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Opinion

When black roofs cost more and most negatively affect our health, why are we installing them?

Published

8 years ago

12 minute read

We are into construction season and summer and the heat is starting to be an issue. We will have some heat waves and we will notice the “Urban Heat Island Effect”.
The city will seem hotter than the county, but we will also notice differences in temperature between light coloured vehicles and darker coloured vehicles, and even the coolness of a white fence.
During heat waves some of the most vulnerable people are those living on the top floor of a building with a black roof.
My biggest question is why are we still putting black roofs on our buildings? Black roofs do not absorb heat in the winter under a foot of white snow. They absorb heat during the hot days making it hotter.

Let’s start at the beginning, by hitting the Google button.

What is the Heat Island Effect?
The elevated temperature in urban areas as compared to rural, less developed areas is referred to as the urban heat island effect. As cities grow and develop, more buildings and people are added. The process of urban development leads to this phenomenon.

What are the Implications of Heat Islands?
Heat islands are considered a form of local climate change as opposed to global climate change. The effects of heat islands are confined to specific areas, and do not have a larger impact on climate change. Despite being confined to a certain locality, heat islands can still make a significant impact.
Of course, one of the most noticeable impacts on urban dwellers is an increase in hot, summer weather. On particularly clear and hot days, when the heat island effect is at its worst, inhabitants of larger cities will notice hotter and more uncomfortable temperatures. When people are hot, they often crank up their air conditioners. Increases in air conditioning use not only results in more heat being released into the air, this also contributes to air pollution, as more greenhouse gas emissions are discharged. This negatively impacts air quality and can also lead to a surge in urban smog.
How Can We Reduce the Heat Island?
Since the impact of heat islands is mostly negative, scientists and researchers are searching for ways to reduce and reverse the effects. Dark roof surfaces are one of the major culprits of temperature increases. One popular technique for combating the heat island effect is installing green roofs on urban buildings. Green roofs, which are lined with soil and certain types of vegetation, can actually help cities regain some of the cooling and evaporative effects that the natural landscape once provided. As this idea becomes more popular, there is more and more scientific evidence that green roofs can reduce heat in urban areas.
Dark building surfaces that absorb more heat account for some of the rising temperatures in urban areas. One simple method for reducing this effect is to paint buildings with light or white colors that do not absorb nearly as much heat. Some cities are also using paint treatments that reflect light to combat the heat island effect. White, Green or Black Roofs? Berkeley Lab Report Compares Economic Payoffs
Looking strictly at the economic costs and benefits of three different roof types—black, white and “green” (or vegetated)—Lawrence Berkeley National Laboratory (Berkeley Lab) researchers have found in a new study that white roofs are the most cost-effective over a 50-year time span. While the high installation cost of green roofs sets them back in economic terms, their environmental and amenity benefits may at least partially mitigate their financial burden.
A new report titled “Economic Comparison of White, Green, and Black Flat Roofs in the United States” by Julian Sproul, Benjamin Mandel, and Arthur Rosenfeld of Berkeley Lab, and Man Pun Wan of Nanyang Technological University in Singapore, provides a direct economic comparison of these three roof types. The study will appear in the March 2014 volume of Energy and Buildings and has just been published online. “White roofs win based on the purely economic factors we included, and black roofs should be phased out,” said study co-author Rosenfeld, a Berkeley Lab Distinguished Scientist Emeritus and former Commissioner of the California Energy Commission
The study analyzes 22 commercial flat roof projects in the United States in which two or more roof types were considered. The researchers conducted a 50-year life cycle cost analysis, assuming a 20-year service life for white and black roofs and a 40-year service life for green roofs.
A green roof, often called vegetated roofs or rooftop gardens, has become an increasingly popular choice for aesthetic and environmental reasons. Rosenfeld acknowledges that their economic analysis does not capture all of the benefits of a green roof. For example rooftop gardens provide storm water management, an appreciable benefit in cities with sewage overflow issues, while helping to cool the roof’s surface as well as the air. Green roofs may also give building occupants the opportunity to enjoy green space where they live or work.
Berkeley Lab Distinguished Scientist Emeritus Art Rosenfeld
“We leave open the possibility that other factors may make green roofs more attractive or more beneficial options in certain scenarios,” said Mandel, a graduate student researcher at Berkeley Lab. “The relative costs and benefits do vary by circumstance.”
However, unlike white roofs, green roofs do not offset climate change. White roofs are more reflective than green roofs, reflecting roughly three times more sunlight back into the atmosphere and therefore absorbing less sunlight at earth’s surface. By absorbing less sunlight than either green or black roofs, white roofs offset a portion of the warming effect from greenhouse gas emissions.
“Both white and green roofs do a good job at cooling the building and cooling the air in the city, but white roofs are three times more effective at countering climate change than green roofs,” said Rosenfeld.
White roofs are most cost-effective
The costs and benefits difference stack that has the highest net present value shows the roof type that is most cost-effective.
The 50-year life-cycle cost analysis found that even the most inexpensive kind of green roof (with no public access and consisting of only sedum, or prairie grass) costs $7 per square foot more than black roofs over 50 years, while white roofs save $2 per square foot compared to black roofs. In other words, white roofs cost $9 per square foot less than green roofs over 50 years, or $0.30 per square foot each year.
The researchers acknowledge that their data are somewhat sparse but contend that their analysis is valuable in that it is the first to compare the economic costs and energy savings benefits of all three roof types. “When we started the study it wasn’t obvious that white roofs would still be more cost-effective over the long run, taking into account the longer service time of a green roof,” Mandel said.
Furthermore while the economic results are interesting, it also highlights the need to include factors such health and environment in a more comprehensive analysis. “We’ve recognized the limitations of an analysis that’s only economic,” Mandel said. “We would want to include these other factors in any future study.”
Black roofs pose health risk
For example, black roofs pose a major health risk in cities that see high temperatures in the summer. “In Chicago’s July 1995 heat wave a major risk factor in mortality was living on the top floor of a building with a black roof,” Rosenfeld said.
For that reason, he believes this latest study points out the importance of government policymaking. “White doesn’t win out over black by that much in economic terms, so government has a role to ban or phase out the use of black or dark roofs, at least in warm climates, because they pose a large negative health risk,” he said.
Rosenfeld, who started at Berkeley Lab in the 1950s, is often called California’s godfather of energy efficiency for his pioneering work in the area. He was awarded a National Medal of Technology and Innovation by President Obama in 2012, one of the nation’s highest honours.
Rosenfeld has been a supporter of solar-reflective “cool” roofs, including white roofs, as a way to reduce energy costs and address global warming. He was the co-author of a 2009 study in which it was estimated that making roofs and pavements around the world more reflective could offset 44 billion tons of CO2 emissions. A later study using a global land surface model found similar results: cool roofs could offset the emissions of roughly 300 million cars for 20 years.
So if black roofs are detrimental to our health, contribute to the issue of Urban Heat Island Effect and costs more, why are we still building black roofs?

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Canada’s river water quality strong overall although some localized issues persist

Published on December 22, 2025

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From the Fraser Institute

By Annika Segelhorst and Elmira Aliakbari

Canada’s rivers are vital to our environment and economy. Clean freshwater is essential to support recreation, agriculture and industry, an to sustain suitable habitat for wildlife. Conversely, degraded freshwater can make it harder to maintain safe drinking water and can harm aquatic life. So, how healthy are Canada’s rivers today?

To answer that question, Environment Canada uses an index of water quality to assess freshwater quality at monitoring stations across the country. In total, scores are available for 165 monitoring stations, jointly maintained by Environment Canada and provincial authorities, from 17 in Newfoundland and Labrador, to 8 in Saskatchewan and 20 in British Columbia.

This index works like a report card for rivers, converting water test results into scores from 0 to 100. Scientists sample river water three or more times per year at fixed locations, testing indicators such as oxygen levels, nutrients and chemical levels. These measurements are then compared against national and provincial guidelines that determine the ability of a waterway to support aquatic life.

Scores are calculated based on three factors: how many guidelines are exceeded, how often they are exceeded, and by how much they are exceeded. A score of 95-100 is “excellent,” 80-94 is “good,” 65-79 is “fair,” 45-64 is “marginal” and a score below 45 is “poor.” The most recent scores are based on data from 2021 to 2023.

Among 165 river monitoring sites across the country, the average score was 76.7. Sites along four major rivers earned a perfect score: the Northeast Magaree River (Nova Scotia), the Restigouche River (New Brunswick), the South Saskatchewan River (Saskatchewan) and the Bow River (Alberta). The Bayonne River, a tributary of the St. Lawrence River near Berthierville, Quebec, scored the lowest (33.0).

Overall, between 2021 and 2023, 83.0 per cent of monitoring sites across the country recorded fair to excellent water quality. This is a strong positive signal that most of Canada’s rivers are in generally healthy environmental condition.

A total of 13.3 per cent of stations were deemed to be marginal, that is, they received a score of 45-64 on the index. Only 3.6 per cent of monitoring sites fell into the poor category, meaning that severe degradation was limited to only a few sites (6 of 165).

Monitoring sites along waterways with relatively less development in the river’s headwaters and those with lower population density tended to earn higher scores than sites with developed land uses. However, among the 11 river monitoring sites that rated “excellent,” 8 were situated in areas facing a combination of pressures from nearby human activities that can influence water quality. This indicates the resilience of Canada’s river ecosystems, even in areas facing a combination of multiple stressors from urban runoff, agriculture, and industrial activities where waterways would otherwise be expected to be the most polluted.

Poor or marginal water quality was relatively more common in monitoring sites located along the St. Lawrence River and its major tributaries and near the Great Lakes compared to other regions. Among all sites in the marginal or poor category, 50 per cent were in this area. The Great Lakes-St. Lawrence region is one of the most population-dense and extensively developed parts of Canada, supporting a mix of urban, agricultural, and industrial land uses. These pressures can introduce harmful chemical contaminants and alter nutrient balances in waterways, impairing ecosystem health.

In general, monitoring sites categorized as marginal or poor tended to be located near intensive agriculture and industrial activities. However, it’s important to reiterate that only 28 stations representing 17.0 per cent of all monitoring stations were deemed to be marginal or poor.

Provincial results vary, as shown in the figure below. Water quality scores in Newfoundland and Labrador, Prince Edward Island, New Brunswick, Saskatchewan and Alberta were, on average, 80 points or higher during the period from 2021 to 2023, indicating that water quality rarely departed from natural or desirable levels.

Rivers sites in Nova Scotia, Ontario, Manitoba and B.C. each had average scores between 74 and 78 points, suggesting occasional departures from natural or desirable levels.

Finally, Quebec’s average river water quality score was 64.5 during the 2021 to 2023 period. This score indicates that water quality departed from ideal conditions more frequently in Quebec than in other provinces, especially compared to provinces like Alberta, Saskatchewan and P.E.I. where no sites rated below “fair.”

Overall, these results highlight Canada’s success in maintaining a generally high quality of water in our rivers. Most waterways are in good shape, though some regions—especially near the Great Lakes and along the St. Lawrence River Valley—continue to face pressures from the combined effects of population growth and intensive land use.

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Agriculture

End Supply Management—For the Sake of Canadian Consumers

Published on December 22, 2025

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This is a special preview article from the:

By Gwyn Morgan

U.S. President Donald Trump’s trade policy is often chaotic and punitive. But on one point, he is right: Canada’s agricultural supply management system has to go. Not because it is unfair to the United States, though it clearly is, but because it punishes Canadians. Supply management is a government-enforced price-fixing scheme that limits consumer choice, inflates grocery bills, wastes food, and shields a small, politically powerful group of producers from competition—at the direct expense of millions of households.

And yet Ottawa continues to support this socialist shakedown. Last week, Prime Minister Mark Carney told reporters supply management was “not on the table” in negotiations for a renewed United States-Mexico-Canada Trade Agreement, despite U.S. negotiators citing it as a roadblock to a new deal.

Supply management relies on a web of production quotas, fixed farmgate prices, strict import limits, and punitive tariffs that can approach 300 percent. Bureaucrats decide how much milk, chicken, eggs, and poultry Canadians farmers produce and which farmers can produce how much. When officials misjudge demand—as they recently did with chicken and eggs—farmers are legally barred from responding. The result is predictable: shortages, soaring prices, and frustrated consumers staring at emptier shelves and higher bills.

This is not a theoretical problem. Canada’s most recent chicken production cycle, ending in May 2025, produced one of the worst supply shortfalls in decades. Demand rose unexpectedly, but quotas froze supply in place. Canadian farmers could not increase production. Instead, consumers paid more for scarce domestic poultry while last-minute imports filled the gap at premium prices. Eggs followed a similar pattern, with shortages triggering a convoluted “allocation” system that opened the door to massive foreign imports rather than empowering Canadian farmers to respond.

Over a century of global experience has shown that central economic planning fails. Governments are simply not good at “matching” supply with demand. There is no reason to believe Ottawa’s attempts to manage a handful of food categories should fare any better. And yet supply management persists, even as its costs mount.

Those costs fall squarely on consumers. According to a Fraser Institute estimate, supply management adds roughly $375 a year to the average Canadian household’s grocery bill. Because lower-income families spend a much higher proportion of their income on food, the burden falls most heavily on them.
The system also strangles consumer choice. European countries produce thousands of varieties of high-quality cheeses at prices far below what Canadians pay for largely industrial domestic products. But our import quotas are tiny, and anything above them is hit with tariffs exceeding 245 percent. As a result, imported cheeses can cost $60 per kilogram or more in Canadian grocery stores. In Switzerland, one of the world’s most eye-poppingly expensive countries, where a thimble-sized coffee will set you back $9, premium cheeses are barely half the price you’ll find at Loblaw or Safeway.

Canada’s supply-managed farmers defend their monopoly by insisting it provides a “fair return” for famers, guarantees Canadians have access to “homegrown food” and assures the “right amount of food is produced to meet Canadian needs.” Is there a shred of evidence Canadians are being denied the “right amount” of bread, tuna, asparagus or applesauce? Of course not; the market readily supplies all these and many thousands of other non-supply-managed foods.

Like all price-fixing systems, Canada’s supply management provides only the illusion of stability and security. We’ve seen above what happens when production falls short. But perversely, if a farmer manages to get more milk out of his cows than his quota, there’s no reward: the excess must be
dumped. Last year alone, enough milk was discarded to feed 4.2 million people.

Over time, supply management has become less about farming and more about quota ownership. Artificial scarcity has turned quotas into highly valuable assets, locking out young farmers and rewarding incumbents.

Why does such a dysfunctional system persist? The answer is politics. Supply management is of outsized importance in Quebec, where producers hold a disproportionate share of quotas and are numerous enough to swing election results in key ridings. Federal parties of all stripes have learned the cost of crossing this lobby. That political cowardice now collides with reality. The USMCA is heading toward mandatory renegotiation, and supply management is squarely in Washington’s sights. Canada depends on tariff-free access to the U.S. market for hundreds of billions of dollars in exports. Trading away a deeply-flawed system to secure that access would make economic sense.

Instead, Ottawa has doubled down. Not just with Carney’s remarks last week but with Bill C-202, which makes it illegal for Canadian ministers to reduce tariffs or expand quotas on supply-managed goods in future trade talks. Formally signalling that Canada’s negotiating position is hostage to a tiny domestic lobby group is reckless, and weakens Canada’s hand before talks even begin.

Food prices continue to rise faster than inflation. Forecasts suggest the average family will spend $1,000 more on groceries next year alone. Supply management is not the only cause, but it remains a major one. Ending it would lower prices, expand choice, reduce waste, and reward entrepreneurial farmers willing to compete.

If Donald Trump can succeed in forcing supply management onto the negotiating table, he will be doing Canadian consumers—and Canadian agriculture—a favour our own political class has long refused to deliver.

The original, full-length version of this article was recently published in C2C Journal. Gwyn Morgan is a retired business leader who was a director of five global corporations.

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