The North American Great Lakes contain about one-fifth of the world’s surface fresh water. In May, new high water level records were set on Lakes Erie and Superior, and there has been widespread flooding across Lake Ontario for the second time in three years. These events coincide with persistent precipitation and severe flooding across much of central North America.

As recently as 2013, water levels on most of the Great Lakes were very low. At that time some experts proposed that climate change, along with other human actions such as channel dredging and water diversions, would cause water levels to continue to decline. This scenario spurred serious concern. Over 30 million people live within the Great Lakes basin, and many depend directly on the lakes for drinking water, industrial use, commercial shipping and recreation. Read more

Many will have read the news story about the sad death of Cameron Gosling who died from cold water shock after jumping into the River Wear on a hot summer’s day. Sadly, Cameron’s death is not an isolated case. About 400 people die annually in the UK as a result of being immersed in cold water – more than die from cycling accidents or fire. Most of the casualties are males under 30 years of age, and most are reported to be good swimmers.

In the 1980s, Frank Golden and I coined the term “cold shock” for the initial physiological responses evoked by being immersed in cold water. At the time, most scientists, the media and the general public thought that hypothermia (low deep body temperature) was the cause of death, a misconception that started with the Titanic disaster. But hypothermia takes at least 30 minutes before it is fatal so couldn’t explain the rapid incapacitation seen in those who die from cold water shock in minutes. Read more

Today, more than 700 million people around the world drink water from unsafe or untreated sources, such as wells, springs and surface water.

About half of these people live in sub-Saharan Africa. In fact, in more than 30 African countries, fewer than 20% of the people have access to safe drinking water.

Climate change is likely to worsen the situation by making water less available in some locations and by changing the amounts and timing when water is available. Read more

Water is essential for human life, but in many parts of the world water supplies are under threat from more extreme, less predictable weather conditions due to climate change. Nowhere is this clearer than in the Peruvian Andes, where rising temperatures and receding glaciers forewarn of imminent water scarcity for the communities that live there.

Peru holds more than 70% of the world’s tropical glaciers. Along the 180 kilometre expanse of the Cordillera Blanca (“white mountains”), more than 250,000 people depend on glaciers for a year-round supply of water. Meltwater from the glaciers supplies rivers, offering a vital supplement to rainwater so that locals can continue irrigating food crops throughout the dry season, from May to October. Read more

On the 500th anniversary of his death, our series Leonardo da Vinci Revisited brings together scholars from different disciplines to re-examine his work, legacy and myth.

Model of hydraulic saw, a reconstruction of Leonardo’s design, in Milan’s National Museum of Science and Technology, 2011. Jakub Hałun via Wikimedia Commons

The artist and polymath Leonardo da Vinci was once famously named a “Master of Water” in the records of the Florentine government.

In this role, he explored diverting the river Arno away from Pisa so as to cut access to the city, then Florence’s enemy, from the sea. It was one of a number of jobs he held that were dedicated to controlling water as a way of wielding power. Read more