Healthy soil can protect land from soaring heat. But our map shows where soil is suffering |
Imagine walking into a double-brick house on a scorching 40°C summer day – it feels cool almost straight away. Now imagine stepping into a corrugated tin shed – it feels like an oven. The difference is simple: some materials slow heat down, while others let it rush through.
Soil works in a similar way. Soil in fully functioning condition can act as a thermal buffer: a giant shock absorber for temperature. It holds water and organic matter such as leaf litter, and slows sharp changes in temperature.
But when soil becomes dry, bare or damaged, that protection weakens. During heatwaves, the roots of crop plants may be sitting in rapidly heating soil.
Our new research shows Australia has “thermal gaps” in large areas. A thermal gap is the difference between a soil’s natural ability to absorb heat and keep temperatures steady, and what it is actually doing now after years of farming, land use change and a warming climate. In some areas, especially across southeastern and central Australia, soils are no longer protecting plants from heat as well as they could.
This matters because soil is not just dirt under our feet. It is a buffer against climate change. Soil controls how heat and moisture move between the land and the atmosphere. When soil loses its buffering power, ground temperatures can rise more quickly.
This can reduce plant growth, lower crop and pasture production, and even affect local weather and climate over large areas.
What we did and what we........