Which ground surface instability event increases as permafrost thaws?

💡 Explanation

Thermokarst lakes expand because permafrost thaw weakens the previously frozen ground due to seasonal thaw depth exceeding the past active layer thickness; therefore lake expansion happens rather than deposition as previously stable terrain subsides.

• Which phenomenon leads to desert formation at approximately 30 degrees latitude north and south?
• Which effect results when tundra thaws and bioturbation increases?
• Which mechanism causes distinct ridges known as 'arêtes' to form between adjacent glacial cirques in mountainous regions?
• Which consequence frequently results when heavy tephra accumulates downwind?
• Which phenomenon enhances coastal upwelling along the western margins of continents due to Ekman transport effect?
• Which pattern results from combined Hadley cell circulation and the Coriolis effect on global wind directions?