Last week we asked readers for their predictions of life in 100 years time. Inspired by ten 100-year predictions made by American civil engineer John Elfreth Watkins in 1900, many of you wrote in with your vision of the world in 2112.

Many of the "strange, almost impossible" predictions made by Watkins came true. Here is what futurologists Ian Pearson (IP) and Patrick Tucker (PT) think of your ideas.

1. Oceans will be extensively farmed and not just for fish (Jim 300)

IP: Likelihood 10/10. We will need to feed 10 billion people and nature can't keep up with demand, so we will need much more ocean farming for fish. But algae farming is also on the way for renewable energy, and maybe even for growth of feedstock (raw materials) or resource extraction via GM seaweed or algae.

PT: Good chance. According to Dennis Bushnell, chief scientist at the Nasa Langley Research Center, saltwater algae that's been genetically modified to absorb more nitrogen from the air than conventional algae could free up to 68% of the fresh water that is now tied up in conventional agriculture. This water could go to thirsty populations.

2. We will have the ability to communicate through thought transmission (Dev 2)

IP: Likelihood 10/10. Transmission will be just as easy as other forms of brain augmentation. Picking up thoughts and relaying them to another brain will not be much harder than storing them on the net.

PT: Good chance. Synthetic telepathy sounds like something out of Hollywood but it is absolutely possible, so long as "communication" is understood to be electrical signals rather than words.

3. Thanks to DNA and robotic engineering, we will have created incredibly intelligent humans who are immortal (game_over)

IP: Likelihood 9/10. It is more likely that direct brain links using electronics will achieve this, but GM will help a lot by increasing longevity - keeping people alive until electronic immortality technology is freely available at reasonable cost.

PT: Good chance. The idea that breakthroughs in the field of genetics, biotechnology and artificial intelligence will expand human intelligence and allow our species to essentially defeat death is sometimes called the Singularity.

4. We will be able to control the weather (mariebee_)

IP: Likelihood 8/10. There is already some weather control technology for mediating tornadoes, making it rain and so on, and thanks to climate change concerns, a huge amount of knowledge is being gleaned on how weather works. We will probably have technology to be able to control weather when we need to. It won't necessarily be cheap enough to use routinely and is more likely to be used to avoid severe damage in key areas.

PT: Good chance. We will certainly attempt to. A majority of scientists in the US support a federal programme to explore methods for engineering the Earth's climate (otherwise known as geoengineering). These technologies aim to protect against the worst effects of manmade climate change.

More readers' predictions English will be spelled phonetically (jim300)

Growing your own vegetables will not be allowed (holierthanthou)

The justice system will be based purely on rehabilitation (Paul)

Instead of receiving information from the media, people will download information directly into their brains (krozier93)

Crops will be grown in sand (jim300)

5. Antarctica will be "open for business" (Dev 2)

IP: Likelihood 8/10. The area seems worth keeping as a natural wilderness so I am hesitant here, but I do expect that pressure will eventually mean that some large areas will be used commercially for resources. It should be possible to do so without damaging nature there if the technology is good enough, and this will probably be a condition of exploration rights.

PT: Pretty close. Before there is a rush to develop Antarctica we will most likely see a full-scale rush to develop the Arctic. Whether the Arctic states tighten control over the region's resources, or find equitable and sustainable ways to share them will be a major political challenge in the decades ahead. Successful (if not necessarily sustainable) development of the Arctic portends well for the development of Antarctica.

6. One single worldwide currency (from Kennys_Heroes)

IP: Likelihood 8/10. This is very plausible. We are already seeing electronic currency that can be used anywhere, and this trend will continue. It is quite likely that there will be only a few regional currencies by the middle of the century and worldwide acceptance of a global electronic currency. This will gradually mean the others fall out of use and only one will left by the end of the century.

PT: Great try! The trend on this is actually more in the opposite direction. The internet is enabling new forms of bartering and value exchange. Local currencies are also now used by several hundred communities across the US and Europe. In other words, look for many more types of currency and exchange not fewer, in the coming decades.

7. We will all be wired to computers to make our brains work faster (Dev 2)

Image caption Will deserts become tropical forests?

IP: Likelihood 10/10. We can expect this as soon as 2050 for many people. By 2075 most people in the developed world will use machine augmentation of some sort for their brains and, by the end of the century, pretty much everyone will. If someone else does this you will have to compete.

8. Nanorobots will flow around our body fixing cells, and will be able to record our memories (Alister Brown)

PT: Good chance. Right now, medical nanorobots exist only in theory and nanotechnology is mostly a materials science. But it's a rapidly growing field. Nanorobots exist within the realm of possibility, but the question of when they will arrive is another matter

IP: Likelihood: 7/10.

9. We will have sussed nuclear fusion (Kennys_Heroes)

IP: Likelihood 10/10. This is likely by 2045-2050 and almost certain by 2100. It's widely predicted that we will achieve this. What difference it makes will depend on what other energy technologies we have. We might also see a growth in shale gas or massive solar energy facilities. I don't think that wind power will be around.

10. There will only be three languages in the world - English, Spanish and Mandarin (Bill Walker)

IP: Likelihood 8/10. This does look like a powerful trend, other languages don't stand a lot of chance. Minor languages are dying at a huge rate already and the other major ones are mostly in areas where everyone educated speaks at least one of the other three. Time frame could be this century.

Image caption Space elevators 'will certainly be around'

11. Eighty per cent of the world will have gay marriage (Paul)

IP: Likelihood 8/10. This seems inevitable to those of us in the West and is likely to mean different kinds of marriages being available to everyone. Gay people might pick different options from heterosexual people, but everyone will be allowed any option. Some regions will be highly resistant though because of strong religious influences, so it isn't certain.

12. California will lead the break-up of the US (Dev 2)

IP: Likelihood 8/10. There are some indications already that California wants to split off and such pressures tend to build over time. It is hard to see this waiting until the end of the century. Maybe an East Coast cluster will want to break off too. Pressures come from the enormous differences in wealth generation capability, and people not wanting to fund others if they can avoid it.

13. Space elevators will make space travel cheap and easy (Ahdok)

IP: Likelihood 8/10. First space elevators will certainly be around, and although "cheap" is a relative term, it will certainly be a lot cheaper than conventional space development. It will create a strong acceleration in space development and tourism will be one important area, but I doubt the costs will be low enough for most people to try.

14. Women will be routinely impregnated by artificial insemination rather than by a man (krozier 93)

PT: Pretty close. At the very least, more couples are choosing advanced fertility techniques over old-fashioned conception. Pre-implantation genetic diagnosis, in which an artificially inseminated embryo is carefully selected among other inseminated embryos for desirability, is becoming increasingly common in fertility clinics. Using this technique, it's now possible to screen an embryo for about half of all congenital illnesses. Within the next decade, researchers will be able to screen for almost all congenital illnesses prior to embryo implantation.

IP: Likelihood 5/10.

15. There will be museums for almost every aspect of nature, as so much of the world's natural habitat will have been destroyed (LowMaintenanceLifestyles)

PT: Pretty close. I cannot comment on the museums but the Earth is on the verge of a significant species extinction event. Protecting biodiversity in a time of increased resource consumption, overpopulation, and environmental degradation will require continued sacrifice on the part of local, often impoverished communities. Experts contend that incorporating local communities' economic interests into conservation plans will be essential to species protection in the next century.

IP: Likelihood 2/10.

16. Deserts will become tropical forests (jim300)

IP: Likelihood 7/10. Desert greening is progressing so this is just about possible.

17. Marriage will be replaced by an annual contract (holierthanthou)

IP: Likelihood 6/10. I think we will certainly see some weaker forms of marriage that are designed to last a decade or two rather than a whole lifetime, but traditional marriage will still be an option. Increasing longevity is the key - if you marry at 20 and live to well over 100, that is far too long a commitment. People will want marriages that aren't necessarily forever, but don't bankrupt them when they end.

18. Sovereign nation states will cease to exist and there will be one world government (krozier93)

PT: Great try! However, I think that the trend is in the direction of more sovereign nations rather than fewer. In the coming years, corporations or wealthy private citizens will attempt to use earth-moving technologies to build their own semi-sovereign entities in international waters.

IP: Likelihood 2/10.

19. War by the West will be fought totally by remote control (LowMaintenanceLifestyles)

IP: Likelihood 5/10.

20. Britain will have had a revolution (holierthanthou)

IP: Likelihood 7/10. Well, possible, but not as likely as some other trends.

You can continue to contribute to the debate on Twitter using the hashtag #100yearpredictions. Ian Pearson is a future technology consultant and conference speaker. Patrick Tucker is spokesperson for the World Future Society and deputy editor of The Futurist magazine.