The green drought: June rainfall has come too late to offer relief to farmers in southern Australia | Andrew B Watkins, Allie Grant and Pallavi Goswami for the Conversation

HOw often mowing your lawn in winter? This may seem a strange way to start a conversation on drought, but the answer helps to explain why our current drought has not broken, despite recent rain – and why spring the lamb can be more expensive this year.

The southern Australia has been running out of rain for 16 months. Western Victoria, the agricultural regions of South Australia (including Adelaide) and even parts of western Tasmania suffer from dry conditions. These precipitation measures began in 1900 at 126 years of age.

Less and less intense rainy meteorological systems have been going through the southern coast since February 2024 compared to normal. In simple terms: the earth has not received enough large rain discharges.

But June finally brought the rain in certain regions assigned to drought; There is even an emerald green shade in the fields of certain agricultural areas. But it is now too cold for plants to grow really quickly, which means that farmers will load hay and buy additional food for livestock until the time warms in the spring.

Too little, too late

This month, some areas have received good precipitation, including places near Melbourne and, to a lesser extent, Adelaide. The people of the city can be forgiven to think that drought has broken and that farmers are delighted. But drought is not that simple.

Unfortunately, precipitation was incoherent, especially more inland. The coastal flood in certain parts of the south of Australia in early June did not extend far to the north. Traditionally, the start of the winter culture season is marked by 25 mm of rain over three days – an “fall break”. But many areas have not received the break this year.

The absence of rain (meteorological drought) worsened the lack of water in the soil for crops and pastures (agricultural drought). Some parts of Australia-Western, SA, Victoria, Tasmania and South South Wales had little humidity in their soils. Thus, rain is quickly absorbed as it drains itself in deeper soils.

To make matters worse, fall was the warmest ever recorded for southern Australia, after its second, the simplest ever recorded. This can increase the “thirst” of the atmosphere, which means that any water on the surface is more likely to evaporate. Recent graduate droughts, such as the drought of Tinderbox 2017-2019 in New South Wales, were particularly impactful.

Some areas may have experienced a “flash dryness” when the landscape and vegetation dry much faster than you think of the lack of rain. In May, significantly high evaporation stress areas were present in south-eastern South Africa, Victoria, southern New South and Northern Tasmania.

At the end of May and early June – and again this week – there were winter dust storms in South Africa. These dust storms are a bad sign of the drought of the soil.

Some regions no longer have enough water to fill the rivers and the dams (hydrological drought). Water restrictions have been introduced into certain parts of the southwest of Victoria and Tasmania. Office river flow forecasts do not seem promising.

Green drought

Remember this analogy to the lawn? The winter cold has already settled in the south. This means that it is simply too cold for any new vigorous growth of the grass and that is why you are not very often turning on your lawn at the moment.

Fresh temperatures, rather than low precipitation, also limit the growth of pastures. While at the distance, the rain has added an emerald shine to a part of the landscape, it is often only a green shade. Up close, it is clear that there is a very limited new growth; Rather than new abundant and vigorous shoots, there is just a little green that goes to surviving herbs. This means a very limited diet for livestock and, to make things worse, green sometimes comes from better suitable winter herbs.

There will be a lot of hay cart, whatever the precipitation, until spring, when the floors start to warm up once again and new growth. All this is added to less stock kept in paddocks or an additional cost in time and money for farmers – and, ultimately, a more expensive spring lamb barbecue.

Does this climate change?

South Australia (Southern Wa, SA, Tasmania, Victoria and Southern NSW) lived almost weekly rain events in autumn and early winter; The cold fronts and the deep rolling pressure systems of the West brought most of the precipitation.

Now there is a much more sporadic diagram in these regions. Harvesting precipitation from April to October and the pasture growth season has decreased by around 10% to 20% from the middle of the last century. The strongest drying trend is obvious during the crucial months between April and July.

Additional reductions in precipitation of the southern growth season are expected by the end of this century, especially in southwest Australia. The southeast regions, including the south of Victoria, certain parts of SA and northern Tasmania, also show a coherent drying trend, with a greater moment spent at drought every decades.

Drought is complex. It is not because it rains that it always liked, or at the right time, or in the right place. To worsen things, a green drought can even deceive us by thinking that everything is fine.

The rupture of meteorological drought will require coherent precipitation over several months. The rupture of agricultural drought will also require more heat in the soils. The prospects suggest that we have to wait for spring.

• Andrew B. Watkins is a associate researcher at the Earth School, the Atmosphere and the Environment at Monash University

• Allie Gallant is an associate professor at the Australian Research Center of Excellent for the 21st century weather at Monash University

• Pallavi Goswami is a postdoctoral researcher in atmospheric sciences at Monash University

• This article includes scientific contributions from David Jones and Pandora Hope from the Australian Meteorology Bureau.

• This article was initially published in the conversation