permafrost

Everyday

Ground that stays frozen all year round for at least two years in a row, found in very cold places like the Arctic, Siberia, Alaska and northern Canada. tree →

In the lessons

In geography and climate lessons, melting permafrost shows global warming: buildings sink, roads crack, and gases trapped inside escape. Frozen mammoths have been found in permafrost. Phrases: thawing permafrost, permafrost layer.

Examples

• In northern Canada, the ground under the moss is permafrost. tree →
• Scientists found a baby mammoth frozen in the permafrost. tree →
• Houses in Siberia are built on stilts above the permafrost. tree →
• As the climate warms, the permafrost is thawing. tree →
• Trees cannot grow deep roots in permafrost. tree →
• Thawing permafrost lets out greenhouse gases. tree →

Note

Uncountable: some permafrost, not a permafrost. From permanent + frost. The top layer may thaw in summer while the ground below stays frozen.