The Earth
Cement has a climate problem — here’s how geopolymers with add‑ins like cork could help fix it
Portland cement drives ~8% of global emissions. Learn how low-carbon geopolymers—enhanced with add-ins like cork—could cut concrete’s footprint.

Alcina Johnson Sudagar, Washington University in St. Louis
Concrete is all around you – in the foundation of your home, the bridges you drive over, the sidewalks and buildings of cities. It is often described as the second-most used material by volume on Earth after water.
But the way concrete is made today also makes it a major contributor to climate change.
Portland cement, the key component of concrete, is responsible for about 8% of global greenhouse gas emissions. That’s because it’s made by heating limestone to high temperatures, a process that burns a large amount of fossil fuels for energy and releases carbon dioxide from the limestone in the process.
The good news is that there are alternatives, and they are gaining attention.
Portland cement: A greenhouse gas problem
Cementlike substances have been used in construction for thousands of years. Architects have found evidence of their use in the pyramids of Egypt and the buildings and aqueducts of the Roman Empire.
The Portland cement commonly used in construction today was patented in 1824 by Joseph Aspdin, a British bricklayer.
Modern cement preparation starts with crushing the excavated raw materials limestone and clay and then heating them in a kiln at around 2,650 degrees Fahrenheit (about 1,450 degrees Celsius) to form clinker, a hard, rocklike residue. The clinker is then cooled and ground with gypsum into a fine powder, which is called cement.
About 40% of the carbon dioxide emissions from cement production come from burning fossil fuels to generate the high heat needed to run the kiln. The rest come as the heat converts limestone (calcium carbonate) to lime (calcium oxide), releasing carbon dioxide.
In all, between half a ton and 1 ton of greenhouse gas is released per ton of Portland cement. Cement is a binding agent that, mixed with water, holds aggregate together to create concrete. It makes up about 10% to 15% of the concrete mix by weight.
Alternative technologies can lower emissions
As populations, cities and the need for new infrastructure expand, the use of cement is growing, making it important to find alternatives with lower environmental costs.

Some techniques for reducing carbon dioxide emissions include substituting some of the clinker – the hard residue typically made from limestone – with supplementary materials such as clay, or fly ash and slag from industries. Other methods reduce the amount of cement by mixing in waste sawdust or recycled materials like plastics.
The long-term solution for reducing cement’s emissions, however, is to replace traditional cement completely with alternatives. One option is geopolymers made from earthen clay and industrial wastes.
Geopolymers: A more climate-friendly solution
Geopolymers can be made by mixing claylike materials that are rich in aluminum and silicon minerals with a chemical activator through a process called geopolymerization. The activator transforms the silicon and aluminum into a structure that will look like cement. All of this can happen at room temperature.
The major difference between cement and geopolymer is that cement is mainly made of calcium, whereas geopolymers are made of silicon and aluminum with some possible calcium in their structure.
These geopolymers have been found to possess high strength and durability, including resilience in freeze-thaw cycles and resistance to heat and fire, which are important requirements in construction. Studies have found that some geopolymers can provide comparable if not better strength than traditional cement and, because they don’t require heat the way clinker does, they can be produced with significantly lower greenhouse gas emissions.
Geopolymers can also be produced from a variety of raw materials rich in aluminum and silicon, including earthen clays, fly ash, blast furnace slag, rice husk ash, iron ore wastes and recycled construction brick waste. Geopolymer technology can be adapted depending on the clay or industrial waste locally available in a region. https://www.youtube.com/embed/NOj3p6m9M7Q?wmode=transparent&start=0 A brief history of cement and geopolymers. Geopolymer International.
An added advantage of geopolymers is that changes to the mixture can produce a range of features.
For example, I and my co-researchers at the University of Aveiro in Portugal added a small amount of cork industry waste – the leftovers from creating bottle corks – to clay-based geopolymer and found it could improve the strength of the material by up to twofold. The cork particles filled the spaces in the geopolymer structure, making it denser, which increased the strength.
Similarly, additives such as sisal fibers from the agave plant, recycled plastic and steel fibers can change geopolymer properties. The additives do not participate in the geopolymerization process but act as fillers in the structure.
The structure of geopolymers can also be designed to act as adsorbents, attracting toxic metals in wastewater and capturing and storing radioactive wastes. Specifically, incorporating materials like zeolite that are natural adsorbents in the geopolymer structure can make them useful for such applications as well.
Where geopolymers are used now
Geopolymers have been used in many types of construction, including roads, coatings, 3D printing, coastal environmental protection, the steel and chemical industries, sewer rehabilitation and building radiation shielding and rocket launchpad and bunker infrastructure.
One of the earliest examples of a modern geopolymer concrete project was the Brisbane West Wellcamp airport in Australia.
It was built in 2014 with 70,000 metric tons of geopolymer concrete, which was estimated to have reduced the project’s carbon dioxide emissions by as much as 80%.
The geopolymer market is currently estimated to be between US$7 billion and $10 billion, with the largest growth in the Asia-Pacific region.
Analysts have estimated that the market could grow at a rate of 10% to 20% per year and reach about $62 billion by 2033.
In several countries, greenhouse gas regulations and green-building certifications are expected to support the continued growth of geopolymers in the construction industry.
Expanding the use of cement alternatives
The advantage of using industrial wastes in geopolymers is a double-edged sword, however. The composition of industrial wastes varies, so it can be difficult to standardize the processing methods. The geopolymer components need to be mixed in particular ratios to achieve desired properties.
Producing the activator for the geopolymer, typically done in chemical facilities, can raise the cost and contribute to the carbon footprint. And the long-term data about these materials’ stability is only now being developed given their newness. Also, these geopolymers can take longer to set than cement, though the setting time can be sped up by using raw materials that react quickly.
Developing cheaper, naturally available activators like agricultural waste rice husk with sustainable supply chains could help lower the costs and environmental impact. Also, printing the recipe on the raw material packaging could help simplify the job of determining the mixing ratio so geopolymers can be more widely used with confidence.
Even though geopolymer technology has some drawbacks, these low-carbon alternatives have great potential for reducing emissions from the construction sector.
Alcina Johnson Sudagar, Research Scientist in Chemistry, Washington University in St. Louis
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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Science
Sonic booms from meteors can release the energy of hundreds of tons of TNT – here’s how they work

Shawn Laatsch, University of Maine
Sonic booms from meteors can release the energy of hundreds of tons of TNT – here’s how they work
As humans, we live out our lives on a planet that is constantly sweeping through a cosmic ocean littered with ancient debris from the formation of the solar system. For the most part, our world glides silently through space, shielded by Earth’s thin atmosphere.
Occasionally, however, the rest of the universe reminds us of its presence with stunning, visceral clarity.
Residents along the Massachusetts–New Hampshire border were startled by a sudden sonic boom on the afternoon of May 30, 2026. A large number of people up and down the Eastern Seaboard witnessed it.
After NASA analyzed imagery from weather satellites, they identified the culprit as a small meteor measuring roughly 3 to 5 feet (1 to 2 meters) across. It was screaming through space at an astonishing 42,000 miles per hour (68,000 kilometers per hour) when it plunged into Earth’s upper atmosphere.
Friction between the meteor and the increasingly dense air quickly turned the kinetic energy of the rock shooting through the sky into blistering heat. At an altitude of roughly 40 miles (60 kilometers), the immense heat and pressure overcame the structural integrity of the meteor, causing it to fragment in a brilliant flash.
The breakup released a staggering burst of energy equivalent to 300 tons of TNT. When an object travels through the air at speeds faster than sound, which is 761 mph (1,225 kph), it creates a shock wave creating a thunderous clap, or sonic boom. While the majority of the rock vaporized, the remaining fragments rained down harmlessly into the waters of Cape Cod Bay.
In the past, such an event might have passed as an unverified sighting in the daytime sky. Today, however, our planet is wired with an accidental network of planetary defense sensors: dashboard cameras, security systems and digital doorbells.
Because meteor entries like this one last only a few fleeting seconds, they were easily missed in the past. Now, our collective digital eyes capture these spontaneous cosmic intrusions almost instantly, bringing the universe directly into our daily news feeds. While dramatic, these events are more common than most people imagine.
As someone who has worked as a planetarium director and astronomy educator for over four decades, I often get emails, social media messages and phone calls about such objects and sightings. While hearing a sonic boom can be a bit unsettling or even shocking, it reminds us we live in an active universe and may want to occasionally look up instead of down at our devices.
A meteoric spring
The Cape Cod fireball was the latest sighting in an active season of meteoritic arrivals. Just months earlier, the solar system seemed to be sending a parade of rocky objects down to Earth.
From March 8-11, observers in Northern Europe witnessed large, slow-moving fireballs in their skies. Enthusiasts and scientists successfully recovered several fragments. Lab analysis of these specimens revealed their place in a fascinating lineage – scientists determined that they had originated from Vesta, a massive, pristine asteroid orbiting between Mars and Jupiter.
On March 17, a 7-ton asteroid measuring roughly 6 feet across entered the atmosphere directly over Lake Erie. Traveling at 45,000 mph (72,400 kph), it generated a brilliant daytime flash and a powerful sonic boom, unloading an energy equivalent to 250 tons of TNT. NASA scientists published data about its trajectory, allowing meteorite hunters to recover pristine fragments in Valley City, just a short drive from Cleveland, Ohio.
Only four days later, on March 21, another cosmic fragment blazed across the skies of Texas. This object was about 3 feet wide, and it traveled at 35,000 mph (56,300 kph), releasing the energy of roughly 26 tons of TNT.
Outside of Houston, homeowner Sherri James was startled by a sudden crash, only to discover a 6-inch (15-cm) hole in her roof and a small piece of the solar system resting on her floor.
Thank goodness for Earth’s atmospheric shield
The benchmark for modern atmospheric impacts is the Chelyabinsk meteor, which exploded over Russia on Feb. 15, 2013.
That object was significantly larger than any of the meteors researchers have observed in 2026, measuring 60 feet (18 m) across and weighing roughly 10,000 tons. When it shattered 18 miles (29 km) above the ground, it produced an airburst with an explosive force 30 times greater than the Hiroshima atomic bomb.
The resulting shock wave shattered glass across hundreds of square miles, injuring nearly 1,500 people and registering as a seismic event between 2.7 and 3.7 on the Richter scale. The incident was a stark reminder that while Earth’s atmosphere is an incredibly effective shield, absorbing the lion’s share of cosmic impacts, a large enough kinetic punch can still reach the surface below.
Despite the dramatic stories around these meteor impacts, history shows that the cosmic lottery rarely targets humans directly. In all of recorded history, there is only one universally confirmed case of a person being directly struck by a space rock.
In 1954, an 8.5-pound (3.8 kg) meteorite crashed through the roof of a house in Sylacauga, Alabama, ricocheted off a heavy wooden radio and struck a sleeping woman named Ann Hodges. Though it left a severe bruise on her hip, the radio absorbed the brunt of the impact. Had it not been for the radio, there is a chance she could have been seriously injured or killed by this object.
Living with the cosmos
So, are you in any imminent danger from meteors? The mathematics of the cosmos provide profound reassurance. The statistical odds of being struck by a meteorite are vanishingly small. You stand a better chance of winning a multimillion-dollar lottery jackpot 10 times in a row than ever being hit by a meteorite.
The vast majority of the tons of space debris that bombard Earth daily arrive as harmless dust grains, burning up as elegant meteors or shooting stars. But when the larger pieces do break through and land on our planet, they offer a rare, tangible connection to the beginning of the solar system.
If you ever happen to witness one of these magnificent fireballs ripping open the sky, consider reporting your observation to the American Meteor Society. The organization keeps track of sightings and falls from around the globe. Recovered fragments provide a way for scientists to gain valuable information about the origin of our solar system, and of our home planet.
Shawn Laatsch, Director of the Versant Power Astronomy Center, University of Maine
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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Automotive
The Road to Cleaner Water: How to Prevent Roads from Polluting Waterways
Everyone loves driving on clean highways and spotless local roads. Few people, however, realize the benefits of clean roads go well beyond mere aesthetics. Cleaner roads also mean cleaner and healthier local rivers, lakes and beaches. Follow these simple year-round tips to help make the waters as fun and healthy as possible this summer.

(Feature Impact) Everyone loves driving on clean highways and spotless local roads. Few people, however, realize the benefits of clean roads go well beyond mere aesthetics. Cleaner roads also mean cleaner and healthier local rivers, lakes and beaches.
That’s because harmful pollutants in local waters often run off untreated from highways and roads during strong storms. Those rains sweep trash, dripped oil, harmful chemicals and even dangerous bacteria from pet waste into local waters via stormways and sewers. This untreated runoff can affect people’s health, make water unsafe for swimming and harm aquatic life. Every year, such man-made “stormwater pollution” even closes portions of recreational rivers and beaches.
It’s up to everyone to help prevent human-caused stormwater pollution. Don’t wait for rain in the forecast to get started. Instead, follow these simple year-round tips from the experts at the California Department of Transportation to help make the cooling waters in California and beyond as fun and healthy as possible this summer.
Trash-Free Trips and Responsible Car Care
Summer can mean more road time traveling to your next adventure. Loose items in truck beds and on roof carriers or trash tossed from car windows can quickly become the next wave of stormwater pollution flowing into local waters. To reduce:
- Secure Your Load: Always securely tarp and tie down anything in a truck bed or on a roof rack. Items falling off vehicles are both a safety hazard and can become roadside debris.
- Keep a Car Trash Catcher: Designate a bag or container in your car for food wrappers, coffee cups and other small trash until you can dispose of it properly.
- Wash Smart: Commercial car washes that recycle water are superior for preventing road dirt and chemicals accumulated on your car from entering storm drains compared to washing in a driveway. If washing at home, do it on your lawn or a permeable surface where the water naturally filters into the ground and not street gutters.

Outdoor Adventures That Leave Only Footprints
Whether you’re hiking a mountain trail, picnicking at the park or relaxing on the beach, remember the outdoor golden rule: pack out everything you pack in. Food wrappers, plastic bottles and even seemingly small items like bottle caps and cigarette butts are some of the most common litter found in parks, waterways and along coastlines. When left behind, they’re not just eyesores; they’re prime candidates for being washed into waterways.
- Pro Tip: Choose reusable water bottles that clip onto bags to reduce pollution from discarded plastic bottles.
At Home and In Your Neighborhood
Even close to home, your actions can make a difference.
- Garden Care: When tidying up your garden or front lawn, sweep leaves and grass clippings into your green bin instead of hosing them down the driveway. Hosing yard waste into road gutters can clog storm drains and cause flooding.
- Pesticide Prevention: To protect waterways from harmful chemical runoff, opt for organic or eco-friendly alternatives for pest and weed control whenever possible.
- Scoop the Poop: Pet waste contains harmful bacteria that can contaminate waterways. In fact, the EPA estimates that just two days’ worth of waste from 100 dogs can produce enough bacteria to close a beach. Always pick up after your pets, especially when walking in your neighborhood or parks, and dispose of it in a trash bin.
Pollution in waterways doesn’t just look bad; it creates real problems, from harming wildlife and ecosystems to causing potential health issues for humans and pets who encounter contaminated water. The cleaner roads and surrounding areas are, the healthier rivers, lakes and beaches become. For more tips and resources, visit CleanWaterCA.com to ensure a clean, healthy summer for everyone.
Photos courtesy of Shutterstock
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SOURCE:
California Department of Transportation
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health and wellness
Warmer temps bring soaring tick populations – here’s how to stay safe from Lyme disease
Tick bites are rising in 2026. Learn where Lyme disease is spreading, early symptoms like the bull’s-eye rash, treatment options, and practical ways to prevent tick bites.
Last Updated on June 6, 2026 by Daily News Staff
Lakshmi Chauhan, University of Colorado Anschutz
Spring’s warmer weather lures people outdoors – and into possible contact with ticks that spread Lyme disease.
Already, the 2026 tick season is booming. On April 23, the Centers for Disease Control and Prevention warned that emergency room visits due to tick bites are at their highest level since 2017. That may portend an especially severe season for Lyme disease and other tick-borne illnesses.
State health departments reported more than 89,000 cases of Lyme disease in 2023, the last year for which data is available. But public health experts believe that close to 500,000 people in the U.S. get Lyme disease every year.
As an infectious disease doctor with experience treating some of this infection’s long-term outcomes, I know that Lyme disease can be tricky because people often don’t notice tick bites and may overlook early symptoms of an infection. But left untreated, the infection can cause serious lingering – and even permanent – health issues.
Here’s what you need to know about Lyme disease to stay safe this season:
What causes Lyme disease?
Lyme disease, named after the Connecticut town where the disease was first identified in 1975, is caused by a group of bacteria called Borrelia – most often, the species Borrelia burgdorferi.
Deer ticks – also called black-legged ticks, and members of a group called Ixodes – transmit the disease after feeding on an infected animal, usually a bird, mouse or deer. When they then bite a person, they can transmit the bacteria into the person’s bloodstream.
Usually, the tick must attach for 24-48 hours to transmit the bacteria causing Lyme disease.
Where and when does Lyme disease occur?
Lyme disease can occur in most regions where deer ticks live.
These ticks are most active in late spring, summer and fall – usually April to November in most regions. They emerge when the temperature is above freezing. In years when winter is shorter, ticks can emerge earlier. And they may be active year-round in regions where freezing temperatures are rare.
Approximately 90% of U.S. cases are reported from states in the Northeast, mid-Atlantic from Virginia to eastern Canada, and Upper Midwest regions including Wisconsin, Michigan and Minnesota. A few cases occasionally pop up in California, Oregon and Washington.
Since 1995, the incidence of Lyme disease in the U.S. has almost doubled.
Warmer weather and changes in rainfall patterns now allow ticks to survive in new regions of the country – and for longer periods. But even in regions where ticks lived before, Lyme disease has become more common due to increases in deer populations. As woodland areas are increasingly being developed, it may be bringing the habitat of deer and mice closer to people, increasing the risk of transmission.
Lyme disease symptoms to watch for
Early symptoms of Lyme disease – fever, muscle aches and fatigue – generally emerge within three to 30 days after a tick bite. Another classic symptom in the first month is a target or bull’s eye rash at the site of tick bite, which occurs in about 70% to 80% of cases.
Other rashes following a tick bite can also occur. Some may be due to irritation from the bite, and not necessarily an infection.
If you know you’ve had a tick bite and experience flu-like symptoms – or if you see a bull’s-eye rash, whether you know you were bitten or not – it’s important to check with your healthcare provider about whether you should be treated with antibiotics.
A blood test for antibodies can help confirm the infection, but it can sometimes yield a false negative result, particularly in the first couple of weeks of the disease.
In most people, the rash goes away on its own. However, treatment may shorten its duration and is important for preventing other symptoms. A two- to four-week course of antibiotics can generally treat Lyme disease. Severe cases might require intravenous antibiotics.
A promising new vaccine for Lyme disease is currently being tested. In March 2026, Pfizer, the pharmaceutical company developing it, announced that in a late-stage study, the vaccine prevented the disease in 70% of people who received it.
Later Lyme symptoms
If left untreated, the bacteria that causes Lyme can spread, potentially causing longer-term symptoms. About 60% of people who get Lyme disease and don’t treat it can develop arthritis.
In rare cases, Lyme disease can also affect the heart and the nervous system. Inflammation in the brain or the tissues surrounding it, called meninges, can cause headaches and neck pain, as well as balance issues and memory and behavior changes. It can also cause nerve damage that results in numbness, tingling and muscle weakness.
These symptoms can appear right away or much later – sometimes months to years after infection. And in cases where the disease wasn’t promptly treated, late-stage symptoms can linger even after antibiotics kill the bacteria.
Scientists don’t fully understand why, but one intriguing study found that some particles from the bacteria’s cell wall leak into the joints and can persist after treatment, spurring ongoing inflammation and arthritis symptoms.
Another reason for Lyme’s long-term effects is that it can trigger autoimmune disease, which is when the immune system attacks its own cells. What’s more, because the nervous system may be particularly sensitive to damage caused by the bacteria and related inflammation, it may take an especially long time to heal. In some situations, the damage could be permanent.
Preventing Lyme disease
Until a vaccine becomes available, there are steps you and your family can take to help protect against Lyme disease:
- Use tick and insect repellents such as DEET and picaridin, which can be applied to skin, and permethrin, which is sprayed onto clothing, to keep ticks at bay. Treating clothing with permethrin may be especially beneficial, since the substance withstands several washes.
- Wear long-sleeve shirts and pants while you are gardening, hiking or walking through grass or woods to prevent tick bites. Wearing light-colored clothes makes ticks more visible, and tucking your pants into your socks can also prevent the little buggers from traveling from your pants, shoes and socks onto your legs.
- Remove your outdoor clothes immediately. Washing and drying clothes at high temperature can help kill any ticks that managed to hitch a ride. And a quick shower immediately after spending time outdoors can wash ticks off the skin before they have a chance to attach.
- If you spend time outdoors, perform daily tick checks, paying special attention to warm areas like your armpits, neck, ears and underwear line. If you find a tick attached, pull it off with tweezers, holding them perpendicular to the skin.
- If you find a tick that may have been on the skin for more than 36 hours, ask your healthcare provider whether a dose of preventive antibiotics – generally given within 72 hours of the bite – would be appropriate.
Lakshmi Chauhan, Associate Professor of Infectious Disease Medicine, University of Colorado Anschutz
This article is republished from The Conversation under a Creative Commons license. Read the original article.
