Augmented reality

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From Wikipedia, the free encyclopedia

Augmented reality using phones and tablets

An example of augmented reality: A man viewing a life-size virtual model of a building

An augmented reality mapping application

Augmented reality (AR), also known as mixed reality (MR), is a form of 3D human–computer interaction that overlays real-time 3D-rendered computer graphics into the real world through a display, such as a handheld device or head-mounted display. This experience is seamlessly interwoven with the physical world such that it is perceived as an immersive aspect of the real environment. In this way, augmented reality alters one's ongoing perception of a real-world environment, compared to virtual reality, which aims to completely replace the user's real-world environment with a simulated one.Augmented reality is typically visual, but can span multiple sensory modalities, including auditory, haptic, and somatosensory.

The earliest functional AR systems that provided immersive mixed reality experiences for users were invented in the early 1990s, starting with the Virtual Fixtures system developed at the U.S. Air Force's Armstrong Laboratory in 1992. Commercial augmented reality experiences were first introduced in entertainment and gaming businesses. Subsequently, augmented reality applications have spanned industries such as education, communications, medicine, and entertainment.

Augmented reality frameworks include ARKit and ARCore. Commercial augmented reality headsets include the Magic Leap 1 and HoloLens. A number of companies have promoted the concept of smartglasses that have augmented reality capability.

Augmented reality refers to experiences that are artificial and that add to the already existing reality. In AR, information about the environment and its objects can be overlaid on the real world. This information can be virtual or real, e.g. seeing other real sensed or measured information such as electromagnetic radio waves overlaid in exact alignment with where they actually are in space. Augmented reality also has a lot of potential in the gathering and sharing of tacit knowledge.

Augmented reality can be defined as a system that incorporates three basic features: a combination of real and virtual worlds, real-time interaction, and accurate 3D registration of virtual and real objects. The overlaid sensory information can be constructive (i.e. additive to the natural environment), or destructive (i.e. masking of the natural environment).

Hardware and displays

A man wearing an augmented reality headset

Magic Leap One AR headset

AR visuals appear on handheld devices (video passthrough) or head-mounted displays (optical see-through or video passthrough). Systems pair a display with sensors (e.g., cameras and IMUs) to register virtual content to the environment; research also explores near-eye optics, projection-based AR, and experimental concepts such as contact-lens or retinal-scanned displays.

Head-mounted displays

Main article: Head-mounted display

AR HMDs place virtual imagery in the user's view using optical see-through or video passthrough and track head motion for stable registration.

Handheld

Phone and tablet AR uses the rear camera (video passthrough) plus on-device SLAM/VIO for tracking.

Projection mapping

Main article: Projection mapping

Projectors overlay graphics onto real objects/environments without head-worn displays (spatial AR).^[20]

AR glasses

Glasses-style near-eye displays aim for lighter, hands-free AR; approaches vary in optics, tracking, and power.

3D tracking

Further information: Simultaneous localization and mapping, Visual odometry, Fiducial marker, and Image registration

AR systems estimate device pose and scene geometry so virtual graphics stay aligned with the real world. Common approaches include visual–inertial odometry and SLAM for markerless tracking, and fiducial markers when known patterns are available; image registration and depth cues (e.g., occlusion, shadows) maintain realism.

Software and standards

Further information: ARKit, ARCore, and Augmented Reality Markup Language

AR runtimes provide sensing, tracking, and rendering pipelines; mobile platforms expose SDKs with camera access and spatial tracking. Interchange/geospatial formats such as ARML standardize anchors and content.

Interaction and input

Further information: Human–computer interaction and Gesture recognition

Input commonly combines head/gaze with touch, controllers, voice, or hand tracking; audio and haptics can reduce visual load. Human-factors studies report performance benefits but also workload and safety trade-offs depending on task and context.

Design considerations

Key usability factors include stable registration, legible contrast under varied lighting, and low motion-to-photon latency. Visual design often uses depth cues (occlusion, shadows) to support spatial judgment; safety-critical uses emphasize glanceable prompts and minimal interaction.

Comparison with mixed reality/virtual reality

Augmented reality (AR) is largely synonymous with mixed reality (MR). There is also overlap in terminology with extended reality and computer-mediated reality. However, In the 2020s, the differences between AR and MR began to be emphasized.

Types of extended reality

In augmented reality, users are not only able to view digital content within their real environment but can also interact with it as if it were a tangible part of the physical world. This is made possible through devices such as Meta Quest 3S and Apple Vision Pro, which utilize multiple cameras and sensors to enable real-time interaction between virtual and physical elements. Mixed reality that incorporates haptics has sometimes been referred to as visuo-haptic mixed reality.

In virtual reality (VR), the users' perception is completely computer-generated, whereas with augmented reality (AR), it is partially generated and partially from the real world. For example, in architecture, VR can be used to create a walk-through simulation of the inside of a new building; and AR can be used to show a building's structures and systems super-imposed on a real-life view. Another example is through the use of utility applications. Some AR applications, such as Augment, enable users to apply digital objects into real environments, allowing businesses to use augmented reality devices as a way to preview their products in the real world. Similarly, it can also be used to demo what products may look like in an environment for customers, as demonstrated by companies such as Mountain Equipment Co-op or Lowe's who use augmented reality to allow customers to preview what their products might look like at home.

Augmented reality (AR) differs from virtual reality (VR) in the sense that in AR, the surrounding environment is real and AR is just adding virtual objects to the real environment. On the other hand, in VR, the surrounding environment is completely virtual and computer generated. A demonstration of how AR layers objects onto the real world can be seen with augmented reality games. WallaMe is an augmented reality game application that allows users to hide messages in real environments, utilizing geolocation technology in order to enable users to hide messages wherever they may wish in the world.

The use of the terms "mixed reality" and "interreality" is clearly defined in the context of physics and may be slightly different in other fields, however, it is generally seen as, "bridging the physical and virtual world".

Recent improvements in AR and VR headsets have made the display quality, field of view, and motion tracking more accurate, which makes augmented experiences more immersive. Improvements in sensor calibration, lightweight optics, and wireless connectivity have also made it easier for users to move around and be comfortable.

History

Virtual Fixtures – early AR system, U.S. Air Force, Wright-Patterson Air Force Base (1992)

Precursors to augmented reality

• 1901: Author L. Frank Baum, in his science-fiction novel The Master Key, first mentions the idea of an electronic display/spectacles that overlays data onto real life (in this case 'people'). It is named a 'character marker'.
• Heads-up displays (HUDs), a precursor technology to augmented reality, were first developed for pilots in the 1950s, projecting simple flight data into their line of sight, thereby enabling them to keep their "heads up" and not look down at the instruments. It is a transparent display.

Earliest developments

• 1968: Ivan Sutherland creates the first optical-see through head-mounted display that has graphics rendered by a computer.
• 1975: Myron Krueger creates Videoplace to allow users to interact with virtual objects.
• 1980: The research by Gavan Lintern of the University of Illinois is the first published work to show the value of a heads up display for teaching real-world flight skills.
• 1980: Steve Mann creates the first wearable computer, a computer vision system with text and graphical overlays on a photographically mediated scene.
• 1986: Within IBM, Ron Feigenblatt describes the most widely experienced form of AR today (viz. "magic window," e.g. smartphone-based Pokémon Go), use of a small, "smart" flat panel display positioned and oriented by hand.
• 1987: Douglas George and Robert Morris create a working prototype of an astronomical telescope-based "heads-up display" system (a precursor concept to augmented reality) which superimposed in the telescope eyepiece, over the actual sky images, multi-intensity star, and celestial body images, and other relevant information.
• 1990: The term augmented reality is attributed to Thomas P. Caudell, a former Boeing researcher.
• 1992: Louis Rosenberg developed one of the first functioning AR systems, called Virtual Fixtures, at the United States Air Force Research Laboratory—Armstrong, that demonstrated benefit to human perception.
• 1992: Steven Feiner, Blair MacIntyre and Doree Seligmann present an early paper on an AR system prototype, KARMA, at the Graphics Interface conference.
• 1993: Mike Abernathy, et al., report the first use of augmented reality in identifying space debris using Rockwell WorldView by overlaying satellite geographic trajectories on live telescope video.
• 1993: A widely cited version of the paper above is published in Communications of the ACM – Special issue on computer augmented environments, edited by Pierre Wellner, Wendy Mackay, and Rich Gold.
• 1995 - Augmented reality was described as a key technology in the reality-virtuality continuum.
• 1995: S. Ravela et al. at University of Massachusetts introduce a vision-based system using monocular cameras to track objects (engine blocks) across views for augmented reality.
• 2004: An outdoor helmet-mounted AR system was demonstrated by Trimble Navigation and the Human Interface Technology Laboratory (HIT lab).

Smartphone AR and modern headsets

Meta 2 augmented reality headset from Meta

• 2009: ARToolkit was ported to Adobe Flash (FLARToolkit) by Saqoosha, bringing augmented reality to the web browser.
• 2015: Microsoft announced the HoloLens augmented reality headset, which uses various sensors and a processing unit to display virtual imagery over the real world.
• 2016: Niantic released Pokémon Go for iOS and Android in July 2016. The game quickly became one of the most popular smartphone applications and in turn spikes the popularity of augmented reality games.
• 2018: Magic Leap launched the Magic Leap One augmented reality headset. Leap Motion announced the Project North Star augmented reality headset, and later released it under an open source license.
• 2019: Microsoft announced HoloLens 2 with significant improvements in terms of field of view and ergonomics.
• 2022: Magic Leap launched the Magic Leap 2 headset.
• 2023: Meta Quest 3, a mixed reality VR headset was developed by Reality Labs, a division of Meta Platforms. In the same year, Apple Vision Pro was released.
• 2024: Meta Platforms revealed the Orion AR glasses prototype.

Uses

Augmented reality for viewing furniture in the real world

Augmented reality has been explored for many uses, including education and business. Some of the earliest cited examples include augmented reality used to support surgery by providing virtual overlays to guide medical practitioners, to AR content for astronomy and welding. Example application areas described below include archaeology, architecture, commerce and education.

Education and training

AR for education and training can overlay 3D models and step-by-step guidance in real settings (e.g., anatomy, maintenance); systematic reviews report learning benefits alongside design and implementation caveats that vary by context and task.

Navigation and maps

Augmented reality navigation overlays route guidance or hazard cues onto the real scene, typically via smartphone "live view" or in-vehicle heads-up displays. Research finds AR can improve wayfinding and driver situation awareness, but human-factors trade-offs (distraction, cognitive load, occlusion) matter for safety-critical use.

See also: Head-up display, Automotive navigation system, Wayfinding

Commerce

In 2021, iBite was the among one of the first iOS applications to integrate Apple's ARKit & RealityKit Swift frameworks for interactive augmented reality digital ordering. iBite allows users to view 3D models of their food before ordering, and allow merchants to upload their own USDZ files which they can generate using iBite's patented photogrammetry software.

In 2018, Apple announced USDZ, a file format based on Universal Scene Description from Pixar, which allows 3D objects to be viewed in AR on iPhones and iPads with iOS 12. Apple has created an AR QuickLook Gallery that allows people to experience augmented reality through their own Apple device.

In 2018, Shopify, the Canadian e-commerce company, announced AR Quick Look integration. Their merchants will be able to upload 3D models of their products and their users will be able to tap on the models inside the Safari browser on their iOS devices to view them in their real-world environments.

AR technology is used by furniture retailers such as IKEA, Houzz, and Wayfair. These retailers offer apps that allow consumers to view their products in their home prior to purchasing anything.

In 2017, Ikea announced the Ikea Place app. It contains a catalogue of over 2,000 products—nearly the company's full collection of sofas, armchairs, coffee tables, and storage units which one can place anywhere in a room with their phone. The app made it possible to have 3D and true-to-scale models of furniture in the customer's living space. IKEA realized that their customers are not shopping in stores as often or making direct purchases anymore. Shopify's acquisition of Primer, an AR app aims to push small and medium-sized sellers towards interactive AR shopping with easy to use AR integration and user experience for both merchants and consumers. AR helps the retail industry reduce operating costs. Merchants upload product information to the AR system, and consumers can use mobile terminals to search and generate 3D maps.

Surgery

One of the first applications of augmented reality was in healthcare, particularly to support the planning, practice, and training of surgical procedures. As far back as 1992, enhancing human performance during surgery was a formally stated objective when building the first augmented reality systems at U.S. Air Force laboratories. AR provides surgeons with patient monitoring data in the style of a fighter pilot's heads-up display, and allows patient imaging records, including functional videos, to be accessed and overlaid. Examples include a virtual X-ray view based on prior tomography or on real-time images from ultrasound and confocal microscopy probes, visualizing the position of a tumor in the video of an endoscope, or radiation exposure risks from X-ray imaging devices. AR can enhance viewing a fetus inside a mother's womb. Siemens, Karl Storz and IRCAD have developed a system for laparoscopic liver surgery that uses AR to view sub-surface tumors and vessels.

Guidance overlays and image fusion support planning and intraoperative visualization across several specialties; reviews note accuracy/registration constraints and workflow integration issues.

The HoloLens is capable of displaying images for image-guided surgery. As augmented reality advances, it finds increasing applications in healthcare. Augmented reality and similar computer based-utilities are being used to train medical professionals. In healthcare, AR can be used to provide guidance during diagnostic and therapeutic interventions e.g. during surgery. Magee et al., for instance, describe the use of augmented reality for medical training in simulating ultrasound-guided needle placement. Recently, augmented reality began seeing adoption in neurosurgery, a field that requires heavy amounts of imaging before procedures.

Smartglasses can be incorporated into the operating room to aide in surgical procedures; possibly displaying patient data conveniently while overlaying precise visual guides for the surgeon. Augmented reality headsets like the Microsoft HoloLens have been theorized to allow for efficient sharing of information between doctors, in addition to providing a platform for enhanced training. This can, in some situations (i.e. patient infected with contagious disease), improve doctor safety and reduce PPE use. While mixed reality has lots of potential for enhancing healthcare, it does have some drawbacks too. The technology may never fully integrate into scenarios when a patient is present, as there are ethical concerns surrounding the doctor not being able to see the patient. Mixed reality is also useful for healthcare education. For example, according to a 2022 report from the World Economic Forum, 85% of first-year medical students at Case Western Reserve University reported that mixed reality for teaching anatomy was "equivalent" or "better" than the in-person class.

Flight training

Building on decades of perceptual-motor research in experimental psychology, researchers at the Aviation Research Laboratory of the University of Illinois at Urbana–Champaign used augmented reality in the form of a flight path in the sky to teach flight students how to land an airplane using a flight simulator. An adaptive augmented schedule in which students were shown the augmentation only when they departed from the flight path proved to be a more effective training intervention than a constant schedule. Flight students taught to land in the simulator with the adaptive augmentation learned to land a light aircraft more quickly than students with the same amount of landing training in the simulator but with constant augmentation or without any augmentation.

Military

Augmented reality system for soldier ARC4 (U.S. Army 2017)

The first augmented reality system that integrated haptic 3D input was the Virtual Fixtures platform, which was developed in 1992 by Louis Rosenberg at the Armstrong Laboratories of the United States Air Force. It enabled human users to control robots in real-world environments using a haptic controller. Published studies showed that by introducing virtual objects into the real world, significant performance increases could be achieved by human operators.

An interesting early application of AR occurred when Rockwell International created video map overlays of satellite and orbital debris tracks to aid in space observations at Air Force Maui Optical System. In their 1993 paper "Debris Correlation Using the Rockwell WorldView System" the authors describe the use of map overlays applied to video from space surveillance telescopes. The map overlays indicated the trajectories of various objects in geographic coordinates. This allowed telescope operators to identify satellites, and also to identify and catalog potentially dangerous space debris.

Starting in 2003 the US Army integrated the SmartCam3D augmented reality system into the Shadow Unmanned Aerial System to aid sensor operators using telescopic cameras to locate people or points of interest. The system combined fixed geographic information including street names, points of interest, airports, and railroads with live video from the camera system. The system offered a "picture in picture" mode that allows it to show a synthetic view of the area surrounding the camera's field of view. This helps solve a problem in which the field of view is so narrow that it excludes important context, as if "looking through a soda straw". The system displays real-time friend/foe/neutral location markers blended with live video, providing the operator with improved situational awareness.

Combat reality can be simulated and represented using complex, layered data and visual aides, most of which are head-mounted displays (HMD), which encompass any display technology that can be worn on the user's head. Military training solutions are often built on commercial off-the-shelf (COTS) technologies, such as Improbable's synthetic environment platform, Virtual Battlespace 3 and VirTra, with the latter two platforms used by the United States Army. As of 2018, VirTra is being used by both civilian and military law enforcement to train personnel in a variety of scenarios, including active shooter, domestic violence, and military traffic stops.

In 2017, the U.S. Army was developing the Synthetic Training Environment (STE), a collection of technologies for training purposes that was expected to include mixed reality. As of 2018, STE was still in development without a projected completion date. Some recorded goals of STE included enhancing realism and increasing simulation training capabilities and STE availability to other systems.

It was claimed that mixed-reality environments like STE could reduce training costs, such as reducing the amount of ammunition expended during training. In 2018, it was reported that STE would include representation of any part of the world's terrain for training purposes. STE would offer a variety of training opportunities for squad brigade and combat teams, including Stryker, armory, and infantry teams.

Researchers at USAF Research Lab (Calhoun, Draper et al.) found an approximately two-fold increase in the speed at which UAV sensor operators found points of interest using this technology. This ability to maintain geographic awareness quantitatively enhances mission efficiency. The system is in use on the US Army RQ-7 Shadow and the MQ-1C Gray Eagle Unmanned Aerial Systems.

In combat, AR can serve as a networked communication system that renders useful battlefield data onto a soldier's goggles in real time. From the soldier's viewpoint, people and various objects can be marked with special indicators to warn of potential dangers. Virtual maps and 360° view camera imaging can also be rendered to aid a soldier's navigation and battlefield perspective, and this can be transmitted to military leaders at a remote command center. The combination of 360° view cameras visualization and AR can be used on board combat vehicles and tanks as circular review system.

AR can be an effective tool for virtually mapping out the 3D topologies of munition storages in the terrain, with the choice of the munitions combination in stacks and distances between them with a visualization of risk areas. The scope of AR applications also includes visualization of data from embedded munitions monitoring sensors.

Navigation

See also: Automotive navigation system

LandForm video map overlay marking runways, road, and buildings during 1999 helicopter flight test

The NASA X-38 was flown using a hybrid synthetic vision system that overlaid map data on video to provide enhanced navigation for the spacecraft during flight tests from 1998 to 2002. It used the LandForm software which was useful for times of limited visibility, including an instance when the video camera window frosted over leaving astronauts to rely on the map overlays. The LandForm software was also test flown at the Army Yuma Proving Ground in 1999. In the photo at right one can see the map markers indicating runways, air traffic control tower, taxiways, and hangars overlaid on the video.

Industrial environments

In industrial environments, augmented reality is proving to have a substantial impact with use cases emerging across all aspect of the product lifecycle, starting from product design and new product introduction (NPI) to manufacturing to service and maintenance, to material handling and distribution. For example, labels were displayed on parts of a system to clarify operating instructions for a mechanic performing maintenance on a system. Assembly lines benefited from the usage of AR. In addition to Boeing, BMW and Volkswagen were known for incorporating this technology into assembly lines for monitoring process improvements. Big machines are difficult to maintain because of their multiple layers or structures. AR permits people to look through the machine as if with an x-ray, pointing them to the problem right away.

Functional mockup

Augmented reality can be used to build mockups that combine physical and digital elements. With the use of simultaneous localization and mapping (SLAM), mockups can interact with the physical world to gain control of more realistic sensory experiences like object permanence, which would normally be infeasible or extremely difficult to track and analyze without the use of both digital and physical aides.

Translation

AR applications such as Word Lens can interpret the foreign text on signs and menus and, in a user's augmented view, re-display the text in the user's language. Spoken words of a foreign language can be translated and displayed in a user's view as printed subtitles.

Human-in-the-loop operation of robots

Recent advances in mixed-reality technologies have renewed interest in alternative modes of communication for human-robot interaction. Human operators wearing augmented reality headsets such as HoloLens can interact with (control and monitor) e.g. robots and lifting machines on site in a digital factory setup. This use case typically requires real-time data communication between a mixed reality interface with the machine / process / system, which could be enabled by incorporating digital twin technology.

Real life ad-blocking

More than one in three surveyed advanced Internet users would like to edit out disturbing elements around them, such as garbage or graffiti. They would like to even modify their surroundings by erasing street signs, billboard ads, and uninteresting shopping windows. Consumers want to use augmented reality glasses to change their surroundings into something that reflects their own personal opinions. Around two in five want to change the way their surroundings look and even how people appear to them.

Apps

Snapchat users have access to augmented reality features. In September 2017, Snapchat announced a feature called "Sky Filters" that will be available on its app. This new feature makes use of augmented reality to alter the look of a picture taken of the sky, much like how users can apply the app's filters to other pictures. Users can choose from sky filters such as starry night, stormy clouds, beautiful sunsets, and rainbow.

Google launched an augmented reality feature for Google Maps on Pixel phones that identifies users' location and places signs and arrows on the device screen to show a user navigation directions.

Concerns

Accidents

In a paper titled "Death by Pokémon GO", researchers at Purdue University's Krannert School of Management claim the game caused "a disproportionate increase in vehicular crashes and associated vehicular damage, personal injuries, and fatalities in the vicinity of locations, called PokéStops, where users can play the game while driving." Using data from one municipality, the paper extrapolates what that might mean nationwide and concluded "the increase in crashes attributable to the introduction of Pokémon GO is 145,632 with an associated increase in the number of injuries of 29,370 and an associated increase in the number of fatalities of 256 over the period of 6 July 2016, through 30 November 2016." The authors extrapolated the cost of those crashes and fatalities at between $2bn and $7.3 billion for the same period.

Privacy concerns

Augmented reality devices that use cameras for 3D tracking or video passthrough depend on the ability of the device to record and analyze the environment in real time. Because of this, there are potential legal concerns over privacy.

According to recent studies, users are especially concerned that augmented reality smart glasses might compromise the privacy of others, potentially causing peers to become uncomfortable or less open during interactions.

Notable researchers

• Ronald Azuma is a scientist and author of works on AR.
• Steve Mann formulated an earlier concept of mediated reality in the 1970s and 1980s, using cameras, processors, and display systems to modify visual reality to help people see better (dynamic range management), building computerized welding helmets, as well as "augmediated reality" vision systems for use in everyday life. He is also an adviser to Meta.
• Dieter Schmalstieg and Daniel Wagner developed a marker tracking systems for mobile phones and PDAs in 2009.
• Ivan Sutherland invented the first augmented reality system, often called The Sword of Damocles, at Harvard University.

Geoengineering

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Geoengineering

 

Examples of geoengineering methods: Solar radiation modification technologies, reforestation in the Seychelles, clouds created by ship exhausts (marine cloud brightening), experimental space mirror.

Geoengineering (also known as climate engineering or climate intervention) is the deliberate large-scale interventions in the Earth’s climate system intended to counteract human-caused climate change. The term commonly encompasses two broad categories: large-scale carbon dioxide removal (CDR) and solar radiation modification (SRM). CDR involves techniques to remove carbon dioxide from the atmosphere and is generally considered a form of climate change mitigation. SRM aims to reduce global warming by reflecting a small portion of sunlight (solar radiation) away from Earth and back into space. Although historically grouped together, these approaches differ substantially in mechanisms, timelines, and risk profiles, and are now typically discussed separately. Some other large-scale engineering proposals—such as interventions to slow the melting of polar and alpine ice—are also sometimes classified as forms of geoengineering.

Some types of geoengineering present political, social and ethical issues. One common objection is that focusing on these technologies could undermine efforts to reduce greenhouse gas emissions. Effective governance and international oversight are widely regarded as essential.

Major scientific organizations have examined the potential, risks, and governance needs of geoengineering, including the US National Academies of Sciences, Engineering, and Medicine, the Royal Society, the UN Educational, Scientific and Cultural Organization (UNESCO), and the World Climate Research Programme.

Methods

Carbon dioxide removal

Planting trees is a nature-based way to remove carbon dioxide from the atmosphere; however, the effect may only be temporary in some cases.

Carbon dioxide removal (CDR) is a process in which carbon dioxide (CO₂) is removed from the atmosphere by deliberate human activities and durably stored in geological, terrestrial, or ocean reservoirs, or in products. This process is also known as carbon removal, greenhouse gas removal or negative emissions. CDR is more and more often integrated into climate policy, as an element of climate change mitigation strategies. Achieving net zero emissions will require first and foremost deep and sustained cuts in emissions, and then—in addition—the use of CDR ("CDR is what puts the net into net zero emissions"). In the future, CDR may be able to counterbalance emissions that are technically difficult to eliminate, such as some agricultural and industrial emissions.

CDR includes methods that are implemented on land or in aquatic systems. Land-based methods include afforestation, reforestation, agricultural practices that sequester carbon in soils (carbon farming), bioenergy with carbon capture and storage (BECCS), and direct air capture combined with storage. There are also CDR methods that use oceans and other water bodies. Those are called ocean fertilization, ocean alkalinity enhancement,^[17] wetland restoration and blue carbon approaches. A detailed analysis needs to be performed to assess how much negative emissions a particular process achieves. This analysis includes life cycle analysis and "monitoring, reporting, and verification" (MRV) of the entire process. Carbon capture and storage (CCS) are not regarded as CDR because CCS does not reduce the amount of carbon dioxide already in the atmosphere.

Solar radiation modification

Proposed solar radiation modification using a tethered balloon to inject sulfate aerosols into the stratosphere

This section is an excerpt from Solar radiation modification.[edit]

Solar radiation modification (SRM) (or solar geoengineering) is a group of large-scale approaches to reduce global warming by increasing the amount of sunlight that is reflected away from Earth and back to space. It is not intended to replace efforts to reduce greenhouse gas emissions, but rather to complement them as a potential way to limit global warming. SRM is a form of geoengineering.

The most-researched SRM method is stratospheric aerosol injection (SAI), in which small reflective particles would be introduced into the upper atmosphere to reflect sunlight. Other approaches include marine cloud brightening (MCB), which would increase the reflectivity of clouds over the oceans, or constructing a space sunshade or a space mirror, to reduce the amount of sunlight reaching earth.

Glacial geoengineering

Arctic sea ice coverage as of 2007 compared to 2005 and also compared to 1979-2000 average

Glacial geoengineering is a set of proposed geoengineering approaches that focus on slowing the loss of glaciers, ice sheets, and sea ice in polar regions and, in some cases, alpine areas. Proposals are motivated by concerns that feedback loops—such as ice-albedo loss, accelerated glacier flow, and permafrost methane release—could amplify climate change and trigger climate tipping points.

Proposed glacial geoengineering methods include regional or local solar radiation management, thinning cirrus clouds to allow more heat to escape, and deploying mechanical or engineering structures to stabilize ice. Specific strategies under investigation are stratospheric aerosol injection focused on polar regions, marine cloud brightening, surface albedo modification with reflective materials, basal interventions such as draining subglacial water or promoting basal freezing, and ice shelf protection measures including seabed curtains.

Glacial geoengineering is in the early research stage and many proposals face major technical, environmental, and governance challenges. Supporters argue that targeted interventions could help stabilize ice sheets, slow sea-level rise, and reduce the risk of passing irreversible thresholds in the climate system. At the same time, experts caution that the effectiveness of these methods remains highly uncertain and that interventions could produce unintended side effects. Glacial geoengineering is generally considered a possible complement to, not a replacement for, efforts to reduce greenhouse gas emissions.

Governance

Most governance issues relating to geoengineering are specific to the category or the specific method. Nevertheless, a couple of international governance instruments have addressed geoengineering collectively.

The Conference of Parties to the Convention on Biological Diversity have made several decisions regarding "climate related geoengineering." That of 2010 established "a comprehensive non-binding normative framework" for "climate-related geoengineering activities that may affect biodiversity," requesting that such activities be justified by the need to gather specific scientific data, undergo prior environmental assessment, be subject to effective regulatory oversight. The Parties' 2016 decision called for "more transdisciplinary research and sharing of knowledge... in order to better understand the impacts of climate-related geoengineering."

The parties to the London Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter and its associated London Protocol have addressed "marine geoengineering." In 2013, the parties to the London Protocol adopted an amendment to establish a legally binding framework for regulating marine geoengineering, initially limited to ocean fertilization and requiring assessment and permitting before any activity proceeds. This amendment has not yet entered into force due to insufficient ratifications. In 2022, the parties to both agreements acknowledged growing interest in marine geoengineering, identified four techniques for priority review, and encouraged careful assessment of proposed projects under existing guidelines while considering options for further regulation. In 2023, they cautioned that these techniques could pose serious environmental risks, highlighted scientific uncertainty about their effects, urged strict application of assessment frameworks, and called for broader international cooperation. Their work is supported by the Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection of the International Maritime Organization.

Global catastrophic risk

From Wikipedia, the free encyclopedia https://en.wikipedia.org/wiki/Global_catastrophic_risk

A global catastrophic risk or a doomsday scenario is a hypothetical event that could damage human well-being on a global scale, endangering or even destroying modern civilization. Existential risk is a related term limited to events that could cause full-blown human extinction or permanently and drastically curtail humanity's existence or potential.

In the 21st century, a number of academic and non-profit organizations have been established to research global catastrophic and existential risks, formulate potential mitigation measures, and either advocate for or implement these measures.

Definition and classification

Scope–severity grid from Bostrom's paper "Existential Risk Prevention as Global Priority"

Defining global catastrophic risks

The term global catastrophic risk "lacks a sharp definition", and generally refers (loosely) to a risk that could inflict "serious damage to human well-being on a global scale".

Humanity has suffered large catastrophes before. Some of these have caused serious damage but were only local in scope—e.g. the Black Death may have resulted in the deaths of a third of Europe's population, 10% of the global population at the time. Some were global, but were not as severe—e.g. the 1918 influenza pandemic killed an estimated 3–6% of the world's population. Most global catastrophic risks would not be so intense as to kill the majority of life on earth, but even if one did, the ecosystem and humanity would eventually recover (in contrast to existential risks).

Similarly, in Catastrophe: Risk and Response, Richard Posner singles out and groups together events that bring about "utter overthrow or ruin" on a global, rather than a "local or regional" scale. Posner highlights such events as worthy of special attention on cost–benefit grounds because they could directly or indirectly jeopardize the survival of the human race as a whole.

Defining existential risks

Existential risks are defined as "risks that threaten the destruction of humanity's long-term potential." The instantiation of an existential risk (an existential catastrophe) would either cause outright human extinction or irreversibly lock in a drastically inferior state of affairs. Existential risks are a sub-class of global catastrophic risks, where the damage is not only global but also terminal and permanent, preventing recovery and thereby affecting both current and all future generations.

Non-extinction risks

While extinction is the most obvious way in which humanity's long-term potential could be destroyed, there are others, including unrecoverable collapse and unrecoverable dystopia. A disaster severe enough to cause the permanent, irreversible collapse of human civilisation would constitute an existential catastrophe, even if it fell short of extinction. Similarly, if humanity fell under a totalitarian regime, and there were no chance of recovery, then such a dystopia would also be an existential catastrophe. Bryan Caplan writes that "perhaps an eternity of totalitarianism would be worse than extinction". (George Orwell's novel Nineteen Eighty-Four suggests an example.) A dystopian scenario shares the key features of extinction and unrecoverable collapse of civilization: before the catastrophe humanity faced a vast range of bright futures to choose from; after the catastrophe, humanity is locked forever in a terrible state.

Potential sources of risk

Main article: Global catastrophe scenarios

Potential global catastrophic risks are conventionally classified as anthropogenic or non-anthropogenic hazards. Examples of non-anthropogenic risks are an asteroid or comet impact event, a supervolcanic eruption, a natural pandemic, a lethal gamma-ray burst, a geomagnetic storm from a coronal mass ejection destroying electronic equipment, natural long-term climate change, hostile extraterrestrial life, or the Sun transforming into a red giant star and engulfing the Earth billions of years in the future.

Arrangement of global catastrophic risks into three sets according to whether they are largely human-caused, human influences upon nature, or purely natural

Anthropogenic risks are those caused by humans and include those related to technology, governance, and climate change. Technological risks include the creation of artificial intelligence misaligned with human goals, biotechnology, and nanotechnology. Insufficient or malign global governance creates risks in the social and political domain, such as global war and nuclear holocaust, biological warfare and bioterrorism using genetically modified organisms, cyberwarfare and cyberterrorism destroying critical infrastructure like the electrical grid, or radiological warfare using weapons such as large cobalt bombs. Other global catastrophic risks include climate change, environmental degradation, extinction of species, famine as a result of non-equitable resource distribution, human overpopulation or underpopulation, crop failures, and non-sustainable agriculture. Experts are also increasingly worried about cascading risks, the use of AI for bioengineering or in nuclear weapons systems, and a variety of other threats.

Methodological challenges

Research into the nature and mitigation of global catastrophic risks and existential risks is subject to a unique set of challenges and, as a result, is not easily subjected to the usual standards of scientific rigour. For instance, it is neither feasible nor ethical to study these risks experimentally. Carl Sagan expressed this with regards to nuclear war: "Understanding the long-term consequences of nuclear war is not a problem amenable to experimental verification". Moreover, many catastrophic risks change rapidly as technology advances and background conditions, such as geopolitical conditions, change. Another challenge is the general difficulty of accurately predicting the future over long timescales, especially for anthropogenic risks which depend on complex human political, economic and social systems. In addition to known and tangible risks, unforeseeable black swan extinction events may occur, presenting an additional methodological problem.

Lack of historical precedent

Humanity has never suffered an existential catastrophe and if one were to occur, it would necessarily be unprecedented. Therefore, existential risks pose unique challenges to prediction, even more than other long-term events, because of observation selection effects. Unlike with most events, the failure of a complete extinction event to occur in the past is not evidence against their likelihood in the future, because every world that has experienced such an extinction event has gone unobserved by humanity. Regardless of civilization collapsing events' frequency, no civilization observes existential risks in its history. These anthropic issues may partly be avoided by looking at evidence that does not have such selection effects, such as asteroid impact craters on the Moon, or directly evaluating the likely impact of new technology.

To understand the dynamics of an unprecedented, unrecoverable global civilizational collapse (a type of existential risk), it may be instructive to study the various local civilizational collapses that have occurred throughout human history. For instance, civilizations such as the Roman Empire have ended in a loss of centralized governance and a major civilization-wide loss of infrastructure and advanced technology. However, these examples demonstrate that societies appear to be fairly resilient to catastrophe; for example, Medieval Europe survived the Black Death without suffering anything resembling a civilization collapse despite losing 25 to 50 percent of its population.

Incentives and coordination

There are economic reasons that can explain why so little effort is going into global catastrophic risk reduction. First, it is speculative and may never happen, so many people focus on other more pressing issues. It is also a global public good, so we should expect it to be undersupplied by markets. Even if a large nation invested in risk mitigation measures, that nation would enjoy only a small fraction of the benefit of doing so. Furthermore, global catastrophic risk reduction can be thought of as an intergenerational global public good. Since most of the hypothetical benefits of the reduction would be enjoyed by future generations, and though these future people would perhaps be willing to pay substantial sums for risk reduction, no mechanism for such a transaction exists.

Cognitive biases

Numerous cognitive biases can influence people's judgment of the importance of existential risks, including scope insensitivity, hyperbolic discounting, the availability heuristic, the conjunction fallacy, the affect heuristic, and the overconfidence effect.

Scope insensitivity influences how bad people consider the extinction of the human race to be. For example, when people are motivated to donate money to altruistic causes, the quantity they are willing to give does not increase linearly with the magnitude of the issue: people are roughly as willing to prevent the deaths of 200,000 or 2,000 birds. Similarly, people are often more concerned about threats to individuals than to larger groups.

Eliezer Yudkowsky theorizes that scope neglect plays a role in public perception of existential risks:

Substantially larger numbers, such as 500 million deaths, and especially qualitatively different scenarios such as the extinction of the entire human species, seem to trigger a different mode of thinking... People who would never dream of hurting a child hear of existential risk, and say, "Well, maybe the human species doesn't really deserve to survive".

All past predictions of human extinction have proven to be false. To some, this makes future warnings seem less credible. Nick Bostrom argues that the absence of human extinction in the past is weak evidence that there will be no human extinction in the future, due to survivor bias and other anthropic effects.

Sociobiologist E. O. Wilson argued that: "The reason for this myopic fog, evolutionary biologists contend, is that it was actually advantageous during all but the last few millennia of the two million years of existence of the genus Homo... A premium was placed on close attention to the near future and early reproduction, and little else. Disasters of a magnitude that occur only once every few centuries were forgotten or transmuted into myth."

Proposed mitigation

Multi-layer defense

Defense in depth is a useful framework for categorizing risk mitigation measures into three layers of defense:

1. Prevention: Reducing the probability of a catastrophe occurring in the first place. Example: Measures to prevent outbreaks of new highly infectious diseases.
2. Response: Preventing the scaling of a catastrophe to the global level. Example: Measures to prevent escalation of a small-scale nuclear exchange into an all-out nuclear war.
3. Resilience: Increasing humanity's resilience (against extinction) when faced with global catastrophes. Example: Measures to increase food security during a nuclear winter.

Human extinction is most likely when all three defenses are weak, that is, "by risks we are unlikely to prevent, unlikely to successfully respond to, and unlikely to be resilient against".

The unprecedented nature of existential risks poses a special challenge in designing risk mitigation measures since humanity will not be able to learn from a track record of previous events.

Funding

Some researchers argue that both research and other initiatives relating to existential risk are underfunded. Nick Bostrom states that more research has been done on Star Trek, snowboarding, or dung beetles than on existential risks. Bostrom's comparisons have been criticized as "high-handed". As of 2020, the Biological Weapons Convention organization had an annual budget of US$1.4 million.

Survival planning

Some scholars propose the establishment on Earth of one or more self-sufficient, remote, permanently occupied settlements specifically created for the purpose of surviving a global disaster.Economist Robin Hanson argues that a refuge permanently housing as few as 100 people would significantly improve the chances of human survival during a range of global catastrophes.

Food storage has been proposed globally, but the monetary cost would be high. Furthermore, it would likely contribute to the current millions of deaths per year due to malnutrition. In 2022, a team led by David Denkenberger modeled the cost-effectiveness of resilient foods to artificial general intelligence (AGI) safety and found "~98-99% confidence" for a higher marginal impact of work on resilient foods. Some survivalists stock survival retreats with multiple-year food supplies.

The Svalbard Global Seed Vault is buried 400 feet (120 m) inside a mountain on an island in the Arctic. It is designed to hold 2.5 billion seeds from more than 100 countries as a precaution to preserve the world's crops. The surrounding rock is −6 °C (21 °F) (as of 2015) but the vault is kept at −18 °C (0 °F) by refrigerators powered by locally sourced coal.

More speculatively, if society continues to function and if the biosphere remains habitable, calorie needs for the present human population might in theory be met during an extended absence of sunlight, given sufficient advance planning. Conjectured solutions include growing mushrooms on the dead plant biomass left in the wake of the catastrophe, converting cellulose to sugar, or feeding natural gas to methane-digesting bacteria.

Global catastrophic risks and global governance

Insufficient global governance creates risks in the social and political domain, but the governance mechanisms develop more slowly than technological and social change. There are concerns from governments, the private sector, and the general public about the lack of governance mechanisms to efficiently deal with risks, negotiate and adjudicate between diverse and conflicting interests. This is further underlined by an understanding of the interconnectedness of global systemic risks. In absence or anticipation of global governance, national governments can act individually to better understand, mitigate and prepare for global catastrophes.

Climate emergency plans

In 2018, the Club of Rome called for greater climate change action and published its Climate Emergency Plan, which proposes ten action points to limit global average temperature increase to 1.5 degrees Celsius. Further, in 2019, the Club published the more comprehensive Planetary Emergency Plan.

There is evidence to suggest that collectively engaging with the emotional experiences that emerge during contemplating the vulnerability of the human species within the context of climate change allows for these experiences to be adaptive. When collective engaging with and processing emotional experiences is supportive, this can lead to growth in resilience, psychological flexibility, tolerance of emotional experiences, and community engagement.

Space colonization

Main article: Space and survival

Space colonization is a proposed alternative to improve the odds of surviving an extinction scenario. Solutions of this scope may require megascale engineering.

Astrophysicist Stephen Hawking advocated colonizing other planets within the Solar System once technology progresses sufficiently, in order to improve the chance of human survival from planet-wide events such as global thermonuclear war.

Organizations

The Bulletin of the Atomic Scientists (est. 1945) is one of the oldest global risk organizations, founded after the public became alarmed by the potential of atomic warfare in the aftermath of WWII. It studies risks associated with nuclear war and energy and famously maintains the Doomsday Clock established in 1947. The Foresight Institute (est. 1986) examines the risks of nanotechnology and its benefits. It was one of the earliest organizations to study the unintended consequences of otherwise harmless technology gone haywire at a global scale. It was founded by K. Eric Drexler who postulated "grey goo".

Beginning after 2000, a growing number of scientists, philosophers and tech billionaires created organizations devoted to studying global risks both inside and outside of academia.

Independent non-governmental organizations (NGOs) include the Machine Intelligence Research Institute (est. 2000), which aims to reduce the risk of a catastrophe caused by artificial intelligence, with donors including Peter Thiel and Jed McCaleb. The Nuclear Threat Initiative (est. 2001) seeks to reduce global threats from nuclear, biological and chemical threats, and containment of damage after an event. It maintains a nuclear material security index. The Lifeboat Foundation (est. 2009) funds research into preventing a technological catastrophe. Most of the research money funds projects at universities. The Global Catastrophic Risk Institute (est. 2011) is a US-based non-profit, non-partisan think tank founded by Seth Baum and Tony Barrett. GCRI does research and policy work across various risks, including artificial intelligence, nuclear war, climate change, and asteroid impacts. The Global Challenges Foundation (est. 2012), based in Stockholm and founded by Laszlo Szombatfalvy, releases a yearly report on the state of global risks. The Future of Life Institute (est. 2014) works to reduce extreme, large-scale risks from transformative technologies, as well as steer the development and use of these technologies to benefit all life, through grantmaking, policy advocacy in the United States, European Union and United Nations, and educational outreach. Elon Musk, Vitalik Buterin and Jaan Tallinn are some of its biggest donors.

University-based organizations included the Future of Humanity Institute (est. 2005) which researched the questions of humanity's long-term future, particularly existential risk. It was founded by Nick Bostrom and was based at Oxford University. The Centre for the Study of Existential Risk (est. 2012) is a Cambridge University-based organization which studies four major technological risks: artificial intelligence, biotechnology, global warming and warfare. All are man-made risks, as Huw Price explained to the AFP news agency, "It seems a reasonable prediction that some time in this or the next century intelligence will escape from the constraints of biology". He added that when this happens "we're no longer the smartest things around," and will risk being at the mercy of "machines that are not malicious, but machines whose interests don't include us." Stephen Hawking was an acting adviser. The Millennium Alliance for Humanity and the Biosphere is a Stanford University-based organization focusing on many issues related to global catastrophe by bringing together members of academia in the humanities. It was founded by Paul Ehrlich, among others. Stanford University also has the Center for International Security and Cooperation focusing on political cooperation to reduce global catastrophic risk. The Center for Security and Emerging Technology was established in January 2019 at Georgetown's Walsh School of Foreign Service and will focus on policy research of emerging technologies with an initial emphasis on artificial intelligence. They received a grant of 55M USD from Good Ventures as suggested by Open Philanthropy.

Other risk assessment groups are based in or are part of governmental organizations. The World Health Organization (WHO) includes a division called the Global Alert and Response (GAR) which monitors and responds to global epidemic crisis. GAR helps member states with training and coordination of response to epidemics. The United States Agency for International Development (USAID) has its Emerging Pandemic Threats Program which aims to prevent and contain naturally generated pandemics at their source. The Lawrence Livermore National Laboratory has a division called the Global Security Principal Directorate which researches on behalf of the government issues such as bio-security and counter-terrorism.