Terres et écosystèmes

Hot, dry and windy conditions over dry fuels in which any ignition spreads fast and suppression fails.

Also: red flag conditions, fire danger

An uncontrolled fire in forest, scrub or grass that burns structures, crops and habitat and fills the air with smoke.

Also: bushfire, forest fire, grass fire

A fire spreading between wildland vegetation and buildings, so that homes become fuel and evacuation routes close.

Also: interface fire

A smouldering fire in peat or coal seams that burns for weeks to years, releasing smoke and carbon and resisting suppression.

Also: smouldering fire, coal seam fire

A lasting change in how often, how large and how intensely landscapes burn, beyond what local ecosystems and communities are adapted to.

Also: megafire era, new fire regime

Clearing of forest for other land uses, losing habitat, carbon storage and watershed protection.

Also: forest clearing

Widespread tree decline and death from drought, heat, pests or disease.

Also: tree mortality, forest decline

A single event, such as windthrow, ice damage or defoliation, that damages a large share of the trees in a stand or landscape.

Also: windthrow, defoliation

A non-native insect or pathogen spreading through forests and killing or weakening trees.

An eruption of a native tree-killing insect, released by warm winters and drought-stressed trees, that kills forest across whole landscapes and raises fire risk.

Also: bark beetle outbreak, budworm outbreak

Long-term decline of the productivity and health of land from erosion, nutrient loss, compaction or salting.

Degradation of dryland into desert-like conditions through climate change and unsustainable land use.

Loss of soil organic matter, structure and nutrients that cuts yields and the water the soil can hold.

Also: soil degradation

Accumulation of salts or sodium in soil, from irrigation or seawater, that stunts crops and breaks soil structure.

Drainage, filling or drying of wetlands that removes flood buffering, water filtering and habitat.

Also: wetland degradation

Clearing or dieback of coastal mangroves, which removes shoreline protection, nursery habitat and carbon stores.

Draining or burning of peatland that oxidises stored carbon, sinks the land and raises fire risk.

Covering of fertile soil by buildings and pavement that permanently removes farmland, raises runoff and floods and removes soil carbon and habitat.

Also: land take, impervious surface spread

Gradual fall in soil pH from fertiliser, acid deposition and crop removal that locks up nutrients, releases toxic aluminium and lowers yields.

Also: acid soils

Decline in the variety and abundance of species and habitats that weakens services such as pollination, fisheries and soil formation.

Also: species decline, habitat loss

Corals expelling their algal partners under heat stress, turning white and often dying, with loss of reef fisheries and shore protection.

Also: reef mortality

A fall in pollinating insects and animals that cuts yields of pollinator-dependent crops and wild plant reproduction.

A fish stock cut so far by fishing, warming or habitat loss that it can no longer sustain catches.

Also: stock collapse

A sudden, large die-off of wild animals from disease, toxins, heat, cold or oxygen loss.

Also: die-off

Damage or injury from wild animals entering farms, villages or roads, and the retaliation that follows against them.

Also: crop raiding, predator attacks

A disease spreading across many wild species and continents that wipes out populations, drives extinctions and can carry pathogens to livestock and people.

Also: chytrid fungus, white-nose syndrome, avian influenza in wild birds.

Broad fall in insect abundance and biomass from habitat loss, pesticides, light and warming that starves birds and fish and weakens pest control and decomposition.

Also: insect apocalypse, insect biomass loss

Warming shifting the timing of flowering, breeding or migration at different rates, so that species miss the food or pollinators they depend on.

Also: timing mismatch, seasonal desynchronisation

Movement of species towards the poles, uphill or deeper as climate warms, reshuffling fisheries, pests and disease vectors and stranding species with nowhere to go.

Also: species redistribution, poleward shift

A swarm of jellyfish or similar animals that clogs power-plant and desalination intakes, kills farmed fish and closes beaches.

Also: jellyfish swarm

Loss of the defining species, structure and functions of an ecosystem, such as a reef, lake, kelp forest or wetland, beyond the point of natural recovery.

Also: ecological collapse, biodiversity collapse

A threshold crossing in a large climate-system component, such as an ocean circulation or a rainforest, that changes regional climate quickly and may not reverse.

Also: tipping point

A drop in global or hemispheric temperature for one to three years after a very large eruption loads the stratosphere with sulphate aerosol.

Also: volcanic winter

Loss of kelp forests to marine heat, grazing urchins or turbid water, replacing them with barren seabed and losing fisheries, carbon and wave shelter.

Also: urchin barrens, kelp loss

Die-off or removal of seagrass meadows from heat, turbidity, nutrients or dredging, losing nursery habitat, sediment stability and stored carbon.

Also: seagrass dieback

A shallow lake switching from clear, plant-rich water to turbid, algae-dominated water once nutrient loading passes a threshold, which then persists even if loading falls.

Also: lake eutrophic flip, shallow lake regime shift.

Spread of shrubs and trees into grasslands and savannas through grazing, fire suppression and rising carbon dioxide, cutting forage and water yield.

Also: bush encroachment, shrub invasion of grassland

Loss of saltmarsh, mudflat and beach habitat trapped between rising seas and fixed defences or development, removing natural flood buffers.

Also: intertidal habitat loss, saltmarsh drowning

Loss of key predators, grazers or prey that cascades through a food web, restructuring the ecosystem and the services it supplies.

Also: trophic cascade, defaunation cascade