7/30/2026 at 7:05:02 PM
Trees respire. They breath in and out. At night time, many trees emit more CO2.And trees don't exist in isolation as these napkin calculation articles consider them (spherical cows and all that). Every single tree on earth relies on mycorrhizal fungi for the vast majority of its nutrients. Fungi break things down release CO2.
Most of our oxygen comes not from forest but from oceans (specifically from phytoplankton, algae, and photosynthetic bacteria). Between 50-80% of it in fact. Likewise, most of the CO2 that has been captured has been captured by the ocean not by forests. About 25-30% of all human emissions have been captured by the ocean.
Forests (and grasslands) are tremendously important for ecosystems and our health but I think this focus on CO2 and oxygen is simply misleading. If that's your concern you should really be focusing on the ocean. Which IMO is in an even more dire strait than our forests
by culi
7/30/2026 at 8:44:41 PM
Forests do net sequester carbon. But if you want to really sock away the carbon you harvest the trees and pyrolize it. It will give you energy (heat) you can use and elemental carbon (biochar). You could bury that a few feet under or innoculate it with microorganisms and work it into fields. Carbon in that form will sit in the soil for hundreds of years. Thousands or millions if you bury it.by msftgreed
7/30/2026 at 9:27:07 PM
I mean technically we already do this: renewable plantation timber is a widespread operation (also why I get kind of annoyed at YouTubers talking about how great the timber is in old homes - yes it's great because it was logged from 50 year old old growth forests and now they're all gone because we cut them down).by XorNot
7/30/2026 at 8:15:39 PM
The ocean breathes in and out too. Very little carbon sinks down to the sea floor. The ocean does happen to absorb a lot of CO2, but that's from acidification rather than photosynthesis.by Aunche
7/30/2026 at 9:11:38 PM
Yes agreed. But the organisms breath "out" much more oxygen than anything else. And yes ocean acidification is both what's driving a massive crisis and saving us from the full impacts of our CO2 output. It's not a pretty pictureby culi
7/30/2026 at 8:17:24 PM
> Most of our oxygen comes not from forest but from oceans (specifically from phytoplankton, algae, and photosynthetic bacteria). Between 50-80% of it in fact.That fact checks out: about 70% of the earth's surface is covered by oceans. It follows that most photosynthesis, thus oxygen comes from oceans.
by theandrewbailey
7/30/2026 at 8:24:48 PM
> Which IMO is in an even more dire strait than our forestsI think you are probably right, but could you kindly elaborate and provide more details? Very curious to hear your view and learn more.
by simonebrunozzi
7/30/2026 at 9:23:26 PM
My opinion is largely colored by the IPCC Ocean/Cryosphere report. I closely followed each IPCC report and this was by far the most "doomer" of the special reports released by the IPCC. Some highlights: - ocean acidification and deoxygination (imo the most alarming and underdiscussed doomsday scenarios of climate change): About 0.5 to 3.3% of dissolved oxygen had been lost between 1970 and 2010 which has led to the rapid expansion of Oxygen Minimum Zones ("dead zones"). Acidity has increased by 30 to 40% and at a clearly accelerating rate. That's 10 times faster acidification than at any other point in the last 300 million years
- they estimated oceans had absorbed about 90% of "excess global heat" and their ability to absorb is slowing rapidly
- up to 99% of permafrost could melt by 2100. Permafrost melting was completely unanalyzed in the 1.5C report due to lack of good data
Forests on the other hand have shown surprising resilience. And, if they survive the impending destabilization, they might in the long term (I mean looong term) even benefit from increased CO2 concentrations as they historically have.
PS the IPCC reports are more accessible than people realize. Even the technical reports are often not much more difficult to parse than the policymaker reports meant for the general public. I'd quite recommend giving them a try
by culi
7/30/2026 at 8:39:18 PM
https://science.nasa.gov/earth/explore/the-ocean-and-climate...Has a pretty good overview. But in brief: Changes in biosphere due to heat and decreasing pH balance due to increased CO2 can leave species unable to adapt fast enough causing deaths.
by vizzier
7/30/2026 at 9:24:05 PM
It can also cause adaptations to go haywire like temperature dependent sex determination where the ratio of male to females in eggs is set by ambient temperatures, skewing breeding population gender too much in one direction.by stevenwoo
7/30/2026 at 8:07:34 PM
If the ocean is the main hero there, why is the forest still important to our health?by feelamee
7/30/2026 at 8:13:20 PM
RainfallAnd at least the forest soil has the same amount of carbon stored.
by davidkwast