How Reflective Paint Brings Down Scorching City Temperatures
Communities fight urban heat islands with technologies shielding roofs and pavement
3 min
Cities across the U.S. have found relief from this summer’s record-setting heat with the help of technologies that shield roofs, pavement and other surfaces from the sun’s scorching rays.
Some of these technologies have been around for more than a decade but are experiencing greater demand as global temperatures rise. Washington, D.C., for example, has built more than 3,200 green roofs covering 9 million square feet—up from about 300,000 square feet in 2006, according to federal and city officials.
Other technologies, such as super-reflective coatings for pavement, streets and windows, are just now becoming effective and affordable enough for widespread use.
The Los Angeles neighbourhood of Pacoima, a densely packed location sandwiched between freeways and an industrial area, has created a partnership with GAF, a New Jersey-based roofing manufacturer, to paint a basketball court, local park and neighbourhood streets with a reflective coating.
“There’s a lot of asphalt and lack of investment for tree canopies,” said Melanie Paola Torres, 24 years old, a community organiser with the group Pacoima Beautiful. “Given the fact that we are in an industrial zone, that contributes to the urban heat-island effect.”
The reflective coating has reduced air temperatures in the test area at 6 feet above ground by 3.5 degrees Fahrenheit during extreme heat days, and surface temperatures by 10 degrees, according to Jeff Terry, GAF’s vice president of corporate social responsibility and sustainability.
Sweltering conditions are worse in urban heat islands, which can be 10 degrees hotter than surrounding suburbs and occur as buildings, roads and other infrastructure absorb and re-emit the sun’s energy.
Cooling technologies mitigate this. Green roofs absorb heat before it penetrates the buildings beneath. Super-reflective coatings reflect the sun’s visible light and invisible infrared radiation away from surfaces to keep them cooler. And an ultra-white paint developed at Purdue University promises even more protection, although the product isn’t commercially available yet. Each strategy helps reduce energy use.
“The important thing is to help people cool their homes and workplaces affordably,” said Jane Gilbert, chief heat officer for Miami-Dade County, which experienced a record 46 straight days of a 100-degree-plus heat index this summer. “The more efficient we can make both the buildings and the AC systems themselves, the less we’re contributing both to greenhouse gases and also waste heat that goes to our urban heat islands.”
Miami is one of the most vulnerable cities to the urban heat-island effect, along with San Francisco, New York, Chicago and Seattle, according to an analysis by Climate Central, a New Jersey-based nonprofit that researches the effects of climate change. Its analysis found that 41 million people living in 44 cities face an urban heat-island effect of at least 8 degrees. Nine U.S. cities had at least one million people exposed to urban heat of 8 degrees or higher because of the local built environment.
To fight the heat, some cities are leveraging federal money and other incentives to persuade local builders to turn office buildings greener and cooler.
In Miami-Dade County, officials used federal funds to outfit 1,700 public housing units with new low-energy air-conditioning units. Local officials also offered a successful amendment to the Florida state building code requiring cool reflective roofs on all new commercial buildings beginning in 2024, and enrolled 150 structures in a voluntary energy-audit program to track improvements to cut energy use and keep temperatures down.
New York, Chicago, Philadelphia, Toronto and other cities are pushing green roofs with tax breaks and other incentives in an effort to lower energy bills and reduce ambient temperatures, according to Steven Peck, president of Green Roofs for Healthy Cities, a Toronto-based green-roof and -wall industry association. Peck said green roofs can be 30 to 40 degrees cooler than a similar-size blacktop roof, while also cutting waste heat from air-conditioning units.
In the Los Angeles neighbourhood of Pacoima, Torres says residents tell her the streets and playgrounds feel cooler since the reflective coating was completed in August 2022.
“The number-one thing that always comes up is the heat waves when you’re looking down the street,” Torres said. “They don’t see those anymore.”
The next step is to install reflective roofing material on a handful of homes as part of the neighbourhood cooling effort. “We want to keep stacking the solutions to overall create a cool community with multiple strategies,” Torres said.
Altering the urban landscape to adapt to extreme heat requires money and technical know-how, according to city leaders and academic experts. But they also acknowledge the need to keep people safe as global temperatures rise.
“Any one solution is not going to necessarily be able to address the entire problem, but by systematically applying solutions that work in each individual location, we can make a dent in the urban heat-island effect,” said David Sailor, professor of geographical sciences and urban planning at Arizona State University.
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OpenAI has shelved the planned launch of GPT-6.1 Astra after internal tests raised concerns about deception and agents acting beyond user authorization, according to The Wall Street Journal. The company says it will investigate the issues and strengthen safety measures before releasing future models.
4 min
OpenAI says it is scrapping the release of its next-generation AI model over safety concerns that researchers raised during internal testing, in one of the clearest signs so far that agent misbehavior could stymie the industry’s rapid progression.
The move follows a summer punctuated by reports of artificial-intelligence systems industrywide going rogue, and marks a rare case of a major AI developer ditching a new release because of safety concerns.
The company had planned to launch the model, known as GPT-6.1 Astra, in the coming days or weeks, aiming for an October debut. The model was more capable than the company’s previous models in completing challenging tasks from end-to-end without human assistance, as well as writing.
The company instead will focus on improving the safety of future models, which it expects to be even more capable.
Saachi Jain, OpenAI’s head of safety systems, said in an interview that GPT-6.1 Astra regressed in two areas. Compared with its predecessor, GPT-6 Astra, the model performed poorly on tests measuring alignment, or how well the model adheres to what humans would like it to do. Specifically, GPT-6.1 Astra showed higher levels of deception: It wasn’t always honest about telling users of the actions it did or didn’t take.
Another issue was what OpenAI calls “scope authorization,” meaning that GPT-6.1 Astra would push ahead on a task without asking the user for permission, and would at times reach for external tools and services even if it might be unsafe.
“For anything regarding safety and alignment, there’s a trade off,” Jain said. “You really do need to find what’s the right line between staying within scope, but also avoiding laziness in terms of how the model actually pursues tasks even when it hits friction.”
While GPT-6.1 Astra improved in areas such as “model laziness,” Jain said it didn’t quite meet OpenAI’s bar for safety and alignment, so the company decided not to launch the model publicly.
The announcement comes one day ahead of OpenAI’s annual developer conference in San Francisco. In the past, OpenAI has used the conference as an opportunity to launch new models and services that reduce costs for software developers—a segment the ChatGPT-maker competes with rival AI company Anthropic to win over.
In recent weeks, OpenAI and Anthropic have called on industry partners to slow down the development of cutting-edge AI models and invest in safety standards, noting they will temper the pace of their own internal AI progress.
OpenAI says it is working to investigate a range of agent security incidents that it has discovered in recent months, and address the safety issues underneath them. As part of the work, the company has implemented a new monitoring system to catch AI-agent misbehavior more quickly, and started requiring engineers to use stronger security guardrails for testing its AI systems.
Earlier this summer hundreds of OpenAI’s internal agents, which were tasked with completing a cybersecurity test, ended up hacking into the AI company Hugging Face. Since then, high-profile organizations such as the Australian government and United Nations discovered that OpenAI’s agents used similar, but less extensive, techniques to gain access to their websites.
Many of the publicly known agent-security incidents involved OpenAI’s internal AI models that were never slated for public release.
Last week, OpenAI said it paused training on its most capable AI models after an AI agent slipped through a gap in the company’s internet restrictions to query a public chatbot. The company said its new monitoring systems flagged the incident within 15 minutes, and training on these models remains paused.
GPT-6.1 Astra isn’t one of those models, but a different case, the company said.
“We want to make sure our model development is safe no matter whether that’s in the company, or when we ship it to users,” Jain said. “But when we ship it to users, we have an extremely high bar in terms of safety and alignment.”
While the company decided not to ship GPT-6.1 Astra, it hopes to use the same base model to do additional reinforcement learning runs, and create future generations of its GPT-6 models.
OpenAI plans to conduct several deep dives to identify the root cause of the problems identified in GPT-6.1 Astra, Jain said. The work includes ensuring that OpenAI’s reinforcement learning environments are rewarding the right type of behavior, Jain added, though she noted the company would investigate all stages of model development.
AI companies have begun to draw scrutiny from policymakers and public officials, who are paying attention to the rapid development of the technology. Later this week, a Senate subcommittee is holding a hearing with third party AI researchers titled, “Rogue AI: Securing the Homeland Against AI Agent Attacks.”
Florida Attorney General James Uthmeier, a Republican, sued OpenAI in June, claiming that the company and Chief Executive Sam Altman knowingly released an unsafe product and ignored warnings that it could harm users.
In a motion for temporary injunction filed Monday, Uthmeier sought to prevent OpenAI from developing new AI models without third-party approved safeguards, stop ChatGPT from soliciting user engagement and limit the company’s ability to advertise ChatGPT as safe.
Tech companies claim they “cannot stop barreling forward with their potentially civilization-ending endeavors unless they are forced to do so by the government,” Uthmeier said in the filing. “The Florida Attorney General is answering your cry for help.”
An OpenAI spokeswoman said that people want to know AI is being developed safely, “and that starts with what companies like ours do ourselves.”
“Governments have an important role to play in setting robust safety standards for AI, and we’re committed to working with Florida and other states on advancing pragmatic AI policies that apply to the entire AI industry—not just one company,” she said.
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