Locals believe that Takeminakata, a Shinto male god, crosses Lake Suwa every winter to visit Yasakatome, the Japanese lake. Only his footprints are left on the ice, in the form of a Sinusoidal ice ridge is called the omiwatari.
Shinto priests began to celebrate the appearance of the Lord in 1397. omiwatari. They used the direction of cracks left by the omiwatariForecast the harvest of the agricultural crops for the coming summer. In the first 250 year of the ice record Except for three years, Lake Suwa freezes every year.During that time, the region experienced widespread famine. However, the lake has only been frozen seven times since 2000.
Lake Suwa, one of many lakes in Northern Hemisphere, is rapidly losing its ice. We found that These lakes see ice melt earlier and form later than usual, leaving less seasonal ice.. Many lakes have had their seasons of ice cover reduced to the bare minimum in recent decades.
If the ice in northern lakes continues its decline at the same rate it will have devastating ecological and cultural consequences.
Rapidly losing ice in lakes
Since the Industrial Revolution, the average ice duration was two weeks shorter per century. Lakes lost up to 34% of their total ice covers. In the last 25 years, the Lakes lost ice six times faster than before, and the rate of loss of ice rose.More than any other time in the past 100-years.
Around 15,000 lakes, including Lake Suwa and the North American Great Lakes — Lake Michigan and Lake Superior — are beginning to Some winters, you can remain ice-free. The most vulnerable to experiencing ice-free winters are lakes located at lower latitudes or in coastal regions.
Large, deep lakesFor ice to form, certain lakes, such as the North American Great Lakes require cold temperatures to maintain their water temperature. Deeper lakes, due to their enormous thermal mass, take longer to cool down in autumn.
Larger lakes with a longer fetch — the area over which the wind blows — also tend to freeze later because they are more sensitive to increased wind action breaking up the initial skim of ice on the lake surface.
Why is ice loss important?
Lake Superior is one The fastest warming lakesThe world. It has lost more than two months of ice covering since 1867. By removing the “lid” of ice, evaporation rates can increase in Lake Superior, as well many other Lakes in the Northern HemisphereFurther, this can impact water availability. The physical barrier between the lake surface, the atmosphere and the lake becomes less ice-y and lakes become ice-free, and this is when the lake’s water availability begins to improve. Potential for evaporationTo occur all year round increases
The lake ecology can be affected all year round by ice loss. A spring that has ice broken up earlier can lead to a better ecosystem. Open-water season longerAnd Summer water temperatures warmer.
Warmer temperatures, less ice cover and more storm events bring more nutrients to the lakes, which leads to widespread summer. blue-green algal bloomsCyanobacterial blooms are also known as cyanobacterial flowers. They were once believed to be impossible in the cold, deep, and pristine waters at Lake Superior.
Some lakes have algal blooms that are particularly thick. This reduces the amount sunlight reaching deeper water depths. Photosynthesis is reduced when there is less sunlight. This ultimately leads to a decrease of the concentration of Dissolved oxygenSupport aquatic life with our support services
Long winters are important for some fish communities. For example, short winters are a good idea. Perch Lake Erie yellowThey produced smaller eggs and less healthy young fish, which were less likely than others to survive to adulthood. The most sensitive stages of fish life to temperature changes are those that occur in the first part of the open-water seasons. Embryos and spawning adults. A later start to summer, i.e., due earlier ice loss, can lead to mismatches in the timing and consequences for critical activities such as spawning or foraging. This can often have wide-ranging ramifications across all aspects of the food web.
A future without lake-ice
Global warming caused by anthropogenic climate changes is causing temperatures to rise. 215,000 lakes might not freeze every winterNearly 5,700 lakes will lose their ice by the end century. Large and deep lakes like Lakes Michigan or Superior are more likely than others to lose their ice.If global air temperatures continue rising, it could be as early as 2060s
Our researchEvidence has shown that lake ice cover has been declining worldwide over the past decade. Only be explainedby an increase in greenhouse gas emissions since before the Industrial Revolution. There is There is no magic solutionLimiting greenhouse gas emissions is not enough to slow climate change or preserve the lake-ice cover.
The ice cover is a way of life for northern communities in winter. Many Canadian kids have learned how skate and play hockey at nearby lakes and ponds. hockey legend, Wayne Gretzky, did in Brantford, Ont. Outdoors are becoming shorter due to warmer winters Ice hockeyAnd Skating seasons.
Ice fishing tournaments are being cancelled more often, which has a wide impact on local economies. For example, the Lake Winnipeg winter ice fishing seasons generates more than $1.7 billion annually. $200 millionEach year.
The increasing instability and inconsistency of the ice cover is a safety risk and is contributing to Increased winter drowningsThrough the ice in northern countries northern Indigenous communities at most risk.
For the Shintos living and working in Suwa, preserving the ice cover is crucial to preserve the spiritual traditions of generations of Shinto priests. Climate projections project that the lake will grow at current greenhouse gas emissions. It is rare for things to freeze in the near future. After 2040, it will not happen again..
Takeminakata, however, will be able to cross the frozen lakes to visit Yasakatome every so often if climate change slows down.