07/08/2021

(HowStuffWorks) What Will Earth Look Like In 500 Years?

HowStuffWorks - Robert Lamb

What will the 26th century look like? Sompong Rattanakunchon/Getty Images

If you could travel back in time five centuries, you'd encounter an Aztec empire nearly at the end of its run, fresh paintings from Raphael, Titian and Durer, and cooler temperatures across the Northern Hemisphere. This was a world in the midst of the Little Ice Age (1300 to 1850 C.E.) and a period of vast European exploration now known as the Age of Discovery.

But what if we could look 500 years into the future and glimpse the Earth of the 26th century? Would the world seem as different to us as the 21st century would have seemed to residents of the 16th century?

The answer to this question largely depends on the relationship between human civilization and our natural environment — its past, its present and, of course, its future. We've been altering Earth since at least the Agricultural Revolution of the Neolithic Age, and scientists disagree on exactly how many animal extinctions from even before that point should be lain at our feet [source: Boissoneault]. We manipulated the evolution of domestic plant and animal species, transformed the landscape and burned fossil fuels to power our way of life.

As a result, the planet's climate has changed — and is changing still. Some experts date the beginning of human climate change back to the Industrial Revolution in the 1800s, others to slash-and-burn agricultural practices in prehistoric times. Either way, overwhelming scientific consensus indicates that human activity is almost certainly responsible for climate-warming trends over the last century.

According to NASA, carbon dioxide levels are up to 412 parts per million as of December 2019, up from 316 ppm in 1958 when scientists first started tracking CO2. Global temperature was up 2.07 degrees Fahrenheit (1.15 degrees Celsius) since 1880, says the National Oceanic and Atmospheric Administration. Meanwhile, Arctic ice declines 12.85 percent per decade, and sea levels rise 3.3 millimeters per year, says NASA.

In other words, our planet is warming, extreme weather continues to increase and our natural surroundings are changing. These changes threaten the balance of already highly exploited natural resources. The United Nations warns that the resulting droughts, floods, heat waves and wildfires will only speed up land degradation and accelerate the danger of severe food shortages. Such shortages are exactly the catalyst that historically leads to social unrest, mass migration and conflict.

So, on one level, 26th-century Earth will have had to come to terms with climate change. According to some computer models, melting Antarctic ice could cause sea levels to rise by 1 foot (0.3 meter) by the end of this century and 26 feet (8 meters) by the year 2300.


VIDEO: What Will Earth Look Like In 500 Years? 2m 01secs

Perhaps our 26th-century ancestors will look back on their ancestors and see that we rallied before the flood. Perhaps they'll see that we made the sorts of technological, cultural and political changes necessary to prevent mass extinctions, political upheaval, environmental destruction and even civilizational collapse. Certainly, courses of action have been set in place to begin the work, as long as we can remain culturally and politically obliged to follow the course.

Or perhaps they'll look back on a people who willingly drove the world into ruin.

Along the way, however, our descendants will advance their technology — and while technology created the risks of anthropogenic climate change and nuclear warfare, it also provides us the potential to change course and improve.


AUDIO: What Will Earth Look Like In 500 Years? 6m 29secs

Theoretical physicist and futurist Michio Kaku predicts that in a mere 100 years, humanity will make the leap from a type 0 civilization to a type I civilization on the Kardashev Scale. In other words, we'll become a species that can harness the entire sum of a planet's energy.
Wielding such power, 26th-century humans could be masters of clean energy technologies such as fusion and solar power. Furthermore, they'd be able to manipulate planetary energy in order to control global climate. Still, futurists disagree on the timing of such a hypothetical upgrade in our technological prowess — and the upgrade is far from assured. As noted skeptic Michael Shermer pointed out in a 2008 Los Angeles Times article, political and economic forces could very well prevent us from making the great leap.

Technology has improved exponentially since the 1500s, and this pace will likely continue in the centuries to come. Physicist Stephen Hawking proposed that by the year 2600, this growth would see 10 new theoretical physics papers published every 10 seconds. If Moore's Law holds true and both computer speed and complexity double every 18 months, then some of these studies may be the work of highly intelligent machines. Then again, he also predicted that overcrowding and energy consumption would make the Earth uninhabitable by 2600.

What other technologies will shape the world of the 26th century? Futurist and author Adrian Berry believes the average human life span will reach 140 years and that the digital storage of human personalities will enable a kind of computerized immortality. Humans will farm the oceans, travel in starships and reside in both lunar and Martian colonies while robots explore the outer cosmos.

These technologies may come in handy, at least for a privileged few, if serious changes aren't put in place to deal with climate change.

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(AU ABC) Listening To The Planet: Understanding The Science Of Ecoacoustics

 ABC Science - Anna Salleh
From the symphony of nomadic birds on their journey across the continent, to the silencing of our forests by bushfires, ecoacoustics could help scientists track environmental change. (Supplied: David Rennie)

Imagine being able to hear the change of Earth's seasons, the effect of climate change on threatened birds, or the southward march of invasive cane toads. Like listening to the heartbeat of the planet, this is exactly the kind of thing researchers in the emerging field of ecoacoustics want to monitor.

Ecoacoustics is the study of sounds produced by the environment, ranging from animal calls to the wind and rain, and even human-made sounds like the hum of traffic.

But the study of biodiversity is a major focus, and Australia is leading the way here with a network of sound recorders planted across the continent, listening to our ecosystems.

Launched in 2019, the Australian Acoustic Observatory (A2O) has now planted hundreds of "ears" in the wild, from Cape York to the red centre, from the lush rivers of Tasmania to the dense forests of Queensland – and even on Cape Barren Island in Bass Strait.

The A2O recorders are solar powered and record onto a removable SD card – this site is in the Northern Territory . (Supplied: David Tucker)
Ecologist Lin Schwarzkopf from James Cook University, who helped design the acoustic observatory, says continent-wide recordings let scientists track all kinds of animals.

"We'll have a much better idea about the migratory routes of birds, how many birds are in these migrations, and where they stop to feed," she says.

"You could also detect the arrival of invasive species like cane toads."

This year, for Science Week, you too will get to listen to some of these sound clips collected by the A2O from across Australia.

Through the ABC's interactive, Hoot Detective, you will be able to help scientists identify owl calls, with the ultimate aim being to get a better idea of what species are where, and how well they're faring.

Experts need "citizen scientists" to help them process the endless hours of recordings being collected, says ornithologist Paul McDonald from the University of New England.

"You're faced with years and years and years of listening," Professor McDonald says.

"We can use the public to help look at a large amount of data in a relatively short amount of time."

Monitoring the environment 24/7  

Some of the acoustic sensors are near water, to capture the many animals that spend time in these areas. ( Tasmanian Land Conservancy Five Rivers Reserve: Matthew Newton) 
Ecoacoustics is particularly welcomed by biodiversity researchers who spend a lot of time on field trips to remote places to painstakingly count, trap and track animals — assuming floods and bushfires don't stop them.

"The beauty of this system is that we've got our recorders out there recording 24/7," Professor McDonald says.

"And they're picking up animals and events like rain that are occurring whether or not the researcher is there.
"It lets us monitor the whole country day in, day out, which is very exciting and something we haven't been able to do before."
Ecoacoustics could also help monitor the recovery of threatened species after events like bushfires, or the explosion in frogs after rain.

Frogs are another vocal animal that can be detected by acoustic sensors. (Wotjulum Frog/ Supplied WA Museum) 
"It's hard to express how little we know about some of these things," Professor Schwarzkopf says.

And while some scientists will focus on tracking individual species, others will be more interested in the overall 'soundscape', listening to the joyous turn of winter into spring — or something more sombre.
"We could possibly hear the end of the world as climate change increases, and it gets quieter as things go extinct."
Ecoacoustics is particularly useful for tracking animals that are hard to find, like the night parrot, koalas, and of course owls.

And storing sound collected over time will give scientists an acoustic "time machine" to explore historical changes to the environment, Professor McDonald says.

Evolution in the use of sound

Ecoacoustics is the latest stage in the evolution of the use of sound by ecologists and biologists.

Listen to Nature Track
Nature Track is a podcast that opens a window on the beautiful sounds of the Australian wilderness. Read more
"Every time there is a new advance in technology, biologists use it," Professor Schwarzkopf says.

It all started with researchers recording individual species, mainly to understand animal communication — a field often called 'bioacoustics'.

"People used to drag big old reel-to-reel recorders into swamps to record frogs," Professor Schwarzkopf says.

"Playback experiments" were next on the cards, where a researcher would, for example, play back a recording of a predator to test what effect this had on its prey.

But longer battery life, recorders that could be left outdoors, and eventually the advent of cheap storage for data, has all paved the way for ecoacoustics.

Some of the A2O recorders are located in places where owls live, like in this Tasmanian Land Conservancy’s Five Rivers Reserve. (Tasmanian Land Conservancy's Five Rivers Reserve: Matthew Newton) 
Computer engineer Paul Roe from the Queensland University of Technology, who leads the A2O, is naturally enthusiastic about this use of sound to monitor the environment.

He says that while remote sensing with satellites and drones is a good way to keep an eye on vegetation, recording sound is the most effective and "non-invasive" way of monitoring animals, especially over large areas.

"Acoustics' time has come," he says.

But scientists will have their work cut out for them making sense of the massive amount of data they're collecting.

With its initial five-year funding, the A2O will collect 2,000 years' worth of data, which amounts to 2,000 terabytes that will need massive cloud storage and powerful computer processing.

"We've translated the problem of in-the-field observation into one of data analysis," Professor Roe says.

"We still need to analyse the data to see what's going on.
"We're trying to make ecology a big data science."
A20 researchers Paul Roe and David Tucker checking on a recorder in the field. (Supplied: David Tucker)
Enter citizen scientists … and artificial intelligence

This is where citizen scientists come into play.

Through projects like Hoot Detective, scientists are recruiting anyone with a connected digital device to help them pick out animal calls from sounds they've collected.

A tool known as the spectrogram is used here — it's a graph that plots frequency against time, and gives a visual representation of a sound clip.

As humans identify sounds in the spectrogram and feed what they've discovered back, that information can be used to train computer programs to automatically recognise calls.

This the sound of a young boobook owl trilling as seen in a spectrogram. (Supplied: Australian Acoustic Observatory) 
These "automatic recognisers" use the same sort of complex machine-learning algorithms involved in face recognition, which need lots of examples to learn from.
"If you want to scale ecological monitoring, you need to find a way to automate it," Professor Roe says.
But while finding individual species in lots of data for humans or computers can be likened to finding "a needle in a haystack", ecoacoustics also involves "zooming out" to "understand the haystack" itself.

For this, researchers can use what's called a "false colour spectrogram", which summarises the information so it fits on your computer screen and codes different sounds in different colours.

"So you can look at a whole night of data in one picture," Professor Roe says.

While you can still zoom in like you do on Google Maps to the level of individual species, zooming out is useful for other things.

"You may not know what you're looking for. You might be just trying to find patterns of change," Professor Roe says.

These false colour spectrograms show different soundscapes over a 24-hour-period – in site 1 you can only hear the wind, whereas in site 2 (a shrubland) there are lots of calls. (Supplied: Marina Scarpellil)
Getting the big picture

Marina Scarpelli is one ecoacoustics researcher who wants to zoom out and get the big picture.

"I am interested in how different ecosystems have different sounds," says Ms Scarpelli, who is doing a PhD at the Queensland University of Technology.

She planted small sound recorders close together in different vegetation types on a semi-arid property in Queensland.

After that she created colour-coded spectrograms using mathematical filters called "acoustic indices," tuned to different sounds in the recording, from birdsong to wind.

"Acoustic indices give you a fingerprint of the sound or the environment," says Professor Roe, one of her supervisors.

"So you can use that a bit like a bar code to characterise the environment and how it's changing."

Marina Scarpelli attaches a small sound recorder to a tree as part of her early research. (Supplied: Marina Scarpelli) 
Early results from Ms Scarpelli's analysis show the shrubland had more birds than the woodland, while areas without vegetation were so quiet, all that could be heard was the sound of the wind that whipped up during the day.

"We could clearly hear the differences and we can also see the differences in the spectrograms," Ms Scarpelli says.

She says the findings were expected because most of the birds in the shrublands are insect-eaters, and insects prefer shrubs to trees.

"Everything ended up making good ecological sense."

Now she has developed a reliable method, Ms Scarpelli will be using A2O data to analyse the acoustic "barcodes" of everything from tropical forests to deserts.

She hopes work like hers helps give us a better idea of our impact on the Earth.

“We know humans are changing the environment really fast, and not for the best in most cases," she says.

"Sound can be a good way to measure how the changes are happening."

Many A2O recorders are on protected properties like this. (Bush Heritage Australia: Tom O'Hara)


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(Washington Post) A Critical Ocean System May Be Heading For Collapse Due To Climate Change, Study Finds

Washington Post - Sarah Kaplan

‘The consequences of a collapse would likely be far-reaching’

An aerial view of Rhode Island shorelines. A weakening of the Atlantic Meridional Overturning Circulation could bring extreme cold to Europe and parts of North America, raise sea levels and disrupt seasonal monsoons. (Salwan Georges/The Washington Post)
Human-caused warming has led to an “almost complete loss of stability” in the system that drives Atlantic Ocean currents, a new study has found — raising the worrying prospect that this critical aquatic “conveyor belt” could be close to collapse.

In recent years, scientists have warned about a weakening of the Atlantic Meridional Overturning Circulation (AMOC), which transports warm, salty water from the tropics to northern Europe and then sends colder water back south along the ocean floor. Researchers who study ancient climate change have also uncovered evidence that the AMOC can turn off abruptly, causing wild temperature swings and other dramatic shifts in global weather systems.

Scientists haven’t directly observed the AMOC slowing down. But the new analysis, published Thursday in the journal Nature Climate Change, draws on more than a century of ocean temperature and salinity data to show significant changes in eight indirect measures of the circulation’s strength.

These indicators suggest that the AMOC is running out of steam, making it more susceptible to disruptions that might knock it out of equilibrium, said study author Niklas Boers, a researcher at the Potsdam Institute for Climate Impact Research in Germany.

If the circulation shuts down, it could bring extreme cold to Europe and parts of North America, raise sea levels along the U.S. East Coast and disrupt seasonal monsoons that provide water to much of the world.

“This is an increase in understanding … of how close to a tipping point the AMOC might already be,” said Levke Caesar, a climate physicist at Maynooth University who was not involved in the study.

Boers’s analysis doesn’t suggest exactly when the switch might happen. But “the mere possibility that the AMOC tipping point is close should be motivation enough for us to take countermeasures,” Caesar said. “The consequences of a collapse would likely be far-reaching.”

The foundations of a house that used to sits along the water near a beach in South Kingstown, R.I. Changes in the Atlantic Meridional Overturning Circulation could lead to rising sea levels on the U.S. East Coast. (Salwan Georges/The Washington Post)

The AMOC is the product of a gigantic, ocean-wide balancing act. It starts in the tropics, where high temperatures not only warm up the seawater but also increase its proportion of salt by boosting evaporation. This warm, salty water flows northeast from the U.S. coastline toward Europe — creating the current we know as the Gulf Stream.

But as the current gains latitude it cools, adding density to waters already laden with salt. By the time it hits Greenland, it is dense enough to sink deep beneath the surface. It pushes other submerged water south toward Antarctica, where it mixes with other ocean currents as part of a global system known as the “thermohaline circulation.”

This circulation is at the heart of Earth’s climate system, playing a critical role in redistributing heat and regulating weather patterns around the world.

As long as the necessary temperature and salinity gradients exist, AMOC is self-sustaining, Boers explained. The predictable physics that make dense water sink and lighter water “upwell” keep the circulation churning in an endless loop.

But climate change has shifted the balance. Higher temperatures make ocean waters warmer and lighter. An influx of freshwater from melting ice sheets and glaciers dilutes North Atlantic’s saltiness, reducing its density. If these waters aren’t heavy enough to sink, the entire AMOC will shut down.

It’s happened before. Studies suggest that toward the end of the last ice age, a massive glacial lake burst through a declining North American ice sheet. The flood of freshwater spilled into the Atlantic, halting the AMOC and plunging much of the Northern Hemisphere — especially Europe — into deep cold. Gas bubbles trapped in polar ice indicate the cold spell lasted 1,000 years. Analyses of plant fossils and ancient artifacts suggest that the climate shift transformed ecosystems and threw human societies into upheaval.

“The phenomenon is intrinsically bi-stable,” Woods Hole Oceanographic Institution President Peter de Menocal said of the AMOC. “It’s either on or it’s off.”

But is it about to turn off now?

“That’s the core question we’re all concerned about,” said de Menocal, who was not involved in Boers’s research.

In its 2019 “Special Report on the Ocean and Cryosphere in a Changing Climate,” the U.N. Intergovernmental Panel on Climate Change projected that the AMOC would weaken during this century, but total collapse within the next 300 years was only likely under the worst-case warming scenarios.

The new analysis suggests “the critical threshold is most likely much closer than we would have expected,” Boers said.

The “restoring forces,” or feedback loops, that keep the AMOC churning are in decline, he said. All the indicators analyzed in his study — including sea surface temperature and salt concentrations — have become increasingly variable.

It’s as though the AMOC is a patient newly arrived in the emergency room, and Boers has provided scientists with an assessment of its vital signs, de Menocal said. “All the signs are consistent with the patient having a real mortal problem.”

The sun rises on the Atlantic Ocean in Barra Del Chuy, Uruguay. (Carolyn Van Houten/The Washington Post)

Physical oceanographers like him are also trying to confirm the AMOC slowdown through direct observations. But the AMOC is so big and complex that it will probably take years of careful monitoring and data collection before a definitive measurement is possible.

“Yet everyone also realizes the jeopardy of waiting for that proof,” de Menocal said.

After all, there are plenty of other indications that Earth’s climate is in unprecedented territory. This summer, the Pacific Northwest was blasted by a heat wave scientists say was “virtually impossible” without human-caused warming. China, Germany, Belgium, Uganda and India have all experienced massive, deadly floods. Wildfires are raging from California to Turkey to the frozen forests of Siberia.

The world is more than 1 degree Celsius (1.8 degrees Fahrenheit) warmer than it was before humans started burning fossil fuels, and it’s getting hotter all the time.

And the apparent consequences of the AMOC slowing are already being felt. A persistent “cold blob” in the ocean south of Greenland is thought to result from less warm water reaching that region. The lagging Gulf Stream has caused exceptionally high sea level rise along the U.S. East Coast. Key fisheries have been upended by the rapid temperature swings, and beloved species are struggling to cope with the changes.

If the AMOC does completely shut down, the change would be irreversible in human lifetimes, Boers said. The “bi-stable” nature of the phenomenon means it will find new equilibrium in its “off” state. Turning it back on would require a shift in the climate far greater than the changes that triggered the shutdown.

“It’s one of those events that should not happen, and we should try all that we can to reduce greenhouse gas emissions as quickly as possible,” Boers said. “This is a system we don’t want to mess with.”

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