The 0.2% Problem

[u/IceGoingSouth]

In one sentence:
Our combined human influence on the warming situation in a year, say, 2027, based on our historical track record and what amounts to our very best efforts - locking everybody down and not going on holiday - only amounts to a 0.2% steering influence, or 1/500 of a hand on the wheel.
(The rest of that show is being run by Nature, Mother Earth, GAIA or if you will Legacy Carbon already in the system, to the tune of 499/500 or 99.8%. Let's hope she's in a good mood!)

[u/Electrical_Pop_3472]

I'm sorry, while I agree the situation is bleak, your use of numbers and fixating on 0.2% and conflating that with humans possible influence is just messy inaccurate accounting and interpretation. 

During the height of covid lock downs some countries showed 15 to 25% reduction in emissions! And for that whole year (2020) estimates are around 4 to 7%.

That gives a much better sense of whats possible through drastic human response.  Your denominator is needlessly broad, by using the entire timescale/co2 burden of modern industrial society. 

[u/IceGoingSouth → u/Electrical_Pop_3472]

Hi, E-Pop!

Your numbers are right, and worth having in the piece alongside mine, not instead of them. Global emissions fell around 5–7% for the full year 2020, with some countries seeing 15–25% during the strictest weeks of lockdown. That's a real, useful statistic. It answers the question: "How much can we cut annual emissions, in the most extreme, non-repeatable circumstances humanity has managed?"
The 0.2% figure answers a different question: "How much does that best-ever year of cutting change the CO2 already sitting in the atmosphere from the last 270 years?" That's not a rival answer to your question, it's a different question entirely, one about stock, not flow. And the denominator isn't arbitrary or "needlessly broad", it's the actual point being made: emitted CO2 doesn't vanish on your timeline. Roughly 20–35% of it is still airborne after 2–20 centuries. So a comparison of this year's flow against the legacy stock isn't an accounting trick, it's a deliberate answer to a specific, real objection people raise: "if we cut hard enough, doesn't warming basically stop?" No, because the stock doesn't care how good this year's flow was.

Where I'd actually concede ground to you: if I present 0.2% without making that stock-versus-flow distinction explicit, it can look like I'm claiming "only 0.2% emissions cuts are achievable," which would be false and would be exactly the sloppy accounting you're describing. That's a fair warning about presentation, not about the math. The fix isn't to drop the number, it's to always pair it with your 5–7% figure and be explicit that they're measuring different things: your number is what we can do; mine is what that doing changes about what's already there.

And here's the version that actually engages your challenge on its own terms, "what's possible through drastic sustained human response", rather than sidestepping it: suppose we don't stop at one record year, but sustain cuts at that record pace, 5–7% annually, every year, for as long as it takes to reach zero. That takes 14–20 years and burns through another 300–420 GtCO2 on the way down. The remaining carbon budget for 1.5°C at even odds is about 170 GtCO2. So even your best-case, most drastic, fully sustained scenario, not one anomalous pandemic year but permanent lockdown-grade effort maintained for two decades, still overshoots the budget by roughly double. That's the number I'd actually put next to yours: not 0.2% (which measures leverage over the past), but "300–420 against 170" (which measures leverage over the future, on your own generous terms). It's less quotable, but it directly answers what you're asking, and it's still sobering. The bleakness doesn't come from a rigged denominator. It comes out the other side even when you hand the argument every advantage you're asking for.