Today’s inspiration comes from bestselling American author Jodi Thomas. In her novel, “Welcome to Harmony,” she wrote, “When trees burn, they leave the smell of heartbreak in the air.”
Earth911 inspirations. Post them and share your desire to help people think of the planet first, every day. Click the poster to get a larger image.
Editor’s Note: This poster was first published on July 21, 2023.
An experimental drug originally developed to treat cancer may help clear HIV from infected cells in the brain, according to a new Tulane University study.
For the first time, researchers at Tulane National Primate Research Center found that a cancer drug significantly reduced levels of SIV, the nonhuman primate equivalent of HIV, in the brain by targeting and depleting certain immune cells that harbor the virus.
Published in the journal Brain, this discovery marks a significant step toward eliminating HIV from hard-to-reach reservoirs where the virus evades otherwise effective treatment.
“This research is an important step in tackling brain-related issues caused by HIV, which still affect people even when they are on effective HIV medication,” said lead study author Woong-Ki Kim, PhD, associate director for research at Tulane National Primate Research Center. “By specifically targeting the infected cells in the brain, we may be able to clear the virus from these hidden areas, which has been a major challenge in HIV treatment.”
Antiretroviral therapy (ART) is an essential component of successful HIV treatment, maintaining the virus at undetectable levels in the blood and transforming HIV from a terminal illness into a manageable condition. However, ART does not completely eradicate HIV, necessitating lifelong treatment. The virus persists in “viral reservoirs” in the brain, liver, and lymph nodes, where it remains out of reach of ART.
The brain has been a particularly challenging area for treatment due to the blood-brain barrier — a protective membrane that shields it from harmful substances but also blocks treatments, allowing the virus to persist. In addition, cells in the brain known as macrophages are extremely long-lived, making them difficult to eradicate once they become infected.
Infection of macrophages is thought to contribute to neurocognitive dysfunction, experienced by nearly half of those living with HIV. Eradicating the virus from the brain is critical for comprehensive HIV treatment and could significantly improve the quality of life for those with HIV-related neurocognitive problems.
Researchers focused on macrophages, a type of white blood cell that harbors HIV in the brain. By using a small molecule inhibitor to block a receptor that increases in HIV-infected macrophages, the team successfully reduced the viral load in the brain. This approach essentially cleared the virus from brain tissue, providing a potential new treatment avenue for HIV.
The small molecule inhibitor used, BLZ945, has previously been studied for therapeutic use in amyotrophic lateral sclerosis (ALS) and brain cancer, but never before in the context of clearing HIV from the brain.
The study, which took place at the Tulane National Primate Research Center, utilized three groups to model human HIV infection and treatment: an untreated control group, and two groups treated with either a low or high dose of the small molecule inhibitor for 30 days. The high-dose treatment lead to a notable reduction in cells expressing HIV receptor sites, as well as a 95-99% decrease in viral DNA loads in the brain .
In addition to reducing viral loads, the treatment did not significantly impact microglia, the brain’s resident immune cells, which are essential for maintaining a healthy neuroimmune environment. It also did not show signs of liver toxicity at the doses tested.
The next step for the research team is to test this therapy in conjunction with ART to assess its efficacy in a combined treatment approach. This could pave the way for more comprehensive strategies to eradicate HIV from the body entirely.
This research was funded by the National Institutes of Health, including grants from the National Institute of Mental Health and the National Institute of Neurological Disorders and Stroke, and was supported with resources from the Tulane National Primate Research Center base grant of the National Institutes of Health, P51 OD011104.
Government agencies, insurance companies and disaster planners rely on national flood risk models from the private sector that aren’t reliable at smaller levels such as neighborhoods and individual properties, according to researchers at the University of California, Irvine.
In a paper published recently in the American Geophysical Union journal Earth’s Future, experts in UC Irvine’s Department of Civil and Environmental Engineering caution that relatively new, nation-scale flood data provides an inadequate representation of local topography and infrastructure, factors known to control the spread of floods in urban areas.
“In our analysis of Los Angeles County, which has a population greater than 40 U.S. states and includes over 80 separate municipalities, we found that estimates of countywide flood exposure from the nationwide data are actually similar to what we find with our more detailed models. However, predictions of which communities and properties are at risk are markedly different,” said lead author Brett Sanders, UC Irvine Chancellor’s Professor of civil and environmental engineering and professor of urban planning and public policy.
“In addition, these differences between models imply a disparity in exposure inequality across social groups, including Black, white and disadvantaged sectors of society,” he said. “Exposure hot spots and social inequalities are key factors that inform urban flood risk planning, and overreliance on this data could lead to maladaptation of protective measures.”
Sanders and colleagues at UC Irvine and the University of Miami developed a more detailed model named PRIMo-Drain that, they said, improves the accuracy of flood inundation predictions by including fine-resolution topographic data; information about levees and channel conditions; and particulars about stormwater infrastructure such as culverts, subsurface pipes and street drains.
“Comparing exposure assessments with nationwide data models versus PRIMo-Drain, we found that city-by-city estimates differed by a factor of 10,” Sanders said. “Additionally, we found that there is only a 1-in-4 chance that the nationwide data and UC Irvine data agree on which properties are at risk of more than a foot of flooding from an extreme event.”
Federal programs to map flood hazards across the U.S. have been unable to keep up with changes in land use and climate, he said, while governments at all levels and the insurance industry urgently need this information to manage risks.
“New, nationwide data sources have emerged from the private sector to meet this demand, but unfortunately, these models are missing the level of detail required to map flood risks accurately in urban areas,” Sanders said. “New models would benefit from the inclusion of more complete representations of drainage infrastructure such as levees, flood channels, culverts and storm drains, as well as bathymetric and hydrologic data.”
He and colleagues also point to a new strategy for better nationwide data.
“Collaborative flood modeling, with scientists and engineers using cutting-edge regional models in coordination with stakeholders, could create an economy of scale that lowers the overhead necessary to cover less wealthy and smaller communities while increasing flood awareness and preparedness across impacted populations,” Sanders said. “Flood risk awareness is critical for participation in flood insurance programs; more accurate data will help insurance companies identify insurable properties; and property owners will be better informed about the cost-effectiveness of flood-proofing.”
Joining Sanders on this project were Jochen Schubert, a UC Irvine research specialist in civil and environmental engineering, and Katharine Mach of the University of Miami. The team received data assistance from First Street Foundation and high-performance computing support from the NCAR-Wyoming Supercomputing Center, which receives funding from the National Science Foundation.
Growing, packaging, transporting, and distributing food is a major source of society’s emissions, accounting for approximately 26% of annual global emissions. Reducing the impact of food production is critical to bringing society back within the planetary boundaries, and Wayne McIntyre, cofounder and CEO of Montreal-based Relocalize, wants to “Decarbonize and hyper-localize food & beverage manufacturing.” The company is developing technology and a business strategy for decentralized food production using automated microfactories that are placed close to major consumer markets. It promises retailers “full control over their supply chain” in exchange for providing just 1,200 sq. feet of space for Relocalize’s operation. The result, Relocalize claims, will be up to 30% savings on products, 90% less CO2 emissions, and other operational savings because the food does not need to be transported long distances. You can learn more at https://www.relocalize.com/
Dive into the Earth911 archives to discover the innovation going on in local food production, distribution, and reuse:
Rural councils should be “deeply engaged” with the planning of renewable energy projects in their backyards to keep communities onside and streamline the energy transition, local government advocates have said.
But not all renewable projects require local government approval, meaning developers are left to deal directly with the community – to mixed results.
In New South Wales, Victoria and Queensland, local councils generally have the power to approve solar farms, but not wind developments which lie with the state government.
Linda Scott, the president of the Australian Local Government Association, said approval powers aside, local governments should be central in planning because it results in “better community acceptance” and “speedier approvals”.
“Where local governments don’t have planning approvals for any major infrastructure project, proponents often forget to speak to local government,” Scott said. “This is almost always a mistake”.
Most of the footprint of the MacIntyre windfarm, the largest in the southern hemisphere, falls within the borders of Goondiwindi regional council in Southern Queensland. The Goondiwindi mayor, Lawrence Springborg, said local councils want a greater say in renewable energy projects.
“We’re not talking about being frustrating and just saying no for the sake of it,” he said. “We understand state priorities and prerogatives, we’re not arguing against that, but in many ways that just sees things being waved through, often without consideration [for local communities].”
Springborg said localised economic benefits of the windfarm are not yet commensurate to the project’s scale. “If we are hosting this for the benefit of our state or our nation or our planet, surely those hosting should be able to be a major beneficiary of economic opportunity,” he said.
The former energy infrastructure commissioner, Andrew Dyer, said while local councils can play an “integral part” in the development of renewable projects, final planning approvals should remain with state and territory governments.
He added that regional councils can face a conflict of interest if a councillor is a potential neighbour or host of a project, which he said is often the case.
“The planning processes for wind, solar and storage systems are very complex,” Dyer said. “By centralising planning, you centralise expertise.”
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MacIntyre’s footprint also partly extends into Southern Downs regional council. The mayor, Melissa Hamilton, said local government should have greater agency over how community benefit funds, established by most energy developers to build social licence, are distributed in regional communities.
“We don’t want to be at the whim of the proponent deciding to do a few community charity items that they choose,” Hamilton said. “No one understands your local issues better than people on the ground.”
The president of the Local Government NSW, Darriea Turley, said the energy transition must be carefully managed to reduce pressure on housing and infrastructure in regional communities.
She said local government should be entrusted with community benefit funds to manage on behalf of the community, which could allow them to bring together the funding of multiple projects to pay for legacy community projects, like swimming pools and road upgrades.
“Collectively managed, the funds can put larger community needs within reach that may not have been possible using the benefit payment from one project alone,” Turley said.
There are 37 renewable energy projects planned, proposed or under construction in the NSW central-west Orana renewable energy zone, many of which lie within Dubbo regional council. The mayor, Mathew Dickerson, said one of local governments’ “greatest frustrations” is a void of policy to guide negotiations between councils and energy developers.
“You want to get as much money as can for your community, but how much is the right amount? What’s fair and reasonable?” Dickerson said.
“I feel like we would have failed as a council if we look back in 10 years’ time and we don’t think ‘wow’ we’ve made the community a better place,” he said.
University of Delaware and Argonne National Laboratory have come up with a chemical reaction that can convert Styrofoam into a high-value conducting polymer known as PEDOT:PSS. In a new paper published in JACS Au, the study demonstrates how upgraded plastic waste can be successfully incorporated into functional electronic devices, including silicon-based hybrid solar cells and organic electrochemical transistors.
The research group of corresponding author Laure Kayser, assistant professor in the Department of Materials Science and Engineering in UD’s College of Engineering with a joint appointment in the Department of Chemistry and Biochemistry in the College of Arts and Sciences, regularly works with PEDOT:PSS, a polymer that has both electronic and ionic conductivity, and was interested in finding ways to synthesize this material from plastic waste.
After connecting with Argonne chemist David Kaphan during an event hosted by UD’s research office, the research teams at UD and Argonne began evaluating the hypothesis that PEDOT:PSS could be made by sulfonating polystyrene, a synthetic plastic found in many types of disposable containers and packing materials.
Sulfonation is a common chemical reaction where a hydrogen atom is replaced by sulfonic acid; the process is used to create a variety of products such as dyes, drugs and ion exchange resins. These reactions can either be “hard” (with higher conversion efficiency but that require caustic reagents) or “soft” (a less efficient method but one that uses milder materials).
In this paper, the researchers wanted to find something in the middle: “A reagent that is efficient enough to get really high degrees of functionalization but that doesn’t mess up your polymer chain,” Kayser explained.
The researchers first turned to a method described in a previous study for sulfonating small molecules, one that showed promising results in terms of efficiency and yield, using 1,3-Disulfonic acid imidazolium chloride ([Dsim]Cl). But adding functional groups onto a polymer is more challenging than for a small molecule, the researchers explained, because not only are unwanted byproducts harder to separate, any small errors in the polymer chain can change its overall properties.
To address this challenge, the researchers embarked on many months of trial and error to find the optimal conditions that minimized side reactions, said Kelsey Koutsoukos, a materials science doctoral candidate and second author of this paper.
“We screened different organic solvents, different molar ratios of the sulfonating agent, and evaluated different temperatures and times to see which conditions were the best for achieving high degrees of sulfonation,” he said.
The researchers were able to find reaction conditions that resulted in high polymer sulfonation, minimal defects and high efficiency, all while using a mild sulfonating agent. And because the researchers were able to use polystyrene, specifically waste Styrofoam, as a starting material, their method also represents an efficient way to convert plastic waste into PEDOT:PSS.
Once the researchers had PEDOT:PSS in hand, they were able to compare how their waste-derived polymer performed compared to commercially available PEDOT:PSS.
“In this paper, we looked at two devices — an organic electronic transistor and a solar cell,” said Chun-Yuan Lo, a chemistry doctoral candidate and the paper’s first author. “The performance of both types of conductive polymers was comparable, and shows that our method is a very eco-friendly approach for converting polystyrene waste into high-value electronic materials.”
Specific analyses conducted at UD included X-ray photoelectron spectroscopy (XPS) at the surface analysis facility, film thickness analysis at the UD Nanofabrication Facility, and solar cell evaluation at the Institute of Energy Conversion. Argonne’s advanced spectroscopy equipment, such as carbon NMR, was used for detailed polymer characterization. Additional support was provided by materials science and engineering professor Robert Opila for solar cell analysis and by David C. Martin, the Karl W. and Renate Böer Chaired Professor of Materials Science and Engineering, for the electronic device performance analyses.
One unexpected finding related to the chemistry, the researchers added, is the ability to use stoichiometric ratios during the reaction.
“Typically, for sulfonation of polystyrene, you have to use an excess of really harsh reagents. Here, being able to use a stoichiometric ratio means that we can minimize the amount of waste being generated,” Koutsoukos said.
This finding is something the Kayser group will be looking into further as a way to “fine-tune” the degree of sulfonation. So far, they’ve found that by varying the ratio of starting materials, they can change the degree of sulfonation on the polymer. Along with studying how this degree of sulfonation impacts the electrical properties of PEDOT:PSS, the team is interested in seeing how this fine-tuning capability can be used for other applications, such as fuel cells or water filtration devices, where the degree of sulfonation greatly impacts a material’s properties.
“For the electronic devices community, the key takeaway is that you can make electronic materials from trash, and they perform just as well as what you would purchase commercially,” Kayser said. “For the more traditional polymer scientists, the fact that you can very efficiently and precisely control the degree of sulfonation is going to be of interest to a lot of different communities and applications.”
The researchers also see great potential for how this research can contribute to ongoing global sustainability efforts by providing a new way to convert waste products into value-added materials.
“Many scientists and researchers are working hard on upcycling and recycling efforts, either by chemical or mechanical means, and our study provides another example of how we can address this challenge,” Lo said.
The complete list of co-authors includes Chun-Yuan Lo, Kelsey Koutsoukos, Dan My Nguyen, Yuhang Wu, David Angel Trujillo, Tulaja Shrestha, Ethan Mackey, Vidhika Damani, Robert Opila, David Martin, and Laure Kayser from the University of Delaware and Tabitha Miller, Uddhav Kanbur, and David Kaphan from Argonne National Laboratory.
Deliveries are getting faster than ever in the U.S., but the faster movement of goods is undercutting the country’s climate progress.
In a new study published July 18 in the journal Nature Energy, a CU Boulder researcher and his collaborator estimate that federal regulations aimed at enhancing heavy-duty trucks’ energy efficiency could be as much as 20% less effective than policymakers initially anticipated.
That’s because the regulations make trucking cheaper. As a result, more shippers will likely switch from using less energy-intensive rail transportation to using more energy-intensive trucks to ship goods.
“We were surprised to see how big of an impact the change in shipping decisions has on our energy use,” said Jonathan Hughes, the paper’s corresponding author and professor in the Department of Economics at CU Boulder. “Increasing vehicles’ energy efficiency is very costly for truck makers, so it’s important to know how much benefit we can get realistically from these costly regulations.”
The rebound effect
In economics, increased consumption due to improved efficiency and reduced costs is known as the rebound effect.
For example, if using an air conditioner consumes much more electricity than using a fan, many people will stick to the fan. But when air conditioners become more efficient, and cooling becomes cheaper, more people will switch to air conditioners. This behavior change would increase overall energy consumption.
Hughes and his collaborators wanted to study the extent of the rebound effect in the freight sector.
“When we think about the challenges in energy and climate change issues, freight transportation is a big, important sector that hasn’t received enough attention,” Hughes said.
The freight sector, which includes transportation of goods by truck, train, ship and airplane, represents approximately 10% of total U.S. energy consumption. Freight movement contributes to 27% of the country’s greenhouse gas (GHG) emissions from the transportation sector, which is the largest source of emissions in the U.S.
The majority of emissions from the freight sector come from trucking, which saw a 76% increase in GHG emissions since 1990.
In a bid to reduce emissions and avoid the worse consequences of climate change, the U.S. Environmental Protection Agency (EPA) has rolled out a series of regulations to improve heavy-duty vehicles’ energy efficiency since 2011. These rules require newly manufactured trucks to achieve better mileage using less fuel and emit less GHG.
In March, the EPA announced the strictest-ever fuel economy standards, aiming to prevent 1 billion metric tons of GHG emissions by 2055.
But while these regulations make trucks more energy-efficient, they also make trucking cheaper by reducing fuel costs. As a result, many shippers may opt to transport their goods by truck instead of rail, because trucks can reach destinations faster, allowing for quicker product sales. The authors note that trucks consume significantly more fuel than rail to transport the same amount of goods over the same distance.
Unintended consequence
Hughes and his collaborator, James Bushnell of University of California at Davis, used newly released data on goods movement from the U.S. Census Bureau to estimate the rebound effect in the freight sector. Using a computer simulation, they calculated the amount of energy saved if the EPA regulations increased new trucks’ fuel efficiency by 5%, which is roughly what the standard is today.
Under this scenario, the team found that the regulations had the potential to save 674 million gallons of gas per year. But when they factored in the increased share of goods forecasted to be shipped by truck due to the rebound effect, the regulations would only save 497 million gallons of fuel — still a significant amount, but 26% less than previously estimated.
Some industries, such as the chemical, animal feed, alcohol and petroleum industries are particularly sensitive to reductions in fuel costs and would likely experience the largest rebound effect, Hughes said.
Accounting for all modes of freight transportation, the team estimated that the rebound effect in the freight sector would reduce the total fuel savings from federal regulations by 20%.
“We show that if we make transportation much more efficient, either through increasing energy efficiency or automation that reduces labor costs, we will likely wind up consuming more energy than we thought we would,” said Hughes.
While the paper focused on the freight sector, Hughes added a similar rebound effect could also exists in the retail sector, which includes businesses like Amazon.
“These regulations that help reduce transportation costs certainly benefit consumers, because we can now purchase things at lower prices. But we show that these rules can be somewhat counterproductive in terms of achieving our climate change and energy goals,” Hughes said.
Hughes said making fuel pricier and transportation more expensive through programs like taxing carbon emissions would be a more effective way to reduce energy use in transportation. But those types of policies tend to be very difficult to get political support for, he added.
“This study shows we should get a more complete picture of the impacts these regulations might have, so we don’t end up adopting policies that lead to unintended negative effects,” he said.
The U.S. has more than 5 million solar installations. This means there are tens of millions of solar panels on roofs and racking systems. Solar energy is fantastic for reducing carbon emissions and promoting energy independence, but what will happen to those photovoltaic (PV) panels at the end of the panel’s 30-year lifespan?
A waste management issue looms as solar systems age and will eventually be decommissioned. Is the U.S. prepared for large-scale solar panel recycling?
“Installations two decades ago are nearing their end of life, and that becomes a challenge for the waste industry,” said Garvin Heath, a senior scientist in the Strategic Energy Analysis Center of the National Renewable Energy Laboratory (NREL). “Because it takes a long time to develop technology and policy and solutions to dealing with end-of-life products, this is something we need to start to address today.”
According to Heath, solar panels could comprise more than 10 percent of global electronic waste by 2050. The Department of Energy has allocated $29 million to support 10 recycling projects in a bid to prepare the nation for the first wave of PV panels, some of which are reaching their end-of-life now.
Solar panel recycling presents an economic opportunity and can spawn new industries. A study by the International Renewable Agency (IRENA) estimates that by 2050, $15 billion could be recovered from recycling solar panels. There are also repair and reuse opportunities for solar panels that fail prematurely. These repaired solar panels are often sold at a discount, creating opportunities in new markets where affordability is an issue.
Glass, plastic, aluminum, and silicon comprise 99 percent of the silicon-based solar panels.
The assembly and variety of materials make solar panels relatively complex. Solar panels consist of 72 percent glass plus plastic, a variety of metals, including lead, copper, gallium, cadmium, and aluminum, along with silicon solar cells. It is a relatively tricky process to recycle solar panels, which involved dissembling, etching, and melting.
There are no national policies in the U.S., but some states are leading the way. Washington state has a solar stewardship program requiring manufacturers to collect panels at their end of life for recycling at no charge to the customer. But the National Renewable Energy Lab reported in 2021 that only 10% of solar panels will be recycled by 2050 if the nation does not accelerate its investments
Europe, by contrast, has had electronic waste policies that require solar panel recycling programs since 2012. Manufacturers are responsible for collecting and recycling of their products. As a result, the E.U. leads in solar panel recycling capacity with dedicated facilities that recycle panels for reuse.
Despite a slow start, a variety of options are available for recycling solar panels in the U.S. Many of these companies focus on business and industrial PV panel recycling, but homeowners have increasing access to recycling services, especially through installers.
Solar panels have a design life of about 30 years. When a solar farm is decommissioned, it is especially important to recycle the panels because it can contain thousands.
On the residential side, it is up to the homeowner and solar contractors to determine when to decommission systems. Sometimes homeowners don’t know if their solar system is still working properly and producing sufficient power. Some solar system owners decommission a functional solar system prematurely. Unfortunately, older solar systems do not have monitoring capabilities like new ones. In this case, a good way to determine if the solar system is producing power is by looking at the display on the inverter.
Most solar panels have a window that will display the power consumption in watts or kilowatts. Some inverters also have lights to help you understand how the system is operating. Search Google for the inverter model you own to find an owner’s manual. Typically, a green light indicates the system is working and a red blinking light indicates an issue. Just because there is an issue doesn’t mean the solar system isn’t producing power.
The solar panels will only produce power during daylight hours, and midday is the best time to check your system’s performance. You can also look at your power bills to determine if you are getting credits for excess power, but this is a less reliable indicator of how the system is performing. Utility bills only show how much surplus power is fed to the grid, not the total energy production.
Although solar panel recycling is still in its at the toddler stage in the U.S., greater recycling options are coming. There is still a bit of time before the quantity of decommissioned solar panels reaches large volumes, so now is the time to create an effective solar panel recycling infrastructure and policies.
Editor’s Note: Originally published on February 4, 2020, this article was updated in July 2024.
The wintry blast sweeping across eastern Australia has set a record for electricity demand in Victoria and propelled wind generation in New South Wales to new highs, with energy authorities preparing for another power peak on Tuesday evening.
Victoria broke a 17-year record for maximum winter electricity demand, with the tally reaching 8,612 megawatts at 6pm on Monday, the Australian Energy Market Operator said.
The demand beat the previous record set in July 2007 by more than 250MW, but that may be challenged as soon as Tuesday evening, Aemo said. By mid-afternoon, temperatures across much of Melbourne were 10C or less with wind chill taken into effect.
A cold snap has seen Victoria break a 17-year winter record for maximum electricity demand – 8,612 MW at 6:00 PM last night. The previous record of 8,351 MW was on 17 July 2007.
AEMO will work with industry to keep the electricity on during another expected peak-demand tonight. pic.twitter.com/Tf7K8C0ZLf
— AEMO (@AEMO_Energy) July 16, 2024
The windy and cold conditions brought snow to elevated regions from Tasmania to NSW. Gusts topped 100km/h at Mount Hotham and Thredbo ski resorts, Weatherzone said.
Windfarms, though, were in their element, supplying as much as a third of the National Electricity Market’s power early on Tuesday morning.
The NEM covers about 80% of Australia’s population, spanning from Queensland to Tasmania and South Australia.
According to Geoff Eldridge, an energy analyst for Global Roam, wind generation in NSW reached 2,293MW just after midnight. Prior to this weather event, spurred by a deep low off Tasmania, the previous record for the state was set in April 2024 at 2179MW.
Over the full 24 hours, the average wind generation was 1,914MW, Eldridge said, beating the previous high of 1,863MW set during that cold snap in April last year.
The widespread and powerful winds also meant the grid barely burned any gas in the past day or so, unlike earlier in the winter.
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A combination of cold, still days and gas production interruptions at Victoria’s Longford site prompted Aemo to issue a “threat notice” given the pace of the draw down in gas supplies in Victoria and NSW.
The prospect that industries might need to have their gas supplies temporarily cut off to ensure households could keep their heating on has since abated. The return of windier weather that reduced the need for gas-fired power generation has helped.
Still, winter is only halfway over and lengthy periods of cool, calm conditions could return to Australia’s south-east. Aemo has said “deliverability risks” could continue until the end of August if the daily drawdown of gas at Victoria’s main Iona storage site exceeds 200 terajoules a day.
In recent years, tree-planting campaigns have been underway in the United States, especially in cities, as part of climate mitigation efforts.
Urban forests can help improve air quality, generate cooling effects, and provide green spaces for outdoor recreation while also serving as an ecological habitat.
Just last year, the U.S. Forest Service announced a $1 billion campaign to expand access to trees and green spaces throughout the country, including in cities.
But a new Dartmouth-led study finds that some areas within urban forests in the U.S., may be more capable than trees growing around city home lawns in adapting to a warmer climate.
The findings are published in Frontiers in Ecology and the Environment.
The researchers were especially interested in understanding the various tree species in cities and correlations between native biodiversity and capacity for tree species to adapt to climate change in terms of water usage and tolerating droughts.
These implications are relevant given that droughts and water shortages in the U.S. are projected to become more frequent in the future.
Using previously published National Science Foundation (NSF) project data from six cities on how land-use changes have made urban areas similar — in Boston, Baltimore, Los Angeles, Miami, Minneapolis-St. Paul, and Phoenix, Arizona — the researchers analyzed tree and shrub species in large public parks with natural areas that were relatively unmanaged and residential yards. They also analyzed reference sites representing the native ecosystems of the region that have been replaced by urban landscapes. Each of the cities represents a different ecological biome, or community of plants and animals, in a particular climate.
When the researchers compared the tree species across the three land-use types within each of the cities, they found that species in parks and natural areas were more drought-tolerant and reflected greater native biodiversity than those in people’s yards.
Most of the tree species found in residential yards were not only non-native, which can lead to species invasion in natural ecosystems, and were also low in drought tolerance and therefore may not be able to survive warmer temperatures expected in the future.
Prior research has found that approximately 30% of the land area in the U.S. is residential land, illustrating that trees planted in yards comprise a large percentage of the trees in an urban forest.
“There has been a lot of emphasis on tree planting in cities but what people are planting in their yards may not necessarily be sustainable in our warming climate,” says lead author Giselle Mejía, a postdoctoral fellow in the Department of Environmental Studies at Dartmouth. “In terms of sustainability standards, we recommend planting trees that are more diverse, more native, and also more climate adaptable in the future.”
“Planting trees that are drought tolerant and require less water than other species is something that should be considered,” says Mejía.
This is already the case for especially dry cities like Phoenix and Los Angeles, which had the most drought-tolerant species in parks and reference sites than any of the other biomes.
Trees in the hottest cities, Los Angeles, Miami, and Phoenix, had the most species with low water-use capacity in addition to drought tolerance. These included the widely planted native species Cornus florida (flowering dogwood) and Magnolia grandiflora (southern magnolia) and non-native species, also known as introduced species, Pyrus calleryana (callery pear) and Schinus terebinthifolius (Brazilian pepper).
“We need to understand the characteristics that people are looking for when they choose a tree to plant in their yard, so that educational platforms and incentives can be created to help get people on board with planting trees that would benefit all of us and potentially adapt to future climate change,” says Mejía.
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