What Europe's shrinking rivers reveal, and why Australia should take notice

In northern Bulgaria, water in the Danube River has fallen so low that scientists say an ancient mammal has once again been exposed to the world.

The remains of what is believed to be a woolly mammoth were uncovered in late July and hailed by historians as a "very important" discovery.

Near the Serbian village of Prahovo, the rusted vessels and broken masts of German warships also resurfaced from the riverbank this month.

"This has literally never happened before; these wrecks ... have never been visible like this. They've always been completely submerged; what we're seeing now is utterly unprecedented," he said.

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The discoveries along Europe's second-longest river come as parts of central and eastern Europe experience prolonged summer heatwaves and drought conditions.

Armin Fojskic, a member of the Zenica Fishermen Association, said if conditions don't ease, he expects a large number of fish to die in European rivers.

"Low levels of water are critical for the fish, especially if it is extremely low, and these past days it has really been extremely low," Fojskic said.

"The main danger for fish is oxygenation of the river; when water flow drops, the river loses oxygen and fish start to suffocate."

According to the European Drought Observatory, about half of Europe and the United Kingdom experienced drought at various levels of intensity in July. Major wildfires have also burned across the continent .

But Peter Gleick, a hydro-climatologist and co-founder of the Pacific Institute in California, believes what Europe has experienced is not in line with normal weather fluctuations.

"Weather is always variable. We always have droughts. We always have floods somewhere at some time ... but what we're seeing now is extreme events worsened by human-caused climate change," Gleick told SBS News.

"We're dumping greenhouse gases into the atmosphere. We know that's warming the planet. We know that it's altering these extreme events by making them more extreme, more frequent, and more intense."

Gleick said the extreme patterns affecting rivers in Europe are similarly impacting water systems across the globe.