Land cover change alters climate through albedo and the carbon cycle, and reduces biodiversity, with feedbacks that drive further change.

What this dot point is asking

Land cover transformation is not just a local change to the surface; it reaches up into the atmosphere and out across ecosystems, altering two global systems at once: climate and biodiversity. Understanding these interrelationships, and the feedback loops between them, is the analytical heart of the land cover unit.

The first pathway is the carbon cycle. Vegetation, especially forests, stores large amounts of carbon in trees and soils and removes carbon dioxide from the atmosphere through photosynthesis, a process called carbon sequestration. When forests are cleared or burned, that stored carbon is released as carbon dioxide, and the lost vegetation can no longer sequester carbon. Deforestation is therefore a major source of greenhouse-gas emissions and a reduction in the planet's capacity to absorb them, intensifying the enhanced greenhouse effect and global warming. Conversely, protecting and restoring forests, peatlands and wetlands strengthens carbon sinks.

The second pathway is surface reflectivity, or albedo. Different land covers reflect different amounts of sunlight. Replacing dark forest with lighter cropland can raise albedo and locally cool, while clearing bright snow or ice exposes darker ground or water that absorbs more heat, warming the surface. Land cover change also alters the water cycle and local climate: forests recycle moisture into the atmosphere through transpiration, so large-scale deforestation can reduce rainfall and dry regional climates, as is feared for parts of the Amazon. Urban surfaces absorb and retain heat, creating urban heat islands.

The third pathway is biodiversity. Land cover change is the leading driver of biodiversity loss worldwide. Clearing and converting natural vegetation destroys habitat, while roads, farms and cities fragment what remains into isolated patches too small to sustain many species. Loss of biodiversity weakens ecosystem services such as pollination, water purification, soil formation and carbon storage, which feeds back on both climate and human wellbeing.

Tasmania shows these processes locally. The Tasmanian Wilderness World Heritage Area stores carbon in tall wet eucalypt forests and ancient Gondwanan vegetation, but warming and dry-lightning fires have burned fire-sensitive species such as pencil pine that may never recover, converting forest to other cover and releasing carbon, a clear climate-biodiversity feedback. Historic clearing of Midlands woodland fragmented habitat and reduced biodiversity. Offshore, ocean warming linked to global climate change has driven the long-spined sea urchin south, where it overgrazes giant kelp forests, transforming productive reef into barren ground and collapsing local biodiversity and fisheries. Globally, Amazon deforestation releases carbon, threatens rainfall recycling and destroys some of the richest biodiversity on Earth.

This pervasive human influence means truly natural environments no longer exist; geographers describe the result as anthropogenic biomes, landscapes whose character is now defined by human modification. Recognising this reframes management: the goal is not to restore an untouched baseline but to manage modified systems for climate stability and biodiversity.

For TCE assessment, explain the mechanisms (carbon cycle, albedo, water cycle, habitat loss and fragmentation) by which a specific land cover change affects climate and biodiversity, identify the feedback loops, and support the analysis with a Tasmanian case such as fire in the World Heritage Area and a global case such as Amazon deforestation. Use the concept of anthropogenic biomes to frame why management of modified environments is now unavoidable.