It was around the 15th century that humans began building telescopes. The next few centuries saw incremental improvements that lead to increasingly detailed observation of the cosmos. During the 20th century things really accelerated (as did all technologies), and by the end of the 20th century they had constructed many very large telescopes, developed sophisticated optics that could compensate for atmospheric distortion, computer systems that could combine multiple telescopes into single interferometers, and further improve quality—they had even placed a few in orbit.
In the first few decades of the 21st century things accelerated even more. Ever larger telescopes were constructed, more were placed in space, with ever larger mirrors and cameras. And they began to detect exoplanets—planets that orbited distant stars rather than the Sun. At first they could only detect the presence of an exoplanet—or often several—in the way they tugged at their central star, or changed it's color or brightness, ever so slightly. But as the telescopes got bigger, and the software increasingly powerful, they began to resolve the planets themselves. At first it was just the fact that there was a planet there, but eventually it was with enough detail to analyze the spectrum of the atmospheres.
The "wobble" and "brightness dipping" methods that had been used for years had identified a large number of "Earth-like" exoplanets—planets that appeared to be the right distance from their host stars to not boil or freeze, and not so large that their gravity would crush multicellular life into a puddle.
Humans desperately wanted to know, were they alone?
By the end of the third decade and into the fourth and fifth decades of their 21st century a grim realization slowly overtook the search. All of the candidate Earths—every single one of them—was cooked. The "good" news was that, yes, life existed elsewhere in the universe. The bad news was it seemed it always, without fail, managed to convert its home planet into a Venus-like hellscape. [At this point I need to talk to a chemist to figure out what plausible chemical we could discuss detecting in an atmosphere that would without a doubt indicate life, but which also could be tied to a runaway greenhouse effect.]
And it appeared they were already too late. Climate change was already far outpacing even the worst-case scenarios scientists had predicted. To avoid the complete destruction of the biosphere humans would have needed to end their fossil fuel use before the mid-20th century, a time at which very few people were even aware there could even be any problem. It seemed like some kind of cosmic trap: whenever intelligent life evolved in the universe, it couldn't develop the scientific comprehension & technological sophistication required to understand how it was changing it's climate until it had already inflicted damage beyond repair. The sheer momentum of the system, the lag between emitting green house gasses from burning fossil fuel and the climate changing was so large that, once "the ball was rolling" it couldn't be stopped—like an oil well drill puncturing an oil reserve under such great pressure that it can't be plugged.
At this point humans began undertaking massive environmental engineering efforts, to no avail. They seeded the oceans with iron, hoping to promote the growth of plankton & accelerate the sequestration of carbon, they began placing billions of reflective panels in the L1 Lagrange point to decrease the solar radiation incident on Earth's surface, they engineered machines that exceeded photosynthesis in their ability to capture carbon—and algae that thrived in the ultra-concentrated carbon dioxide exhaust of the remaining fossil fuel-powered vehicles & power plants scrubbed all excess CO2 from the waste. But it was too little, too late. The process had already begun. Even many of those with a strong grasp of human-caused climate change—who understood the role humans played, the physics of situation—even many of them had not thought the consequences could be so cataclysmic, or that they would progress so rapidly. They had expected the process to play out over centuries and millennia, not merely decades.
That is a short story I've been thinking about for years now, based on the idea that climate change could be an existential threat to our species (& great filter to intelligent life in general). Some ideas for an alternate title or a subtitle include, the year we resolved the Fermi paradox. I need to re-read it but I started envisioning it as a tale told several decades from now, about how in the recent past they had observed these extrasolar planets & discovered just how dire climate change really was, but that it was too late by then, and that it is even too late now. Bill Nye's Venus comparison is really stuck in my head, as implausible as it seems, I cannot figure out if it's possible to dismiss it entirely.
I don't actually think climate change is an existential threat, I expect that many humans will survive it—but I do think it is the biggest problem humans have ever faced. Bill Nye has occasionally pointed out that Venus is very similar to Earth, with the primary difference being it's atmospheric composition and position closer to the Sun, which give it an uninhabitable surface temperature of 462° C (more than 900° F). I'm not sure Nye has ever suggested that Earth could potentially become “uninhabitably” hot, but if that is a possibility then climate change would be an existential threat, and I would think we are probably doomed. (I also expect humans will eventually engage in massive climate engineering projects to mitigate the effects.)
It's not clear whether it is even possible for a technologically sophisticated species (like ourselves) to avoid climate change issues. Understanding the problem requires a degree of technological & scientific sophistication, and science & technology require a certain level of energy consumption, and fossil fuels (along with biomass) will always be the “best first,” in the sense that they're the most convenient (since understanding the negative externalities takes a long time). If turning an Earth-like planet into a Venus-like planet is easy, or it's very hard not to, then climate change would be a great filter resolving the Fermi paradox. (My intuition (for what it's worth) is that the Fermi paradox is easily resolved by the combination of extreme rarity of technologically sophisticated life (comparable to our own) and the enormous size of the universe. And probably some habitability restrictions on galaxies too (e.g. areas of denser star formation, like the inner half of spiral galaxies, probably have too many supernova wiping life off them to support intelligent life). I also suspect that interstellar travel is much more difficult than we have yet conceived, and may even be impossible for complex life like ourselves, though it does seem likely that our technology will one day be able to colonize much of the galaxy. If in 10 million years “humans” still haven't found life outside of Earth, I can imagine us turning the entire galaxy into a beacon to signal to other galaxies, though that raises all sorts of weird questions about how such a thing could even be done.)
At present many people are optimistic that renewable technologies like wind turbines & solar panels will save the day, but I'm very skeptical of this. In part because we don't have a very good way of storing energy we produce, and in part because both technologies require a lots of space. My mother installed solar panels on her house a few years ago, and my older brother and I were discussing how she might store excess energy to use at night, so we did some calculations to estimate it.
Today her panels generated about 47 kWh of electrical power. So what would it take to store that energy? We could lift a 1-ton weight (2000 lbs) 62,400 feet into the air, obviously impractical. The house is about 20 feet tall, so we could lift 6.24 million pounds 20 feet into the air. She has a pool which holds about 20,000 gallons of water, weighing about 167,000 lbs—we could lift that to 748 feet. Seems that water towers can hold around a million, or 1.5 million, gallons of water, at a height of about 150 feet. That could store about 500 kWh worth of energy. There are some good & bad caveats to mention too, in the bad category, storage systems are not 100% efficient, the wikipedia article on pumped-water storage claims 70-80% efficiency (which is well above what I would have expected), in the good category is that we needn't store all of the energy we produce, most people probably consume far less energy at night. (Though refrigerators run constantly, many computers, heaters and air conditioners.)
Big pumped storage facilities use reservoirs (cause as you can see, a water tower is only going to provide energy storage for a small neighborhood). But reservoirs introduce additional problems. Flooding vegetation (as is the case in most hydroelectric plants) produces methane for decades (methane is 25 times as potent as carbon dioxide at trapping heat, but on the bright side doesn't last for many centuries, like carbon dioxide does). They can also use a lot of concrete, which also creates a lot of carbon dioxide.
My dad once told me he heard you could power the whole country (or the world?) with a square of solar panels 93 miles on a side. After thinking about it some I asked him one day if he had considered just how enormous that area is. The US is about 3000 miles wide from the Atlantic coast to the Pacific, so imagine we paved a highway from one side to the other, but instead of the usual highway width (say, 50-75 feet for two lanes in each direction plus a median), our highway is a mile wide (5,280 feet). That would give us 3,000 square miles of road. But a square 93 miles on a side is 93 x 93 = 8,649 square miles. So our highway needs to be almost 3 miles wide (15,840 feet)! And remember it's made of photovoltaic cells not pavement! And this is ignoring all the additional room that will be needed for the power lines needed to connect the panels to cities. It's also ignoring the fact that the panels don't last forever—in a few decades you have to start replacing all of them. (Granted this is true of all power creation.)
Nathan Myrhvold says the average American uses about 11 kW of electrical energy, and that a toaster uses about 1 kW, so you can think of it as each of us running 11 toasters all the time. (Brand (I think?) estimated that we each use about 18 kW of energy, but that includes the non-electrical power, like heating & cooling our homes, driving our cars, building things...) Myrhvold makes the point that right now it's mostly Europeans, Americans, the Japanese—mostly the wealthiest countries, that consume so much power, but that everyone else will be consuming comparable amounts of power in several decades. Worse, there are more than 7.4 billion (7,400,000,000) people alive today, and we expect the population to continue growing to maybe (optimistically) 9 billion (9,000,000,000) to 11 billion (11,000,000,000) over the next century. (It's debatable whether or not it will continue growing, or stabilize & shrink in the distant future.)
So our problem is a combination of the amount of energy we use (and who are we to say others shouldn't be able to too?) and the sheer number of people there are (and will be). And there isn't much we can do about either of those facts. We know more than enough about the physical world to know that we're not going to discover a new source of energy. (Though fusion power, assuming it someday becomes viable, would likely help.) We can improve the efficiency of some things, but no where near enough to solve these problems. We can try to reduce our consumption, but there are limits to that too (if you don't heat your home enough you'll freeze to death; you need to transport food; fertilizers and growing food for 7-11 billion people requires a lot of energy too.)
Which brings me to nuclear power.
Imagine you were locked in a large room with a lot of people, and someone needed to poop. Faced with the choice of them pooping in a corner, or aerosolizing their poop and dispersing it throughout the air of the room as a fine mist, the choice is obvious right? (I've had a overwhelming revulsion for poop my entire adult life, until a few years ago when I got very sick and found out what it is like to have your butt wiped by grown men (they were nurses). Turns out when you're faced with death, poop isn't that big a deal.) As disgusting as this analogy is, the emissions of coal fueled power plants are far worse. Coal power stations aren't just creating greenhouse gases that will trap additional heat for centuries, they also emit radioactive waste directly into the atmosphere. The emissions of coal plants aren't just disgusting and unsanitary, they're downright poisonous.
Nuclear power on the other hand, is akin to pooping in a bucket in the corner. (One other important factor to consider—the energy density of uranium is about a million times greater than coal, so in the analogy the choice should be between pooping in a bucket, or a million times as much poop dispersed in the air.) People worry about what we would do with nuclear waste, and people talk about making containers that would store it for 10,000 or even 1,000,000 years—but these ideas are stupid. In reality we should store the waste, keep it safe, monitor it, maintain it, guard it. When we notice the containers corroding, we study the problem, understand the cause, and fix it. If something so devastating happens to our civilization that all memory of the hazards of nuclear waste is lost, then we have much bigger problems to worry about than what “the next guy to find the waste will do”.
- Add lots of links!
- Link to Nathan Myrhvold's toaster analogy,
- to the TED talk on nuclear power,
- to the article on coal waste,
- to the By the Numbers article,
- and to the Stewart Brand (I think?) calculations on Renewistan.
- Go into more detail addressing the cost concerns of fission power and the technological changes from the last few decades.
I watched Dunkirk last night with my mom (I had seen it before), and there is a scene with a long dock (there's probably a better name for it?) packed full of men, and a few planes are coming in to bomb it, and at first one guy turns around, searching for the source of the noise, then a few more turn, then many, and then the whole group of men turn. Watching it I was thinking about how it would probably start as a subtle enough noise that most people wouldn't hear it, especially considering that we don't all hear equally well, some are better & worse than others. Some people might just look around more, or happen to be looking in that direction. But as the noise increases, and ultimately, as people notice others around them looking in a particular direction, eventually everyone's attention is drawn to it. The same will be true of anything, including climate change. Right now, it's turned a lot of heads, but not all of them. And additionally, not everyone see it as comparable to a series of planes preparing to dive-bomb them. Granted, there are many who likely have “over-hyped” concerns, many who “have faith” that we'll figure it out somehow, and of course many who don't think it's a problem (some even who don't think it could possibly be a problem!). There are others who agree it's a problem but not worth the financial costs. Of course none of us truly know, but that's the problem. (Well, a problem.) And the more we know about it the worse it appears to be.
The Paleocene-Eocene Thermal Maximum (PETM) was an event around 55-56 million years ago, when for reasons unknown, carbon in Earth's atmosphere increased dramatically, resulting in a 5-8°C increase in global temperatures.
However, the amount of released carbon, according to a recent study, suggest a modest 0.2 gigatonnes per year (at peaks 0.58 gigatonnes); humans today add about 10 gigatonnes per year.
The problem is the product of the number of people and the necessities of a modestly comfortable life. Forget cars, airplanes, and electricity for the moment, just consider that most climates require either heating or air conditioning at some point throughout the year (and both in some cases). Consider that every person needs food, which requires fertilizers to grow.