130

Go back to the cold war era and start a "Russians are trying to warm the planet" scare. You will need a lot of money to fund some big advertising campaigns. You also want to seed a few specific technologies like nuclear and solar power to try and push them along. Let ignorance and paranoia work towards the betterment of mankind for a change. It's ...


90

The climate of Earth has been roughed up quite a bit last century. But it has no idea what it's got coming with this portal of yours. Earth turns into Venus. Update: As R.M. pointed out, the amount of energy is not 'maybe a long term thing', it's the Major Issue. This has been fixed now. How much water are we talking? Let's say your portal is 10km below ...


65

It is technically possible to burn carbon dioxide, but not in a practical way. The reason burning carbon produces energy is that the total potential energy of carbon and oxygen is minimized by the CO2 configuration. Splitting them up into carbon and oxygen again requires an addition of energy. Therefore, in order to burn carbon dioxide, you need to find ...


44

•98% of all the landmass is wasteland/desert •The two poles are some big chunks of ice, each covering about 20% of earths area This is rather confusing. Yes, I get that there are also cold deserts, but next to the glacier there will be the melting zone, where the bonanza of water will inevitably favor life. •There are only two climate zones, hot ...


41

This will not work at all The short version If you drop an ice cube into a room temperature drink, the drink will be slightly colder for a little while. But what happens then? Answer: the drink warms up again until it has the same temperature as its surroundings. What happens when these melt? Does the drink stay cold? No, it does not. (Image source) The ...


37

What keeps my planet's water from irreversibly concentrating over time on the frigid wastes while the rest of the planet dries up? When ice piles up, it will exercise pressure. The closer to the terminator, the less the ice. As a consequence, pressure gradient will tend to push the ice sheet toward the terminator, where it will melt, returning water to the ...


36

It takes a lot of energy to move the Earth In this question, I calculate the energy needed to move the Earth. In order to move the Earth by 1m in orbit, you will need to expend about $2\times10^{22}$ Joules. This is about five orders of magnitude greater than the largest atomic bomb, and only one order of magnitude less than the Chicxulub asteroid that ...


35

Two of my favorites for this scenario. Dig. Fresno is pretty close to what you describe. This guy Forestiere bought land sight unseen thinking he would grow fruit and nut trees but on getting there realized it was worthless. So he dug. When he got low enough, he planted the trees. Take a tour off hwy 99 and visit fresno's best kept secret •A hand-...


33

The mad scientist sledgehammer option for this particular nut. Kill a very large slice of the world population. It worked when Europe colonised the Americas, so many natives were killed it actually changed the global climate. America colonisation ‘cooled Earth's climate’ He travels back in time to the height of the cold war at its most unstable & ...


29

Comets are tiny Halley's mass is 2.2×1015 kg. A cubic kilometer of water has a mass※1 of 1 × 1012 kg Oceans hold 1.35 × 10 9 cubic kilometers, which gives us 1.35 21 kg of water. So, the mass of the Halley is half a millionth of the ocean. If it is 200 C colder than Earth oceans (say −180° C for the comet, 20° C for the ocean) when dropped, the calculus of ...


29

First observation: The portals as described in the question create a perpetuum mobile. Salt water under high pressure (from the ground of the Mariana trench) wells up at some point in the Sahara desert, becoming a fine source of hydroelectric power. It will create a river of salt water that may fill up some basins and eventually reaches the sea (either the ...


24

You can’t use carbon dioxide as fuel, and that’s not what the article you cite is about. You can turn carbon dioxide (plus hydrogen or water) into fuel, but the process will need more energy than you will later release by burning the fuel, so you’ll need to get that energy from somewhere. But yes; if you get the energy without burning fossil fuels and you ...


22

TLDR; The equations: $$r_{B} = \sqrt{\frac{F}{2.46\times 10^{-14}}}$$ or rearranging for $$F = r_{B}^{2} \times 2.46\times 10^{-14}$$ Where $F$ is the fraction of light blocked ($F=0.01$ gives your $1\%$) and $r_{B}$ is the radius of your satellite in meters which will achieve this. For one percent reduction, using the equations above, we need a ...


21

You're trying to cure the sickness by alleviating a symptom. You can't cure global warming by putting more pollution into the air. You may temporarily bring the patient's temperature down, but humanity will respond by turning up the heat. In the end, you'll make global warming much, much worse. Please keep in mind that global-warming/climate-change/name-...


21

Librations. That is, the tidally locked planet is not in a perfectly circular orbit, and so the portion of the planet that is sun-facing is not constant. This is because the rate of rotation is (extremely nearly) constant, but the rate of revolution around the sun changes due to the non-circular nature. For the Earth's Moon, this is only a few degrees. If ...


20

To me, it's the same as if you'd said: Stopping global warming by leaving the fridge open. Ice needs to be produced. This requires large quantities of energy for freezing water, which requires more and more power plants. You need large quantities of ice. There are 1386 million cubic kilometres of water on Earth (Wiki), they need to be cooled. Even if: You ...


18

You're positing a world that has no surface plants. That's... implausible. There are plants out there that can manage climatic extremes far worse than anything humans could live through. Plants actively thrive in concentrations of CO2 that humans would find lethal. You might easily have a massive die-off as climate change modified local conditions, but ...


18

According to your link: The process can work with any level of carbon dioxide concentration, Wu says -- they have tested it all the way from 2 percent to 99 percent -- but the higher the concentration, the more efficient the process is. The atmospheric concentration of carbon dioxide is .0391%. That's well under 2%. This would not work well at ...


16

The best solution is to not nuke the poles. The poles are really-really-really big. The arctic ice sheet is around 20000km$^3$ of ice, or 20000000000000m$^3$! That's 1.8334 × 10$^1$$^6$ kilograms of ice. Melting ice takes 333.55 kJ/kg, so we'll need about 6,100,000,000 TJ of energy to melt it all. The RS-28 you reference is believed to be able to ...


16

Here is an idea: What if Henry Ford had built his assembly line for an electric car rather than a gas powered car? Before the assembly line brought down the price of the Model T, electric cars were actually less expensive than gas cars. The assembly line would have made these even cheaper. Electric cars and infrastructure would need more electric power ...


16

Direct bootstrap of nuclear fission technology in the 1700s. Sounds crazy right? Not so fast. In order to reliably prevent runaway climate change, we must prevent the situation that caused it, namely cheap coal and oil power. This is quite well accomplished by getting there first with uranium, plutonium, and thorium reactors all at once. Since mining won't ...


14

Could we do this? Yes, we could. It's been proposed before in a number of forms. Most calculations agree that this sunshade would need to reduce solar insolation by anywhere from 2-10%. If we take an optimistic figure - the lower bound of 2% - then we could achieve this by putting a shade 4.5 million square kilometers in area at the Sun-Earth Lagrange point,...


13

@SJuan76 's answer is incomplete. He did the math to show the small cooling effect of, but didn't show the heating effect. I shamelessly copied his cooling numbers, and added heating numbers to compare. Comets have a small cooling effect Halley's mass is $2.2\times10^{15} \text{kg}$. A cubic kilometer of water has a mass of $1\times10^{12} \text{kg}$ ...


13

First: how big to appear as big as the moon if in a typical satellite orbit? Here is a fine image of the ISS passing in front of the moon and we can use it to gauge their relative apparent sizes. from https://www.space.com/6870-spot-satellites.html When I blew them up, I measured the diameter of the moon at 567 pixels and the ISS at 14. 567/14 = 40 so a ...


13

The surface conditions you're describing are closer to an ice age than any other situation. In practice the ice caps covered only 35% of the land mass, though they locked up the vast majority of the fresh water. This means that the ice age was one of the driest periods in the planet's history. The more of the water that's locked up in the poles the drier ...


12

Prevent Chernobyl and Three Mile Island so that adoption of nuclear power isn't regressed. This might not completely solve the problem but if it cuts enough emissions to buy a couple decades so that renewables and electric cars and other technologies become economical soon enough to prevent cataclysmic warming.


12

No. The mass extinction you're hoping for—no plants and only microscopic animals—is impossible from these conditions. At the point that humans left the planet, it was possible for animal and plant life to exist, even if it was limited to certain areas. Because otherwise, they'd be dead before they left. Once humans were gone, they stopped their ...


11

Effectiveness 10/10. Move further from the sun, you get less incoming solar radiation, so you cool the planet. Practicality 0/10. Planets are heavy. More specifically, the energy needed to increase the earth's orbit would be absolutely astronomical (all puns intended). The solution used in Futurama as you describe it is also utterly impractical. The ...


11

I assume you prefer a scientifically correct answer, as in the portal can't violate energy conservation. In that case, we just can't have portals. But we can have a long tube, and lets just ignore friction inside that tube so we simulate most of the portal stuff. It does not even matter if the portaltube would end in the marianna trench. Just a few meters ...


11

Keeping traveling back even when incentive is lost A big problem with solving problems trough time travel is that once it is fixed the incentive to travel back in time is lost and thereby no one will travel back in time to keep the timeline fixed. So what the time traveler has to do is leave a note. Either to himself, or if he never gets born in the new ...


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