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That landscape is now warming, drying and burning in ways that scientists warned about decades ago.
The ACT has warmed by around 1.4 degrees Celsius since 1910, with more very hot days and longer heatwaves recorded in recent decades.1
Rainfall has become more variable, with declines in cool season rainfall in south eastern Australia contributing to reduced runoff into rivers and storages.2
These climatic shifts are reshaping ecosystems across the territory, from endangered grasslands to alpine bogs.
Terrestrial ecosystems and biodiversity
Box gum grassy woodlands and natural temperate grasslands are among the most threatened ecosystems in south eastern Australia.
Both communities are listed as critically endangered under national law due to historic clearing and fragmentation.3
Climate change adds a new layer of stress by increasing heat extremes and soil moisture deficits.
Researchers have documented increased tree dieback in parts of Canberra’s urban forest following prolonged drought and heat, particularly affecting species such as yellow box and Blakely’s red gum.4
Urban foresters report canopy thinning and higher mortality among exotic deciduous species that were planted for a cooler twentieth century climate.
Hotter and drier conditions reduce flowering and seed set in grasses and forbs, which diminishes food resources for insects and seed eating birds.
Ecologists in the ACT have observed shifts in bird assemblages after drought years, with declines in woodland dependent species and increases in more generalist birds.
Some reptile species appear to be shifting activity patterns to avoid extreme heat, which can alter predator and prey dynamics.
Vegetation stress also creates opportunities for invasive plants such as African lovegrass to expand into disturbed grasslands.
Climate driven stress interacts with grazing pressure and invasive animals, compounding habitat degradation.
Fire regimes and post fire recovery
The Black Summer fires of 2019 to 2020 burnt almost 90 per cent of Namadgi National Park.
That season was preceded by record low rainfall and high temperatures across the region.5
Climate change increases the frequency of extreme fire weather in south eastern Australia.6
In Namadgi, some alpine ash stands experienced high severity fire that killed mature trees and triggered concerns about regeneration under a warmer climate.
Repeated or more intense fires can shorten the interval between burns below the time needed for obligate seeding plants to reach maturity.
After severe fires, heavy rainfall events have caused erosion on steep slopes, transporting ash and nutrients into waterways.
Land managers balance hazard reduction burns with biodiversity protection, yet windows for safe burning are narrowing as fire seasons lengthen.
Ecologists warn that if warming continues, some vegetation communities may shift to new states that differ markedly from those recorded in the past century.
Water resources, rivers and lakes
Reduced cool season rainfall has lowered inflows into Canberra’s storages during drought periods.
The Millennium Drought demonstrated how quickly storage levels can fall under sustained rainfall deficits.7
Higher air temperatures increase evaporation from soils and water bodies, further reducing effective runoff.
In the Murrumbidgee River and urban creeks, lower flows and higher water temperatures stress native fish and macroinvertebrates.
Warmer water holds less dissolved oxygen, which can impair aquatic life.
Cyanobacterial blooms have occurred repeatedly in Lake Burley Griffin during warm months, reflecting nutrient inputs and elevated temperatures.8
More intense storms following dry periods can wash sediments and nutrients into waterways, degrading water quality.
Climate projections for the ACT indicate further reductions in average runoff under higher global warming scenarios, with greater declines at 2 and 3 degrees compared with 1.5 degrees.2
Urban ecology, heat and living infrastructure
Canberra’s identity as a garden city depends on its tree canopy.
Urban heat island effects intensify during heatwaves, placing additional stress on street trees.
Studies across Australian cities show that extreme heat events increase tree mortality and reduce growth rates, especially where soil moisture is limited.9
The ACT Government has set targets of 30 per cent canopy cover and 30 per cent permeable surfaces by 2045 to improve resilience.
Whether these targets can offset projected warming depends on species selection, irrigation and protection of mature trees.
Community groups report fewer pollinators during prolonged dry spells, which affects urban biodiversity and home gardens.
Loss of canopy also reduces shading and cooling, feeding back into higher local temperatures.
Soil health and land degradation
Drought reduces soil moisture and microbial activity, which are essential for nutrient cycling.
Heatwaves can cause surface crusting that limits water infiltration.
When intense rainfall follows drought, bare soils are vulnerable to erosion.
After the 2020 fires, storm events mobilised sediments into rivers and reservoirs, highlighting the link between fire and erosion.
Projected increases in rainfall intensity raise the risk of gully erosion on rural lands in the ACT region.2
Compounding and cascading impacts
Drought weakens vegetation, which increases fire risk.
Fire removes ground cover, which amplifies erosion during subsequent storms.
Dust and smoke reduce air quality, affecting human health and outdoor activity.
These cascading impacts demonstrate that climate events do not occur in isolation.
If warming and drying trends continue over the next two to three decades, risks include further biodiversity loss, altered water security and degraded urban amenity.
Climate impacts on ecosystems feed back into human systems through smoke pollution, reduced recreational water quality and loss of cultural landscapes.
Adaptation, monitoring and governance
The ACT monitors ecological indicators including vegetation condition, water quality and species populations through State of the Environment reporting.10
Recent reports identify climate change as a key driver of declining ecological condition.
Conservation strategies increasingly incorporate climate projections and connectivity planning to allow species movement.
Adaptation actions include restoring riparian vegetation, diversifying urban tree species and protecting climate refugia in reserves.
Scientists, Ngunnawal custodians and community volunteers contribute local knowledge to monitoring and land management programs.
Socio ecological and justice dimensions
Access to green space supports physical and mental wellbeing.
Communities in hotter suburbs with lower canopy cover may experience greater heat exposure.
Rural landholders face economic and ecological pressures as drought and fire reshape landscapes.
Decisions about which landscapes to prioritise for protection reflect social values as well as ecological science.
Conclusion
Canberra’s ecology stands at a crossroads shaped by global forces and local choices.
The evidence shows that warming and drying trends are already altering woodlands, waterways and urban green spaces.
These changes interact with legacy pressures such as fragmentation and invasive species.
Policy targets for canopy cover, water management and biodiversity conservation offer pathways to adaptation, yet their success depends on sustained investment and rigorous monitoring.
If global warming is limited closer to 1.5 degrees rather than 3 degrees, projected declines in runoff, fire weather and heat extremes are likely to be less severe.2
The future of the ACT’s ecosystems will therefore depend both on local stewardship and on broader efforts to reduce greenhouse gas emissions.
The city in a landscape can endure, but only if climate risk is treated as a central organising principle of planning and conservation.
References
- CSIRO and Bureau of Meteorology, Climate Change in Australia projections
- IPCC Sixth Assessment Report Working Group I
- Australian Government, Box Gum Grassy Woodlands
- ACT State of the Environment Report
- Bureau of Meteorology Annual Climate Statement 2019
- IPCC Sixth Assessment Report Working Group II
- Bureau of Meteorology, The Millennium Drought
- ACT Government, Lake Burley Griffin Water Quality
- CSIRO Urban Heat Research
- Australia State of the Environment Report