LAUSR

Taliks are bodies or layers of unfrozen ground in permafrost areas. Recent research on taliks has been driven largely by the potential for release of greenhouse gases as taliks expand, and engineering challenges associated with thawing permafrost. Observations of talik configuration and development have been assisted by advances in geophysical techniques that complement mechanical and thermal measurements. Suprapermafrost taliks have been observed in a range of settings associated with disturbance from wildfire and infrastructure. These features are included in a revised talik classification scheme presented in this paper. Observations of methane release have renewed interest in lake talik initiation and development, resulting in substantial efforts to model thaw lake expansion. Hotspots of methane release have also been identified at saline springs. Recent simulations indicate that groundwater flow can significantly accelerate talik expansion and that incorporating heat advection may be required for accurate transient simulations. Ongoing global warming is expected to exacerbate the effects of surface disturbances on talik development and limit the ability of permafrost to recover in marginal permafrost areas.