A new study has brought together more
than 25 years of satellite data, combined with ground measurements,
to assess the state of Earth's lakes. The results show a troubling
rise in temperature that the researchers claim could have a big
impact on our environment.
The study made use of a combination of satellite temperature readings and ground-based measurements of 235 lakes on six different continents. While the satellite readings provide a global picture of lake temperatures, they only cover surface readings, while ground-based observations detect temperatures throughout the water bodies.
According to the researchers, this combination monitoring method – alongside the geographically diverse nature of the sample – provides the most complete picture of how lake temperatures are changing globally.
Specifically, the results show that the average temperature in the lakes has been rising by 0.61 degrees Fahrenheit every 10 years. While that might not seem too significant, it's a higher rate of warming than witnessed in either the atmosphere or the ocean, and the long-term effects could be pronounced.
The researchers predict that the continued increase in lake temperature will bring with it an increase in algal blooms by a much as 20 percent over the next century, lowering the water's oxygen levels while increasing toxicity for fish and animal life. Additionally, the temperature rise could cause an overall rise in methane emissions by as much as four percent in the coming decade.
The temperature increases are a little less pronounced in warm-water tropical lakes, but even then are still significant enough to have a negative impact on the fish. This could be a particular problem in areas such as the African Great Lakes, where fish is a major source of food.
All in all, if the temperature rise is left to continue, it could have significant negative impacts on the environment.
"The pervasive and rapid warming observed here signals the urgent need to incorporate climate impacts into vulnerability assessments and adaptation efforts for lakes," say the researchers.
The findings of the study were published in the journal Geophysical Research Letters.