Are there any lakes in your hometown? What color are they? Around one-third of the world's lakes are blue, according to a study in September 2022. But global warming may lead them to turn green or even brown, and countries with most lakes may be affected the most. If the temperature continues to rise, one in every ten lakes might change color.
Xiao Yang from Southern Methodist University in the US and his team analyzed (分析) the color of over 85,000 lakes based on the satellite photos taken from 2013 to 2020. The study has found that lakes in places with cooler summer average air temperatures-below 19℃-were more likely to be blue than lakes in places with warmer summers.
According to the research, the color of a lake is partly decides by what's in the water. Water molecules absorb the long wavelengths of sunlight, such as red and yellow, leaving behind the shorter ones presenting green and blue. Simply put, the cleaner the water, the bluer it looks.
Lakes serve as an important part of our environment, with their color being one of the oldest ways to determine the health of an ecosystem. Humans get their drinking water from lakes, streams and ground water. As they become greener, people may lose lots of clean water. Because of this, dealing with the water of such lakes becomes more expensive.
At the same time, blue lakes are also a source of a place to help people stay peaceful. Some countries according to Catherine O' Reilly, even considered blue lakes as a spiritual(精神的) place. As these lakes disappear, they may feel upset.