Why it matters

Fire and ice

15th March 2008

The high Arctic could change to a land of shrubs, fires, and ever-accelerating climate change

---

Over the coming centuries, the tundra and permafrost of the high Arctic could change to a landscape of shrubs and even periodic fires. A new study, based on analysis of sediment cores, in the journal the Public Library of Science ONE reports that at the end of the last ice age, 9,000 to 14,000 years ago, the tundra was covered in birch shrubs and experienced forest fires much more often than the infrequent blazes of modern times. “There is a precedent for high fire frequencies in the tundra, ranging from one every 75 to 150 or more years,” says Philip Higuera, lead author of the study. “This is an important component of the climate system that we haven’t considered yet.”

The Arctic stores about a third of the Earth’s soil carbon at the moment. Melting permafrost and burning tundra could release huge amounts of carbon into the atmosphere. This would exacerbate global warming, accelerate the thawing of the Arctic, and possibly increase vegetation prone to periodic fires. Scientists have already documented the presence of more shrubs in the north.

Nobody can predict exactly what will happen – melting permafrost, for example, might eliminate the risk of fire by keeping the tundra too wet. But one thing is certain: It’s going to warm faster than almost anywhere else on Earth, and the changes will be dramatic.

Published in The Green Report in The Globe and Mail

---

• Tags:
• Climate Change
• Permafrost
• Positive Feedbacks
• The Arctic

---