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Topics: Applied Physics, Atmospheric Science, Chemistry, Climate Change, Global Warming

Note: It's disheartening that geoengineering, made popular by science fiction novels and plots in Star Trek, is being considered because we're too selfish to change our behavior.

More and more climate scientists are supporting experiments to cool Earth by altering the stratosphere or the ocean.

As recently as 10 years ago most scientists I interviewed and heard speak at conferences did not support geoengineering to counteract climate change. Whether the idea was to release large amounts of sulfur dioxide into the stratosphere to “block” the sun’s heating or to spread iron across the ocean to supercharge algae that breathe in carbon dioxide, researchers resisted on principle: don’t mess with natural systems because unintended consequences could ruin Earth. They also worried that trying the techniques even at a small scale could be a slippery slope to wider deployment and that countries would use the promise of geoengineering as an excuse to keep burning carbon-emitting fossil fuels.

But today, climate scientists more openly support experimenting with these and other proposed strategies, partly because entrepreneurs and organizations are going ahead with the methods anyway—often based on little data or field trials. Scientists want to run controlled experiments to see if the methods are productive, to test consequences, and perhaps to show objectively that the approaches can cause serious problems.

“We do need to try the techniques to figure them out,” says Rob Jackson, a professor at Stanford University, chair of the international research partnership Global Carbon Project, and author of a book on climate solutions called Into the Clear Blue Sky (Scribner, 2024). “But doing research does make them more likely to happen. That is the knotty part of all this.”

As Earth’s Climate Unravels, More Scientists Are Ready to Test Geoengineering, Mark Fischetti, Scientific American

Worrying trend Reliable climate models are needed so that societies can adapt to the impact of climate change. (Courtesy: Shutterstock/Migel)

Topics: Applied Physics, Atmospheric Science, CERN, Civilization, Climate Change

It was a scorcher last year. Land and sea temperatures were up to 0.2 °C (32.36 °F) higher every single month in the second half of 2023, with these warm anomalies continuing into 2024. We know the world is warming, but the sudden heat spike had not been predicted. As NASA climate scientist Gavin Schmidt wrote in Nature recently: “It’s humbling and a bit worrying to admit that no year has confounded climate scientists’ predictive capabilities more than 2023 has.”

As Schmidt went on to explain, a spell of record-breaking warmth had been deemed “unlikely” despite 2023 being an El Niño year, where the relatively cool waters in the central and eastern equatorial Pacific Ocean are replaced with warmer waters. Trouble is, the complex interactions between atmospheric deep convection and equatorial modes of ocean variability, which lie behind El Niño, are poorly resolved in conventional climate models.

Our inability to simulate El Niño properly with current climate models (J. Climate 10.1175/JCLI-D-21-0648.1) is symptomatic of a much bigger problem. In 2011 I argued that contemporary climate models were not good enough to simulate the changing nature of weather extremes such as droughts, heat waves and floods (see “A CERN for climate change” March 2011 p13). With grid-point spacings typically around 100 km, these models provide a blurred, distorted vision of the future climate. For variables like rainfall, the systematic errors associated with such low spatial resolution are larger than the climate-change signals that the models attempt to predict.

Reliable climate models are vitally required so that societies can adapt to climate change, assess the urgency of reaching net-zero or implement geoengineering solutions if things get really bad. Yet how is it possible to adapt if we don’t know whether droughts, heat waves, storms or floods cause the greater threat? How do we assess the urgency of net-zero if models cannot simulate “tipping” points? How is it possible to agree on potential geoengineering solutions if it is not possible to reliably assess whether spraying aerosols in the stratosphere will weaken the monsoons or reduce the moisture supply to the tropical rainforests? Climate modelers have to take the issue of model inadequacy much more seriously if they wish to provide society with reliable actionable information about climate change.

I concluded in 2011 that we needed to develop global climate models with spatial resolution of around 1 km (with compatible temporal resolution) and the only way to achieve this is to pool human and computer resources to create one or more internationally federated institutes. In other words, we need a “CERN for climate change” – an effort inspired by the particle-physics facility near Geneva, which has become an emblem for international collaboration and progress.

Why we still need a CERN for climate change, Tim Palmer, Physics World

Filled with briny lakes, the Quisquiro salt flat in South America's Altiplano region represents the kind of landscape that scientists think may have existed in Gale Crater on Mars, which NASA's Curiosity Rover is exploring. Credit: Maksym Bocharov

Topics: Astrobiology, Astrophysics, Atmospheric Science, Mars, NASA, Planetary Science

The most surprising revelation from NASA's Curiosity Mars Rover—that methane is seeping from the surface of Gale Crater—has scientists scratching their heads.

Living creatures produce most of the methane on Earth. But scientists haven't found convincing signs of current or ancient life on Mars, and thus didn't expect to find methane there. Yet, the portable chemistry lab aboard Curiosity, known as SAM, or Sample Analysis at Mars, has continually sniffed out traces of the gas near the surface of Gale Crater, the only place on the surface of Mars where methane has been detected thus far. Its likely source, scientists assume, are geological mechanisms that involve water and rocks deep underground.

If that were the whole story, things would be easy. However, SAM has found that methane behaves in unexpected ways in Gale Crater. It appears at night and disappears during the day. It fluctuates seasonally and sometimes spikes to levels 40 times higher than usual. Surprisingly, the methane also isn't accumulating in the atmosphere: ESA's (the European Space Agency) ExoMars Trace Gas Orbiter, sent to Mars specifically to study the gas in the atmosphere, has detected no methane.

Why is methane seeping on Mars? NASA scientists have new ideas, Lonnie Shekhtman, NASA, Phys.org.

Topics: Applied Physics, Atmospheric Science, Existentialism, Futurism, Lasers, Robotics, Science Fiction

"Laser" is an acronym for Light Amplification by the Stimulated Emission of Radiation. As the article alludes to, the concept existed before the actual device. We have Charles Hard Townes to thank for his work on the Maser (Microwave Amplification by the Stimulated Emission of Radiation) and the Laser. He won the Nobel Prize for his work in 1964. In a spirit of cooperation remarkable for the Cold War era, he was awarded the Nobel with two Soviet physicists, Aleksandr M. Prokhorov and Nikolay Gennadiyevich Basov. He lived from 1915 - 2015. The Doomsday Clock was only a teenager, born two years after the end of the Second World War. As it was in 2023, it is still 90 seconds to midnight. I'm not sure going "Buck Rogers" on the battlefield will dial it back from the stroke of twelve. Infrared lasers are likely going to be deployed in any future battle space, but infrared is invisible to the human eye, a weapon for which you only need a power supply and not an armory; it might appeal not only to knock drones out of the sky, but to assassins, contracted by governments who can afford such a powerful device, that will not leave a ballistic fingerprint, or depending on the laser's power: DNA evidence.

Nations around the world are rapidly developing high-energy laser weapons for military missions on land and sea, and in the air and space. Visions of swarms of small, inexpensive drones filling the skies or skimming across the waves are motivating militaries to develop and deploy laser weapons as an alternative to costly and potentially overwhelmed missile-based defenses.

Laser weapons have been a staple of science fiction since long before lasers were even invented. More recently, they have also featured prominently in some conspiracy theories. Both types of fiction highlight the need to understand how laser weapons actually work and what they are used for.

A laser uses electricity to generate photons, or light particles. The photons pass through a gain medium, a material that creates a cascade of additional photons, which rapidly increases the number of photons. All these photons are then focused into a narrow beam by a beam director.

In the decades since the first laser was unveiled in 1960, engineers have developed a variety of lasers that generate photons at different wavelengths in the electromagnetic spectrum, from infrared to ultraviolet. The high-energy laser systems that are finding military applications are based on solid-state lasers that use special crystals to convert the input electrical energy into photons. A key aspect of high-power solid-state lasers is that the photons are created in the infrared portion of the electromagnetic spectrum and so cannot be seen by the human eye.

Based in part on the progress made in high-power industrial lasers, militaries are finding an increasing number of uses for high-energy lasers. One key advantage for high-energy laser weapons is that they provide an “infinite magazine.” Unlike traditional weapons such as guns and cannons that have a finite amount of ammunition, a high-energy laser can keep firing as long as it has electrical power.

The U.S. Army is deploying a truck-based high-energy laser to shoot down a range of targets, including drones, helicopters, mortar shells and rockets. The 50-kilowatt laser is mounted on the Stryker infantry fighting vehicle, and the Army deployed four of the systems for battlefield testing in the Middle East in February 2024.

High-energy laser weapons: A defense expert explains how they work and what they are used for, Iain Boyd, Director, Center for National Security Initiatives, and Professor of Aerospace Engineering Sciences, University of Colorado Boulder

This map shows the size and shape of the ozone hole over the South Pole on September 21, 2023, the day of its maximum extent, as calculated by the NASA Ozone Watch team. Moderate ozone losses (orange) are visible amid widespread areas of more potent ozone losses (red).

NASA Earth Observatory

Topics: Antarctica, Atmospheric Science, NASA, Ozone Layer

Goddard Spaceflight Center: What is Ozone?

Editor’s note: This article has been updated to clarify the ranking of the 2023 ozone hole.  It is the 12th largest single-day hole on record and the 16th largest when averaged from Sept 7 to Oct 13.

The 2023 Antarctic ozone hole reached its maximum size on Sept. 21, according to annual satellite and balloon-based measurements made by NASA and NOAA. At 10 million square miles, or 26 million square kilometers, the hole ranked as the 12th largest single-day ozone hole since 1979.

During the peak of the ozone depletion season from Sept. 7 to Oct. 13, the hole this year averaged 8.9 million square miles (23.1 million square kilometers), approximately the size of North America, making it the 16th largest over this period. 

“It’s a very modest ozone hole,” said Paul Newman, leader of NASA’s ozone research team and chief scientist for Earth sciences at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Declining levels of human-produced chlorine compounds, along with help from active Antarctic stratospheric weather, slightly improved ozone levels this year.”

2023 Ozone Hole Ranks 16th Largest, NASA and NOAA Researchers Find