Summer 2023 was the hottest on record by a huge margin. Hundreds of millions of people suffered as heat waves cooked Europe, Japan, Texas and the Southwestern U.S. Phoenix hit 110 degrees Fahrenheit (43 degrees Celsius) for a record 54 days, including a 31-day streak in July. Large parts of Canada were on fire. Lahaina, Hawaii, burned to the ground.

As an atmospheric scientist, I get asked at least once a week if the wild weather we’ve been having is “caused” by climate change. This question reflects a misunderstanding of the difference between weather and climate.

Consider this analogy from the world of sports: Suppose a baseball player is having a great season, and his batting average is twice what it was last year. If he hits a ball out of the park on Tuesday, we don’t ask whether he got that hit because his batting average has risen. His average has gone up because of the hits, not the other way around. Perhaps the Tuesday homer resulted from a fat pitch, or the wind breaking just right, or because he was well rested that day. But if his batting average has doubled since last season, we might reasonably ask if he’s on steroids.

Unprecedented heat and downpours and drought and wildfires aren’t “caused by climate change” – they are climate change.

The rise in frequency and intensity of extreme events is by definition a change in the climate, just as an increase in the frequency of base hits causes a better’s average to rise.

And as in the baseball analogy, we should ask tough questions about the underlying cause. While El Niño is a contributor to 2023’s extreme heat, that warm event has only just begun. The steroids fueling extreme weather are the heat-trapping gases from burning coal, oil and gas for energy around the world.

Nothing ‘normal’ about it

A lot of commentary uses the framing of a “new normal,” as if our climate has undergone a step change to a new state. This is deeply misleading and downplays the danger. The unspoken implication of “new normal” is that the change is past and we can adjust to it as we did to the “old normal.”

Unfortunately, warming won’t stop this year or next. The changes will get worse until we stop putting more carbon dioxide and other greenhouse gases into the atmosphere than the planet can remove.

The excess carbon dioxide humans have put into the atmosphere raises the temperature – permanently, as far as human history is concerned. Carbon dioxide lingers in the atmosphere for a long time, so long that the carbon dioxide from a gallon of gasoline I burn today will still be warming the climate in thousands of years.

That warming increases evaporation from the planet’s surface, putting more moisture into the atmosphere to fall as rain and snow. Locally intense rainfall has more water vapor to work with in a warmer world, so big storms drop more rain, causing dangerous floods and mudslides like the ones we saw in Vermont, California, India and other places around the world this year.

By the same token, anybody who’s ever watered the lawn or a garden knows that in hot weather, plants and soils need more water. A hotter world also has more droughts and drying that can lead to wildfires.

So, what can we do about it?

Not every kind of bad weather is associated with burning carbon. There’s scant evidence that hailstorms or tornadoes or blizzards are on the increase, for example. But if summer 2023 shows us anything, it’s that the extremes that are caused by fossil fuels are uncomfortable at best and often dangerous.

Without drastic emission cuts, the direct cost of flooding has been projected to rise to more than US$14 trillion per year by the end of the century and sea-level rise to produce billions of refugees. By one estimate, unmitigated climate change could reduce per capita income by nearly a quarter by the end of the century globally and even more in the Global South if future adaptation is similar to what it’s been in the past. The potential social and political consequences of economic collapse on such a scale are incalculable.

Fortunately, it’s quite clear how to stop making the problem worse: Re-engineer the world economy so that it no longer runs on carbon combustion. This is a big ask, for sure, but there are affordable alternatives.

Clean energy is already cheaper than old-fashioned combustion in most of the world. Solar and wind power are now about half the price of coal- and gas-fired power. New methods for transmitting and storing power and balancing supply and demand to eliminate the need for fossil fuel electricity generation are coming online around the world.

In 2022, taxpayers spent about $7 trillion subsidizing oil and gas purchases and paying for damage they caused. All that money can go to better uses. For example, the International Energy Agency has estimated the world would need to spend about $4 trillion a year by 2030 on clean energy to cut global emissions to net zero by midcentury, considered necessary to keep global warming in check.

Just as the summer of 2023 was among the hottest in thousands of years, 2024 will likely be hotter still. El Niño is strengthening, and this weather phenomenon has a history of heating up the planet. We will probably look back at recent years as among the coolest of the 21st century.

This article was updated Sept. 15, 2023, with NOAA and NASA also confirming summer 2023 the hottest on record.

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.

Earthquakes, large and small, happen every single day along zones that wrap around the world like seams on a baseball. Most don’t bother anybody, so they don’t make the news. But every now and then a catastrophic earthquake hits people somewhere in the world with horrific destruction and immense suffering.

On Sept. 8, 2023, a magnitude 6.8 earthquake in the Atlas Mountains of Morocco shook ancient villages apart, leaving thousands of people dead in the rubble. In February 2023, a large area of Turkey and Syria was devastated by two major earthquakes that hit in close succession.

As a geologist, I study the forces that cause earthquakes. Here’s why some seismic zones are very active while others may be quiet for generations before the stress builds into a catastrophic event.

Earth’s crust crashes into itself and pulls apart

Earthquakes are part of the normal behavior of the Earth. They occur with the movement of the tectonic plates that form the outer layer of the planet.

You can think of the plates as a more or less rigid outer shell that has to shift to allow the Earth to give off its internal heat.

These plates carry the continents and the oceans, and they are continuously in slow-motion crashes with one another. The cold and dense oceanic plates dive under continental plates and back into Earth’s mantle in a process known as subduction. As an oceanic plate sinks, it drags everything behind it and opens a rift somewhere else that is filled by rising hot material from the mantle that then cools. These rifts are long chains of underwater volcanoes, known as mid-ocean ridges.

Earthquakes accompany both subduction and rifting. In fact, that is how the plate boundaries were first discovered.

In the 1950s, when a global seismic network was established to monitor nuclear tests, geophysicists noticed that most earthquakes occur along relatively narrow bands that either fringe the edges of ocean basins, as in the Pacific, or cut right down the middle of basins, as in the Atlantic.

They also noticed that earthquakes along subduction zones are shallow on the oceanic side but get deeper under the continent. If you plot the earthquakes in 3D, they define slablike features that trace the plates sinking into the mantle.

An experiment: How an earthquake works

To understand what happens during an earthquake, put the palms of your hands together and press with some force. You are modeling a plate boundary fault. Each hand is one plate, and the surface of your hands is the fault. Your muscles are the plate tectonic system.

Now, add some forward force to your right hand. You will find that it will eventually jerk forward when the forward force overcomes the friction between your palms. That sudden forward jerk is the earthquake.

Scientists explain earthquakes using what’s known as the elastic rebound theory.

Fast plates move at up to 8 inches (20 centimeters) per year, driven mostly by the oceanic slabs sinking at subduction zones. Over time, they become stuck to each other by friction at the plate boundary. The attempted motion deforms the plate boundary zone elastically, like a loaded spring. At some point, the accumulated elastic energy overcomes the friction and the plate jerks forward, causing an earthquake.

But the plate-driving forces do not stop, so the plate boundary starts to accumulate elastic energy again, which will cause another earthquake – perhaps soon or perhaps far in the future.

In the oceans, plate boundaries are narrow and well defined because the underlying rocks are very stiff. But within the continents, plate boundaries are often broad zones of deformed mountainous terrain crisscrossed by many faults. Those faults may persist for eons, even if the plate boundary becomes inactive. That is why sometimes earthquakes occur far from plate boundaries.

Earthquakes, fast and slow

The cyclic behavior of faults allows seismologists to estimate earthquake risks statistically. Plate boundaries with fast motions, such as the ones along the Pacific rim, accumulate elastic energy rapidly and have the potential for frequent large-magnitude earthquakes.

Slow-moving plate boundary faults take longer to reach a critical state. Along some faults, hundreds or even thousands of years can pass between large earthquakes. This allows time for towns to grow and for people to lose ancestral memory of past earthquakes.

The earthquake in Morocco is an example. Morocco is located on the boundary between the African and the Eurasian plates, which are slowly crashing into each other.

The huge belt of mountains that extends from the Atlas of North Africa to the Pyrenees, Alps and most of the mountains across southern Europe and the Middle East is the product of this plate collision. Yet because these plate motions are slow near Morocco, large earthquakes are not so frequent.

Preparing for the big one

An important fact about catastrophic earthquakes is that, in most cases, the earthquakes don’t kill people – falling buildings do.

Most Americans have heard of California’s San Andreas Fault and the seismic risk to San Francisco and Los Angeles. The last major earthquake along the San Andreas Fault hit at Loma Prieta, in the San Francisco Bay area, in 1989. Its magnitude, 6.9, was comparable to that of the earthquake in Morocco, yet 63 people died compared with thousands. That’s largely because building codes in these earthquake-prone U.S. cities are now designed to keep structures standing when the Earth shakes.

The exceptions are tsunamis, the huge waves generated when an earthquake shifts the seafloor, displacing the water above it. A tsunami that hit Japan in 2011 had horrific consequences, regardless of the quality of engineering in coastal towns.

Unfortunately, earthquake scientists can’t predict exactly when an earthquake might occur; they can only estimate the hazard.

Jaime Toro, Professor of Geology, West Virginia University

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

On Sept. 12, 2023, the Centers for Disease Control and Prevention recommended the newly formulated COVID-19 vaccines for all Americans ages 6 months and up, hours after its expert advisory committee voted 13 to 1 in favor of recommending the vaccines.

The CDC’s broad recommendation comes one day after the Food and Drug Administration approved Moderna’s and Pfizer’s updated mRNA vaccines that target a previously dominant variant of the omicron family called XBB.1.5. The updated shots will be available to the public within days.

The Conversation asked Prakash Nagarkatti and Mitzi Nagarkatti, a husband and wife team of immunologists from the University of South Carolina, to weigh in on how the new vaccines might stand up against the latest COVID-19 variants that are swirling across the globe.

1. How are the new vaccines different from the previous?

When the first vaccine against COVID-19 was rolled out in December 2020, it was designed as a monovalent vaccine, meaning that it was formulated against only the original SARS-CoV-2 virus. That vaccine, as well as the updated ones, target the spike protein, which the virus uses to infect our cells and cause the disease.

That design made sense before the virus began mutating into a complex family tree of variants and sublineages. But as the virus structure shifted over time, the antibodies produced in response to the original vaccine became less effective against the new variants.

This necessitated the development in 2022 of new “bivalent” vaccines that targeted both the original strain of SARS‑CoV‑2 and new viral variants such as the omicron BA.4 and BA.5 lineages that were dominant in mid-2022.

But, not surprisingly, new variants of the virus continued to emerge.

In June 2023, the FDA asked vaccine developers to formulate new fall shots to target the then-dominant XBB.1.5 subvariant.

The FDA approved that monovalent mRNA-based vaccine based on the overall efficacy data presented by the vaccine manufacturers.

Unfortunately, XBB.1.5 is no longer the dominant strain in the U.S.; it has been displaced by other variants from the XBB lineage, thereby raising concerns about the potential efficacy of the new shot. As of mid-September, the dominant variants nationwide are EG.5, also known as Eris, followed by FL.1.5.1 – called Fornax – and XBB.1.16.6.

Meanwhile, a new highly mutated omicron offshoot, BA.2.86, nicknamed Pirola, is making its way across the globe – albeit so far in small numbers.

2. Who should get a new shot?

The CDC recommended that everyone ages 6 months old and up should get an updated COVID-19 vaccine so that they can be better protected against developing serious outcomes from COVID-19, including hospitalization. The agency noted that people who received the 2022-2023 bivalent COVID-19 shot “saw greater protection against illness and hospitalization than those who did not.”

Most Americans will be able to get the newly formulated vaccine at no cost, according to the CDC.

The FDA approved a single shot of the updated vaccine for anyone ages 5 and older – regardless of whether they were previously vaccinated or not. The agency also approved unvaccinated individuals 6 months to 4 years of age to receive three doses of the updated Pfizer vaccine or two doses of the updated Moderna vaccine.

3. How effective could the updated shot be against the latest variants?

Based on its current assessment, the CDC indicates that the BA.2.86 variant may be able to cause infection even in people who have been previously vaccinated or those who have had COVID-19 infection in the past. But the CDC says it still expects the updated fall 2023 booster shot to be effective at reducing severe disease and hospitalization.

Moderna reported in August 2023 that the new monovalent mRNA COVID-19 vaccine gave a “significant boost” in antibodies that are protective against two of the currently circulating variants: EG.5 – which is responsible for most cases in the U.S. as of mid-September – and FL.1.5.1. Then, in early September, Moderna announced that its most recent data from human trials showed an 8.7-fold increase in neutralizing antibodies against the newest variant, BA.2.86, following vaccination with the updated shot.

Similarly, new pre-clinical data from Pfizer shows that its version of the new mRNA vaccine produced antibodies that were effective at neutralizing the XBB.1.5, BA.2.86 and EG.5.1 variants.

This early research suggests that the new mRNA vaccines – although developed specifically against XBB.1.5 – are still effective against some of the most prevalent variants.

Novavax, which specializes in traditional protein-based vaccines, also announced in August that its updated COVID-19 vaccine directed against the XBB variant produced a broad neutralizing antibody response against key variants in animal studies. However, the company does not yet have data on its vaccine’s performance against two other key variants, FL.1.5.1 and BA.2.86. The Novavax vaccine has not yet gone up for FDA review, but its approval is also expected within months.

It is important to keep in mind that while all three vaccines have been shown to trigger antibodies that can neutralize most of the currently circulating variants, it is unclear whether the vaccines will be able to effectively prevent COVID-19 infection in humans. Such clinical studies are time-consuming, so given the urgency and speed needed to develop vaccines against the ever-changing COVID-19 variants, vaccine manufacturers rely on antibody levels as an indicator of protection.

4. Is there a ‘right’ time to get the new vaccine?

Antibodies produced after a COVID-19 infection or vaccination last for about six months, and then their levels start declining. This is called “waning immunity.”

About a year after getting a COVID-19 infection or vaccination, only a small fraction of antibodies can be detected. This is why health care providers recommend getting another shot if a year has passed since you were vaccinated or had an active infection.

It has become very clear that vaccines against COVID-19 do not provide 100% protection against catching a new COVID-19 infection, but they can make illness from the infection milder, shorter or both.

In addition, vaccines provide significant protection from hospitalization and death and may help protect against developing long COVID.

Viral infections normally peak in the winter, which is why experts advise getting both COVID-19 and flu vaccine shots in the months of September and October. For convenience, the two shots can be safely taken at the same time. This is because the immune cells that produce antibodies against one vaccine agent are distinct from those that produce antibodies against the other vaccine agent.

However, taking two different vaccines at the same time could cause more side effects, such as fever, aches and pain. This is especially the case for people who have experienced such side effects in the past after taking the COVID-19 and flu vaccines separately.

In addition, a newly approved vaccine against the respiratory syncytial virus, or RSV, is now recommended for people ages 60 and up.

5. Should some people wait for the updated Novavax vaccine?

The Moderna and Pfizer vaccines use the more recent vaccine technology based on mRNA, which instructs the body to produce a protein from a small portion of the SARS-CoV-2 virus. The immune system responds by producing antibodies.

In contrast, the Novavax vaccine relies on a more traditional approach to vaccine production, injecting the viral protein directly into the body to stimulate antibody production. So while the two vaccine types use different pathways to trigger antibodies against the virus, the end result is the same.

The CDC has reported rare cases of myocarditis, which is inflammation of the heart muscle, following vaccination with the Moderna and Pfizer mRNA vaccines. However, the same is true of the Novavax vaccine. So all three vaccines carry this very rare risk.

It is noteworthy that myocarditis is most frequently seen in adolescent and young adult males.

Although some people may have a preference for the traditional protein-based vaccine by Novavax, those who are at higher risk of catching COVID-19 should not wait for the approval of the Novavax vaccine to get their shot.

Prakash Nagarkatti, Professor of Pathology, Microbiology and Immunology, University of South Carolina and Mitzi Nagarkatti, Professor of Pathology, Microbiology and Immunology, University of South Carolina

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

As people, we are all shaped by the neighborhoods we grew up in, whether it was a bustling urban center or the quiet countryside. Objects in distant outer space are no different.

As an astronomer at the University of Arizona, I like to think of myself as a cosmic historian, tracking how supermassive black holes grew up.

Like you, every supermassive black hole lives in a home – its host galaxy – and a neighborhood – its local group of other galaxies. A supermassive black hole grows by consuming gas already inside its host galaxy, sometimes reaching a billion times heavier than our Sun.

Theoretical physics predicts that black holes should take billions of years to grow into quasars, which are extra bright and powerful objects powered by black holes. Yet astronomers know that many quasars have formed in only a few hundred million years.

I’m fascinated by this peculiar problem of faster-than-expected black hole growth and am working to solve it by zooming out and examining the space around these black holes. Maybe the most massive quasars are city slickers, forming in hubs of tens or hundreds of other galaxies. Or maybe quasars can grow to huge proportions even in the most desolate regions of the universe.

Galaxy protoclusters

The largest object that can form in the universe is a galaxy cluster, containing hundreds of galaxies pulled by gravity to a common center. Before these grouped galaxies collapse into a single object, astronomers call them protoclusters. In these dense galaxy neighborhoods, astronomers see colliding galaxies, growing black holes and great swarms of gas that will eventually become the next generation of stars.

These protocluster structures grow much faster than we thought, too, so we have a second cosmic problem to solve – how do quasars and protoclusters evolve so quickly? Are they connected?

To look at protoclusters, astronomers ideally obtain images, which show the galaxy’s shape, size and color, and a spectrum, which shows the galaxy’s distance from Earth through specific wavelengths of light, for each galaxy in the protocluster.

With telescopes like the James Webb Space Telescope, astronomers can see galaxies and black holes as they were billions of years ago, since the light emitted from distant objects must travel billions of light-years to reach its detectors. We can then look at protoclusters’ and quasars’ baby pictures to see how they evolved at early times.

It is only after looking at spectra that astronomers determine whether the galaxies and quasars are actually close together in three-dimensional space. But getting spectra for every galaxy one at a time can take many more hours than any astronomer has, and images can show galaxies that look closer together than they actually are.

So, for a long time, it was only a prediction that massive quasars might be evolving at the centers of vast galactic cities.

An unprecedented view of quasar environments

Now, Webb has completely revolutionized the search for galaxy neighborhoods because of an instrument called a wide-field slitless spectrograph.

This instrument takes spectra of every galaxy in its field of view simultaneously so astronomers can map out an entire cosmic city at once. It encodes the critical information about galaxies’ 3D locations by capturing the light emitted from gas at specific wavelengths – and in only a few hours of observing time.

The first Webb projects are hoping to look at quasar environments focused on a period about 800 million years after the Big Bang. This time period is a sweet spot in which astronomers can view these monster quasars and their neighbors using the light emitted by hydrogen and oxygen. The wavelengths of these light features show where the objects emitting them are along our line of sight, allowing astronomers to complete the census of where galaxies live relative to bright quasars.

One such ongoing project is led by the ASPIRE team at the University of Arizona’s Steward Observatory. In an early paper, they found a protocluster around an extremely bright quasar and confirmed it with 12 galaxies’ spectra.

Another study detected over a hundred galaxies, looking toward the single most luminous quasar known in the early universe. Twenty-four of those galaxies were close to the quasar or in its neighborhood.

In ongoing work, my team is learning more details about mini galaxy cities like these. We want to figure out if individual galaxies show high rates of new star formation, if they contain large masses of old stars or if they are merging with one another. All these metrics would indicate that these galaxies are still actively evolving but had already formed millions of years before we observed them.

Once my team has a list of the properties of the galaxies in an area, we’ll compare these properties with a control sample of random galaxies in the universe, far away from any quasar. If these metrics are different enough from the control, we’ll have good evidence that quasars do grow up in special neighborhoods – ones developing much faster than the more sparse regions of the universe.

While astronomers still need more than a handful of quasars to prove this hypothesis on a larger scale, Webb has already opened a window into a bright future of discovery in glorious, high-resolution detail.

Jaclyn Champagne, JASPER Postdoctoral Researcher, University of Arizona

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