Regional/Local Impacts of Global Warming in the Great Lakes

[wdmn]

Here is my two week update on Lake Superior ice cover and my modified forecast for the rest of the season.

From my post #97 above:

"The four best analog years indicate a wide range of possibilities for this year, from about 19% maximum cover to 63%, with three of the four being within the 19-27% range. Unfortunately due to the large uncertainty in the 2 week forecast, it would be folly to make a more constrained prediction. However, the current best bet is in the range of 20%-40%, with lake max ice reaching 9 - 25% in January."

The ice is behaving pretty well this year. It just reached a new maximum extent of about 13% (image 1), which places it right in line with the predicted Jan. max of 9-25%. This also places it right on the best-fit model of past data, with 33 extreme cold days counted across the three stations so far. Though it may grow further, the forecast suggests the prime ice forming days this month are behind us, and I don't think it will make it to the 25% upper threshold before declining some.

I do not have a good sense of what to expect from weather in February. An average year would see about 21 extreme cold days across the three stations in February. We are also forecast to get a few more before the end of January, which could mean we hit about 60 days this year, or a maximum extent of about 58%, which would fall near the upper end of our first prediction, but outside of the best-bet range.

However, the better analog years, and the 2 week forecast still suggest a lower maximum extent, so I am sticking with the range of 19-63% but moving the current best bet up slightly to between 28-48%.

This puts me close, but not exactly in line with the NOAA GLERL modeling, which predicted a max of 52.3% for Lake Superior earlier this week: https://noaaglerl.blog/2022/01/19/forecasting-maximum-great-lakes-ice-cover-in-2022/

I'll check back in 2 weeks.

[gerontocrat]

Since 13th February - the data used in the article below - ice cover has recovered somewhat, rising from 7% to 19.4 % by the 25th February. I guess the new ice is very thin.

https://research.noaa.gov/article/ArtMID/587/ArticleID/2941/Low-ice-on-the-Great-Lakes-this-winter
Low ice on the Great Lakes this winter
Ice coverage has reached a record low in the Great Lakes for this time of year.

As of February 13, 2023, only 7 percent of these five freshwater lakes was covered in ice, which is significantly below the 35-40 percent ice cover that is expected for this time of year, according to NOAA’s Great Lakes Environmental Research Laboratory (GLERL).

Ice extent across the basin briefly jumped up to 21 percent in early February in response to a cold snap, but has been declining since. Maximum ice cover typically occurs between mid-February and early March.

Air temperatures are the main factor affecting ice cover on the Great Lakes, and a warmer than average January contributed to the lack of ice. According to the U.S. National Ice Center, each of the five lakes experienced warmer than average air temperatures in January. In addition, it was an especially warm January across the contiguous U.S.: The average temperature was 35.2 degrees F (5.1 degrees above average) according to NOAA, and January 2023 Earth’s seventh-warmest January on record.

Although there is year-to-year variability in the ice cover of the lakes, NOAA research has found that in recent years ice cover is in a downward trend. An analysis led by Jia Wang, an ice climatologist at NOAA's GLERL, found significant declines in average ice cover of the Great Lakes between 1973 and 2017. During the winter period of those 44 years, which runs from December 1 to April 30, average ice cover on the Great Lakes declined about 70 percent.

Ice cover protects the shoreline of lakes – without it, high waves can scour the coastline and cause severe flooding.

Low ice coverage on the lakes can be a set up for large severe “lake effect” snow storms, says Ayumi Fujisaki-Manome, a researcher at NOAA’s Cooperative Institute for Great Lakes Research at the University of Michigan. “The moisture and heat from the lake surface water are absorbed into the atmosphere by storm systems, and then fall back to the ground as snow in the winter. When ice is not present, we can end up with big snow storms like those that hit Buffalo, New York in December.

Although human-caused warming plays a role in this decline, other key factors contributing to reduced ice loss are long-term patterns of climate variability over the Pacific and Atlantic oceans. Four patterns of climate variability are contributing to ice cover changes: the North Atlantic Oscillation, the Atlantic Multidecadal Oscillation, the Pacific Decadal Oscillation, and the El Niño-Southern Oscillation.

“Each year, we have to look at these four patterns to model ice cover,” said Wang. “Right now, the Pacific Decadal Oscillation together with the North Atlantic Oscillation are causing warming in the Great Lakes.”

GLERL will continue to monitor the ice levels, and will announce end-of-season ice extent later this year.

For more information, please contact Alison Gillespie, NOAA Communications, at alison.gillespie@noaa.gov

Attachments source: https://coastwatch.glerl.noaa.gov/ice.html

[gerontocrat]

NSIDC in their April 5 Report on Sea Ice also has a section on the US Great Lakes Winter Ice
(see https://nsidc.org/arcticseaicenews/)

The decline continues....

click attached image to enlarge

[The Walrus]

NSIDC in their April 5 Report on Sea Ice also has a section on the US Great Lakes Winter Ice
(see https://nsidc.org/arcticseaicenews/)

The decline continues....

click attached image to enlarge

That amounts to 6th lowest in the 60-yr NOAA record base.

https://noaaglerl.blog/2021/02/04/five-decades-of-great-lakes-ice-cover-data-and-where-to-find-it/

[neal]

low ice in great lakes, again

[gerontocrat]

Very low sea ice in the Great Lakes in January.
Even if it recovers this month, it must be thin and easily melt.
Canada & the North of the USA seem to have had a warm winter overall.

https://www.theguardian.com/environment/2024/feb/12/great-lakes-average-ice-cover

Great Lakes average ice cover drops to 6%, one of lowest levels ever recorded

Scientists say global heating is driving ice loss and warmer water, as ice cover falls short of 50-year average of 18%

The average ice cover over the five Great Lakes was just 6% last month, placing it among the least icy Januarys since records began 50 years ago, according to the National Oceanic and Atmospheric Administration (Noaa).

The Great Lakes – Superior, Huron, Michigan, Erie and Ontario – are located at or near the US-Canada border, and are connected by a network of smaller lakes and rivers that span a combined surface area of 95,000 sq miles, making it the largest freshwater system in the world.

While some year-to-year variation in ice cover is normal, scientists say global heating is driving ice loss and warmer water temperatures, and is likely to worsen if no action is taken soon.

“In direct response to warming air temperatures, we are observing rapid ice loss and warming summer water temperatures,” said Professor Sapna Sharma, an expert in environmental stressors on lakes at York University in Toronto. “If the planet continues to warm, 215,000 lakes may no longer freeze every winter and almost 5,700 lakes may permanently lose ice cover by the end of the century.”

The Great Lakes hold more than 20% of Earth’s freshwater, with half of that in Lake Superior, the largest and most northerly of the five. Ice records show a 25% drop in basin-wide ice cover, and a trend toward fewer frozen days across the Great Lakes since 1973.

“There is a trend: a 5% decline in average ice cover per decade, which may not sound huge but it is a substantial decrease,” said James Kessler, a physical scientist and ice expert at Noaa’s Great Lakes Environmental Research Lab.

“Open [unfrozen] lakes bring more rain rather than snow, which has knock-on environmental, cultural and societal impacts.”

Some areas have been hit worse than others. Ice records dating back to 1857 show that several bays on Lake Superior froze every winter until about 1997. Since then, as global heating has intensified, some have experienced entirely ice-free winters.

“The Great Lakes are now experiencing much lower ice cover, but in many regions, no ice at all. Large and deep lakes, including bays in Lakes Michigan and Superior, are most likely to permanently lose ice cover as soon as the 2060s if greenhouse gas emissions are not mitigated,” said Sharma.

The depth and breadth of the water system means what happens in the Great Lakes doesn’t stay in the Great Lakes. In years with less or no ice cover, the lakes experience higher evaporation rates, warmer water and lower oxygen levels, making it harder for native coldwater fish to thrive and causing a knock-on effect on the entire food chain. Increased evaporation rates lead to lower water levels and fewer wetlands in the surrounding areas, adding stress on animal species already struggling to find food and adapt to warmer temperatures.

The snow and ice are key to Great Lakes culture and tourism, and the region boasts outdoor activities such as tobogganing, outdoor skating, dog sledding and ice fishing, as well as a multibillion-dollar snow removal industry. In warmer winters recreational activities are canceled, tourism takes a hit and drownings rise due to the unstable ice.

Less ice also frees hundreds of cargo ships to traverse the Great Lakes all year round, and means fewer ice breakers to clear shipping channels, saving money for the commercial shipping industry.

[trm1958]

AS I live in the GL region, I wonder what an AMOC collapse would mean for the climate this far west of the Gulf Stream?