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1 big thing: Melting of Himalayan glaciers has doubled
A new study on central Himalayan glaciers in India, China, Nepal and Bhutan finds that this region has been losing ice during the 21st century at twice the rate it did during the previous 25 years. This trend was likely driven by increasing air temperatures, the study, published in Science Advances, finds.
Why it matters: This region is home to so much ice that it's sometimes referred to as Earth's "Third Pole." Runoff from ice melt nourishes some of the most populous nations on Earth, and the fate of these glaciers are thus intertwined with the ability of this region to sustain high population growth and avert conflict over increasingly stressed water supplies.
This study provides some of the clearest evidence yet that air temperature is a main control knob for glacial melt in the Himalayas, which was not previously known.
“Even glaciers in the highest mountains of the world are responding to global air temperature increases driven by the combustion of fossil fuels.”— Joseph Shea, University of Northern British Columbia, who was not involved in the study, in a statement
What they did: The study analyzed 650 Himalayan glaciers along a 1,243-mile transect of the mountain range, representing 55% of the region's total ice volume.
- Researchers used a combination of repeat NASA satellite and declassified Cold War-era spy satellite photographs to construct a set of three-dimensional digital elevation models for each glacier.
- By examining the differences between the historical reconstruction and measurements of contemporary glacier surfaces derived from modern satellites, the researchers were able to detect glacier mass changes over time.
What they found: Of the total ice mass that existed in the study area in 1975, 87% of it still was present in 2000. Only 72% was present just 16 years later.
- According to study lead author Josh Maurer of Columbia University, the main section of the Himalayas lost an average of about 4 billion tons of ice per year between 1975 and 2000.
- During the period from 2000 to 2016, however, the glaciers lost an average of about 8 billion tons of ice per year.
Context: A separate study, published last month in the journal Nature, found that the meltwater coming off the glaciers high in the Himalayas is 1.6 times greater than the rate needed to keep the glaciers in balance with snowfall.
- Previous studies have come to differing conclusions about how Himalayan glaciers have been faring in a warming world, or presented a limited geographical view.
- A report released in February found that the Himalayas could lose two-thirds of its glaciers by 2100 if greenhouse gas emissions are not significantly curtailed.
But, but, but: The study notes that there are uncertainties involved in what is driving increased ice loss in the 1,243-mile region.
- While temperatures have increased, there are also areas where precipitation has decreased, which could be shrinking these glaciers.
- In addition, the role of soot deposition from cars and coal-fired power plants in South Asia is little understood, but could be accelerating ice loss as well.
- Some Himalayan glaciers outside the region studied show countervailing trends, with glaciers remaining relatively stable or growing slightly.
2. The intensifying national debate over vaccine exemption rules
As measles spreads and U.S. public officials try to prevent the disease from becoming endemic in the U.S. again, a debate is heating up nationally over whether to mandate vaccines or tighten laws that allow for more individual choice, Eileen Drage O'Reilly writes.
Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases, tells Axios instead of mandating vaccines, it's time now for states to tighten their exemptions — "the flexibility has gone too far."
Driving the news: Trust in government and in the health care system tend to be linked to people believing that vaccines are safe, according to Imran Khan, head of public engagement at Wellcome, a global charitable foundation. Kahn discussed Wellcome's major Global Monitor Report on a panel Wednesday.
- That report also found highly industrialized nations — particularly in France, U.S., U.K. and Japan — showed a relatively high level of distrust in vaccine safety, mostly due to what Khan calls the "complacency effect."
- The problem is high-income people are living in nations where the disease hasn't been endemic for a long time and forget how bad such illnesses can be. And this is compounded by feeling the health care system is "robust" enough to heal them when they do get sick, Khan adds.
- Of note: The report was based on a large Gallup World Survey of 144,000 people, which was conducted in more than 140 countries among people 15 and older.
Fauci said philosophical and religious exemptions need a "good look."
- "If you look closely at religious exemptions, a lot of people are really claiming philosophical exemptions" because the religious mandate may not be there, Fauci said. New York is working on this topic with its Jewish community.
- Philosophical exemptions in particular need to be tightened, he added. "We can't have that and have a health care situation that's gotten out of control."
Go deeper: Read the rest of Eileen's story.
3. Two nearby, Earth-sized planets
This week, scientists announced the discovery of two potentially habitable planets orbiting a small, cool star only 12.5 light-years away, reports Axios' Miriam Kramer.
What they found: Researchers using the CARMENES instrument in Spain found the planets orbiting Teegarden’s star, which is only about 8% of the mass of our Sun.
- The planets are about the mass of Earth and orbit the star in its “habitable zone” — the theoretical orbit where a planet can sustain water on its surface.
- The new discovery will be published in the journal Astronomy & Astrophysics.
Why it matters: Discoveries like this one help to paint a picture of a galaxy teeming with exoplanets (worlds that orbit stars other than a sun).
- “At this point, I’d be surprised if a nearby star didn’t have exoplanets around it,” astronomer Jessie Christiansen, who wasn’t involved in the new work, told Axios via email.
Details: CARMENES found the planets using a method of exoplanet discovery known as radial velocity, which looks for small wobbles in a star produced by a planet’s gravity as it orbits.
- “We observed this star for three years, looking for periodic variations in its velocity,” Mathias Zechmeister, lead author of the study, said in a statement. “The data clearly show the existence of two planets.”
- Scientists suggest that, if there is intelligent life on one of the planets orbiting this star, they might be able to observe Earth passing in front of the Sun — called a transit — between the years 2044 and 2496.
Background: So far, scientists have discovered about 4,000 exoplanets orbiting stars near and far.
- We don’t know if any of these worlds can or do support life, however. New telescopes with more advanced capabilities will be needed to find out of a world is truly Earth-like or not.
But, but, but: Some scientists are skeptical that small, red dwarf stars are capable of hosting planets that could support life. This is because these small stars tend to be temperamental.
While Teegarden’s star is on the quiet side, other red dwarfs regularly shoot off massive flares, possibly destroying any chance for life on worlds orbiting them.
4. Axios stories worthy of your time
Our violent Sun (Miriam Kramer)
Listen to Apollo 11 in real time (Miriam Kramer)
With antibiotic resistance growing, WHO promotes monitoring tool (Eileen Drage O'Reilly)
5. What we're reading elsewhere
6. Something wondrous: How soap bubbles freeze
When soap bubbles freeze, beautiful crystals tend to swarm around their inner perimeter, like a snow globe, until the bubble is entirely full of these jagged-shaped formations.
In a study published this week, scientists investigated soap bubble freezing in a lab setting for the first time, with a particular focus on heat transfer processes.
Why it matters: As the New York Times notes, the study's findings could have "applications for flash freezing food, creating tastier ice cream or even developing antifreeze materials."
While observations of soap bubbles freezing have been made for centuries, and are popular on YouTube, scientists have had an incomplete understanding of how these snow globe-like formations actually occur.
What they found: When bubbles came into contact with an icy surface inside a walk-in freezer, water flowed upward from the base of the bubble.
- Ice crystals then developed from the bottom up, carried away from a dividing zone separating frozen and unfrozen sections of the bubble via paths known as Marangoni currents. (Marangoni flow is the movement of a liquid from areas of low to high surface tension.)
- Eventually, within a matter of just 10 or so seconds, the entire bubble can freeze over
Between the lines: The study found that soap bubbles that come into contact with a frozen surface, yet are surrounded by milder air, tended to discourage the formation of ice crystals throughout the bubbles. They failed to freeze completely.