Some of the most ethereal, unique ecosystems in the world are enshrouded in clouds. The fate of Earth's cloud forests, and the specialized species they harbor, is a concern facing climate scientists and conservationists around the world.

The big picture: Tropical montane cloud forests and páramo, which are alpine ecosystems that occur above the tropical cloud forests between about 11 degrees north and 9 degrees south latitude, are losing the mist that defines them as the planet's climate changes largely due to human emissions of greenhouse gases.

• Another factor is land use change, with deforestation also posing a threat.

Background: Previous studies have shown that there is a risk that cloud forests will see less frequent cloud immersion, thereby depriving moisture-adapted vertebrate and vegetation species of a vital water source.

Where and how significantly cloud immersion frequency and intensity will change has been unknown.

Details: In a comprehensive new study published in PLOS One, scientists found that cloud forests and páramo are likely to see marked contraction and drying during the next several decades.

• The fog and mist that enshrouds these ecosystems forms in part from orographic lift: As warm, moist air ascends up mountain slopes, it cools and condenses to form clouds and precipitation.
• As the climate warms, warm air will have to rise farther before it cools sufficiently to form clouds, thereby shrinking cloud forest habitat.

What they did: The researchers produced detailed maps of cloud forest ecosystems and páramo and modeled thresholds for cloud forest minimum elevation and other parameters.

• They used high-resolution climate models based on various emissions scenarios to project future changes in key cloud forest variables.

What they found: The study finds that in about 25–45 years, 70%–86% of páramo are likely to be drier or "be subject to tree invasion."

• The study also found that tropical cloud forests will see a cloud immersion decline that shrinks or dries 57%–80% of neotropical cloud forests, including all cloud forests in Mexico, Central America, the Caribbean, much of Northern South America and parts of southeast Brazil.
• If greenhouse gas emissions continue unabated, however, the estimates rise to 86% of neotropical cloud forests and 98% of páramo shrinking or declining.
• Cloud immersion is projected to increase in just 1% of all tropical cloud forests, the study finds.

The bottom line: According to lead author Eileen Helmer of the International Institute of Tropical Forestry, the study breaks new ground in showing the global extent of cloud immersion impacts.

• The new study paints a clear picture of widespread declines in cloud immersion and warns of "widespread extinction" of some species living in these fragile ecosystems.

But, but, but: The news for cloud forests is not all grim, Helmer says. "We found that the land with a cloud forest climate in most regions is largely forested, which may help species persist in the face of climate change," she said, noting that governments could take steps to protect intact cloud forests from future deforestation.

Figuring out whether a planet is habitable will take more than just understanding its orbit. According to a new study in the journal Science, scientists will also need to study a world’s atmosphere, magnetic field and even geological composition in order to really know if it’s capable of hosting life, reports Axios' Miriam Kramer.

The big picture: Researchers have been hunting for habitable exoplanets using space and ground-based telescopes for years, but assessing whether a world can support life or not is difficult.

• Considerable time is spent focusing on whether a planet is in its star’s “habitable zone” — an orbit in which liquid water can be sustained on the surface — but that alone can’t predict whether life will exist.
• “To focus the search for extraterrestrial life, scientists must assess which features of Earth are essential to the development and sustenance of life for billions of years and whether the formation of such planets is common,” the study says.

Details: While understanding an exoplanet’s atmosphere is a good way to start a hunt for life, scientists will also need to learn more about a planet’s composition to see if it’s Earth-like.

• “The heart of habitability lies in the planetary interior,” the study says.
• If a world’s core is liquid iron like Earth’s, it could produce a sufficiently strong magnetic field to shield its surface from incoming harmful radiation, protecting water and possible life on its surface.

Even plate tectonics have bearing on habitability because the cycling of a planet’s crust helps control its climate, the study notes.

“By having these different variables, we can say this is the most likely — of all the planets that have been found — this one is the most likely to be habitable or to be most Earth-like,” study co-author Anat Shahar of the Carnegie Institution for Science told Axios.

What’s next? Although scientists have discovered thousands of exoplanets so far, very few of them are thought to be potentially habitable. However, as more powerful telescopes come online, researchers should gain a better understanding of what secrets these planets may be hiding.

Infectious disease experts tell Axios they agree with a dire scenario painted in a new UN report saying that, if nothing changes, antimicrobial resistance (AMR) could be "catastrophic" in its economic and death toll, Axios' Eileen Drage O'Reilly writes.

Threat level, per the report: By 2050, AMR could kill 10 million people per year, in its worst-case scenario. Annual economic damage could be comparable to the 2008–09 financial crisis.

What they're saying: Experts tell Axios that action must be taken or the grim scenario will come true.

"Unfortunately, I think if we don't do anything differently, the estimates are absolutely realistic. ... Like global warming, the longer we delay action, the worse it's going to get."

By the numbers: Currently, at least 700,000 people die each year due to drug-resistant diseases, including 230,000 people from multidrug-resistant tuberculosis, per the UN.

Common diseases — like respiratory infections, STDs and urinary tract infections — are increasingly untreatable as the pathogens develop resistance to current medications.

What needs to be done: Experts say the mindset around antibiotics usage needs to change, as do incentives for companies to develop new antibiotics.

• "We need to think of antibiotics (developing and protecting them) as a public good — much like we invest in things like national parks, public libraries, roads, bridges, traffic lights," says Pamela Yeh, assistant professor at UCLA.

Mathers says the traditional drug manufacturing process doesn't work for public companies because investors prefer drugs that need to be taken regularly.

• She points to the case of Achaogen, a California biotech company that generated buzz when it won one of the few antibiotic approvals in recent years with Zemdri, but was recently forced to file for bankruptcy.

But, but, but: Some progress has been made.

• Some new antibiotics are proving to be life-saving, Mathers says, pointing to a new type of combination antibiotics that is "saving lives."
• Research continues, such as a study published today in the journal PLOS Pathogens that says they've figured out how the superbug Enterococcus faecalis is able to cause disease.
• Antibiotic use in animal husbandry is slowly being tackled, and the FDA issued a 5-year plan to promote the proper use of antibiotics.

The bottom line: Action must be taken to avoid a catastrophic future.

Go deeper:

• To tackle antibiotic resistance, researchers try new approaches
• Growing antibiotic resistance is dire concern, health experts say
• The antibiotics market is falling apart

Scientists hunting for gravitational waves — ripples in the fabric of space and time sent out by cataclysmic collisions — have had a busy month, writes Miriam.

The LIGO and Virgo observatories tasked with detecting these waves began their newest observing run on April 1, and they've already found evidence of 5 possible gravitational wave signals.

• The observatories are 40% more sensitive following upgrades made since the last observing run ended.

The big question: By detecting these gravitational waves on Earth, scientists can work backward to find out more about what created those ripples, giving us new insights into some of the most extreme objects in the universe.

“The entire astrophysics community is very excited that we’ve already seen 5 candidate events in four weeks,” LIGO astrophysicist Jess McIver said during a press conference Thursday.

Details: Three of the gravitational wave signals are thought to be from two merging black holes, with the fourth believed to have been emitted by colliding neutron stars. The fifth, and perhaps most exciting, seems to be from the merger of a black hole and a neutron star.

• If confirmed, this will mark the first neutron star-black hole merger ever documented.

All five signals still need to be confirmed through follow-up analysis.

How it works: LIGO and Virgo are able to detect these gravitational waves through very precise instrumentation. When a gravitational wave passes through Earth’s part of space, every atom warps ever so slightly.

• A laser runs down the arms of LIGO and Virgo’s three L-shaped detectors. Once the laser hits the end of the detector, a mirror bounces the light back to the middle.
• If no gravitational wave has passed through, the beams of light should arrive back at the bend in the L at the same time, but if there’s a mismatch, a gravitational wave may have been observed.

What’s next? Unlike earlier observing campaigns, the two observatories have started releasing their detections in real time, allowing other observatories to make follow-up observations.

Global warming's "fingerprint" found in drought trends as early as 1900

Skimming Saturn's rings (Miriam Kramer)

The origin story behind cosmic phenomenon STEVE (Miriam Kramer)

Potentially catastrophic Cyclone Fani nears Indian coast as a Category 4 storm

U.S. measles cases top 700 as officials urge vaccinations

Deepfakes for good (Kaveh Waddell)

From Apples to Popcorn, Climate Change Is Altering the Foods America Grows (Kim Severson, New York Times)

Biggest Denisovan fossil yet spills ancient human’s secrets (Matthew Warren, Nature News)

Fossil of 85-foot blue whale is largest ever discovered (Tim Vernimmen, National Geographic)

Indonesia plans to move its capital out of Jakarta, a city that's sinking (Merrit Kennedy, NPR)

In 1995, astronomers directed the Hubble Space Telescope to stare at one piece of the sky for 1 million seconds.

Why it matters: This resulted in images showing galaxies that had never been seen before, some of which are so far away that it's taken billions of years for light from them to reach us. The image this led to is called the Hubble Deep Field, and at the time it was the farthest peek into the universe on record.

Subsequent deep-field surveys have yielded views of galaxies even farther away, particularly as updated cameras have added to Hubble's capabilities.

"These surveys provided astronomers with a huge scrapbook of images, showing how, following the big bang, galaxies built themselves up over time to become the large, majestic assemblages seen today in the nearby universe," NASA wrote in a statement about the deep-field surveys.

What's new: On May 2, astronomers released a new deep-field image that cobbles together exposures from several of the previous galaxy hunts.

• This is now the "largest, most comprehensive 'history book' of galaxies in the universe," NASA says. The Hubble Legacy Field, as it's called, shows nearly 7,500 separate Hubble exposures over 16 years.
• The image mosaic contains about 265,000 galaxies stretching back between 13.3 billion years ago to just 500 million years after the Big Bang.