While such a cataclysmic outcome of warming temperatures from greenhouse gas pollution is considered unlikely, recent studies have shown it’s more plausible than previously thought.
Projections for an extreme sea level scenario for New York City under NOAA's new guidelines.
Based on that research, the federal government increased its worst-case scenario for the rise of the seas worldwide by a quarter in January compared with 2014 findings, up to an average of more than 8 feet by 2100.
This article was originally published at Climate Central
The impact would be even worse around the U.S. A National Oceanic and Atmospheric Administration report warned that regional effects of gravity and ocean current changes triggered by the start of the ice sheet’s collapse could lead to more than 12 feet of sea level rise engulfing some coastlines in the Lower 48. That’s about the height of a one-story house.
NOAA’s extreme sea level rise scenario would leave many American coastal cities almost completely submerged. For example, unless hulking new defenses are built to protect against floods, portions of New York City that are currently home to more than 800,000 would be underwater, Climate Central analysis of NOAA data shows.
“It’s a scenario that we hope never occurs,” said William Sweet, a NOAA oceanographer who coordinated production of the agency’s sea level report, published in January. “It’s probably very unlikely, but definitely possible.”
Miami, Virginia Beach, Boston and even Stockton, a river port city in California’s Central Valley, face some of the greatest risks. Climate Central researchers on Wednesday published a report, maps and 3D renderings viewable in Google Earth showing the potential impacts nationwide.
There may be a 1-in-1,000 chance of the extreme scenario playing out if current pollution trends continue, though researchers say the figure is speculative, with more study needed. The likelihood nearly entirely vanishes if the global economy transitions quickly from polluting fuels to clean energy, as is envisioned by the Paris climate treaty. Weak climate policies and high pollution trends mean the world is not on track to meet the treaty’s central goals.
While it can be easy to dismiss the possibility of low-probability events occurring, they sometimes do occur.
The surprise western path taken by Hurricane Sandy into New York and New Jersey is only expected once every 700 years. By one estimate, California had a 1 percent chance of escaping its deep drought within two years — long odds it recently overcame. And President Trump won the election despite polls showing he had a slim chance of doing so.
The extreme sea level scenario was included with others in NOAA’s report to help local governments, agencies and other planners prepare for potential future shoreline conditions.
“We know this is a possibility, and the key task of science will be to figure out how probable it is,” said Robert Kopp, a sea level rise researcher at Rutgers University who helped compile the NOAA report. “We can be reasonably confident that we’re not going to be in the extreme scenario in the next couple of decades. Getting onto that extreme pathway — that’s something that would happen in the second half of the century.”
Data released with the report focused on the U.S., where coastal counties are home to 40 percent of the national population. Extreme levels of sea level rise would be higher along American coastlines than for global averages.
While Americans have released a quarter of all the pollution warming the planet since 1850, the U.S. is among the countries least vulnerable to the effects of global warming, with poor countries like Cambodia, Bangladesh and Senegal in the most danger. Under the extreme scenario, some islands could disappear, with island nations obliterated.
In a study published in the journal Nature Climate Change last week, University of Georgia demographer Mathew Hauer warned of mass migrations within the U.S. if seas rise 6 feet this century. The study projected that Florida could lose more than 2 million residents by 2100 — far more than any other state.
Hauer’s modeling suggested more than 1 million would move to Texas as they flee the effects of rising seas elsewhere. Migration flows would be “even more pronounced” under the extreme scenario outlined by NOAA, he said.
The January report was an update to projections included in the federal government’s 2014 National Climate Assessment, with extreme sea level rise scenarios based on recent Antarctic ice sheet modeling. It was published shortly before Trump took office with a goal of eliminating Obama-era climate protections.
The Antarctic ice sheet is the world’s largest reserve of frozen water, meaning its collapse would contribute more to the rise of the seas than the melting of glaciers elsewhere or the collapse of Greenland’s ice sheet. Because it’s so large, Antarctica’s ice sheet is relatively stable, although it’s already melting under the effects of rising temperatures. Scientists are trying to figure out how stable it really is.
Only a few coastal areas in the Lower 48 outside the Pacific Northwest were projected to receive less than 10 feet of sea level rise under the extreme scenario. Seas could rise along some Gulf of Mexico shores by more than 12 feet and by more than 11 feet along the much of the Atlantic coast.
“To get on that extreme scenario, you would need a large contribution from Antarctica,” Kopp said. “If you’re in a scenario that includes a large contribution from Antarctica, the U.S. is going to be getting more than the global average.”
Modeling by scientists at UMass and Penn State has shown how such a collapse could occur. Shelves of ice protruding from the continent would melt away as temperatures rise, and meltwater would seep into the ice sheet and crack it, producing cliffs of ice that collapse into the sea.
“In the worst case, the collapse will be in full swing by 2100, but will continue for centuries,” said Rob DeConto, a UMass professor who helped produce the modeling-based research, described last year in a high-profile study published in Nature.
By John Upton, ClimateCentral
The classic psychological account would ascribe these mistakes to a failure of executive control, provoked by some external stimulus. That is, the problem comes from the brain’s inability to resolve the conflict between an automatically activated stereotype, and a consciously held egalitarian belief. Seeing a black face might automatically activate the stereotype that black men are more dangerous, leading to activity in brain areas implicated in fear responses. But this automatic response, which could trigger a fight-or-flight reaction, should be suppressed when the fear is irrational. Yet the tensions between automatic and control processes are not always readily resolved, and result in errors.
New strands of work in psychology, neuroscience and philosophy of mind challenge this brain-centric orthodoxy. Researchers of ‘embodied cognition’ focus instead on the brain’s interdependence on physiological processes that allow an organism to sustain itself. From this point of view, the mind must be understood as embedded in a body, and the body as embedded in a physical, social and cultural environment. Reality is not simply out there for the taking, but is summoned via the constant fluctuations of our own organic matter. As the French philosopher Maurice Merleau-Ponty wrote in Phenomenology of Perception (1945): ‘The body is our general medium for having a world.’
Among neuroscientists, it’s increasingly popular to think of the brain not as a passive organ that receives and reacts to stimuli, but as more of an inference machine: something that actively strives to predict what’s out there and what’s going to happen, maximising the chances of staying alive. But the body isn’t simply controlled top-down. Rather, its signals are constantly combining with the brain’s inferences to generate our perception of the world. Imagine you hear a door slamming: you’re more likely to picture an intruder if you’re watching a scary movie than if you’re listening to soothing music. You make that prediction (otherwise quite unlikely) because it accounts for your fast heart-rate and the sound of the door.
We still know very little about exactly how these processes might relate to the phenomenon of racism, but now we have some idea of where to look. If the predictive story of behaviour is correct, perception (including that of the police) suddenly seems a lot closer to belief, and is a lot more embodied, than we used to think. Recent studies highlight the influences of visceral signals across many domains, from emotional processing and decision-making to self-awareness. For example, scary stimuli are judged to be more fearful when presented during heartbeats, rather than between heartbeats.
At my lab at Royal Holloway, University of London, we decided to test whether the cardiac cycle made a difference to the expression of racial prejudice. The heart is constantly informing the brain about the body’s overall level of ‘arousal’, the extent to which it is attuned to what is happening around it. On a heartbeat, sensors known as ‘arterial baroreceptors’ pick up pressure changes in the heart wall, and fire off a message to the brain; between heartbeats, they are quiescent. Such visceral information is initially encoded in the brainstem, before reaching the parts implicated in emotional and motivational behaviour. The brain, in turn, responds by trying to help the organism stabilise itself. If it receives signals of a raised heart-rate, the brain will generate predictions about the potential causes, and consider what the organism should do to bring itself down from this heightened state. This ongoing heart-brain dialogue, then, forms the basis of how the brain represents the body to itself, and creates awareness of the external environment.
In our experiment, we used what’s known as the ‘first-person shooter’s task’, which simulates the snap judgments police officers make. Participants see a white or black man holding a gun or phone, and have to decide whether to shoot depending on the perceived level of threat. In prior studies, participants were significantly more likely to shoot an unarmed black individual than a white one.
But we timed the stimuli to occur either between or on a heartbeat. Remarkably, the majority of misidentifications occurred when black individuals appeared at the same time as a heartbeat. Here, the number of false positives in which phones were perceived as weapons rose by 10 per cent compared with the average. In a different version of the test, we used what’s known as the ‘weapons identification task’, where participants see a white or black face, followed by an image of a gun or tool, and must classify the object as quickly as possible. When the innocuous items were presented following a black face, and on a heartbeat, errors rose by 20 per cent.
Yet in both instances, when the judgment happened between heartbeats, we observed no differences in people’s accuracy, irrespective of whether they were responding to white or black faces. It seems that the combination of the firing of signals from the heart to the brain, along with the presentation of a stereotypical threat, increased the chances that even something benign will be perceived as dangerous.
It’s surprising to think of racial bias as not just a state or habit of mind, nor even a widespread cultural norm, but as a process that’s also part of the ebbs and flows of the body’s physiology. The heart-brain dialogue plays a crucial role in regulating blood pressure and heart rate, as well as motivating and supporting adaptive behaviour in response to external events. So, in fight-or-flight responses, changes in cardiovascular function prepare the organism for subsequent action. But while the brain might be predictive, those predictions can be inaccurate. What our findings illustrate is the extent to which racial and possibly other stereotypes are hijacking bodily mechanisms that have evolved to deal with actual threats.
The psychologist Lisa Barrett Feldman at Northeastern University in Boston coined the term ‘affective realism’ to describe how the brain perceives the world through the body. On the one hand, this is a reason for optimism: if we can better understand the neurological mechanisms behind racial bias, then perhaps we’ll be in a better position to correct it. But there is a grim side to the analysis, too. The structures of oppression that shape who we are also shape our bodies, and perhaps our most fundamental perceptions. Maybe we do not ‘misread’ the phone as a gun; we might we actually see a gun, rather than a phone. Racism might not be something that societies can simply overcome with fresh narratives and progressive political messages. It might require a more radical form of physiological retraining, to bring our embodied realities into line with our stated beliefs.
By Manos Tsakiris
This article was originally published at Aeon and has been republished under Creative Commons.
