By Jennifer Weeks
Oppressive heat across much of North America since the end of June has buckled roads and driven Major League Baseball players off the field. July is the warmest time of year for much of the nation, so more heat waves could develop in the coming weeks. These articles from our archive offer insight into heat wave impacts, and some ways to cope with them.
1. Air conditioning: Solution and Problem
As incomes rise in developing countries, millions of people are buying air conditioners. That's good news, since fewer people will be exposed to unhealthy temperatures. For example, economist Lucas Davis of the University of California, Berkeley predicts that nearly 100 percent of Mexicans will have air conditioning within a few decades.
But generating electricity to run all those ACs will produce huge quantities of carbon dioxide emissions from fossil fuel combustion, plus emissions of refrigerants that also are powerful greenhouse gases. Paradoxically, then, the spread of air conditioning could worsen climate change, heating the planet up even more.
Energy demand for space cooling is growing rapidly in India and around the world, driven by rising incomes. EIA
To avoid that scenario, air conditioners will need to become more energy-efficient, and power generation will have to shift to low- and zero-carbon sources, such as wind and solar power. In Davis' view, adopting a carbon tax would promote those shifts and provide incentive to design cooling features into buildings. "We need efficient markets if we are going to stay cool without heating up the planet," he wrote.
2. Urban Hot Spots
City dwellers are especially at risk during heat waves because built surfaces, such as roads and buildings, trap heat during the day and release it at night. And within these urban heat islands, groups with the fewest resources—typically, minorities and the poor—are most vulnerable.
In a study in Hartford, University of Connecticut anthropologist Merrill Singer found that low-income Latino residents were well aware that climate change was making their city hotter and worried about coping with summer heat waves:
"Participants reported feeling excluded from local preparatory efforts to mitigate adverse impacts. They said they received no information about preparing for climate change, except for notices that the city had started opening up a few cooling stations in the lobbies of air-conditioned buildings during the summer."
Singer's research shows the need to reach out to disadvantaged groups in analyzing how climate change will affect cities – and to ensure that all residents have a voice.
3. Many Tools for Cooling
Emergency cooling centers are one way to mitigate the effects of heat waves, but cities need to do more. Nick Rajkovich, assistant professor of architecture at the University at Buffalo, has worked with planners around Cleveland to understand how they prepare for hot weather. Strategies there include planting more trees and shrubs, which provide shade and cool the air; weatherizing buildings with window shades and light-colored, reflective materials; and preparing emergency kits for power outages that include food, water and radios.
Urban trees reduce air conditioning needs by 30%. They make cities greener, healthier & happier places to live… https://t.co/sI2GYsIg6R— United Nations (@United Nations)1521666157.0
Most importantly, in Rajkovich's view, different agencies and organizations need to talk to each other and plan together so they can take complementary steps. "In Cleveland, preparing for extreme heat events has brought professionals together and encouraged overlapping approaches because no single strategy is foolproof," he observed. Officials "should pursue multiple solutions rather than looking for one 'best' option."
4. Rooftop Solutions
One way to make buildings more heat-proof is to weatherize their roofs, either by painting them white to reflect heat (so-called "cool roofs") or covering them with plants, which cool by absorbing water. But both options require careful planning to ensure that they will be effective in particular locations.
Ashish Sharma, assistant professor of civil and environmental engineering at the University of Notre Dame, studied how well green and cool roofs reduced urban heat island effects in Chicago. He found that while both techniques had a net cooling effect, they also reduced breezes from nearby Lake Michigan and altered air circulation in their immediate neighborhoods.
Each of these approaches has pluses and minuses, Sharma notes. Green roofs provide habitat for plants and insects and can help clean the air by absorbing pollutants. However, they also increase humidity by releasing water from their leaves and cost more to install and maintain than cool roofs. Geography can factor into the choice:
"Cities in northern latitudes, such as New York, Portland and Toronto, can benefit from green roofs because they have adequate water to irrigate them. In contrast, cool roofs are more appropriate for cities in arid and semi-arid environments such as the southwestern United States."
5. Grounded by the Heat
Extreme heat affects physical structures as well as the people inside them. In 2017 extreme heat forced dozens of flight cancellations at airports in the U.S. Southwest—just when their passengers were probably thrilled to be escaping 120-degree temperatures.
As Columbia University's Radley Horton and Ethan Coffel explain, airplanes fly by generating lift through the flow of air over and under their wings. The amount of lift that a wing generates is affected by the density of the air, and warmer temperatures make air less dense. They write:
"The lower the air density, the faster an airplane must travel to produce enough lift to take off. It takes more runway to reach a higher speed, and depending on how long the airport's runway is, some airplanes might risk running out of room before reaching sufficient speed."
Sometimes airlines are forced to manage this issue by limiting how much weight planes can carry. Typically this happens at airports in hot regions, like Phoenix, or those with short runways, such as LaGuardia in New York City. But such measures could become much more common. Ultimately, Horton and Coffel predict, manufacturers could even have to redesign airplanes to operate safely in a hotter world.
Editor's note: This article is a roundup of stories from The Conversation's archive. Reposted with permission from our media associate The Conversation.
In 2010, world leaders agreed to 20 targets to protect Earth's biodiversity over the next decade. By 2020, none of them had been met. Now, the question is whether the world can do any better once new targets are set during the meeting of the UN Convention on Biodiversity in Kunming, China later this year.
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By Andrew Rosenberg
The first 24 hours of the administration of President Joe Biden were filled not only with ceremony, but also with real action. Executive orders and other directives were quickly signed. More actions have followed. All consequential. Many provide a basis for not just undoing actions of the previous administration, but also making real advances in public policy to protect public health, safety, and the environment.
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By Ana Maldonado-Contreras
- Your gut is home to trillions of bacteria that are vital for keeping you healthy.
- Some of these microbes help to regulate the immune system.
- New research, which has not yet been peer-reviewed, shows the presence of certain bacteria in the gut may reveal which people are more vulnerable to a more severe case of COVID-19.
You may not know it, but you have an army of microbes living inside of you that are essential for fighting off threats, including the virus that causes COVID-19.
How Do Resident Bacteria Keep You Healthy?<p>Our immune defense is part of a complex biological response against harmful pathogens, such as viruses or bacteria. However, because our bodies are inhabited by trillions of mostly beneficial bacteria, virus and fungi, activation of our immune response is tightly regulated to distinguish between harmful and helpful microbes.</p><p>Our bacteria are spectacular companions diligently helping prime our immune system defenses to combat infections. A seminal study found that mice treated with antibiotics that eliminate bacteria in the gut exhibited an impaired immune response. These animals had low counts of virus-fighting white blood cells, weak antibody responses and poor production of a protein that is vital for <a href="https://doi.org/10.1073/pnas.1019378108" target="_blank">combating viral infection and modulating the immune response</a>.</p><p><a href="https://doi.org/10.1371/journal.pone.0184976" target="_blank" rel="noopener noreferrer">In another study</a>, mice were fed <em>Lactobacillus</em> bacteria, commonly used as probiotic in fermented food. These microbes reduced the severity of influenza infection. The <em>Lactobacillus</em>-treated mice did not lose weight and had only mild lung damage compared with untreated mice. Similarly, others have found that treatment of mice with <em>Lactobacillus</em> protects against different <a href="https://doi.org/10.1038/srep04638" target="_blank" rel="noopener noreferrer">subtypes of</a> <a href="https://doi.org/10.1038/s41598-017-17487-8" target="_blank" rel="noopener noreferrer">influenza</a> <a href="https://doi.org/10.1371/journal.ppat.1008072" target="_blank" rel="noopener noreferrer">virus</a> and human respiratory syncytial virus – the <a href="https://doi.org/10.1038/s41598-019-39602-7" target="_blank" rel="noopener noreferrer">major cause of viral bronchiolitis and pneumonia in children</a>.</p>
Chronic Disease and Microbes<p>Patients with chronic illnesses including Type 2 diabetes, obesity and cardiovascular disease exhibit a hyperactive immune system that fails to recognize a harmless stimulus and is linked to an altered gut microbiome.</p><p>In these chronic diseases, the gut microbiome lacks bacteria that activate <a href="https://doi.org/10.1126/science.1198469" target="_blank" rel="noopener noreferrer">immune cells</a> that block the response against harmless bacteria in our guts. Such alteration of the gut microbiome is also observed in <a href="https://doi.org/10.1073/pnas.1002601107" target="_blank" rel="noopener noreferrer">babies delivered by cesarean section</a>, individuals consuming a poor <a href="https://doi.org/10.1038/nature12820" target="_blank" rel="noopener noreferrer">diet</a> and the <a href="https://doi.org/10.1038/nature11053" target="_blank" rel="noopener noreferrer">elderly</a>.</p><p>In the U.S., 117 million individuals – about half the adult population – <a href="https://health.gov/our-work/food-nutrition/2015-2020-dietary-guidelines/guidelines/" target="_blank" rel="noopener noreferrer">suffer from Type 2 diabetes, obesity, cardiovascular disease or a combination of them</a>. That suggests that half of American adults carry a faulty microbiome army.</p><p>Research in my laboratory focuses on identifying gut bacteria that are critical for creating a balanced immune system, which fights life-threatening bacterial and viral infections, while tolerating the beneficial bacteria in and on us.</p><p>Given that diet affects the diversity of bacteria in the gut, <a href="https://www.umassmed.edu/nutrition/melody-trial-info/" target="_blank" rel="noopener noreferrer">my lab studies show how diet can be used</a> as a therapy for chronic diseases. Using different foods, people can shift their gut microbiome to one that boosts a healthy immune response.</p><p>A fraction of patients infected with SARS-CoV-2, the virus that causes COVID-19 disease, develop severe complications that require hospitalization in intensive care units. What do many of those patients have in common? <a href="https://www.cdc.gov/mmwr/volumes/69/wr/mm6912e2.htm" target="_blank" rel="noopener noreferrer">Old age</a> and chronic diet-related diseases like obesity, Type 2 diabetes and cardiovascular disease.</p><p><a href="http://doi.org/10.1016/j.jada.2008.12.019" target="_blank" rel="noopener noreferrer">Black and Latinx people are disproportionately affected by obesity, Type 2 diabetes and cardiovascular disease</a>, all of which are linked to poor nutrition. Thus, it is not a coincidence that <a href="https://www.cdc.gov/mmwr/volumes/69/wr/mm6933e1.htm" target="_blank" rel="noopener noreferrer">these groups have suffered more deaths from COVID-19</a> compared with whites. This is the case not only in the U.S. but also <a href="https://www.washingtonpost.com/world/europe/blacks-in-britain-are-four-times-as-likely-to-die-of-coronavirus-as-whites-data-show/2020/05/07/2dc76710-9067-11ea-9322-a29e75effc93_story.html" target="_blank" rel="noopener noreferrer">in Britain</a>.</p>
Discovering Microbes That Predict COVID-19 Severity<p>The COVID-19 pandemic has inspired me to shift my research and explore the role of the gut microbiome in the overly aggressive immune response against SARS-CoV-2 infection.</p><p>My colleagues and I have hypothesized that critically ill SARS-CoV-2 patients with conditions like obesity, Type 2 diabetes and cardiovascular disease exhibit an altered gut microbiome that aggravates <a href="https://theconversation.com/exercise-may-help-reduce-risk-of-deadly-covid-19-complication-ards-136922" target="_blank" rel="noopener noreferrer">acute respiratory distress syndrome</a>.</p><p>Acute respiratory distress syndrome, a life-threatening lung injury, in SARS-CoV-2 patients is thought to develop from a <a href="http://doi.org/10.1016/j.cytogfr.2020.05.003" target="_blank" rel="noopener noreferrer">fatal overreaction of the immune response</a> called a <a href="https://theconversation.com/blocking-the-deadly-cytokine-storm-is-a-vital-weapon-for-treating-covid-19-137690" target="_blank" rel="noopener noreferrer">cytokine storm</a> <a href="http://doi.org/10.1016/S2213-2600(20)30216-2" target="_blank" rel="noopener noreferrer">that causes an uncontrolled flood</a> <a href="http://doi.org/10.1016/S2213-2600(20)30216-2" target="_blank" rel="noopener noreferrer">of immune cells into the lungs</a>. In these patients, their own uncontrolled inflammatory immune response, rather than the virus itself, causes the <a href="http://doi.org/10.1007/s00134-020-05991-x" target="_blank" rel="noopener noreferrer">severe lung injury and multiorgan failures</a> that lead to death.</p><p>Several studies <a href="https://doi.org/10.1016/j.trsl.2020.08.004" target="_blank" rel="noopener noreferrer">described in one recent review</a> have identified an altered gut microbiome in patients with COVID-19. However, identification of specific bacteria within the microbiome that could predict COVID-19 severity is lacking.</p><p>To address this question, my colleagues and I recruited COVID-19 hospitalized patients with severe and moderate symptoms. We collected stool and saliva samples to determine whether bacteria within the gut and oral microbiome could predict COVID-19 severity. The identification of microbiome markers that can predict the clinical outcomes of COVID-19 disease is key to help prioritize patients needing urgent treatment.</p><p><a href="https://doi.org/10.1101/2021.01.05.20249061" target="_blank" rel="noopener noreferrer">We demonstrated</a>, in a paper which has not yet been peer reviewed, that the composition of the gut microbiome is the strongest predictor of COVID-19 severity compared to patient's clinical characteristics commonly used to do so. Specifically, we identified that the presence of a bacterium in the stool – called <em>Enterococcus faecalis</em>– was a robust predictor of COVID-19 severity. Not surprisingly, <em>Enterococcus faecalis</em> has been associated with <a href="https://doi.org/10.1053/j.gastro.2011.05.035" target="_blank" rel="noopener noreferrer">chronic</a> <a href="https://doi.org/10.1016/S0002-9440(10)61172-8" target="_blank" rel="noopener noreferrer">inflammation</a>.</p><p><em>Enterococcus faecalis</em> collected from feces can be grown outside of the body in clinical laboratories. Thus, an <em>E. faecalis</em> test might be a cost-effective, rapid and relatively easy way to identify patients who are likely to require more supportive care and therapeutic interventions to improve their chances of survival.</p><p>But it is not yet clear from our research what is the contribution of the altered microbiome in the immune response to SARS-CoV-2 infection. A recent study has shown that <a href="https://doi.org/10.1101/2020.12.11.416180" target="_blank" rel="noopener noreferrer">SARS-CoV-2 infection triggers an imbalance in immune cells</a> called <a href="https://doi.org/10.1111/imr.12170" target="_blank" rel="noopener noreferrer">T regulatory cells that are critical to immune balance</a>.</p><p>Bacteria from the gut microbiome are responsible for the <a href="https://doi.org/10.7554/eLife.30916.001" target="_blank" rel="noopener noreferrer">proper activation</a> <a href="https://doi.org/10.1126/science.1198469" target="_blank" rel="noopener noreferrer">of those T-regulatory</a> <a href="https://doi.org/10.1038/nri.2016.36" target="_blank" rel="noopener noreferrer">cells</a>. Thus, researchers like me need to take repeated patient stool, saliva and blood samples over a longer time frame to learn how the altered microbiome observed in COVID-19 patients can modulate COVID-19 disease severity, perhaps by altering the development of the T-regulatory cells.</p><p>As a Latina scientist investigating interactions between diet, microbiome and immunity, I must stress the importance of better policies to improve access to healthy foods, which lead to a healthier microbiome. It is also important to design culturally sensitive dietary interventions for Black and Latinx communities. While a good-quality diet might not prevent SARS-CoV-2 infection, it can treat the underlying conditions related to its severity.</p><p><em><a href="https://theconversation.com/profiles/ana-maldonado-contreras-1152969" target="_blank">Ana Maldonado-Contreras</a> is an assistant professor of Microbiology and Physiological Systems at the University of Massachusetts Medical School.</em></p><p><em>Disclosure statement: Ana Maldonado-Contreras receives funding from The Helmsley Charitable Trust and her work has been supported by the American Gastroenterological Association. She received The Charles A. King Trust Postdoctoral Research Fellowship. She is also member of the Diversity Committee of the American Gastroenterological Association.</em></p><p><em style="">Reposted with permission from <a href="https://theconversation.com/a-healthy-microbiome-builds-a-strong-immune-system-that-could-help-defeat-covid-19-145668" target="_blank" rel="noopener noreferrer" style="">The Conversation</a>. </em></p>
By Jeff Masters, Ph.D.
The New Climate War: the fight to take back our planet is the latest must-read book by leading climate change scientist and communicator Michael Mann of Penn State University.
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