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Weather, climate envelopes and warming levels

Drafted with AI help (22 Oct 2026); not yet reviewed. Issuer definitions are added only from a stored source.

Grids and stations

Weather stations measure at a point; a grid interpolates between them. PLOT shows both and says which is which. The grid gives every place a value; a station gives a longer, checked record nearby.

Grid cell: A square of about 5 km by 5 km (0.05°) in SILO's gridded climate, interpolated from weather stations. A cell is an estimate for the square, not a measurement at a point, and misses microclimate.

The reference period

Everything is compared with 1961–1990, before most recent warming. A different reference gives different numbers, so the period is always printed beside them.

Reference period: The years an envelope is measured over. PLOT uses 1961–1990, the standard climate normal before most recent warming; 1991–2020 is the alternative.

Climate envelopes

An envelope describes the climate a habitat or species has lived with where it is mapped. Because mapped extents are what is left after clearing, an envelope is narrower than what the habitat could tolerate.

Derived: A statistic PLOT computes from observations with a published method, such as a climate envelope. Not itself observed, and not a projection.
Climate envelope: The range of climate a habitat or species lived with during a reference period: the 5th to 95th percentile of yearly values across its mapped extent. Derived by PLOT; a realised range, not its tolerance.

Outside the envelope

Being outside the envelope is a pressure, not an outcome. Whether the vegetation changes is a separate, observed question.

Share outside the envelope: How often a mapped extent's climate falls outside its reference envelope on any core measure: the share of its area, year by year, compared with the same share in the reference period itself. A pressure indicator, not a measure of condition or of what will happen to the vegetation.

Global warming levels

A warming level is a state of the world, not a date. Different models reach +2 °C in different years; PLOT shows the median across models and keeps their range.

Global warming level: How much warmer the whole world is than 1850–1900 (+1.5, +2, +3 °C), not a year. PLOT applies each climate model's change at that level to the reference period. Modelled, with a range across models.

Sea level

Tide gauges measure the sea against the land they stand on. Only a gauge with a continuous datum gives a trustworthy trend.

Tide gauge quality: PSMSL keeps two sets: research quality, where the gauge's datum is continuous, and metric, where it may have jumped. A trend from a metric record may include datum shifts.

Fire

Fire history records perimeters, not severity. The tolerable fire interval says how often a vegetation group can burn; some groups, like saltmarsh, have none set.

Recorded fire: A fire perimeter in the state's fire history: bushfires and planned burns. A record of where fire was mapped, not of how severe it was; no record is not evidence of no fire.
Tolerable fire interval: The minimum and maximum years between fires a vegetation group can take without losing species, set by the state for each ecological fire group. Some groups have none set.