What dangerous environmental phenomenon occurs when drained peat catches fire?

Tropical peat swamp forests are unique wetland ecosystems characterized by waterlogged acidic soils where decomposed organic vegetation accumulates over millennia as thick peat beds. In Malaysia, undisturbed peat swamps act as immense terrestrial carbon sinks, sequestering more carbon per hectare than dry lowland dipterocarp rainforests. Also, peat swamps function as hydrological sponges: during the torrential northeast monsoon, they absorb torrential rainfall and mitigate downstream flash floods, slowly releasing stored freshwater during subsequent dry spells. However, extensive drainage for monoculture oil palm plantations lowers water tables, desiccating peat and rendering it susceptible to smouldering subterranean fires that generate hazardous transboundary haze.

Answer and explanation

Correct answer: C. Smouldering subterranean fires produce persistent hazardous haze.

  1. Step 1: Locate the discussion of fire hazards in the passage regarding drained and dry peatlands.
  2. Step 2: Verify the environmental impact: the text notes that because peat consists of deep underground carbonaceous matter, ignited peat produces flameless, smouldering subterranean fires that burn below the surface and generate dense, persistent transboundary haze across Southeast Asia.
Answer
Smouldering subterranean fires produce persistent hazardous haze.
Why not the others: Volcanic eruptions are tectonic and magmatic events completely independent of surface vegetation fires; dissolving concrete bridges is an exaggerated physical impossibility for acid rain; permafrost melting occurs exclusively in Arctic and sub-polar zones, not tropical Southeast Asia.

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