Ashtar Command Book Blog : Termination shock

Tuesday, September 30, 2025

Termination shock

A propos the previous blog post about the recent bizarre turn of the climate crisis.

What is the meaning of the term "termination shock"? Is it a term from science fiction adapted to the climate crisis?

Good question — “termination shock” has two quite different uses, depending on context:

1. Astronomy / Space Physics (original meaning)

In astrophysics, the termination shock is the boundary in the solar system where the solar wind (charged particles streaming out from the Sun) slows down abruptly as it meets the interstellar medium.
It’s literally a “shock front” — like a cosmic speed bump.
NASA’s Voyager spacecraft crossed the termination shock in the 2000s.
So the phrase has a long-standing scientific meaning outside of climate discussions.

2. Climate Change / Geoengineering

More recently, climate scientists and policy thinkers adopted the term to describe a dangerous scenario:
- If humanity were to artificially cool the Earth using solar geoengineering (e.g., by spraying reflective particles in the stratosphere) and then suddenly stop those interventions, global temperatures would rebound very rapidly.
- This sudden and extreme warming is called “termination shock.”
The idea is that gradual warming gives ecosystems and societies some time (though painful) to adapt — but a sudden temperature spike would be catastrophic.

3. Science Fiction Usage

The phrase has also been used in science fiction.
- Most recently, Neal Stephenson’s 2021 novel Termination Shock is explicitly about geoengineering and climate collapse.
- But this is after the climate-science usage had already become common, so it’s not purely an SF invention.

✅ Answer in short:

No, it didn’t originate in science fiction.
It’s originally an astronomy term, then borrowed by climate science to describe a specific geoengineering risk, and only later popularized in sci-fi novels like Stephenson’s.

Would you like me to explain in detail how the climate version of termination shock might actually play out (e.g., over years or decades) if solar geoengineering were started and then stopped?

Yes, please.

Alright — let’s unpack how termination shock would unfold in a climate/geoengineering context.

1. Background: Solar Geoengineering

Idea: Cool Earth artificially by reflecting some sunlight back into space.
Leading proposal: Stratospheric aerosol injection (SAI) → spraying reflective particles (like sulfate aerosols) into the upper atmosphere.
This would reduce global temperatures quickly — mimicking volcanic eruptions like Mount Pinatubo (1991), which cooled the planet by ~0.5 °C for a year or two.

2. What “Termination Shock” Means

If geoengineering is started and then suddenly stopped (due to war, economic collapse, political ban, accident, etc.), the Earth would:
- Immediately be exposed again to the full greenhouse effect of accumulated CO₂.
- Temperatures would rebound very quickly (decades of warming compressed into just a few years).

3. Why It’s Dangerous

Rate of warming is the killer:
- Without geoengineering → warming happens gradually (still fast in geological terms, but decades-long).
- With geoengineering → warming is masked. If stopped, warming could happen at 10× the normal rate (e.g., ~1 °C per decade instead of ~0.1 °C).
Ecosystem shock: Plants, animals, and oceans can adapt somewhat to slow change, but not to sudden jumps. Many species would collapse.
Human systems: Agriculture, water supplies, and cities would face unprecedented climate stress in a very short time.
Political instability: Sudden global crisis could trigger mass migration, famine, and conflict.

4. Timescale Example

Let’s imagine:

2050: Earth has warmed by +2.0 °C.
Humanity deploys stratospheric aerosols, reducing net warming to +1.5 °C.
Geoengineering continues for 50 years. Meanwhile, CO₂ keeps accumulating. By 2100, “masked” warming is actually +4.0 °C, but the world only feels +1.5 °C because of the aerosols.
If geoengineering stops in 2100 → Earth “catches up” rapidly. Temperatures surge +2.5 °C within a decade or two.
That’s termination shock: a massive temperature jump compressed into one or two human generations.

5. Why Scientists Worry

Termination shock makes long-term reliance on geoengineering very risky.
If it becomes the “crutch” that masks warming, future generations could be locked into maintaining it forever — with no safe way to stop.
That’s why most experts argue geoengineering should (if ever used) only be a temporary supplement, not a substitute for cutting greenhouse gas emissions.

✅ Summary:
Termination shock is the nightmare scenario of solar geoengineering: a sudden halt in artificial cooling causes rapid, catastrophic warming. The “shock” isn’t just higher temperatures — it’s the speed of change, far beyond what ecosystems and human societies could adapt to.

Do you want me to also explain how likely scientists think this is (e.g., are we realistically on track for such a scenario, or is it mostly theoretical)?

Yes.

Great — let’s look at how likely termination shock is, based on current science and policy discussions.

1. Is Geoengineering Even Happening Yet?

Right now (2025), no country is deploying full-scale solar geoengineering.
Only small-scale research exists (e.g., Harvard’s SCoPEx project — testing aerosol behavior).
Many scientists and policymakers are cautious, because of the risks (including termination shock).

2. Conditions Needed for Termination Shock

Termination shock only happens if:

Solar geoengineering is deployed long-term (decades, even centuries).
Greenhouse gases keep accumulating during that time.
The intervention suddenly stops.

So, if humanity:

Cuts CO₂ emissions seriously → termination shock is much less of a risk (because there’s less “masked” warming).
Uses geoengineering as a crutch while continuing business as usual → the risk is very high.

3. Expert Assessments

IPCC (Intergovernmental Panel on Climate Change, 2021 report)
- Notes that termination shock is a major risk of stratospheric aerosol injection.
- Warns that sudden cessation could cause warming rates 10× faster than current trends.
National Academies (US, 2021)
- Strongly advise against large-scale deployment until emissions are under control.
- Suggest research into governance and risk management, precisely because termination shock is considered plausible if geoengineering is misused.

4. Political & Governance Issues

Termination shock isn’t just a technical risk — it’s political:
- If only one country or coalition runs the geoengineering program, others might sabotage it or force it to stop.
- If global crises (war, collapse, economic depression) make it impossible to maintain, it could end abruptly.
That makes termination shock more likely than if there were stable, long-term global cooperation (which history suggests is hard to guarantee).

5. So How Likely Is It?

In the near term (next 20–30 years): Unlikely. No country is seriously planning deployment yet.
In the long term (late 21st century):
- If emissions stay high and warming gets severe, desperation could make geoengineering tempting.
- If that happens without emission cuts, termination shock risk becomes very real.
Many scientists see it as a plausible 22nd-century scenario, not science fiction.

✅ Summary:
Termination shock is not an immediate threat — it requires long-term geoengineering, which hasn’t started yet. But if humanity leans on solar geoengineering as a substitute for reducing emissions, then yes: the risk is very real, and scientists take it seriously as a possible late-century or next-century crisis.

Would you like me to also cover the possible ways to reduce the risk of termination shock (e.g., gradual phase-out strategies, hybrid approaches with carbon removal)?

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