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QLDGeographyQuick questions
Unit 3: Responding to land cover transformations
Quick questions on Climate feedback loops and land cover for QCE Geography Unit 3
3short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is positive feedback?Show answer
The ice-albedo feedback is the clearest example. Bright snow and ice reflect most incoming solar energy (high albedo). As warming melts them, they expose dark ocean or dark ground that absorbs far more energy (low albedo). The extra absorbed energy warms the surface, melting more ice, exposing more dark surface, and so on.
What is negative feedback?Show answer
Negative feedbacks stabilise the system. Higher atmospheric carbon dioxide can stimulate plant growth in some conditions (carbon fertilisation), drawing down a little extra carbon. Cooler, wetter conditions can let forest expand and sequester more carbon. These dampening loops exist but are generally weaker than the amplifying ones for land cover and climate, which is why net warming continues.
What are tipping points?Show answer
A tipping point is a threshold beyond which a feedback drives the system into a new state that is difficult or impossible to reverse on human timescales. Examples include large-scale Amazon dieback, collapse of major ice sheets and widespread permafrost thaw. The concern is that land cover change can push systems toward these thresholds, so managing land cover is partly about keeping systems away from tipping points.
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