These Covid-19 vaccine candidates could change the way we make vaccines — if they work

As urgency mounts for a Covid-19 coronavirus vaccine, a key question for scientists is whether this pandemic will be the watershed moment for two new technologies that have never before seen widespread use in humans. If proven effective, these approaches could dramatically speed up the development of other new vaccines and drastically lower costs, heralding a new era in the fight against infectious disease.

The main technologies gaining traction are vaccines that use an adenovirus vector and mRNA. Rather than construct a new vaccine from scratch, the idea behind these technologies is to use a standard set of parts, like a repurposed virus or a nanoparticle, to carry genetic material into a cell. That material — DNA or RNA — can then code for specific proteins from a virus.

Once one of these delivery platforms are proven safe, it’s just a matter of tweaking DNA and RNA strands. That’s much faster than conventional vaccines, which involve culturing large quantities of viruses that are then weakened, inactivated, or separated into tiny fragments and purified — processes that require years of cumbersome trial-and-error and safety testing.

“If the new platforms work in a way, that may actually change how other vaccines are produced,” Rahul Gupta, senior vice president and chief medical and health officer at the March of Dimes, told reporters during a National Press Foundation webinar on August 7. “So we may be at the cusp of very much a new technology that we’re going to see for the first time in over a century, basically.”

Researchers using these new platforms have recently posted some encouraging results. On Thursday, the pharmaceutical giant Pfizer published results of its phase 1 and phase 2 clinical trials for its mRNA-based vaccine platform in the journal Nature. Moderna is now entering phase 3 trials for its mRNA platform for Covid-19.

Meanwhile, Oxford University’s Jenner Institute is partnering with AstraZeneca to develop a vaccine using an adenovirus vector platform. It has also published some early promising results.

But there is a lot of competition, with more than 200 coronavirus vaccine candidates under investigation around the world. Two dozen are undergoing testing in humans, and six are in phase 3 clinical trials as of August 13.

A vaccine effort of this scale is astonishing for a disease that was discovered less than a year ago. But the immense health and economic devastation of the Covid-19 pandemic has prompted an unprecedented level of collaboration among scientists, as well as funding from governments, private companies, and philanthropists. That’s why some scientists expect there will be enough data proving the safety and efficacy of a Covid-19 vaccine in record time, possibly by the end of the year or early 2021. An effective, widely available vaccine would be a major step toward ending the pandemic.

However, there is no guarantee that any of these candidates will succeed, let alone whether a new vaccine technology will triumph over tried-and-true methods. Although companies working with the new platforms have readily cleared the earlier stages of clinical trials, they are now at the mercy of larger, slower phase 3 trials, where a lot can happen to derail their progress.

That’s why it’s important to understand how these novel strategies for preventing infection work, what they bring to the table, and the critical caveats to consider.

How most older vaccines work

Vaccines work by coaching the immune system to fight off a specific pathogen. When you get one, your white blood cells are being introduced to a potential threat, such as a virus or bacterium. That gives the immune system time to start mounting a response so that if the pathogen shows up another time, the body can quickly neutralize it.

Vaccines have been around in various forms for centuries, but the 20th century saw a boom in new ones for diseases such as polio, anthrax, pneumonia, meningitis, Hepatitis A, and influenza.

The conventional strategies for constructing vaccines that offer strong, long-lasting immunity involve mimicking the target. One of the most effective ways to do this is with a live attenuated vaccine. Here, a live form of the virus or bacterium is cultivated in such a way that it is weakened when given to a human. The pathogen can reproduce somewhat, but rarely enough to make the recipient sick. The most common vaccines — against smallpox, measles, mumps, and rubella — use live attenuated viruses.

Vaccines can also target toxic products of a bacterium or virus. Toxoid vaccines, like those for diphtheria and tetanus, are stable and safe but often require multiple doses.

Another approach is to use an inactivated version of the pathogen, usually a live pathogen that has been deliberately killed by heat or with a chemical treatment. This is the approach behind vaccines for diseases like Hepatitis A and rabies. Inactivated pathogen vaccines also often require more than one dose or boosters to retain immunity.

But instead of using whole-virus or bacterium particles, scientists can also use purified fragments of a pathogen — known as antigens — to trigger an immune reaction. These subunit vaccines tend to be stable, but they’re tricky to do right and often generate a weaker immune response than whole-pathogen vaccines.

Developing a vaccine using any of these methods, however, is time-consuming, often taking more than a decade to demonstrate that they’re safe and effective. That’s far too long during a pandemic like the one sweeping the world right now.

The new Covid-19 vaccine platforms harness human cells to make key components

Both mRNA vaccines and adenovirus vector vaccines build on the idea of a subunit vaccine. In the case of SARS-CoV-2, the virus that causes Covid-19, the most common subunit of interest is the spike protein.

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This protein is the business end of the virus. It’s what the coronavirus uses to dock with the ACE2 receptor on a human cell in order to enter the cell, make copies of itself, and then spread to other cells.

Scientists reason that they can coax the immune system to generate antibodies to this spike protein. Antibodies are proteins made by the immune system that attach to specific parts of a pathogen, thereby disabling it or marking it for destruction by other immune cells. If antibodies bind to the spike protein of a live SARS-CoV-2 virus, they could prevent it from causing an infection.

But with these new platforms, it’s not the spike protein of the virus that’s being injected, it’s the genetic instructions for making it. The main differences between mRNA vaccines and adenovirus vector vaccines are the genetic material they use and how they get it into the cell. The mRNA vaccines use mRNA, while adenovirus vaccines use DNA.

Once the instructions are inside the cell, the cell’s machinery reads them to manufacture the spike protein of the virus. The newly minted spike proteins are either secreted from the cell or attached to its surface, where other cells from the immune system can identify the spike protein and begin manufacturing antibodies to it.

The process ends up not only mimicking a key structure of the virus but also imitating how the virus works during an infection, which could potentially generate a stronger immune response and yield better protection compared with other approaches. And because these proteins are produced from within cells rather than injected from the outside, they may be less likely to provoke adverse reactions in the recipient.

How mRNA vaccines work

On August 11, President Donald Trump announced that the US government would buy 100 million doses of Moderna’s mRNA coronavirus vaccine in a deal valued at $1.53 billion, bringing the country’s total investment in the company to $2.48 billion. (The Department of Health and Human Services previously said it would buy 100 million doses of Pfizer’s mRNA vaccine.)

These are just a couple of the big bets the federal government has placed on different vaccine manufacturers, but the fact that it’s investing so much in a new approach like mRNA signals how much promise it holds.

mRNA stands for messenger ribonucleic acid. It’s a molecule that’s copied from DNA in a cell’s nucleus and used as the code for making a specific protein. If you think of the DNA in the nucleus as a giant cookbook containing all the recipes for all the meals you’ll ever eat, mRNA is the notecard you use to jot down instructions for making your favorite banana bread.

Compared to DNA, mRNA is shorter in length, less stable, and designed to be disposable. Your cells are making and breaking down mRNA strands all the time.

With an mRNA vaccine, the idea is to get a segment of mRNA that codes for a specific viral protein into a cell. For vaccine developers, that means that instead of going through the tedious process of isolating and purifying subunits of a virus, they can just change the code in a strand of mRNA. That makes the development process much faster than conventional approaches, which can take months or years.

“mRNA can literally be completed in days to weeks to create a brand-new vaccine,” said Drew Weissman, a professor of medicine at the University of Pennsylvania. He noted that it took only 66 days from when the genome of the SARS-CoV-2 virus was sequenced to when the first patient was injected with an mRNA-based Covid-19 vaccine.

One of the challenges with using mRNA is that your body can perceive it as a threat, as many viruses use RNA to encode their genomes. There are a lot of enzymes in the body that can readily digest RNA before it gets into a cell. (There are even RNA-digesting enzymes on your skin.) Free-floating mRNA strands in the body can trigger inflammation, so to shield the mRNA until it gets into a cell, developers encase it inside a lipid nanoparticle — a tiny oil bubble. The RNA strand itself is also modified to make it less inflammatory.

Once the mRNA is coded, modified, and encapsulated, it can then be injected. “All modified RNA vaccines for Covid are given intramuscularly, just like old-fashioned flu shots,” Weissman said.

While mRNA is getting a lot of attention, similar approaches are also undergoing tests. Inovio is developing a coronavirus vaccine that uses a double-stranded ring of DNA known as a plasmid. It requires a hand-held device to induce an electric current near the injection site, causing pores within the cell to open, which allows the plasmid to enter. The instructions in the plasmid can then be used to make viral proteins. The company expects to start phase 3 trials in September.

How recombinant adenovirus vector vaccines work

The other new vaccine platform technology for Covid-19 is the adenovirus vector. This is the approach companies such as CanSino Biologics and Johnson & Johnson are using for their vaccines. It’s also the basis for the famous vaccine candidate from Oxford University’s Jenner Institute, which is being developed with AstraZeneca and is now in phase 3 clinical trials.

The Russian government announced this week that it has an adenovirus vector vaccine for Covid-19, too. Dubbed Sputnik V, the vaccine has been registered for use, though many researchers outside of Russia are concerned that the vaccine gained approval without going through the full battery of clinical trials.

Adenoviruses are a family of viruses that usually cause mild illnesses with symptoms resembling those of a common cold or influenza, though an infection can be dangerous for people who have compromised immune systems or certain preexisting conditions.

“This suggests that they are less pathogenic and they can inherently induce protective immunity through nasal routes for respiratory infections,” University of Alberta Faculty of Medicine and Dentistry professor Babita Agrawal, who studies the immune system, said in an email. “Therefore, a vaccine based on [an adenovirus vector] could be certainly a good vaccine candidate against SARS-CoV-2.”

The virus itself is usually less than 100 nanometers in diameter and shaped like an icosahedron — a 20-sided shape with triangle faces, similar to D20 dice. At its corners, it has fibers that stick out.

The adenovirus is very efficient at getting into cells. Researchers have experimented with the adenovirus for years as a tool for gene therapy but are now applying it to vaccines.

Scientists figured out they could modify the virus to harness its breaking-and-entering skills without causing an infection. Instead, the virus can deliver a piece of genetic material inside a cell, serving as a vector.

In the case of Covid-19, researchers are again looking at getting the instructions for making the spike protein of SARS-CoV-2 into the cell.

The way it works is that researchers take the genome of the adenovirus and cut out the section that allows it to reproduce. Then they splice in a section of DNA that codes for the spike protein, turning the adenovirus into a recombinant vector.

Because the adenovirus is a DNA virus, it has to get its genetic material not just into a cell but into the cell’s nucleus.

“It goes into the nucleus, but it does not insert into the genome,” said Hildegund C.J. Ertl, a professor at the Wistar Institute’s Vaccine & Immunotherapy Center. “It’s a fairly transient effect.”

Once in the nucleus, the DNA coding for the spike protein is transcribed into mRNA and then transported out of the nucleus into the cell’s cytoplasm, where it’s translated into protein.

So if the modified virus can’t reproduce, how do scientists make more of them? William Wold, chair of the molecular microbiology and immunology department at the Saint Louis University School of Medicine, explained that recombinant viruses are cultured in cell lines that provide the missing hardware to allow them to make copies of themselves. “It’s easy to make large batches of the virus,” said Wold. But without these engineered cells, the virus can’t spread.

However, there are some drawbacks. Because versions of the adenovirus spread in humans, there are many people who have immunity. To get around this, groups like the team at Oxford are using a chimpanzee adenovirus as a vector, which is different enough from human adenoviruses that most people’s immune systems won’t react to it right away.

But once a vaccine is delivered using a chimpanzee adenovirus, it’s likely that many people would develop immunity to the new vector. That would make it difficult to use the same platform again for another vaccine.

The new Covid-19 vaccine platforms still face the same hurdles as conventional approaches: Phase 3 clinical trials and manufacturing

While new vaccine approaches have helped speed up early development, they are now entering phase 3 trials, where tens of thousands of people are randomly selected to receive either the vaccine or a placebo. Simply recruiting enough suitable participants can take weeks. Many vaccine candidates, including those using the new platforms, require two doses, often several weeks apart. Concluding the trials depends on waiting and seeing how the virus spreads among those who received the vaccine and those who didn’t. That can take months.

“The one thing you can’t truncate are these phase 3 trials,” Paul Offit, director of the Vaccine Education Center at the Children’s Hospital of Philadelphia, told reporters during the National Press Foundation webinar. “The proof is in the pudding. Phase 3 is the pudding.”

The main challenge will be demonstrating that the vaccines actually provide protection against the coronavirus. In clinical trials, researchers have found that both mRNA and adenovirus vaccines can make the body produce antibodies to the virus and trigger a response from immune cells.

Those are good signs, but they don’t guarantee that the vaccine recipient is shielded from infection. For Covid-19, the specific combination of responses from the body that indicate whether someone is immune to the virus remains unknown. This combination is called the correlate of protection, or the correlate of immunity.

Without knowing the correlate of protection for Covid-19, researchers can find out if a vaccine is effective only when it’s tested against the actual virus. That means waiting to see how vaccinated people respond when they’re exposed.

Phase 3 trials also provide an important final safety check. Most side effects related to these new vaccine platforms — fever, muscle pain, soreness, chills — have been pretty minor in early clinical trials. But more significant and less-frequent complications could emerge during large-scale testing, when people with imperfect health or preexisting conditions start receiving the vaccines. It’s important to ensure that such problems are rare, since a Covid-19 vaccine would potentially have to be given to billions of people.

If a new vaccine platform does get approval, making enough vaccines will be the next challenge. The world has decades of experience producing conventional vaccines, but companies are still learning how to manufacture the new platforms in large quantities.

“The starting line is a little further back. We don’t have the reassurance from the widespread use of the same technology in a different vaccine,” said Jesse Goodman, a professor of medicine at Georgetown University and former chief scientist at the Food and Drug Administration. “For example, when we had the 2009 [H1N1] influenza pandemic, those vaccines were made using the technology and facilities and manufacturing processes that we used every year for flu vaccines.”

It’s one thing to make small batches of an mRNA or adenovirus vaccine in a laboratory. It’s quite a different endeavor to make billions of doses on multiple assembly lines in different parts of the world. Such large-scale production would need a global supply chain and validation to ensure that the facilities provide a consistent product. That infrastructure has yet to be built.

And since the majority of the world remains vulnerable to the disease, any coronavirus vaccine will need to be deployed on a much larger scale than existing vaccines in order to limit the spread of the virus.

That’s pushing governments and institutions to take some unprecedented steps to prepare. “The one thing that’s happened with this vaccine that I’ve never seen happen before is that pharmaceutical companies have already started making vaccines for people, even if they haven’t been approved yet,” Weissman said.

But there’s still no guarantee that any coronavirus vaccine will come to fruition. The first vaccine across the line may not be the best one; multiple vaccines for different population subsets, such as the elderly, will likely be needed. So even if an mRNA vaccine or adenovirus vaccine for Covid-19 gains approval, it may be prudent to continue pursuing a conventional vaccine as well.

And vaccines alone are not enough. Ending the Covid-19 pandemic will still demand measures like social distancing until sufficient numbers of people are vaccinated to create herd immunity. Although the timing of when a phase 3 trial for a Covid-19 vaccine might conclude is largely out of our hands, we can set the stage for the end of the pandemic now by limiting the spread of this deadly disease.


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A simpler, more useful way to tax carbon

For most of the 21st century, putting a price on carbon dioxide emissions (either a carbon tax or a cap-and-trade system) has been seen as the serious person’s climate-change policy, preferred by economists, claimed to have bipartisan appeal, and backed relentlessly by tribunes of Beltway conventional wisdom like the Washington Post editorial board.

In the past few years, though, carbon pricing has fallen out of favor with activists. These days, the left has aligned around standards, investments, and justice: sector-specific emissions standards, large-scale public spending on low-carbon infrastructure, and an overarching focus on the most vulnerable and hardest-hit communities.

Nonetheless, it would be wrong to say that the bulk of climate opinion has turned against carbon pricing. Relatively few people think it’s a bad or entirely useless policy. They just see it as one tool in the policy toolbox, a complement to, not a replacement for, the many other policy tools available. Climate campaigners would prefer a carbon price with more modest aspirations, designed as part of a policy portfolio.

Academia has heard this call and, lo, it hath delivered.

The latest issue of the journal Nature Climate Change contains a study that attempts to sketch out a new approach to pricing carbon, one that does not suffer from the arrogance and overreach of previous attempts. (The authors are Noah Kaufman and Peter Marsters of Columbia University’s Center on Global Energy Policy, Wojciech Krawczyk and Haewon McJeon of the University of Maryland, and Alexander R. Barron of Smith College — I’ll just call it the Kaufman paper.)

Rather than the conventional method of determining a carbon price, which involves wildly uncertain far-future climate projections from scientists and a whole range of social value judgments from economists, they advocate for a more modest approach, with prices tied to short-term goals and arrived at through democratic deliberation. It’s a refreshingly practical approach, a way to help policymakers rather than dictating to them.

Let’s look at the details. I’ll start with the big flaw of carbon pricing to date — the problem the authors are trying to solve — and then take a look at how they propose to solve it.

Carbon pricing has been arrogant in its pretensions and its aspirations

Cap-and-trade systems (which cap emissions and create tradable emissions credits) have largely lost their cachet. California’s system is faltering; the Northeast’s Regional Greenhouse Gas Initiative is still running smoothly, but its effects are modest. Policymakers and economists have come to fear that the markets cap-and-trade creates are subject to manipulation and that they can’t ratchet toward zero emissions fast enough.

And so, what carbon-pricing action there is these days is around carbon taxes. (There are several carbon-tax proposals floating around Congress.)

Traditionally, the more enthusiastic carbon tax advocates have leaned on two flawed assumptions. The first is that there is an “optimal” price for carbon, which perfectly captures the balance between the costs of climate damages and the costs of decarbonizing. The second is that, once that price is determined, a tax on carbon is the “first best” and only necessary policy; other carbon-reduction policies will just distort the perfect market balance struck by the price.

The “optimal” carbon price is known in the biz as the “social cost of carbon” (SCC). The pretense of the social cost of carbon is that economists will add up all the projected damages of climate change to determine the all-in marginal cost of an additional ton of emissions. The tax on carbon will be set at that amount, which means we will purchase exactly as much climate mitigation as is “worth it.”

However, economists cooking up an optimal carbon price and presenting it to policymakers as a fait accompli fails to meet the public’s needs in three big ways.

First, determining climate damages is a wildly complex undertaking. It involves models built on a whole panoply of assumptions and inputs, many of which, the Kaufman paper says, are “inherently uncertain, such as the appropriate discount rates, risk aversion levels, issues around inequality, and attempts to assign monetary values to non-economic climate damages.”

Because of the complexity and uncertainties, the range of values produced by economists for the social cost range widely. “Meta-analyses find recent SCC estimates that range from under US$0 per ton of CO2 to over US$2,000 per ton,” the paper writes. Even if the outliers are excluded, estimates still range by hundreds of dollars. That doesn’t give policymakers much to go on.

Second, all of those uncertain variables — equity, the value of future generations, the value of other species — are buried in models, where they are effectively invisible to policymakers. Assigning value to these variables involves social and ethical decisions, but those decisions are being made by economists rather than through democratic deliberation. Policymakers have no real way of knowing what kinds of considerations produce what kinds of prices.

And third, the values for the social cost of carbon spit out by models have no connection to the policy goals they are meant to serve. They are not designed to achieve particular ends and their effects are uncertain, which, again, isn’t very helpful for policymakers.

The social cost produced by this contentious and values-laden process is meant to capture all the damage done by carbon emissions, meaning it is designed to be the principle, even only, carbon-reduction policy. But that assumes that unpriced carbon is the only market distortion that needs addressing, which flies in the face of real-world experience. The best economic and political theory now suggests that a portfolio approach to climate change, a broad package of policies, has the best chances of success.

But a carbon tax designed around the social costs is designed to be totalizing — it offers no guidance for how to craft a carbon price meant to complement other policies.

There’s a better way to design a carbon tax

Kaufman and his co-authors propose an alternative design framework for a carbon tax: a near-term to net zero (NT2NZ) approach.

In a nutshell, rather than asking what the optimal carbon price is in some econo-metaphysical sense, the approach begins by asking: Given other policies in place and a reasonable set of assumptions, what price on carbon is required to drive emissions to net zero on schedule?

This approach has a number of advantages. It doesn’t require any complex calculations about the damages of climate change decades hence, so the biggest uncertainties are taken off the table and it can produce much more precise, actionable price estimates. It puts values-based decisions about social and ethical trade-offs in the hands of policymakers rather than economists. And it is reverse-engineered from specific policy goals, so it doesn’t require any guessing about its effects. In all these ways, it is much more tangibly useful to policymakers.

To see how these advantages play out, let’s look at the four steps the authors lay out for designing a near-term to net-zero carbon tax.

1) Pick a date to hit net zero

The climate situation is simple: either the world reaches net-zero carbon emissions or global temperatures keep rising forever. Every nation must reach net zero; the only choice is how fast. Different countries will move at different speeds depending on their individual circumstances, level of economic development, and risk valuations. These decisions should be made by policymakers, out in the open.

2) Craft an emissions pathway to the net-zero target

As the Kaufman paper notes, “an infinite number of pathways are conceivable between current emissions levels and a future net-zero target.” Some pathways emphasize near-term reductions. Others emphasize R&D aimed at larger reductions later. Some rely on electrification, some include biofuels, some include nuclear power, some include negative emissions. Some are “straight line” reductions, others show a peak and then a decline.

Again, decisions about the appropriate pathway should be made by policymakers, based on national circumstances and values.

3) Determine the carbon price consistent with the emissions pathway in the near term

Energy-economic models can be used to estimate a carbon price that will help meet the desired target. Unlike the models that estimate SCC, energy-economic models can integrate the effects of multiple policies, so they can show a carbon tax how to be a team player.

The models and their projections are built on assumptions about the future trajectory of energy technologies, consumer behavior, and policy. Those things are more difficult to predict the farther out in the future, so these kinds of models are generally most useful when planning for the short term, the next decade or so. Beyond that, the assumptions become educated guesses.

So Kaufman et. al recommend that the models be used to determine near-term carbon prices rather than to guess what prices might need to be in 2050. “Focusing on the near term,” they say, “means that CO2 price estimates should not be unduly influenced by assumptions about the highly uncertain long-term evolution of technologies and behavior.”

In short, they urge that plans be made based on what we can see immediately ahead of us, not hopes for technological miracles decades out.

4) Periodically repeat steps 1-3

Knowledge in the fields of climate, energy, and technology evolves rapidly; policymakers should periodically set new goals and craft new pathways based on the latest science and democratic opinion.

There are a variety of ways to do this kind of “adaptive management.” Carbon prices could be adjusted automatically based on predetermined metrics — boosted if interim emission targets are not being met, or lowered if energy prices rise too high. Or prices could be adjusted every five years through an inclusive stakeholder process.

“Pairing a long-term emissions target with a set of iterative near-term policies is not novel,” the paper says. “The United Kingdom, for example, has adopted a national target of net-zero GHG emissions by 2050 and sets five-year carbon budgets to act as stepping-stones.” This approach fits well with the Paris climate agreement, which requires countries to submit new nationally determined contributions (NDCs, or commitments to reduce greenhouse gases) every five years.

NT2NZ carbon taxes in the US would be high, but not ridiculously high

To illustrate, Kaufman et. al determine near-term to net-zero carbon prices for the US that would yield straight-line emission reductions to a series of net-zero targets.

The chart below tells the tale. On the left, you can see the emission pathways to net-zero in 2040, 2050, and 2060 respectively. On the right, you can see the carbon prices necessary to reach those targets: $32, $52, and $93 per metric ton in 2025, with prices almost double that in 2030.

The black bar lines on the right-hand chart represent the range of carbon tax proposals currently before Congress, revealing that the near-term to net-zero prices are roughly within the range of what lawmakers are discussing.

As the colored bars on the right show, each estimate is actually a fairly wide range. That has to do with the sensitivity of models to a variety of assumptions, from the cost of various energy sources to the rate of innovation to the success of complementary policies. If any of those variables unfold differently than Kaufman et al. have projected, then the carbon price estimates would change accordingly.

The chart below shows how much changes in these variables affect the final price estimates. As you can see, a great deal depends on the price of oil and the success of other policies, both of which are extremely difficult to predict.

Setting near-term to net-zero carbon prices is not easy. It still requires tons of judgment calls about future developments. But at least this approach puts those judgment calls on the table where policymakers can see them.

The politics of the near-term to net-zero approach

The near-term to net-zero model has a great deal to recommend it over the conventional social cost of carbon method. It is a more modest approach to carbon pricing, more iterative, cooperative, transparent, and democratic. It is much more concretely helpful to policymakers than the endless cosmic quest to determine a precise social cost.

In a sense, however, its strengths are also its vulnerabilities. All those value-laden decisions previously made by economists in spreadsheets would be open to public dispute and manipulation. Every time policymakers revisited the tax, it would be a chance for vested interests to make mischief and complicate it with exemptions and conditions.

Basically, the near-term to net-zero approach exposes carbon pricing directly to democracy. Whether you think that’s a good idea or not depends on your assessment of the health of the world’s big democracies. There is certainly a school of thought that says complex decisions like this should be made by experts — something like California’s model, where the state legislature sets broad targets and direction and the Air Resources Board carries them out.

But if the world is truly to reach net zero, all the world’s polities will eventually have to buy into the effort. It can’t be done successfully if driven purely from the top down. When polities and policymakers are ready, they will find a carbon price a helpful tool, and the modest approach is a helpful way of crafting one.


Will you become our 20,000th supporter? When the economy took a downturn in the spring and we started asking readers for financial contributions, we weren’t sure how it would go. Today, we’re humbled to say that nearly 20,000 people have chipped in. The reason is both lovely and surprising: Readers told us that they contribute both because they value explanation and because they value that other people can access it, too. We have always believed that explanatory journalism is vital for a functioning democracy. That’s never been more important than today, during a public health crisis, racial justice protests, a recession, and a presidential election. But our distinctive explanatory journalism is expensive, and advertising alone won’t let us keep creating it at the quality and volume this moment requires. Your financial contribution will not constitute a donation, but it will help keep Vox free for all. Contribute today from as little as $3.

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Hurricane Laura hits Gulf Coast as an “extremely dangerous” storm

The National Hurricane Center warned that Hurricane Laura will cause “life-threatening storm surge” reaching up to 40 miles inland and rising up to 20 feet as the storm made landfall in Texas and Louisiana.

Laura reached the Gulf Coast after midnight on Thursday morning at an “extremely dangerous” Category 4 strength, with winds reaching 140 mph. After landfall, it weakened to a still dangerous Category 2 storm.

During a Wednesday news conference, Louisiana Gov. John Bel Edwards said Laura’s storm surge would reach levels not seen since 1957’s Hurricane Audrey.

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“The storm surge flooding is starting now in Louisiana,” Edwards said. “It’s well ahead of the storm. It will just get worse over the next day or so.”

Texas Gov. Greg Abbott implored residents to evacuate. “The conditions of this storm are unsurvivable, and I urge Southeast Texans to take advantage of these final few hours to evacuate, secure their property, and take all precautions to keep themselves and their loved ones safe,” he said at a Wednesday press conference.

Laura is expected to cause flash floods and a life-threatening storm surge in areas from High Island, Texas, to the mouth of the Mississippi River, inundating places that rarely see such high water levels.

About 20 million people reside in the path of the storm and more than 500,000 have been ordered to evacuate, a task complicated by the Covid-19 pandemic.

“The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline,” the NHC reported in its latest hurricane bulletin. Storm surge, where high winds push water inland several feet above high tide, is often the deadliest consequence of hurricanes.

Laura may also spawn tornadoes and drench the Gulf Coast with up to 10 inches of rainfall. Initially, Laura was projected to make landfall alongside Hurricane Marco, but Marco weakened to tropical storm strength and quickly fizzled out as it made landfall on Tuesday.

Laura, on the other hand, underwent rapid intensification, a hallmark of several recent major hurricanes. Rapid intensification is defined as a gain of 35 mph or more in wind speed over 24 hours. In Laura’s case, the storm went from below hurricane strength with 65 mph winds early Tuesday to Category 4 strength on Wednesday, then weakened somewhat to a Category 2 storm after hitting land, with winds still dangerously high. Further weakening is expected on Thursday.

The storm’s US landfall comes amid an unusually active hurricane season, one that the National Oceanic and Atmospheric Administration predicted back in May.

For Gulf Coast residents, Laura is stirring eerie echoes of past storms. Hurricane Harvey in 2017 swept over Texas at Category 4 strength and inundated Houston with a gargantuan amount of rain that left the city soaked for weeks.

Laura is also making landfall in the US around the 15th anniversary of Hurricane Katrina, a Category 5 storm that resulted in 1,200 deaths as it struck New Orleans. Both Harvey and Katrina are tied as the costliest storms on record. Laura is now the strongest August hurricane in the Gulf of Mexico since Katrina, Colorado State University meteorologist Phil Klotzbach told USA Today. The storm is believed to have killed at least 23 people in Haiti and the Dominican Republic.

The destruction recent storms caused was fueled by coastal development in vulnerable areas as well as climate change amplifying sea-level rise, and the damaging elements of extreme weather like heavy rainfall.

It’s likely Laura will also come with a high price tag. “I do expect this to be a multi-billion dollar disaster,” said meteorologist Jeff Masters on a conference call with reporters on Tuesday.

Forecasts show that Laura’s current course takes the storm far inland to states like Arkansas before hooking east on Friday.

How to follow Hurricane Laura:

  • The National Hurricane Center has a page updating every few hours with the latest watches and warnings for Laura. Check it out.
  • Follow the National Hurricane Center on Twitter; it will provide updates with all the latest forecasts, hazards, and warnings.
  • Follow the Capital Weather Gang’s Twitter account. These folks tend to live-tweet storm updates.
  • Here’s a Twitter list of weather experts via meteorologist and journalist Eric Holthaus. These experts will give you up-to-the-second forecasts and warnings.

New goal: 25,000

In the spring, we launched a program asking readers for financial contributions to help keep Vox free for everyone, and last week, we set a goal of reaching 20,000 contributors. Well, you helped us blow past that. Today, we are extending that goal to 25,000. Millions turn to Vox each month to understand an increasingly chaotic world — from what is happening with the USPS to the coronavirus crisis to what is, quite possibly, the most consequential presidential election of our lifetimes. Even when the economy and the news advertising market recovers, your support will be a critical part of sustaining our resource-intensive work — and helping everyone make sense of an increasingly chaotic world. Contribute today from as little as $3.

What makes California’s current major wildfires so unusual

Wildfires continue burning in California, with unhealthy air from smoke still cloaking some parts of the state. Combined with the Covid-19 pandemic, the fires are compounding risks that have been brewing for years.

Fire officials have grouped some of the smaller fires in an area into complexes to coordinate their response. The largest of these is the SCU Lightning Complex. It had burned more than 365,000 acres as of Wednesday across parts of the southern San Francisco Bay Area, including Santa Clara and Alameda counties. The SCU Lightning Complex was 25 percent contained as of Wednesday morning.

To the north, the LNU Lighting Complex near Napa has burned more than 357,000 acres and destroyed or damaged 937 structures. Thousands were forced to evacuate. The fire was 33 percent contained as of Wednesday morning, and officials anticipate the flames could spread further.

At least 650 wildfires have raged across the Golden State, burning more than 1.25 million acres, since August 15, leaving at least seven people dead, according to Cal Fire.

Many of the blazes were ignited by a massive dry lightning storm last week concentrated in the San Francisco Bay Area.

“We had close to 11,000 strikes in a matter of three days,” said Brice Bennett, a spokesperson for the California Department of Forestry and Fire Protection (Cal Fire). “With an already-warm weather pattern and very, very dry conditions here in California, with those lightning strikes coming through, over 367 new fires were started.”

Smoke, soot, and ash from the fires also shrouded Northern California in the dirtiest air in the world at several points last week.

Wildfires are nothing new for Californians, who have grown wearily accustomed to the destruction, smoke, and evacuations in recent years. But this summer’s blazes stand out for their scale, timing, locations, and intensity, even among recent record-breaking fire seasons. And as David Wallace-Wells writes for New York’s Intelligencer, “What is most remarkable about the fires of 2020 is that these complexes are burning without the aid of dramatic wind, which is typically, even more than the tinder of dry scrub and forest, what really fuels California fire.”

The wildfires are just one of several disasters affecting California right now. The state has been in a two-decade megadrought, and was scorched by a record-breaking heat wave in early August, with several days in a row of temperatures reaching triple digits in some places, even at night. Temperatures in Death Valley topped 130 degrees Fahrenheit. That heat led to rolling blackouts as utilities struggled to meet cooling demand.

All the while, the Covid-19 pandemic is still a threat, making the already difficult task of controlling wildfires even harder.

Here are the factors that have fueled the recent fires and are now complicating the efforts to control them.

Extreme heat, strange storms, and climate change set the stage for California’s fires

The lightning storm around the San Francisco Bay Area that sparked many of the current California fires was a rare event.

“The last time we had something like this was over a decade ago, actually,” said Bennett. The fact that lightning started these fires is also noteworthy. The vast majority of wildfires in California are ignited from human sources — power lines, arson, neglected campfires, and so on.

But the fires wouldn’t have been so bad were it not also for the extreme heat that’s been baking the state for weeks.

“This is a big, big, prolonged heat wave characterized not only by hot daytime temperatures but also record-warm overnight temperatures and an unusual amount of humidity,” said Daniel Swain, a climate scientist at the University of California Los Angeles and a researcher at the National Center for Atmospheric Research. “It turns out increased humidity plays a role in why there are so many fires right now.”

A decaying tropical storm earlier this month in the eastern Pacific Ocean sent a plume of moisture over California. Amid the scorching heat, the moisture formed clouds that generated immense amounts of wind, thunder, and lightning but very little rain. “The humidity was high enough to produce these thunderstorms, but not high enough to produce significant flooding rainfall that would mitigate fire risk,” Swain said.

Much of California’s vegetation was also parched and primed to burn, and concerns that this would be an exceptionally bad fire year started to emerge in February as the state emerged from one of its driest winters on record. This was then followed by an abnormally hot spring. “There were a number of unusually significant early-season heat waves this spring both in Northern and in Southern California,” Swain said.

And California is now experiencing the impacts of climate change, which is manifesting in fires. The weather in California is becoming more volatile. Temperatures are also rising, which is causing the state’s forests, grasslands, and chaparral to dry out even more. The state already has millions of dead trees stemming from years of drought and pests like pine beetles. More heat could stress these ecosystems even further.

“It’s not just how hot are the heat waves; it’s how hot is it the rest of the time,” Swain said. “What really matters is the sustained warming and drying over seasons and years.”

Some of California’s current fires are in areas that don’t regularly burn

It’s important to remember that fires are a normal part of the ecology in California, from the coniferous forests in the Sierra Nevada to the chaparral shrubland in the south. Periodic blazes clear out decaying vegetation, restore nutrients to the soil, and help plants germinate.

Humans, however, continue to make California’s wildfires worse at every step. By suppressing naturally occurring fires, fuel has accumulated in forests and shrublands, increasing the danger when fires do ignite. People are also building closer to areas that are prone to burn. That increases the likelihood of starting fires and raises the blazes’ damage toll. People have also introduced invasive plant species like eucalyptus trees, which have spread throughout California and readily ignite. And burning fossil fuels emits greenhouse gases that are warming the planet, increasing the amount of vegetation that can burn.

Even with this backdrop, some of the fires in California stand out because they are raging in places that don’t burn very often.

“I think what’s key to understand is that different parts of California have very different normal fire seasons,” said Crystal Kolden, an assistant professor of fire science at the University of California Merced. “And that’s in part because California is such a big state. It has really variable topography and different vegetation or ecosystems across the state.”

Because the coastal forests are under the influence of marine weather systems, they are much cooler and retain more moisture than the pine forests of the Sierra Nevada and other inland areas. The coastal forests do burn periodically and are home to many species that have adapted to fire, but they rarely ignite during the summer.

That some portions of them have burned is remarkable, a product of high atmospheric pressure over the area that allowed heat to accumulate and overwhelm the cooling effect from the ocean. “Those coastal areas are incredibly dry, incredibly hot relative to normal, and that arid and hot condition had this potential to have really explosive fires,” Kolden said.

Covid-19 is adding a wallop to California’s fires

The Covid-19 pandemic has rattled every part of society, and firefighting efforts are not immune. “It definitely has affected our response, primarily in our inmate fire crews,” Bennett said.

California often relies on prison labor to bolster its firefighting efforts, with almost 200 inmate fire crews. Inmates are paid between $2 and $5 a day, plus $1 per hour when fighting a fire. But with severe Covid-19 prison outbreaks in the state, some inmates were released to relieve overcrowding. Others were hampered by infections, and many remain under quarantine. The number of available inmate fire crews has been nearly halved.

Anticipating a severe fire season, state officials did line up an additional 800 seasonal firefighters, but they have to take additional precautions. Fire crews are essentially staying in small bubbles, where they live and work with just each other, to help limit coronavirus transmission.

At base camps where fire crews rest and refuel, officials have designated more space for workers to maintain social distance.

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The state is also facing a budget crunch, with the economic slowdown because of the pandemic. That’s led some fire prevention maintenance measures — like clearing dry grass away from roads and buildings — to languish.

As for the Californians fleeing the fires, Covid-19 has made it harder to coordinate evacuations and shelters. The declining air quality from the wildfires is also a threat to people with Covid-19, since exposure to air pollution can damage airways and make people more susceptible to respiratory infection. Extreme heat also worsens the public health impact of Covid-19 as people spend more time in enclosed spaces together to avoid the heat.

And the current round of blazes may take weeks to extinguish, raising the concern that stiff autumn winds — the Santa Ana winds in the south and the Diablo winds in the north — may spread the flames again.


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Hurricane Laura: The danger of storm surge, explained

Hurricane Laura made landfall at 1 am ET Thursday in Cameron, Louisiana, as a fierce Category 4 hurricane with 150 mph winds. It has since downgraded to a Category 1 hurricane, with wind speeds of 75 mph, and is moving north.

But perhaps the most dangerous part of the storm may be the storm surge that still threatens coastal areas.

Storm surge, or coastal flooding, tends to be the deadliest aspect of hurricanes. It results from the storm’s winds pushing water onshore several feet above the normal tide, and it can trap people in their homes, wash away houses, and make rescue missions harrowing and slow. Rising sea levels linked to climate change have also increased the risk of storm surge and property damage in coastal cities and regions.

The National Hurricane Center (NHC) said Thursday morning a storm surge warning was still in effect from Sabine Pass, Texas to Port Fourchon, Louisiana; this kind of warning means a danger of life-threatening flooding. People located in these zones should follow evacuation and other instructions from local officials.

But so far, the highest storm surge reported seems is 9 feet, according to meteorologist Chris Gloninger:

But other meteorologists say it’s too soon to assess the total storm surge from Hurricane Laura. The water pushed on land by the winds could also still reach up to 40 miles inland “and flood waters will not fully recede for several days after the storm,” according to the NHC.

The larger the area with tropical storm-force winds, the more potential for those winds to push water onshore, and the greater the impact of storm surge, Colorado State University atmospheric scientist Chris Slocum says. Portions of Louisiana, Mississippi, and Arkansas could also see up to 6 to 12 inches of rain with isolated totals of 18 inches from Laura, which will add to the floodwaters.

The storm surge “is a life-threatening situation,” the NHC warns in its latest forecast. “Persons located within these areas should take all necessary actions to protect life and property from rising water and the potential for other dangerous conditions.”

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How to follow Hurricane Laura:

  • The National Hurricane Center has a page updating every few hours with the latest watches and warnings for Laura. Check it out.
  • Follow the National Hurricane Center on Twitter; it will provide updates with all the latest forecasts, hazards, and warnings.
  • Follow the Capital Weather Gang’s Twitter account. These folks tend to live-tweet storm updates.
  • Here’s a Twitter list of weather experts via meteorologist and journalist Eric Holthaus. These experts will give you up-to-the-second forecasts and warnings.

New goal: 25,000

In the spring, we launched a program asking readers for financial contributions to help keep Vox free for everyone, and last week, we set a goal of reaching 20,000 contributors. Well, you helped us blow past that. Today, we are extending that goal to 25,000. Millions turn to Vox each month to understand an increasingly chaotic world — from what is happening with the USPS to the coronavirus crisis to what is, quite possibly, the most consequential presidential election of our lifetimes. Even when the economy and the news advertising market recovers, your support will be a critical part of sustaining our resource-intensive work — and helping everyone make sense of an increasingly chaotic world. Contribute today from as little as $3.