This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: In the highlands of Papua New Guinea, crops have been killed by drought and frost. Severe frosts have destroyed food crops such as taro, sweet potatoes, bananas and sugarcane, leaving some local communities scrambling for food.
El Niño is producing conditions similar to those associated with previous frosts—including those of 1972, 1997–98 and 2015–16—that left thousands of Papua New Guineans without food and water. This may seem like a faraway, albeit worrying, problem for those in Australia. After all, we typically talk about climate change through the lens of heat and drought.
But for Australian farmers, frost risk is a growing concern. This is particularly true as the strengthening El Niño—a naturally occurring weather phenomenon that drives variations in temperature and winds across the Pacific—threatens to bring increasingly fierce and frequent frosts to farming regions. Radiation frost, commonly known as frost, typically forms after a cold, clear and windless night.
Clear skies, rather than cloudy ones, allow more heat to be released into the atmosphere. This causes the temperature of the soil and air to drop. Dry conditions can speed up the cooling process because parched soils store less daytime heat.
While moist soil can retain more warmth and buffer the effects of subzero temperatures, it can't completely protect crops or plants from severe frosts. Cold air is generally heavier than warmer air, meaning dense cold air flows into valleys and other low-lying areas. These are known as frost hollows.
Calm conditions stop this cold air from moving or mixing with warmer winds. Chilly temperatures can indicate when frost may strike. Depending on where you are, if the minimum forecast temperature is 3°C (37°F) or below, you could be in for a frost.
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