Human lifespans have been going up for decades, and most of us can expect to see 80 even if we aren't that careful about our habits. What if that were boosted to 150? Some say the first people to reach 150 are alive right now. There are centenarians alive today who have seen two world wars, the invention of nuclear power and jet planes, and the remaking of the world map. How might the world look to the denizens of 2163? We spoke to experts in the field to get a taste of it. Technology plays a big role, but it could be human behavior and society that will change the most.

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In the future, nanorobots will patrol our bodies and destroy disease as it breaks out.iStockPhoto

Living to 150 will largely be a result of better medicine. Gene therapy is already on track to cure disease. It has the capacity to repair mitochondrial disease before birth. A century or more from now, it will likely have made cancer a thing of the past, as well as other genetic disorders ranging from cystic fibrosis to muscular dystrophy.

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Meanwhile stem cell therapies could help us grow new organs and even limbs. People will be healthier longer, perhaps because their aging body parts will be replaced with fresh ones. And tiny nanomachines the size of cells could be on task in our bodies, repairing damage as it occurs or eliminating disease.

What will happen to human jobs once robots become capable of doing most of the basic tasks?iStockPhoto

Robots are already a fixture in manufacturing, and computers do some jobs better than people. So what happens to the future of employment, especially if people live so long they won't retire until they're 100 years old?

"If most goods and food can be produced with few or a modest percentage of people involved, then the focus shifts to services," said Glen Heimstra, a consultant and founder of Futurist.com. He noted that a lot of service jobs involve interacting with real people, and that's not likely to change.

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Entertainment will be another key area for work. "Think of all the words being written right now on the Web, all the images being uploaded, all the videos being produced, by both professionals and amateurs. It seems a safe prediction that this will increase."

And how about the idea of a guaranteed income in order to keep the capitalistic machine running? It isn't as far-fetched as it sounds: Alaska gives a payment to every citizen that comes from oil revenues. This rather rosy scenario depends on human civilization getting past one huge bottleneck: energy.

Satellites could beam solar power energy down from orbit.NASA

Even today, solar power is getting more competitive in the market with fossil fuels as photovoltaic technology improves. But other alternatives to oil may see their day.

Nuclear may yet see a renaissance, for example, as there are several technologies in the works to make nuclear plants safer and deal with the nagging problem of radioactive waste.

Meanwhile there has been progress, if slow, towards working fusion reactors that produce tremendous amounts of energy (think: the sun) without the dangerous levels of radiation. And some people predict that we'll send a set of solar- satellites into space that will beam solar energy down from orbit. The day may actually come when humans wean themselves from fossil fuels.

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On the flip side, we might not be able to get the necessary technologies up and running fast enough. "There is a possibility that we are in an energy and resource over-shoot situation, and will not be able to adjust in time to avert a crash," Hiemstra said, though that's less likely in his opinion.

In that case, our 150-year-olds may be looking at life that's a lot like it was 150 years in the past where energy-intensive machines like cars and planes were reserved only for the very wealthy.

The proliferation of private companies engaged in space flight already means that in the future, we'll have colonies outside of Earth. Wikimedia Commons

If humans continue to spew CO2 into the atmosphere at the same rate, global temperatures will rise anywhere from 3 degrees Fahrenheit to nearly 11 degrees in the next century. Sea levels are predicted to rise between two to six feet, said Gavin Schmidt, a climatologist and Deputy Chief of NASA's Goddard Institute for Space Studies. "To get a sense of what this would mean in daily life you might want to look at Venice -- increasing incidences of flooding at high tide and during storms and slow adaptation to the new reality."

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Our 150-year-old might be telling her great grandchildren about the good ole days in the legendary city of New Orleans, which by then will be underwater. Gone would be Miami Beach and a big piece of the Netherlands and Bangladesh. China's current boom towns of Guangdong and Shenzhen might look like those villages submerged under the reservoir created by the Three Gorges Dam.

Future citizens of the Earth may only know animals such as chimpanzees, elephants, and lions from books.Firefly Productions/CORBIS

Human activity has meant both habitat loss and direct death for thousands of species. As a result, one of the biggest mass extinction events since the Cretaceous Period 65 million years ago looms on Earth's horizon. Anthony Barnosky, a palaeobiologist at the University of California, Berkeley, predicts that in 300 years time, 75 percent of all mammal species will have disappeared from this planet.

Anyone living 150 from now may only know big animals such as the apes, chimpanzees, elephants, lions and tigers from books (or whatever medium is current then).

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At the same time, invasive species will fill niches, and our great-grandchildren won't know anything different. "Look at Hawaii," said Quentin Wheeler, taxonomist and professor at the School of Sustainability at Arizona State University. "All those flowers that the tourists love are mostly invasive species. The local flora was decimated."

Instead of elephants, we may have boa constrictors and coyotes.

A "wet connection" will likely link the organic tissue of brains with computerized technology.KTSDESIGN/Science Photo Library/iStockPhoto

A century and a half from now, typing on a keyboard might look as old fashioned as writing with a quill pen. Instead, humans will more likely connect directly to computers via their brains.

That will involve some kind of "wet" connection, said Douglas H. Smith, M.D., professor of neurosurgery and director of the University of Pennsylvania's Center for Brain Injury and Repair. Wet connections use engineered nerves or nerve-like materials to link organic material to computer material. Such interfaces would allow for directly controlling a virtual keyboard.

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Using word processing software or accessing the Internet would happen via eye implants.

"Imminent access to the Internet will also transform education -- all the world's history will be just a nerve impulse away," he said. "Such immediate availability of information will change the way we feel about family and friends. A loved one on the other side of the world could essentially go through the day with you."

Computers of the future will be able to hold conversations and perhaps even be self-aware.IBM

Computers are already pretty smart and pretty fast. IBM's Watson was able to demonstrate in 2011 its ability to handle natural language and reasoning by defeating that year's Jeopardy! champion. And in June, 2013, China's Tianhe-2 was dubbed the fastest supercomputer in the world. It can accomplish 33,860 trillion calculations per second.

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By 2163, wqe will have long surpassed the singularity, the moment at which computers overtake humans in intelligence. That is predicted to happen around 2045. People of the future might be able to upload and download their memories to computers, hold conversations with machines and ask them for assistance with any number of tasks.

The future of space travel might resemble the explosion in information technology that marked the 1990s.Wikimedia Commons

One of the wild cards of the future is that we might become a true space-faring society. Hiemstra said the proliferation of private companies engaged in space flight, along with the technological advances since the Apollo era, might push us toward an "inflection point," and that the future of space travel might resemble the explosion in information technology that marked the 1990s.

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There are two private companies with serious asteroid-mining proposals, and several companies -- and the Chinese -- are proposing human spaceflight projects. Our 150-year-old might have Skype-like chats with her descendants living in orbit, or on the Moon or Mars.

By analyzing the contents of exoplanet atmospheres, it's probable that humans will discover extant or extinct life outside of the Earth.Creasource/Corbis

Astronomers have found hundreds of planets around other stars. The question is whether any of them have life. "Within the next 25 to 50 years, we will have the ability to observe essentially the entire radio portion of the electromagnetic spectrum across the entire sky, instantaneously," said Andrew Siemion, an astronomer at the University of California, Berkeley.

"Within the next 150 years (probably within the next 50), we will discover extant or extinct life outside of the Earth," he said. "Most likely this discovery will be made spectroscopically, through analyzing the contents of exoplanet atmospheres, but it may also be made via in-situ measurements on other bodies in our own solar system."

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New technology will be a big part of solving the mystery of life on other planets. "Instead of tediously tuning our radio telescopes around tiny bands of frequencies and pointing a telescope at many, many positions, we will cover everything, all at once. If the assumptions that led us to look for narrow-band radio signals in the first place are correct, we will discover intelligent life," said Siemion.

And if we see nothing, it would mean there's something pretty special about us -- or at least, that ET doesn't use a radio to phone home.

In an ultra-networked world, people may have to create different online personas to meet different needs. iStockPhoto

Since it's likely that people will be living in a networked world, one thing that might look different is how we relate to other people, and the data that makes up the sum total of our interactions. We already have security cameras following us everywhere, and Google and Facebook both collect and keep tons of information about their users. That might mean people have to come up with different "faces" for a given context, similar to how Facebook users have separate accounts for business and for friends.

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"The whole concept of privacy is always being renegotiated," said Samuel Collins, a professor of anthropology at Towson University. And it's likely that people will need help to manage that, probably from a piece of software. That by itself could have a big effect on how we conceive of privacy. On top of that, it's easier than ever before to track people. "We're already at the Orwellian stage," Collins said. "We need to think about what comes after that."

Changing one's own body might be as easy as putting on or taking off cosmetics.iStockPhoto

Along with the technology to meld humans with computers, future citizens of Earth will have genetic engineering and biological enhancements at their fingertips.

"Biological enhancements, to the extent we can do it at all, is dangerous and expensive," said futurist Jamais Cascio. "But for people living [in the future] it will be casual and boring." Changing one's own body might be as easy as putting on or taking off cosmetics. That means more than changing a face or hair color. "Someone might say 'I will be a woman today,' or 'I will be a man today.'" More exotic enhancements like extra arms or adaptations to extreme environments could mean that some people look bizarre to our "modern" eyes.