By Kathiann Kowalski for Inside Climate News.
Broadcast version by Farah Siddiqi for Ohio News Connection reporting for the Solutions Journalism Network-Public News Service Collaboration

Lake Erie's harmful algal blooms have started sooner and had longer peak periods over the past decade compared to earlier years, newly released data shows. Warming temperatures linked to climate change are a cause, according to researchers for NOAA's National Centers for Coastal Ocean Science, with interactions among species likely playing a role as well.

The NOAA scientists discussed the shift and forecast a moderate to above-moderate algal bloom for the lake's western basin this summer during a briefing last month at Ohio State University and Ohio Sea Grant's Stone Laboratory, off the coast of Put-in-Bay on Lake Erie.

Algal blooms occur when cyanobacteria, or blue-green algae, grow out of control due to a combination of excess nutrients, weather patterns and other ecological factors. The blooms can be a serious public health problem because some types of cyanobacteria produce toxins. Microcystin, for example, can lead to skin rashes, gut problems and liver and kidney issues. Relatively high levels of it in August 2014 prompted a two-day shutdown of Toledo's public water supply, which comes from Lake Erie.

"We were certainly caught off guard, and the impact was hundreds of thousands of people were without drinking water," said Sean Corson, director of the National Centers for Coastal Ocean Science. The total economic impact of the 2014 water crisis was around $65 million, he said.

Even when toxic strains aren't the problem, algal blooms can still affect Ohio's lake-focused businesses and other activities. Aside from the ugliness of neon green scum, people can't distinguish between toxic and non-toxic strains by eye. Such uncertainty discourages lake-based activities, such as beach visits and fishing. Blooms also add to costs for water treatment plants.

Out-of-control cyanobacteria don't provide good eating for the rest of the lake's food web, either. And they contribute to so-called dead zones, areas with very low levels of dissolved oxygen that can't support aquatic life.

For more than a decade, NOAA has worked with partners in the state, including the Ohio Sea Grant Program, the National Center for Water Quality Research at Heidelberg University, the Ohio State University and the University of Toledo, to forecast the severity of the blooms in Lake Erie's western basin. It's the shallowest part of the lake, with abundant fish. Water is likely to warm faster and blooms flourish there more readily than elsewhere in the lake. Water in Lake Erie generally moves from west to east.

Last year's bloom was significantly larger than the smaller-than-average event researchers had predicted. So the forecast team took a closer look at the data.

From 2012 through 2023, Lake Erie's algal blooms have generally started in July, compared to the previous decade when blooms usually kicked in during August, said NOAA oceanographer Rick Stumpf, who plays a leading role in the forecasting program. The lake's algal blooms during the past decade also have had longer peak periods, resembling plateaus instead of short spikes.

"Blooms are starting earlier. They're lasting longer. Their peaks are larger. So, by some measures, they're getting worse," Corson said.

"Temperature is the overall driver," Stumpf said, noting ongoing trends of warmer summers and less ice cover in winters. But it's not a simple matter of warmer water producing the changes. The team's current hypothesis is that the shift to earlier algae blooms with longer peak periods reflects both climate change and ecological interactions.

Diatoms are a type of single-cell algae found in Lake Erie, which play an important part in its food webs. They generally outcompete cyanobacteria for nutrients early in the season, when water is cooler, Stumpf explained. The diatoms provide good eating for tiny lake organisms called zooplankton. Changing conditions in the lake could be increasing the degree to which the zooplankton multiply and feast on the diatoms, perhaps suppressing their populations sooner than in earlier years. By the time that happens, cyanobacteria, which prefer warmer water anyway, may have a clearer path to use extra nutrients in the water and grow out of control.

Research is ongoing to better understand what's been happening, Stumpf said. It could help fine-tune future forecasts. But climate change is definitely a factor in the mix.

"We know that climate is changing. We know that this is happening in states here in the Great Lakes region," Corson said. Changes in Ohio include a trend toward warmer average temperatures and more intense rainfall that usually increases stormwater runoff.

When soil can't absorb that runoff, it carries nutrients from fertilizers into waterways, along with other pollution. Fertilizer runoff from farms is a major source of both phosphorus and nitrogen, although some amounts also come from places like golf courses and suburban subdivisions.

Researchers are seeing shifts in algal bloom patterns elsewhere in the United States. But "changes are really specific to the individual area where you are," Corson said. Many coastal areas are experiencing warming trends and changes in precipitation patterns, along with shifts in land use that increase the amount of impervious surfaces. "Those are all occurring, and the shapes of the blooms are changing as well," he said.

The Outlook This Summer

The severity of Lake Erie's algal blooms varies from year to year. Factors include the levels of nutrient loading from the Maumee River basin, which covers a large part of northwestern Ohio, along with smaller areas in Indiana and Michigan.

The basin accounts for nearly half of the total phosphorus going into Lake Erie's western basin each year, according to Laura Johnson, who heads the National Center for Water Quality Research. She and others are especially interested in the amount of bioavailable phosphorus reaching the lake's western basin each year. Bioavailable means the phosphorus is in a form algae can use.

Estimates for that loading each spring come from flow data and chemical analyses of samples pulled at stream monitoring equipment in Waterville, which accounts for roughly 96 percent of the watershed. More than 60 percent of the area's total bioavailable phosphorus loading from March 1 through June 23 happened in April, Johnson said.

That month was the wettest on record for the region, and more rainfall generally means more fertilizer runoff. However, it was also a mild winter. Relatively dry soils could absorb a fair amount of the runoff, which prevented "crazy flash floods," Johnson said. Some phosphorus remains in the lake from prior years' discharges.

Stumpf and his team fed information from Johnson's group and other data into three models to estimate how severe this year's algal bloom will be on a scale from 1 to 10. "Three models give you a better chance of bracketing the right result," Stumpf explained.

This year's work also reflects a tweak to account for the changing pattern of earlier starts and longer peaks for Lake Erie's algal blooms. "Now we're training those models on data from 2013 to 2023," Stumpf said. The more current data should improve the models' results.

For this year, NOAA predicted a Level 5 bloom, with a range of 4.5 to 6. Fortunately, Corson said, technology continues to improve ongoing monitoring of algal blooms. Water treatment plants' technology has improved as well, he noted.

"The bloom isn't all over the lake all the time," Stumpf stressed. Wind patterns and other factors determine which areas are affected at any particular time. Checking NOAA's updated forecasts can help for planning recreational activities.

"That's going to show you where the bloom is going," said Chris Winslow, director of Ohio Sea Grant and Ohio State University's Stone Laboratory. The Ohio Department of Health's BeachGuard webpage also reports sampling results for cyanobacteria toxins and E. coli bacteria.

Researchers also advise common sense. If the water appears green and scummy, "keep yourself, your kids and your pets out of the water," Stumpf said. Not all algal blooms have high levels of the toxin-producing strains, but it's not worth taking chances.


Kathiann Kowalski wrote this article for Inside Climate News.


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New Mexico's decades-long drought combined with climate change have more farmers and ranchers embracing the six healthy soil principles, tailoring how each parcel of land is managed.

New Mexico's farming practices date back at least 2,500 years but the state's Healthy Soil Working Group said the arid climate and diverse ecology make a one-size-fits-all approach ineffective.

Dave Dubois, climatologist at New Mexico State University, said the recent storm should improve this year's snowpack but farmers and ranchers must plan five or 10 years into the future.

"The scenarios from climate change models are showing warmer temperatures, hotter droughts and then more evaporation," Dubois explained. "How do you manage all that in a system where we still have agriculture as our cultural identity?"

Agriculture is the state's third-largest industry after energy and aerospace. The majority of New Mexico's farmland is heavily dedicated to growing grass, which feeds livestock, provides sod and serves as a cover crop to protect soil health between harvests.

Many factors contribute to soil degradation: intensive farming practices, deforestation, overgrazing, urbanization and erosion.

Ernest Diswood, a Navajo conservation leader, said using regenerative techniques, he has been improving his range soil since 2009.

"We're seeing, despite the drought now, about 21 species of grasses and we're probably between 700 to 1,000 pounds an acre," Diswood outlined. "For the Navajo Indian Reservation, that's usually a pretty good number."

Keeping soil covered is one of the six healthy soil principles.

Ralph Vigil, owner of Molino de la Isla Organics and an eighth-generation acequia farmer, changed his practices nearly 20 years ago. A lack of moisture led him to reduce the East Pecos land where he grows organic vegetables from five acres, to a half-acre. To improve the soil, he now uses drip irrigation and other conservation techniques.

"The acequia sees less water; I've done more cover-cropping to try to help build my soil, keeping my cover present at all seasons because (of) no snowpack, lack of rain and wind," Vigil emphasized. "Wind is beating us up and it doesn't go away. So, just trying to keep that soil covered at all times."

Significant cuts made by the Trump administration to the Natural Resources Conservation Service are expected to reduce climate-friendly programs nationwide.


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Nine in ten people in Colorado and across the globe are worried about climate change and want governments to do something about it, according to a new survey, but they mistakenly assume that others do not share their view.

Anthony Leiserowitz, director of the Yale Program on Climate Change Communication, called this a perception gap.

"The average person believes that other people in their own country tend not to worry about climate change that much when, in fact, the majority of people in most countries do worry about climate change," he said.

That gap in perception has real-world policy implications. In the U.S., almost 80% of congressional staffers underestimated their constituents' support for reducing climate pollution, sometimes by more than 50 percentage points. Leiserowitz said helping more people understand that they are not in the minority could unlock a social tipping point that moves leaders to act.

He pointed to one example where 96% of liberal Democrats and 78% of conservative Republicans supported helping farmers protect and restore soil to absorb more carbon dioxide. But he said progress is stymied by misperceptions.

"If your perception is that Republicans are absolutely against climate policy, then many people might then conclude - especially if you're a policy maker - that we shouldn't be taking action when, in fact there's overwhelming support, even among conservative Republicans," he continued.

Decades of misinformation campaigns, aiming to protect fossil-fuel company profits, play a big role in perception gaps. But Leiserowitz said gaps also persist because any two individuals, not knowing what the other thinks, are likely to avoid topics they believe are controversial, including climate change.

"So, that leads neither of us to talk about it. Well, now expand that to 300 million people, and you can see that we start slipping down this 'spiral of silence.' Nobody talks about it, so nobody talks about it. Which means nobody talks about it," he concluded.


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As Boulder and local governments across the U.S. turn to courts to pay for rebuilding after wildfires, floods and other extreme weather events linked to a changing climate, a new study shows it is now possible to pinpoint specific companies that could be held accountable.

Justin Mankin, associate professor of geography at Dartmouth College and study coauthor, said using advanced modeling, his team calculated a price tag for the impacts of extreme heat, just one climate hazard, linked to carbon dioxide and methane emissions from 111 companies over 30 years.

"The world would be $28 trillion more wealthy had those companies found ways to mitigate the extreme heat impacts of those emissions," Mankin reported.

Researchers found 10 fossil-fuel companies - including Chevron, ExxonMobil and Saudi Aramco - were responsible for half of the total losses.

Oil and gas companies have argued in court it was not possible to assign blame to their company's carbon or methane molecules in the atmosphere compared with all the other molecules released. They have also noted oil and gas production has produced numerous public benefits and wealth.

Using emissions data and advanced climate models, Mankin pointed out it is now possible to see what the world would look like if any particular corporation had not produced emissions. He added other industries have not gotten off the hook, including "Big Pharma," just because they produced breakthrough medicines and vaccines.

"That doesn't absolve them for their role in, say, generating the opioid crisis," Mankin contended. "Courts have ruled that they had a role in generating the opioid crisis, and needed to compensate harmed individuals for that."

Hundreds of lawsuits have been filed to hold corporations and trade associations accountable for climate damages. Colorado's Supreme Court has heard oral arguments but has not yet ruled on a case brought by San Miguel County and the city and county of Boulder seeking compensation from ExxonMobil and Suncor Energy.


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