Warmer surface water temperatures and declining winter ice cover suggest that climate change is affecting the Great Lakes, including Lake Ontario, says a report released this week by the International Joint Commission.

The report evaluates 16 indicators of the Great Lakes' health and water quality. And for the most part, the measurements are trending in a good direction. The presence of most toxic chemicals is down, beach closings have remained level, and populations of some native species, such as lake sturgeon, have begun to recover. But other problems, such as invasive species and nutrient pollution, still pose challenges in some parts of the Great Lakes, the report says.

Climate change, though important, is just one part of the picture. And it isn't affecting all lakes equally. For example, Lake Superior, the largest and coldest of the Great Lakes, is warming more than the other lakes, the report says. For all of the lakes, the average surface water temperatures increased by .05 to .06 degrees Celsius between 1985 and 2009, it says.

All of the lakes have experienced a decline in winter ice cover, but Lake Ontario's loss has been the steepest, the report says. Between 1973 and 2010, the lake's ice cover declined by 88 percent, it says.