Climate change warming world's lakes, says study

A new study by NASA and the National Science Foundation reveals that climate change is rapidly warming lakes around the world. The findings were published last Wednesday (December 16) in Geophysical Research Letters and announced at the American Geophysical meeting in San Francisco that same day. The study used temperature data taken via satellites and ground measurements from 235 lakes around the world and analyzed temperature changes over 25 years. "What we wanted to do was see how lakes were changing over the entire globe and look at what variations there were in the warming rates across the globe but also how much variation there was between lakes that were close together," said Sam Hook, the Science Division Manager at NASA's Jet Propulsion Laboratory and co-author of the study. According to Hook, lakes are warming at an average of 0.61 degrees Fahrenheit (0.34 degrees Celsius) each decade. The temperature changes are caused by different factors, including less cloud covers. "One of the things that we noticed which was quite interesting was that these lakes are actually, in some cases, warming faster than the air temperatures because the air temperatures, you know, change in an instant, whereas the water temperatures, they reflect what is going on in the entire environment around them. So, it could be a reflection of there being less cloud cover, it could be a consequence of more glacial melt water coming into the lake. All these different processes taking place and they integrate them and they warm more gradually but the consequences of that warming can be very serious," said Hook. Increase in lake temperatures can damage the ecosystems around the lake, making it harder for fish to survive and for people to use the bodies of water. "If we looked at these warming rates, a project of what would happen in the next century then what we would see is that algal blooms would go up by about 20 percent, this is the green algae that you see in the lakes, often times in the summer and some of that green algae that is added, some of it contains harmful toxins and so what it can do is, it puts restrictions on people going out on the water or using the water for drinking purposes and things like that. So, there are real consequences to the actual lake ecosystem," said Hook. According to Hook, decreasing pollution can help slow down the temperature changes in lakes.