Ask Science
Ask a science question, get a science answer.
Community Rules
Rule 1: Be respectful and inclusive.
Treat others with respect, and maintain a positive atmosphere.
Rule 2: No harassment, hate speech, bigotry, or trolling.
Avoid any form of harassment, hate speech, bigotry, or offensive behavior.
Rule 3: Engage in constructive discussions.
Contribute to meaningful and constructive discussions that enhance scientific understanding.
Rule 4: No AI-generated answers.
Strictly prohibit the use of AI-generated answers. Providing answers generated by AI systems is not allowed and may result in a ban.
Rule 5: Follow guidelines and moderators' instructions.
Adhere to community guidelines and comply with instructions given by moderators.
Rule 6: Use appropriate language and tone.
Communicate using suitable language and maintain a professional and respectful tone.
Rule 7: Report violations.
Report any violations of the community rules to the moderators for appropriate action.
Rule 8: Foster a continuous learning environment.
Encourage a continuous learning environment where members can share knowledge and engage in scientific discussions.
Rule 9: Source required for answers.
Provide credible sources for answers. Failure to include a source may result in the removal of the answer to ensure information reliability.
By adhering to these rules, we create a welcoming and informative environment where science-related questions receive accurate and credible answers. Thank you for your cooperation in making the Ask Science community a valuable resource for scientific knowledge.
We retain the discretion to modify the rules as we deem necessary.
view the rest of the comments
Something you are missing is that, at night, trees respire. That is, they take in oxygen and release carbon dioxide.
Now I'm not sure of the whole 30 year thing, but perhaps that's part of the calculation.
I think the simplest answer is - they are wrong.
Trees’s structures are made up largely from cellulose and lignin (https://en.wikipedia.org/wiki/Lignin - for the chemical structure).
Both are very rich in carbon.
The next time someone says that to you - point to a tree and explain that - that thing over there is largely comprised of carbon that has been extracted from the atmosphere by photosynthesis- so what are you talking about?
Yeah, it's the simplest answer, and likely correct. But a more interesting question is why they got it wrong and what assumptions and misconceptions did they make to arrive at the wrong answer.
They may respire, but they must absorb more than they respire, because that's where the wood comes from...
Not necessarily. The two things aren't related. You yourself burn way more calories in a year than you store in your body or use for growth. Respiration is not just about growing. It's about using energy for cellular processes: immune system, transporting chemicals around the organism, replacing old cells.
An organism can grow at one rate and use energy (expelling CO2) for other functions at a different rate. They aren't really related.
They are related, because the energy they use and the mass they grow both come from absorbed CO2.
In other words, every molecule of CO2 expelled by a tree was previously absorbed by the tree. Unlike humans, energy use by trees is carbon neutral. Which means trees cannot grow unless they absorb more CO2 than they expel.
That makes sense. I didn't think about it that way.
I'm not sure, why you're interpreting my comment as a general statement. I'm specifically talking about trees. While it's theoretically possible that they get carbon from the ground and actually respire more into the air than they absorb, while also growing wood, that would be extremely surprising to me. Unless there's data supporting it, I don't see why we should entertain the thought...
On average they emit around half the carbon they absorb so this wouldn't explain that fact.
It's almost definitely false.
That makes no sense. The human body is on average carbon neutral. You eat carbon and then you excrete it. Same as trees. Except you don't continuously grow like a tree for potentially centuries.
Taking solid carbon in food and turning it into CO2 is not carbon neutral.
Of course it is. No carbon was created. And unless you're putting on weight, your mass stayed the same. Carbon in, carbon out. I'm not talking about CO2 neutral.
Wtf? You can't make up your own definition of "carbon neutral" and then make arguments about it on the internet.
Yeah, no shit, but that's not what the rest of us are talking about.
I'm not making up any shit wth? How dense are you? A tree is carbon negative because it sequesters carbon continuously. A human adult is not, it's carbon neutral - when observed in isolation. The human system is carbon neutral. It doesn't matter where the car on comes from. You expel the same amount as you injest. I think honestly you're the one who doesn't understand what carbon neutral really means.
Turning carbon in the environment into CO2 by oxidizing it is NOT carbon neutral! If that was the case, then every car, plane, and coal power plant would be "carbon neutral". That's very obviously not the case.
It's ALL about CO2! For the love of god, go read some articles. You have no idea what you're talking about.