• Introduce our recent work and findings, what do the findings mean to us?

Role of carbon in the world, and in the U.S.Role of carbon in the world, and in the U.S.

Wikipedia: year 2000

Carbon in EcosystemsCarbon in Ecosystems

Carbon cycle in ecosystems

Carbon cycle in ecosystems

Forests Wetlands

Agricultural lands Grasslands Aquatic systems

What do we know?What do we know?

C stock in ecosystems estimated from various sources Annual C stock change in and

between ecosystems from EPA(Tg C)

Data are for CONUS only

What we don’t know (so well)?What we don’t know (so well)?

What are spatial and temporal patterns and trends of the C stocks and fluxes?

How does climate change affect C stock and sequestration?

What is the role of LULC change? Land management? Natural disturbances?

USGS LandCarbon Assessment Objectives and Scope

USGS LandCarbon Assessment Objectives and Scope

Scope:

1. Five primary ecosystems: forests, shrub/grasslands, croplands, wetlands and aquatic (rivers, lakes, coastal waters) systems

2. Two types of assessment: baseline (current) and future projections (“forecasts”)

3. Carbon storage and sequestration; fluxes of CO2, N2O, and CH4

4. Effects of natural and anthropogenic processes (e.g. climate change, wildfire, land use change, and land management activities)

5. All 50 States

Objectives:

1. To implement the 2007 Energy Independence and Security Act (EISA), Section 712

2. To improve scientific understanding of carbon sequestration and GHG fluxes in ecosystems related to land use, using research results from USGS and other organizations

Methodology of the Assessment Methodology of the Assessment

• Current fire areas and GHG emissions

• Future fire areas and GHG emissions

• Current fire areas and GHG emissions

• Future fire areas and GHG emissions

• Current LULC maps• Future scenarios• Future LULC maps• Forest age change

• Current LULC maps• Future scenarios• Future LULC maps• Forest age change

Aquatic C and GHG methodsAquatic C and GHG methods

Terrestrial C and GHG modeling

Terrestrial C and GHG modeling

Analysis, Report, Data Distribution

Analysis, Report, Data Distribution

Input data: inventory, remote sensing, climate,

soil, land management

Monitoring R&D

Information and Products Produced Annually from 2001 to 2050

Assessment conducted at a regional scaleAssessment conducted at a regional scale

1st

2nd

3rd

4th

IPCC 4th Assessment ScenariosIPCC 4th Assessment Scenarios

Current and future potential LULC changes in Great Plains

Current and future potential LULC changes in Great Plains

Wildland fire: current and future potentialWildland fire: current and future potential

Baseline and Future Potential Carbon TrendsBaseline and Future Potential Carbon Trends

  Forests Grasslands Ag lands Wetlands Water TotalCONUS from literature 57,000 16,000 20,000 62,000   155,000Forest Service Great Plains 2,096          USGS GP assessment 1,162 2,614 3,438 216   7,500

Current C Budget in Great Plains RegionCurrent C Budget in Great Plains Region

Future LULC and C Changes in the Great PlainsFuture LULC and C Changes in the Great Plains

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Net Changes Between Years

Lessons learned from the GP assessmentLessons learned from the GP assessment

There are many science gaps that affect the overall quality of the assessment

Biogeochemical models are very limited

It takes a lot of resources (time and money) to attribute effects of carbon sequestration to climate change, land use, land management, and natural disturbances; we were unable to do a good enough job

Still no good way to quantify uncertainties

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