What causes environmental change and how is sustainability assessed?
Human activity drives environmental change at multiple scales, and sustainability frameworks help assess whether systems can persist over time.
Natural and human causes of environmental change, key impacts, and how sustainability is defined and measured, using Tasmanian and global cases.
Reviewed by: AI editorial process; not yet individually human-reviewed
Have a quick question? Jump to the Q&A page
What this dot point is asking
Environmental change refers to shifts in the condition of natural systems: the atmosphere, hydrosphere, biosphere and lithosphere. Change has always occurred through natural processes such as volcanic activity, glacial cycles and natural climate variability. What concerns geographers today is the pace and scale of human-induced change. Since the Industrial Revolution, and accelerating after about 1950 in what many scientists call the Great Acceleration, human pressures on the environment have grown sharply alongside population, consumption and global flows.
The main drivers of human-induced change are population growth, rising per-capita consumption, technology and energy use, and land-use change. Burning fossil fuels increases atmospheric carbon dioxide, intensifying the enhanced greenhouse effect and driving climate change. Deforestation, agriculture and urban expansion alter habitats and the carbon cycle. Pollution affects air, water and soil. These pressures interact: climate change worsens biodiversity loss, which in turn weakens ecosystem services such as pollination, clean water and carbon storage.
Key impacts include warming temperatures, sea-level rise, ocean acidification and warming, more frequent and intense extreme events, and biodiversity decline. Tasmania provides clear local evidence. The seas off eastern Tasmania are a global ocean-warming hotspot, warming faster than the global average. This has driven the southward spread of the long-spined sea urchin from New South Wales waters, which overgrazes kelp and creates barren rocky reefs, damaging giant kelp forests and the abalone and rock-lobster fisheries that depend on them. Warmer water also stresses farmed salmon in summer. Tasmania has also experienced severe bushfires, including fires that have burned ancient, fire-sensitive Gondwanan vegetation in the Tasmanian Wilderness World Heritage Area, vegetation that may not recover.
To assess sustainability, geographers use frameworks and indicators. The three pillars (environment, society, economy) or the "triple bottom line" judge whether an activity supports all three over the long term. The ecological footprint measures the biologically productive land and water needed to support consumption and absorb waste, compared with available biocapacity; when footprint exceeds biocapacity, the use is unsustainable. The planetary boundaries framework identifies thresholds, such as for climate change and biodiversity loss, beyond which Earth systems may shift dangerously. The United Nations Sustainable Development Goals provide a global set of targets and indicators.
A useful approach in answers is to distinguish causes, impacts and responses, and to apply a sustainability lens explicitly. For any change, ask: what is the natural baseline, what human drivers are operating, what are the environmental, social and economic consequences, and is the current use within ecological limits? Strong responses quantify change where possible and recognise that sustainability involves trade-offs between competing values and time scales.