There are a lot of ideas about what's good for the climate that aren't necessarily true. Here we check some of the most common claims against what we can actually find sourced — including when the sourcing turns out weaker than the claim's reach, or when we simply can't find an answer. It should be fun to explore and build your own knowledge; that's the entire point of this page.
MIXED EVIDENCE
Is hand-washing dishes better for the climate than a dishwasher?
Probably not, if you wash under a running hot tap — but the claim you've heard comes from industry-funded research, not independent studies.
The two most-cited studies here — Rainer Stamminger's University of Bonn study (113 participants, 7 European countries) and a separate 10-year US comparison — are funded by dishwasher/detergent manufacturers and Whirlpool respectively. That doesn't make the numbers wrong (the underlying physics makes sense: a machine uses a fixed, small volume of efficiently-heated water, while an open tap runs the whole time), but we haven't found an independent replication. One exception holds up even in the industry-funded data: the two-basin method (scrape, wash in one basin of hot soapy water, rinse in a second basin of cold water, no running tap) matches or beats the machine.
NOT VERIFIED
How many times must a reusable (Teflon/PTFE) baking sheet be used before it beats parchment paper for the climate?
We can't answer this — and that's the actual finding.
We looked for an independent life-cycle comparison between the two. Everything we found was marketing copy from companies that sell PTFE baking sheets, without a single concrete manufacturing-footprint figure for either product. It's tempting to guess a "reasonable" number — but that's exactly the kind of unsourced claim this site exists to avoid. If you know a real study (e.g. an ecoinvent-style comparison of PTFE/fibreglass production against bleached/silicone-coated paper), we'd genuinely like to hear about it.
WELL SUPPORTED
Flying on vacation vs. the train?
The train wins decisively — typically 80-95% lower emissions, depending on which country's electricity grid the train runs on.
A domestic flight emits roughly 246 g CO2e per passenger-km. European trains range from about 6 g (Eurostar, 66% French nuclear power) to about 40 g (UK rail) — a 6-7x spread between rail lines alone, because "the train" is really a proxy for "the electricity grid behind it". Taking the train instead of a domestic flight typically cuts emissions by around 86%.
OUR OWN CALCULATION
Car vs. train, when it's an EV — how full does the car need to be to win?
Surprisingly: charged on the Danish grid, an EV with just ONE person aboard can already match or beat the train's per-passenger emissions.
No existing study answers this directly for Denmark, so this is our own calculation — but built on sourced figures, not a guess. Denmark's grid emitted about 156 g CO2e/kWh in 2025 (84% renewable, mostly wind). A typical EV uses 15-20 kWh/100 km, giving roughly 23-31 g CO2e/km when charged in Denmark. Compared against European rail's 6-40 g per passenger-km (see above), a single person in a Denmark-charged EV is already in the same range as, or below, UK/German rail. This is a calculation, not a citation — we still need DSB's own figure to make this a real Denmark-vs-Denmark comparison instead of borrowing UK/German rail numbers.
WELL SUPPORTED
How do you actually change your habits so it has a real positive impact?
The four most effective individual actions are rarely the ones you hear about.
Wynes & Nicholas (2017), a peer-reviewed study in Environmental Research Letters based on 148 scenarios from 39 sources, ranks four individual actions as most effective at cutting emissions: having one fewer child, living car-free, avoiding air travel, and a largely plant-based diet. The study's real point is as important as the list: school textbooks and government guidance rarely mention the first three, focusing instead on much lower-impact actions like recycling and changing light bulbs. There's a genuine gap between what actually works and what you're usually told.
WELL SUPPORTED
How climate-heavy are Danes compared to other nations?
Explore it yourself — the map and time trend below are live data from Our World in Data.
Two figures are worth telling apart: territorial emissions (what's emitted within a country's own borders) and consumption-based emissions (what's emitted to produce everything the country actually consumes, imports included). Denmark's two numbers differ meaningfully — which is itself a finding: part of our climate footprint is "exported" to other countries' factories. The map below is Our World in Data's own interactive chart, embedded directly — always current, never a static copy.