At this point in the COVID-19 pandemic, nearly everyone has experienced the panic and uncertainty that come with having mild COVID-like symptoms – such as a cough and sore throat – only to test negative day after day. With cold and flu season just around the corner, that state of frustrating uncertainty is likely to strike most of us again.

Both COVID-19 and the flu are contagious respiratory illnesses that have similar symptoms, making it difficult to distinguish between the two viral infections without a lab test. Testing is the only way to know which virus is causing your symptoms. In fact, labs are working to create one test that can detect both COVID-19 and the flu.

As a nursing professor with experience in public health promotion, I am often asked about the differences between the flu and COVID-19. This year I am fielding many questions about the timing of getting the new COVID-19 booster and the flu shot and whether they can be given together.

Parsing the symptoms

Symptoms of both COVID-19 and the flu can range from mild – or no noticeable symptoms at all – to severe. While flu infection does not typically affect one’s ability to taste or smell, loss of taste or smell has been a common symptom associated with COVID-19 infection. Both infections can cause fevers, chills, body aches and fatigue. More severe symptoms of either infection include difficulty breathing and subsequent infections like pneumonia.

During the 2021-2022 flu season, the term “flurona” made its way into the COVID-19 vernacular. Flurona refers to a simultaneous infection with both the flu and COVID-19. While only a few cases of co-infections have been reported, it would not be surprising to see more of them this coming flu season. Vaccination for both the flu and COVID-19 is your best protection against both.

Timing the shots

With the newly formulated COVID-19 booster shot now available and flu season just around the corner, a natural question is whether there is an optimal timing for the two shots.

The answer to that question is to get both as soon as possible. It is important to consider that it takes approximately two weeks after vaccination for the body to develop antibodies from both the COVID-19 vaccines and the flu vaccine.

As long as you have completed your primary COVID-19 vaccine series and it has been at least eight weeks since your last COVID-19 booster, now is the time to get the updated COVID-19 vaccine that targets both the original strain of SARS-CoV-2 – the virus that causes COVID-19 – and the most recent omicron subvariants. The original COVID-19 vaccines and booster series have dramatically reduced the number of COVID-19 infection and death rates, as well as cases of severe COVID-19 that lead to hospitalization.

While everyone 6 months of age and older are recommended to receive both the COVID-19 and flu vaccines, certain populations have a higher risk for severe infection, such as pregnant women, and should be extra vigilant about getting vaccinated.

Further, among those vaccinated against COVID-19, symptoms during an infection tend to be milder. However, due in part to the quickly evolving nature of the virus, it’s become clear that immune protection from COVID-19 vaccination or infection does not last forever. While studies show that the primary COVID-19 series maintains efficacy against severe disease and death six months after vaccination, protection against infection decreases by between 20% to 30% by six months after vaccination.

This decline in immune protection is exactly why booster shots are so critical. Without a large uptake of booster shots in the population, COVID-19 infection rates could surge again.

Timing is also important with the flu vaccine. Flu cases typically begin to rise in October and peak between December and February, but can last through May. Ideally, people should get vaccinated before flu begins to spread, making September or early October the ideal flu vaccination time.

A difficult flu season ahead

Due to lockdowns, reduced travel, school closures and mask mandates in the first and second years of the pandemic, both the 2020-2021 and 2021-2022 flu seasons were estimated to have fewer hospitalizations and deaths from the flu compared to many of the pre-pandemic years.

In the fall of 2021, experts became concerned about the potential for a COVID-19 and flu “twindemic,” especially as COVID-19 restrictions were lifting and masks were coming off. Fortunately, the worst didn’t bear out – flu numbers in the 2021-2022 season did not return to pre-pandemic levels. However, the possibility of a “twindemic” is not out of the picture for the coming flu season.

Flu seasons are inherently difficult to predict. With most people traveling again, schools open, mask mandates lifted and workers headed back to the office, people are undoubtedly going to be exposed to germs that they have been more protected from for the last two and a half years.

To further compound this, flu vaccine rates have been lower during the pandemic, suggesting that Americans may be out of the habit of getting their annual flu shot.

Pairing the shots

Many are also wondering whether they can or should get both the updated COVID-19 booster and the flu shot at the same time. The good news is, yes, it is safe for both adults and children 12 years of age and up who are eligible for the updated COVID-19 booster to get these vaccines simultaneously.

A recent study found that common vaccine side effects such as pain at the injection site occurred at slightly higher rates when someone received the flu vaccine and a COVID-19 vaccine at the same time, as opposed to receiving only a COVID-19 booster. However, those reactions, including fatigue and headache, were mild and resolved within a day or two.

You don’t need to make two separate vaccine visits as long as you are due for your next COVID-19 shot. However, I don’t recommend waiting to get your flu shot if you are not yet due for a COVID-19 booster. The Centers for Disease Control and Prevention suggests everyone receive their flu vaccine by the end of October. But if you miss that deadline, it is absolutely better to get vaccinated later in the season than not at all.

Community matters too

Getting the flu and COVID-19 vaccines isn’t just about your own health, it’s about family and community health too. Communities with higher vaccination rates have fewer opportunities to spread the virus.

Keep in mind that many people cannot be vaccinated because they have weakened immune systems or are undergoing treatments. They depend on those around them for protection. While one person may experience mild symptoms if they contract the flu or COVID-19, they could spread the virus to others who could become severely ill. Because it’s impossible to predict how people will react if they get sick, getting the flu and COVID-19 vaccines is the best prevention strategy.

Libby Richards, Associate Professor of Nursing, Purdue University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The U.S. Senate voted to ratify an international treaty on Sept. 21, 2022, and join 137 other countries in agreeing to phase out a class of climate-warming chemicals that are widely used as coolants in refrigerators, air conditioners and heat pumps.

If you’re getting a sense of déjà vu, don’t be surprised.

These chemicals, called hydrofluorocarbons, or HFCs, were commercialized in the 1990s as a replacement for earlier refrigerants that were based on chlorofluorocarbons, or CFCs. CFCs were destroying the ozone layer high in the Earth’s atmosphere, which is essential for protecting life from the Sun’s harmful ultraviolet radiation.

HFCs are less harmful than CFCs, but they create another problem – they have a strong heat-trapping effect that is contributing to global warming.

If HFCs can be phased down globally – as many countries have agreed to do under the 2016 Kigali Amendment to the Montreal Protocol, the treaty just ratified by the U.S. Senate on a bipartisan vote – that would avoid about half a degree Celsius of temperature rise compared to preindustrial times. China, a major producer of these chemicals, ratified the amendment effective Sept. 15, 2021. And the U.S. Environmental Protection Agency finalized a rule in 2021 to cut HFCs production and imports.

Let’s take a closer look at what HFCs are and what might replace them next.

How HFCs keep rooms and food cool

Refrigerators and air conditioning use a technology known as a heat pump. It sounds almost miraculous – heat pumps use energy to take heat out of a cold place and dump it in a warm place.

Here’s how a refrigerator works: A fluid – CFCs back in the old days, and now HFCs – circulates in the walls of the refrigerator, absorbing the ambient heat to keep the fridge cooled down. As that liquid absorbs the heat, it evaporates. The resulting vapor is pumped to the coils on the back of the refrigerator, where it is condensed back to a liquid under pressure. In the process, the heat that was absorbed from inside the fridge is released into the surrounding room.

Air conditioners and home heat pumps do the same thing: they use electric-powered compressors and evaporators to move heat into or out of a house.

Choosing the right fluid for a refrigerator means finding a substance that can be evaporated and condensed at the right temperatures by changing the pressure on the fluid.

CFCs seemed to fit the bill perfectly. They didn’t react with the tubing or compressors to corrode the equipment, and they weren’t toxic or flammable.

Unfortunately, the chemical stability of CFCs turned out to be a problem that threatened the whole world, as scientists discovered in the 1980s. Leaking CFCs, mostly from discarded equipment, remain in the atmosphere for a long time. Eventually they make their way to the stratosphere, where they are finally destroyed by UV radiation from the sun. But when they break down, they create chlorine that reacts with the protective ozone, letting dangerous radiation through to the Earth’s surface.

When production of CFCs was eliminated in the 1990s to protect the ozone layer, new refrigerants were developed and the industry shifted to HFCs.

Why HFCs are a climate problem

HFCs are like CFCs but much more reactive in air, so they never reach the stratosphere where they could harm Earth’s protective radiation shield. They largely saved the world from impending ozone disaster, and they are now found in refrigerators and heat pumps everywhere.

But while HFCs’ chemical reactivity prevents them from depleting the ozone layer, their molecular structure allows them to absorb a lot of thermal radiation, making them a greenhouse gas. Like carbon dioxide on steroids, HFCs are extremely good at capturing infrared photons emitted by the Earth. Some of this radiant energy warms the climate.

Unlike carbon dixoide, reactive HFCs are consumed by chemistry in the air, so they only warm the climate for a decade or two. But a little bit goes a long way – each HFC molecule absorbs thousands of times as much heat as a carbon dixoide molecule, making them powerful climate pollutants.

HFCs leaking from discarded cooling equipment are estimated to contribute about 4% of global greenhouse gas emissions – about twice as much as aviation.

This is why it’s time to retire HFCs and swap them out for alternative refrigerants. They’ve done their job saving the ozone layer, but now HFCs are a major contributor to short-term global warming, and their use has been increasing as demand for cooling increases around the world.

What can replace HFCs?

Because they are so powerful and short-lived, stopping the production and use of HFCs can have a significant cooling effect on the climate over the next couple of decades, buying time as the world converts its energy supply from fossil fuels to cleaner sources.

The good news is that there are alternative refrigerants.

Ammonia and hydrocarbons like butane evaporate at room temperature and have been used as refrigerants since the early 20th century. These gases are short-lived, but they have a downside. Their greater reactivity means their compressors and plumbing have to be more corrosion-resistant and leak-proof to be safe.

The chemical industry has been developing newer alternatives intended to be safer for both people and climate, but as we saw with CFCs and HFCs, inert chemicals can have unintended consequence. Several industry leaders have supported efforts to phase out HFCs.

So, it’s time for another generation of cooling equipment. Just as TVs and audio equipment and light bulbs have evolved over past decades, refrigerators and air conditioners will be replaced by a new wave of improved products. New refrigerators will look and work just like the ones we’re used to, but they will be much gentler on the climate system.

This updates an article originally published on May 4, 2021, with the U.S. Senate ratifying the Kigali Amendment.

Scott Denning, Professor of Atmospheric Science, Colorado State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Electric planes might seem futuristic, but they aren’t that far off, at least for short hops.

Two-seater Velis Electros are already quietly buzzing around Europe, electric sea planes are being tested in British Columbia, and larger planes are coming. Air Canada announced on Sept. 15, 2022, that it would buy 30 electric-hybrid regional aircraft from Sweden’s Heart Aerospace, which expects to have its 30-seat plane in service by 2028. Analysts at the U.S. National Renewable Energy Lab note that the first hybrid electric 50- to 70-seat commuter plane could be ready not long after that. In the 2030s, they say, electric aviation could really take off.

That matters for managing climate change. About 3% of global emissions come from aviation today, and with more passengers and flights expected as the population expands, aviation could be producing three to five times more carbon dioxide emissions by 2050 than it did before the COVID-19 pandemic.

Aerospace engineer and assistant professor Gökçin Çınar develops sustainable aviation concepts, including hybrid-electric planes and hydrogen fuel alternatives, at the University of Michigan. We asked her about the key ways to cut aviation emissions today and where technologies like electrification and hydrogen are headed.

Why is aviation so difficult to electrify?

Aircraft are some of the most complex vehicles out there, but the biggest problem for electrifying them is the battery weight.

If you tried to fully electrify a 737 with today’s batteries, you would have to take out all the passengers and cargo and fill that space with batteries just to fly for under an hour.

Jet fuel can hold about 50 times more energy compared to batteries per unit mass. So, you can have 1 pound of jet fuel or 50 pounds of batteries. To close that gap, we need to either make lithium-ion batteries lighter or develop new batteries that hold more energy. New batteries are being developed, but they aren’t yet ready for aircraft.

An electric alternative is hybrids.

Even though we might not be able to fully electrify a 737, we can get some fuel burn benefits from batteries in the larger jets by using hybrid propulsion systems. We are trying to make that happen in the short term, with a 2030-2035 target for smaller regional planes. The less fuel burned during flight, the fewer greenhouse gas emissions.

How does hybrid aviation work to cut emissions?

Hybrid electric aircraft are similar to hybrid electric cars in that they use a combination of batteries and aviation fuels. The problem is that no other industry has the weight limitations that we do in the aerospace industry.

That’s why we have to be very smart about how and how much we are hybridizing the propulsion system.

Using batteries as a power assist during takeoff and climb are very promising options. Taxiing to the runway using just electric power could also save a significant amount of fuel and reduce the local emissions at airports. There is a sweet spot between the added weight of the battery and how much electricity you can use to get net fuel benefits. This optimization problem is at the center of my research.

Hybrids would still burn fuel during flight, but it could be considerably less than just relying entirely on jet fuel.

I see hybridization as a mid-term option for larger jets, but a near-term solution for regional aircraft.

For 2030 to 2035, we’re focused on hybrid turboprops, typically regional aircraft with 50-80 passengers or used for freight. These hybrids could cut fuel use by about 10%.

With electric hybrids, airlines could also make more use of regional airports, reducing congestion and time larger planes spend idling on the runway.

What do you expect to see in the near term from sustainable aviation?

Shorter term we’ll see more use of sustainable aviation fuels, or SAF. With today’s engines, you can dump sustainable aviation fuel into the same fuel tank and burn it. Fuels made from corn, oilseeds, algae and other fats are already being used.

Sustainable aviation fuels can reduce an aircraft’s net carbon dioxide emissions by around 80%, but supply is limited, and using more biomass for fuel could compete with food production and lead to deforestation.

A second option is using synthetic sustainable aviation fuels, which involves capturing carbon from the air or other industrial processes and synthesizing it with hydrogen. But that’s a complex and costly process and does not have a high production scale yet.

Airlines can also optimize their operations in the short term, such as route planning to avoid flying nearly empty planes. That can also reduce emissions.

Is hydrogen an option for aviation?

Hydrogen fuel has been around a very long time, and when it’s green hydrogen – produced with water and electrolysis powered by renewable energy – it doesn’t produce carbon dioxide. It can also hold more energy per unit of mass than batteries.

There are two ways to use hydrogen in an airplane: either in place of regular jet fuel in an engine, or combined with oxygen to power hydrogen fuel cells, which then generate electricity to power the aircraft.

The problem is volume – hydrogen gas takes up a lot of space. That’s why engineers are looking at methods like keeping it very cool so it can be stored as liquid until it’s burned as a gas. It still takes up more space than jet fuel, and the storage tanks are heavy, so how to store, handle or distribute it on aircraft is still being worked out.

Airbus is doing a lot of research on hydrogen combustion using modified gas turbine engines with an A380 platform, and aiming to have mature technology by 2025. Australia’s Rex airline expects to start testing a 34-seat, hydrogen-electric airplane for short hops in the next few years.

Due to the variety of options, I see hydrogen as one of the key technologies for sustainable aviation.

Will these technologies be able to meet the aviation industry’s goals for reducing emissions?

The problem with aviation emissions isn’t their current levels – it’s the fear that their emissions will increase rapidly as demand increases. By 2050, we could see three to five times more carbon dioxide emissions from aviation than before the pandemic.

The International Civil Aviation Organization, a United Nations agency, generally defines the industry’s goals, looking at what’s feasible and how aviation can push the boundaries.

Its long-term goal is to cut net carbon dioxide emissions 50% by 2050 compared with 2005 levels. Getting there will require a mix of different technologies and optimization. I don’t know if we’re going to be able to reach it by 2050, but I believe we must do everything we can to make future aviation environmentally sustainable.

Gökçin Çınar, Assistant Professor of Aerospace Engineering, University of Michigan

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Astronomers now routinely discover planets orbiting stars outside of the solar system – they’re called exoplanets. But in summer 2022, teams working on NASA’s Transiting Exoplanet Survey Satellite found a few particularly interesting planets orbiting in the habitable zones of their parent stars.

One planet is 30% larger than Earth and orbits its star in less than three days. The other is 70% larger than the Earth and might host a deep ocean. These two exoplanets are super-Earths – more massive than the Earth but smaller than ice giants like Uranus and Neptune.

I’m a professor of astronomy who studies galactic cores, distant galaxies, astrobiology and exoplanets. I closely follow the search for planets that might host life.

Earth is still the only place in the universe scientists know to be home to life. It would seem logical to focus the search for life on Earth clones – planets with properties close to Earth’s. But research has shown that the best chance astronomers have of finding life on another planet is likely to be on a super-Earth similar to the ones found recently.

Common and easy to find

Most super-Earths orbit cool dwarf stars, which are lower in mass and live much longer than the Sun. There are hundreds of cool dwarf stars for every star like the Sun, and scientists have found super-Earths orbiting 40% of cool dwarfs they have looked at. Using that number, astronomers estimate that there are tens of billions of super-Earths in habitable zones where liquid water can exist in the Milky Way alone. Since all life on Earth uses water, water is thought to be critical for habitability.

Based on current projections, about a third of all exoplanets are super-Earths, making them the most common type of exoplanet in the Milky Way. The nearest is only six light-years away from Earth. You might even say that our solar system is unusual since it does not have a planet with a mass between that of Earth and Neptune.

Another reason super-Earths are ideal targets in the search for life is that they’re much easier to detect and study than Earth-sized planets. There are two methods astronomers use to detect exoplanets. One looks for the gravitational effect of a planet on its parent star and the other looks for brief dimming of a star’s light as the planet passes in front of it. Both of these detection methods are easier with a bigger planet.

Super-Earths are super habitable

Over 300 years ago, German philosopher Gottfried Wilhelm Leibniz argued that Earth was the “best of all possible worlds.” Leibniz’s argument was meant to address the question of why evil exists, but modern astrobiologists have explored a similar question by asking what makes a planet hospitable to life. It turns out that Earth is not the best of all possible worlds.

Due to Earth’s tectonic activity and changes in the brightness of the Sun, the climate has veered over time from ocean-boiling hot to planetwide, deep-freeze cold. Earth has been uninhabitable for humans and other larger creatures for most of its 4.5-billion-year history. Simulations suggest the long-term habitability of Earth was not inevitable, but was a matter of chance. Humans are literally lucky to be alive.

Researchers have come up with a list of the attributes that make a planet very conducive to life. Larger planets are more likely to be geologically active, a feature that scientists think would promote biological evolution. So the most habitable planet would have roughly twice the mass of the Earth and be between 20% and 30% larger by volume. It would also have oceans that are shallow enough for light to stimulate life all the way to the seafloor and an average temperature of 77 degrees Fahrenheit (25 degrees Celsius). It would have an atmosphere thicker than the Earth’s that would act as an insulating blanket. Finally, such a planet would orbit a star older than the Sun to give life longer to develop, and it would have a strong magnetic field that protects against cosmic radiation. Scientists think that these attributes combined will make a planet super habitable.

By definition, super-Earths have many of the attributes of a super habitable planet. To date, astronomers have discovered two dozen super-Earth exoplanets that are, if not the best of all possible worlds, theoretically more habitable than Earth.

Recently, there’s been an exciting addition to the inventory of habitable planets. Astronomers have started discovering exoplanets that have been ejected from their star systems, and there could be billions of them roaming the Milky Way. If a super-Earth is ejected from its star system and has a dense atmosphere and watery surface, it could sustain life for tens of billions of years, far longer than life on Earth could persist before the Sun dies.

Detecting life on super-Earths

To detect life on distant exoplanets, astronomers will look for biosignatures, byproducts of biology that are detectable in a planet’s atmosphere.

NASA’s James Webb Space Telescope was designed before astronomers had discovered exoplanets, so the telescope is not optimized for exoplanet research. But it is able to do some of this science and is scheduled to target two potentially habitable super-Earths in its first year of operations. Another set of super-Earths with massive oceans discovered in the past few years, as well as the planets discovered this summer, are also compelling targets for James Webb.

But the best chances for finding signs of life in exoplanet atmospheres will come with the next generation of giant, ground-based telescopes: the 39-meter Extremely Large Telescope, the Thirty Meter Telescope and the 24.5-meter Giant Magellan Telescope. These telescopes are all under construction and set to start collecting data by the end of the decade.

Astronomers know that the ingredients for life are out there, but habitable does not mean inhabited. Until researchers find evidence of life elsewhere, it’s possible that life on Earth was a unique accident. While there are many reasons why a habitable world would not have signs of life, if, over the coming years, astronomers look at these super habitable super-Earths and find nothing, humanity may be forced to conclude that the universe is a lonely place.

Chris Impey, University Distinguished Professor of Astronomy, University of Arizona

This article is republished from The Conversation under a Creative Commons license. Read the original article.