This post was a joke and wasn't supposed to be educational or a debate, but it very dramatically broke containment, and the replies have by and large been making the assumption that I was trying to make Claims. I want to close the book on this, so let's actually sit down and discuss some of the nuances here. I promise I'll be polite.
If you're interested in geosciences, please consider reading this! And if you have any additions or corrections, I only ask that you circle me into them. I might cop an attitude sometimes, but I really truly love this stuff, and I couldn't call myself a researcher if I couldn't handle good-faith discussion.
I don't claim any of this as 100% unequivocal, immutable fact, nor do I present myself as a foremost authority on seismology. This is a post going into some of the simple science behind earthquakes and long-term climate change. Let's all learn together.
A SUPPLEMENTARY FIELD GUIDE TO EARTHQUAKES, TECTONICS, CLIMATE CHANGE, AND YES EVEN FRACKING.
A little bit of context first?
When we talk about "global warming", what do we mean? Global warming is a kind of limited (and outdated) term referring to the warming of the atmosphere by human (anthropogenic) influences. Now we understand that anthropogenic influences do much more than just make summers hotter, and the term climate change is much more widely applicable.
What do we mean by "exacerbating"? In short: making worse. Anthropogenic climate change is demonstrably responsible for increasing the severity of natural disasters. In recent years we've seen increases in the frequency and strength of things like wildfires, hurricanes/cyclones and floods, directly affected by our influence on the climate. But what about earthquakes?
What determines the severity of an earthquake?
Earthquakes are a natural byproduct of the cyclic build-up and release of energy along points of weakness (faults) in the Earth's crust. The severity (magnitude) of an earthquake is directly proportional to the amount of stress a fault can withstand (accommodate) before it releases it (ruptures), which is in turn directly proportional to the surface area of the fault.
You can sort of think of it like trying to stretch a rubber band until it breaks; Less force is needed to snap a thin rubber band than a thick rubber band, and you can snap a lot of thin rubber bands faster than you can snap a lot of thick ones.
This is why more severe earthquakes are also more rare; not only do they take longer to build up, once you start getting up in the scale there are just fewer and fewer places in the world where they actually can build up at all (faults that are large enough to accommodate them).
[Map of 6.0+ Mw ("strong quake") epicenters from 1907-2017. Black dots indicate the five total earthquakes over 9.0+ Mw that have occurred in that time. You might notice that almost every single quake on this map occurred on or around a major tectonic plate boundary, because faults large enough to produce quakes of 6.0+ Mw are pretty much only found in these locations]
Earthquakes are measured on a logarithmic scale from 1-10, with each step up being 10 times stronger than the magnitude below it. Most of the quakes Earth experiences daily are 1.0-3.0 Mw, which are rarely felt by humans, while extreme magnitudes occur less frequently, taking tens or hundreds (if not thousands) of years to build up.
What exactly builds up an earthquake?
Short answer: Plate tectonics, baby. Longer answer: Stress in the crust is the natural result of how Earth is structured. The rigid lithosphere (crust and upper mantle) is underlain by the ductile asthenosphere (viscous mantle layer). You can kind of think of the lithosphere and asthenosphere like a chocolate shell over ice cream, or ice on a river, or literal crust on bread.
[Diagram of the Earth's internal layers. The left side shows the simple divisions we use day-to-day, while the right side shows the specific geological divisions. The lithosphere and asthenosphere are the uppermost layers, comprising (but not equivalent to) the crust and upper mantle, and the most directly involved in tectonic motion.]
Heat energy from Earth's core causes the molten mantle to move (convect) and this moves everything above it. As the more ductile asthenosphere moves below the lithosphere, stress is applied to the rigid material above, causing it to internally deform (strain) by folding, fracturing and stretching. Because of density and thickness differences in the lithosphere, this movement will cause it to drag and move against itself as well. This deformation creates fault systems, places of weakness where this stress is focused. Think of watching the crust on bread crack as the dough in the center rises, or ice break up on a river as water flows under it.
Tectonic plates are massive chunks of the lithosphere that are thick and strong in their centers and weak along their edges where large fault systems subsequently form, like perforated edges on paper or the burned edges of a cookie. Faults can appear anywhere where tectonic stresses are being accommodated, but the largest, most active, and most felt by humans are located at or around plate boundaries.
[Map of Earth's major tectonic plate boundaries. Red (and pink) lines indicate divergent or extensional boundaries, where crust moves apart and new crust is created. Purple lines indicate convergent boundaries where two thick crustal blocks collide and uplift. Blue lines indicate convergent boundaries where crust of different densities collide, with lighter, thicker crust subsuming and destroying heavier, thinner crust, called subduction. Yellow lines indicate transform boundaries, where plates strike and slip against each other. The most severe earthquakes in the world almost always occur at subduction zones.]
This seems pretty self-sufficient. Does the climate really have no effect on tectonics?
It does and it doesn't, but mostly it does. While it's true that the major drivers of plate tectonics come from the fundamental structure of the Earth itself, it's not reasonable to think of these processes as being divorced from the rest of Earth's climate system. Tectonics are an integral part of what made Earth capable of hosting a breathable atmosphere and habitable climate in the first place. But that's a whole other post. In the simplest terms, Earth's climate system doesn't just involve the weather (atmosphere), it also includes our water (hydrosphere), our ice (cryosphere), living organisms (biosphere), and the lithosphere. All of these systems are interconnected to some degree, and changes in one will cause some changes in others, but the degrees to which those changes are felt by different systems vary quite a bit.
The lithosphere is arguably one of least sensitive spheres in the system, at least in regards to direct changes brought on by changes in the others, as the major drivers of tectonic motion come from inside the Earth rather than on its surface. But there are exceptions to this "rule" (like in almost everything in science). One of the biggest ways the other systems in the climate can affect the behaviour of the lithosphere is their influence on something called isostacy.
Well, no. Again, I never intended the original post to be educational or informative. If I'd brought up all the little nuances of the climate system right at the beginning, the original post would have looked like this one. And no one wants to read that. But we're doing it now, so let's move on.
Isostacy is a weird concept, but it more or less describes a gravitational equilibrium between objects of different densities. In the geological sense, isostacy describes the way the crust (lithosphere) positions itself on top of the mantle (asthenosphere). Like an iceberg only having a small part of its total mass visible above the water, crustal blocks "float" at different elevations controlled by their densities and thicknesses.
[Simple diagram of isostacy in the crust. Continental crust (dark green), composed of less dense rock, sits at higher elevations than oceanic crust (light green), which is significantly denser, and its thickness supports these elevations by providing a deep "root" beneath the surface for balance.]
Isostacy is ongoing all the time, minutely adjusting the elevation of the crust constantly. It's sensitive to anything that changes the pressures, thicknesses, and density of the crust, particularly the addition or removal of material on the surface. When an elevation adjustment is brought on by the removal of material this is referred to as isostatic rebound.
You can think of isostatic rebound like pushing a rubber duck underwater in a bath with your hand; the downwards force you apply with your hand against the upwards force of the duck controls the vertical elevation of the duck, and you can push it underwater. But the duck, like the less-dense crust, wants to be at equilibrium (at the surface), so lessening the force or removing your hand entirely will cause the duck to move back upwards.
[Screenshot of a Youtube video titled “Crushing a family of Rubber Ducks with Hydraulic Press!”. A family of ducks are about to be crushed]
What does this have to do with the climate stuff, isn't this about climate stuff?
Isostatic adjustment is a very slow process that is usually the result of the equally slow erosion or uplift of mountains and other high-elevation parts of the crust (which are climate-controlled by wind and water! Interconnectivity!). But one of the biggest factors in the addition and removal of material on the surface, especially in Earth's recent history (geologically speaking, that's the last few million years), is ice cover.
During glacial maximums (cold peaks of ice ages, of which there have been many in Earth's history), massive amounts of freshwater are sequestered on land in the form of ice sheets. During the last glacial maximum (the LGM, ~21,000 years ago), major ice sheets existed in Antarctica, Greenland, North and South America, and Northern Europe, and collectively covered close to 25% of the Earth's land area. In the present day (an interglacial or glacial minimum), this number is closer to 10%.
[Map of the approximate locations of the Earth's major ice sheets during the LGM. Only the Greenland and Antarctic Ice Sheets exist in the present day, and are significantly smaller.]
Post-glacial rebound describes the process of isostatic adjustment that occurs when these massive amounts of ice, which exert pressure on the underlying lithosphere, melt and the land beneath rises in their absence.
[Simple diagram of post-glacial isostatic rebound. The heavy mass of ice creates extra pressure on the crustal block, pushing it downwards to meet a new equilibrium. When the ice melts, that pressure is released, and the crust rebounds back upwards, getting back to a position of equilibrium with the mantle.]
Glaciation is climate change. In the interconnected climate system, the atmosphere, hydrosphere, cryosphere and lithosphere all play roles in the onset of glacial cycles; Air and ocean circulation, tectonic controls on seaways and wind current paths, sea level rise and fall, and ice intensity all contribute to the climate being able to transition between glacial and interglacial states.
So the climate system affects isostatic rebound. How does isostatic rebound affect earthquakes?
A major effect of isostatic rebound, beyond a change in elevation, is a change in where stress in the crust is being accommodated and felt. Quakes are affected by stress, so any major change in stress in the crust will naturally have an effect on them.
There's a lot of evidence to say that, during glacial maxima, there was a reduction in surface tectonic activity in regions that hosted large ice sheets. A good example of this is the Andes, which are to this day an incredibly active volcanic region, but experienced very few, if any, volcanic eruptions during the LGM when they were covered by an ice sheet. After the ice receded, there's evidence for an increase in explosive eruptions occurring in the region, owing to the release of pressure on the crust. Kind of like if that rubber duck from the earlier analogy had feelings, and started gasping for air once you let it come back to the surface.
Won't that happen if we melt the ice caps?
Well, yes, but here's the thing: It is happening. Like, right now. But it's not because of anthropogenic climate change. We are indeed living in a world feeling the tectonic effects of post-glacial rebound, but it's not rebound from what's happening in Greenland and Antarctica in 2025, it's rebound that began nearly 20,000 years ago at the natural decline of the LGM.
[Left: Map of the approximate locations of the Earth's major ice sheets during the LGM. Right: Heat-map of post-glacial isostatic adjustments continuing to the present day. Red indicates areas of relative uplift (rebound) and blue indicates areas of relative lowering (subsidence). All of these adjustments are occurring in places of massive or complete ice loss at the end of the LGM]
So will anthropogenic climate change make earthquakes worse?
Short answer: Yes. Slightly longer answer: Not in a way that matters that much. Long answer: Sure, but we're almost definitely not going to be around to feel much of it. You and I for sure aren't, and neither will our grandchildren or their children. Assuming the ice sheets melt completely tomorrow, it's unlikely we'd feel any significant or detrimental affects of post-glacial rebound on our quality of life for hundreds of years—if the human race is even still here at that point, which looks less and less likely with every passing year.
Increases in quakes in faulted areas previously covered by ice will likely happen, but all the while we'd continue to feel the stronger and more consist effects of earthquakes driven by pure plate motion. Truly severe quakes, like the 8.8 Mw one in Russia this year that inspired the original post, would (and do) continue to occur with or without human input.
They occur because of deep and immutable tectonic forces, stresses built up over tens to hundreds of years, and rupturing along fault systems potentially hundreds of kilometers in length. They just happen, and unlike wildfires and hurricanes, which get more devastating every single year because of the direct impact of humans, there isn't anything we can do to stop earthquakes from happening where they severely impact us. Wildfires can be mitigated by controlled burning and more diverse vegetation, and attempts at cooling the atmosphere and oceans could result in fewer severe storms, but we can't stop plates from moving. They just do that.
That's what I meant by "not directly exacerbated". Earthquakes are always going to happen the way they do, especially the really bad ones, because this is just how the Earth has worked for the last ~1 billion years.
What about fracking though?
This was a point brought up by a lot of people that I think simply misunderstood the premise of this whole thing. But it's worth mentioning.
Hydraulic fracturing (fracking) is the process of extracting gas and oil (hydrocarbons) from beneath the surface by injecting a high pressure fluid into the ground and cracking it apart. It's one of the most environmentally damaging methods of resource extraction done by humans, and it has consequences that can include artificially inducing earthquakes (induced seismicity).
Induced seismicity from hydrocarbon extraction is usually caused by the process of wastewater disposal by injection into the extraction wells. Injecting fluid into the sub-surface puts extra pressure on pre-existing faults that can cause them to rupture prematurely, but there are several controls on this. One, there must already be a fault in the area, so low-earthquake risk areas are unlikely to feel the effects. Two, large faults that produce severe earthquakes don't really co-exist with on-land hydrocarbon targets in the first place, so the resulting quakes are relatively small.
[Map of basins with potential oil and gas targets from 2013. Basins, former shallow seafloor, are rich in oil and gas because unlike very tectonically active parts of the crust, which regularly rupture and expel any fluids and gas beneath them, they don't rupture much, and instead provide stable, protective "cap" layers that trap oil and gas beneath them.]
I'm not trying to excuse fracking or any hydrocarbon industry. I firmly believe it's highly unethical from multiple angles, but what I want to emphasise is that in the context of earthquake severity, they are very low on the list of factors to worry about. Most injection-induced quakes aren't felt by humans at all, and those few that are are low magnitude. They're not the kind of disastrous quake that we mean when we talk about natural disasters in a human cost context.
Why does that distinction even matter? They're still causing earthquakes, aren't they?
Sure, but that's not really that relevant to the discussion here. When we talk about climate change making natural disasters more dangerous, we're talking about disasters that are actually dangerous. While you might feel a 3.3 Mw earthquake, the ones that are properly going to hurt you are much larger, and aren't being produced by fluid injection. And while we might be able to slow potential new seismicity in areas with ice cover by stopping ice retreat, that won't affect major earthquake centers that were ice-free long before humans had any say in the matter.
But maybe that's too pedantic. I'm not here to say people were wrong about it being a problem. But, in my view, fracking is more of an evil weather-machine situation, in that it's bypassing changing the climate entirely and instead directly forcing effects. That's bad, but it's not really "climate change". The actual effects of hydrocarbon extraction on the climate are felt in the acidification of the oceans and atmosphere from the burning of fossil fuels, not in an increase or magnification of major Pacific Rim quakes that would be happening regardless.
So is this not a problem at all?
Well, no! As much as I'm speaking to the best of my knowledge here, I'm a humble sedimentologist, not a seismologist, and those in the field will have more nuanced and diverse opinions on the matter of anthropogenic effects on earthquakes. There isn't a lot of definitive research on it at the moment, so there's an ever-present possibility that someone might drop a research paper tomorrow that proves earthquakes ARE super-duper definitely made worse by climate change and we should all run for our lives.
But, in the meantime, this is where it stands with what we know.
In conclusion, I guess: One of the coolest things about earthquakes from my point of view is how inevitable they are. They're a byproduct of what makes Earth so singular in our understanding of the universe; plate tectonics, and they're a constant throughout history. We can't even really predict them that well, only give guesses based on how long it's been since a specific fault has ruptured and how big of a quake we think it has the capacity to produce. The only thing we do know is that they will come eventually, and all we can do is prepare.
Finally, the severity of the secondary effects of earthquakes are ABSOLUTELY affected by climate change, even if the quakes themselves aren't. Tsunamis, floods, and land collapse are made more dangerous by rising sea levels, coastline loss, and changes in weather patterns.
So, we can't really hold the Earth together, and plate tectonics will keep trucking long after we've wiped ourselves off the face of the planet. But we can work hard to reduce the number of things that are directly killing us at fault of our own, and that's definitely worth trying.
Anyway. I'm gonna go touch grass.
Extra reads and resources:
[VIDEO] How Plate Tectonics Works (and why it matters)
[VIDEO] What causes ice ages?
Isostatic rebound: How does the Earth recover from an ice age?
Evidence for an increase in volcanic activity after ice sheet retreat.
The variable severity of fracking induced seismicity in Western Canada
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