"The number of weather related disasters such as severe rain or ice storms has grown over the past 100 years from almost one per year in the early 1900s to an annual average of about three since the year 2000." Ice cover on the Great Lakes is 26 per cent lower than it was 50 years ago, the report found. "And Ontario's growing season has lengthened by about 13 days from 1950 to 2018," Shulz said. There are increased algae blooms in Lake Erie and rising levels of microplastics in Lake Ontario. Dissolved oxygen levels, important for aquatic organisms such as fish, are improving in Lake Simcoe, but do not meet the environment minister's targets. The report said 60 per cent of monitored rivers and streams rate "poor" to "very poor" for biological health.