According to a recent study, if global warming persists, blue lakes all over the world run the risk of turning green-brown.

According to a study published on September 22, 2022 in Geophysical Research Letters, the air, temperature, precipitation, lake depth, and elevation, coupled with elements like silt and algae, impact the colour.

Less than one-third of the lakes in the world are blue, and many of those are deeper. They live in high-latitude regions that receive a lot of precipitation and winter ice cover.

69 percent of all lakes are green or brown. They are more widespread and can be found in arid regions along coastlines and in the interiors of continents.

To determine the most common colours of 85,360 lakes and reservoirs, the researchers examined 5.14 million satellite images taken between 2013 and 2020.

In order to characterise the colour as it might fluctuate periodically due to an algal bloom, they examined the most common lake colour over a period of seven years. Users can examine the results thanks to the authors' interactive map.

The study also examined how various warming scenarios, in the event that climate change persists, will affect water colour.

The study's lead author, Catherine O'Reilly, stated in a press statement that 'warmer water, which creates more algal blooms, will tend to tilt lakes towards green colours.'

Due to climate change, the number of blue lakes, which are common in the Rocky Mountains, northeastern Canada, northern Europe, and New Zealand, may decrease.

According to the authors, a simple yet effective indicator of water quality that may be observed from satellites on a worldwide scale is the colour of the water.

Prior studies have used more intricate and precise scale measurements to assess the overall health of lake ecosystems. This methodology provides a tool to look at how isolated lakes are affected by climatic changes.

O'Reilly predicted that the cost of treating the water will increase due to changes in water quality that are likely to occur as lakes became greener.

Changes in water colour may also have recreational and cultural implications in nations like Sweden and Finland, where lakes are prevalent traditionally. As global warming increases, northern European lakes will likely lose their winter ice cover, which could have an impact on winter and cultural activities.

Nobody desires to swim on a green lake, according to O'Reilly. According to him, some of the lakes that we may have always considered to be havens or sacred spaces may be disappearing as the colour changes.