Ancient Permafrost and a Future, Warmer Arctic
(Science, Volume 321, Number 5896, pp. 1648, September 2008)
- Duane G. Froese, John A. Westgate, Alberto V. Reyes, Randolph J. Enkin, Shari J. Preece

"We report the presence of relict ground ice in subarctic Canada that is greater than 700,000 years old, with the implication that ground ice in this area has survived past interglaciations that were warmer and of longer duration than the present interglaciation."
Near-surface permafrost degradation: How severe during the 21st century?
(Geophysical Research Letters, Volume 34, Issue 9, May 2007)
- G. Delisle
"Based on paleoclimatic data and in consequence of this study, it is suggested that scenarios calling for massive release of methane in the near future from degrading permafrost are questionable."