• CarbonIceDragon
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    12 days ago

    I don’t really get why this source first emphasizes that carbon molecules have an effect regardless of source, but then says that it is wrong for humans to “take credit” for photosynthesis. If something, human caused or otherwise causes an increase in plant cover such as to cause an increase in carbon stored in plant biomass, the atmosphere doesn’t care if humans did that or if plants did.

    • Jim East@slrpnk.netOP
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      12 days ago

      My understanding is that they want to consider only the effect that human activities are having on the climate, and so they account for all sources of humans’ emissions, but the amount of photosynthesis currently happening would happen even in the absence of human activity. Including photosynthesis in the accounting for humans’ emissions therefore doesn’t make sense, whereas accounting for deforestation is crucial, as that is a real change due to human activity; even if deforested land reforests itself, the initial emissions would not have occurred if not for humans’ actions.

      • CarbonIceDragon
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        12 days ago

        Sure, but if unforested land is artificially forested, or deforested land is reforested faster than would occur naturally, or human activity causes an increase in plant cover unintentionally (for example, if increased carbon dioxide spurs in increase in plant growth beyond the previous norm), then the photosynthesis done by those extra plants would be caused by humans, surely?

        • Jim East@slrpnk.netOP
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          12 days ago

          If historically unforested land is artificially forested, then that might be worth crediting to humans, but that has never happened on a meaningful scale, and realistically, I don’t know if it could. If deforested land grows back (at whatever rate), then that is just nature cleaning up the mess as it always has, and the amount of carbon dioxide sequestered on that land is always going to be less than what would have been sequestered had humans not slashed and burned the vegetation in the first place. The forest has to recapture the amount of carbon dioxide released by deforestation just to “catch up” before it can continue where it left off, so to speak.