The World Health Organization made mistakes in its initial response to COVID-19, but as it comes under criticism, it's important to remember the world still needs the agency.

Why it matters: President Trump's decision this week to withhold money from the agency could damage its efforts to fight the next pandemic and other health threats. For all its problems, the WHO remains the only global institution charged with combating the global threat of infectious disease.

Background: Despite its grand name and purpose — to "keep the world safe" — the actual scope of the WHO is limited by both its budget and the political realities of international governance.

With a biennial budget of $6.3 billion, the WHO has about as much cash to spend as a large urban hospital system in the U.S., and significantly less than the U.S. Centers for Disease Control and Prevention.

• Like all UN agencies, the WHO is not independent in any real sense from its member countries.
• In the case of its early response to COVID-19, this meant the agency was ultimately dependent on the Chinese government. It wasn't until mid-February — weeks after the outbreak began in Wuhan — that a WHO team was permitted to enter China to begin investigations.

Early on, many WHO officials appeared to underplay the potential global threat posed by the novel coronavirus.

• What they're saying: In a press conference the day after Trump's attacks, WHO Director-General Tedros Adhanom Ghebreyesus told reporters the agency's performance would eventually be reviewed, as it was after previous outbreaks, but "for now, our focus — my focus — is on stopping this virus and saving lives."

What's next: Without a revolution in how national governments treat international governance, the WHO will likely continue operating under inherent limitations. But there are steps the agency could take to improve global disease response in particular.

• The WHO could be more transparent about what it can and what it can't do, and what it knows and what it doesn't know. While it may not be realistic for the WHO to publicly criticize a government like China for holding back information, it could make it clearer to the rest of the world what it isn't being told about an outbreak.

In an increasingly politically divided world, the need for a global broker of some kind on infectious disease will only grow. Geopolitics may still be driven by nation-states, but as we've learned with COVID-19, viruses do not respect borders.

• Defunding the WHO is like voting to "de-fund fire depart in the middle of a fire, on the grounds they ought to have got to the fire sooner," Lawrence Gostin, the director of the O'Neill Institute for National and Global Health Law at Georgetown University, tweeted on Thursday.
• While the focus with COVID-19 has been on the U.S. and China, the biggest losers in a world without the WHO would be poor countries that are much more dependent on the UN agency for assistance. And the next pandemic is just as likely to come from one of them.

The bottom line: An imperfect WHO is still better than a nonexistent one, and policymakers can make the best use of the agency if they fully understand what it can and cannot do.

A French startup has pioneered a new way of using enzymes to recycle plastics more efficiently than current methods.

Why it matters: Existing recycling procedures for many plastics downgrade the material, only staving off the day in which it will end up in a landfill. A method that could fully recycle plastics would be a game-changer.

Of the roughly 359 million tons of plastics produced each year worldwide, more than half ends up in a landfill or the natural environment.

• Part of the reason such a small percentage of plastics is recycled is that the material tends to degrade during the current recycling process. What remains can often only be used for low-value products.
• This is especially true for the most abundant form of plastics, PET, which is used in bottles and packaging.

The startup Carbios, founded in 2011, has discovered enzymes that can break down a plastic bottle in a matter of hours, producing leftover material good enough to reconstitute into new bottles.

How it works: The company analyzed tens of thousands of different enzymes found in environments polluted by PET. One enzyme, found in a heap of leaf compost, proved capable of reducing a PET bottle into chemical building blocks that could be used to make new, high-quality plastic bottles.

• Carbios is working on a demonstration plant south of Lyon, France, and if the work goes well, it expects to license the first commercial plant using its technology by 2024 or 2025.

"There is such a high demand for recycled plastic that we won't be able to meet the goals set by regulators and big brands without the introduction of new technology like this."

Yes, but: Like all new technologies, the key will be ensuring the process makes economic sense for recyclers at the commercial level.

A large portion of the American Southwest is in the grip of a climate change-induced megadrought, a new study finds.

The big picture: This is the first megadrought of the climate change era, and it comes at a time when expanding cities and farms in the region are demanding more and more water.

A megadrought is a severe drought that lasts not for months or even years but for decades, often over a vast amount of land.

• Geological records suggest the American Southwest has been hit by such megadroughts multiple times over the last few thousand years. But past megadroughts had been caused by natural weather fluctuations.

Driving the news: The new research, published in Science, indicates the current megadrought is at least partially due to human-caused emissions of greenhouse gases. The resulting warmer temperatures and earlier snowmelt have intensified the drought, which now ranks as the second-worst over the past 1,200 years.

• According to the researchers, 30-50% of the current megadrought can be attributed to climate change.
• A megadrought is difficult enough to deal with on its own, but for decades population in the desert Southwest has been growing at least twice as fast as the U.S. as a whole. That means more people competing for less water.

What they're saying: "The real take-home is that the Southwest is being baked by the burning of fossil fuels and other human activities, and the future implications are dire if we don’t stop climate change," University of Michigan climate researcher Jonathan Overpeck told the Washington Post.

If you haven't changed your mind, you haven't been paying attention. The coronavirus crisis has moved so fast, in so many different directions, that everybody who's intellectually honest has had to recalibrate their beliefs multiple times to take account of new information, my Axios colleague Felix Salmon writes.

Why it matters: Known unknowns are almost inconceivably enormous. For instance, how many people will die of COVID-19 in the U.S.? The answer could be tens of thousands, roughly where it is now — or it could be millions, if no vaccine is found and the virus ends up infecting most of the population.

The big picture: Extreme actions — whether they come in the form of U.S. monetary policy or strict New Zealand-style lockdowns — are often taken not because of what we know but more because of what we don't know.

The bottom line: We need to trust the individuals in authority, or else their actions will never have any real effect. If what they say one day (you must wear masks!) contradicts what they said the previous day, that just means they're responsibly changing their message in light of new information.

Go deeper.

Hollywood is all but writing off 2020. What does that mean for the future of movies? (Chris Lee — Vulture)

• With film production frozen, what movies that do come out in 2020 may be seen on your streaming platform.

Higher ed institutions should seize on the crisis to create better admission standards (Conor P. Williams — The 74 Million)

• As colleges pick up the pieces of a lost semester or more, one education expert argues now is the time to do away with mandatory testing standards for admissions.

Lives vs. the economy (Sarah Gonzalez and Kenny Malone — Planet Money)

• As we debate that very question, this podcast from NPR uncovers how economists came up with a widely agreed upon figure for the value of a human life: $10 million.

How the lockdown could create a new working class (Olga Khazan — Atlantic)

• The new definition of the working class is those who can't work from home — and they may just become a new labor movement.

April 17 was International Bat Appreciation Day, so I hope you thanked your local chiroptera.

Why it matters: Bats are amazing animals that can see in the dark and keep the world clean of dangerous insects like mosquitoes, and they're the only mammals capable of sustained flight. Yes, they may be the source of the novel coronavirus, but no one's perfect.

Bats have been getting a bad rap for a while, which, admittedly, they could do more to dispel.

• It's not just the novel coronavirus — horseshoe bats were eventually identified as the animal reservoir of the SARS virus. Bats are also believed to be the possible sources of the Ebola and Marburg viruses.
• And of course vampire bats literally drink blood — from cattle — and spread rabies.

How it works: It's not clear why bats are so often connected to viral spillovers from animals to humans. One theory goes that there is something in the immune system of bats that seems to speed up viral evolution, which makes them more likely to produce pathogens that can jump the species barrier.

• But research published this week found no evidence that there was anything special about bats. Rather, the number of viruses passed between animals and human beings is roughly proportional to the number of species in each order, and bats are both numerous and diverse.

Whatever they might be doing to humans, bats are having a hard enough time on their own.

• About 40% of American bat species are in severe decline, and the population of some bats has been decimated by a fungal infection called white-nose syndrome.

The bottom line: Bats are more scared of you than you are of them, so appreciate a bat today — ideally from a safe and healthy distance.