**Impacts of Permafrost Thaw on Infrastructure and Ecosystems\
in Arctic Alaska**

Randy Schumann, CR Earth Surface Processes Team

**Statement of Problem**

As permafrost thaws, the impacts of the resulting landscape changes are
dramatic, and potentially catastrophic. Land surface collapse in
thermokarst areas forms wetlands, sinks, and gullies that alter surface
and ground-water hydrology and form new habitats for plants, birds, and
mammals, while destroying or displacing others. These land surface
changes also adversely affect all forms of human infrastructure that
depended on foundations of permanently frozen ground, including
buildings, roads, bridges, pipelines, and oil and gas drilling and pump
pads. In addition, the uneven landscape surface disrupts migration paths
of Arctic land mammals such as caribou, musk oxen, and bears, and the
ecosystem changes may adversely affect migratory waterfowl routes and
nesting sites. Hunting may no longer be sustainable for Alaska Native
peoples in some areas. Coastal areas once protected by solidly frozen
ground are now experiencing vastly accelerated rates of coastal erosion.

**Objectives**

Monitoring and assessment of permafrost distribution, thickness, and
extent, land surface changes, surface- and ground-water hydrology,
coastal erosion rates and extents, and distributions and numbers of key
plant and animal species will provide input for modeling of potential
future impacts, and provide information to planners, decisionmakers, and
responders to assist in addressing the impacts of future landscape and
ecosystem changes in Arctic Alaska.

The critical questions to be addressed are:

-   What is the current rate of permafrost melt in Arctic Alaska? What
    projections can be made for rates and extents of permafrost melting
    through the rest of the 21^st^ century?

-   What are the potential land-surface, hydrologic, and ecosystem
    changes resulting from permafrost melt, and what are the potential
    impacts on human infrastructures and plant and animal communities?

Results of these studies, or at least the methodologies used, should be
applicable to similar Arctic areas across the Northern Hemisphere.

**Work Strategy**

A comprehensive assessment of all existing applicable monitoring data
from within and outside of USGS must be made to identify sources of
historic data and reveal the quality and spatial extent of the current
monitoring network. Gaps must be identified and a monitoring strategy
developed that incorporates a network of cooperators and partners to
insure adequate expertise, resources, and spatial coverage can be
attained. Ground-based and aerial geophysical data (electromagnetic,
resistivity) can be used to map the depth to frozen ground (thickness of
active layer) as well as extent of continuous/discontinuous permafrost
across large areas. Electrical conductivity measurements may also be
used to produce thermal profiles of permafrost soils (Vic Labson, pers.
comm.). Repeated geophysical surveys would be a valuable and effective
monitoring methodology.

Coastal erosion models must account for changes in erosional resistance
of ice-free, relatively unconsolidated tundra soils compared to
ice-cemented deposits. Land subsidence models used in earthquake-prone
areas could be recalibrated to simulate effects on building and
infrastructure stability under melting permafrost conditions. Hydrologic
models must account for changes in water availability and hydraulic
conductivity of tundra aquifers due to ice melt, as well as due to
future changes in climatic regimes in the Arctic. Impacts on plant and
animal communities can be assessed through monitoring of key indicator
species, and by modeling changes in biomes using models that incorporate
forcings from climate, land-surface, and hydrologic changes. Such models
likely do not currently exist, at least as a single, comprehensive
entity. Therefore, the various modeling communities must work together
to create integrated models that can incorporate such seemingly
disparate data sets in order to address the complexity of the natural
system.

**Relevance and Impact**

The ability to manage public lands and resources in Arctic regions will
be greatly impacted by the projected land surface, hydrologic, and
ecosystem changes caused by permafrost melt. Although some projected
changes, such as migration of woodlands into areas currently occupied by
tundra, may take centuries or possibly millennia, other changes, such as
formation of vast collapse areas and wetlands, and disruption of
drainage systems, are happening over the course of one or a few years.
Adjustments in management strategies could involve trading
responsibility for parcels of land among different government agencies
(e.g. FWS with BLM), or changing land-use plans in areas affected by
landscape and ecosystem changes. Moreover, efforts to protect and/or
re-engineer infrastructure will be greatly aided by data on the rate and
extent of permafrost melt and on projections of the anticipated impacts.

**Partnerships**

Alaska Native corporations and villages

Bureau of Land Management

Fish and Wildlife Service

Forest Service

National Park Service

Various cities and boroughs of Alaska

Alaska state government agencies

Universities

Energy companies