The link between respiration climate change is bigger than most people think. Plants release about 60 petagrams of carbon each year through respiration alone. That's roughly six times more than all human fossil fuel use combined. This plant carbon release is part of the global carbon cycle plants have run for millions of years in your world.
When I first read about forest carbon balance studies, the numbers shocked me. Your forests pull in huge amounts of CO2 through photosynthesis each year during the growing season. But they give back almost half of that carbon through respiration day and night all year. The net gain is what matters for your climate, and it can flip to a loss when conditions change.
The total carbon exchange between plants and air hits about 120 billion tons per year on your planet. Photosynthesis pulls in roughly 120 Gt. Respiration pushes out about 60 Gt in return to the air. The other 60 Gt stays locked in plant tissue until the plant dies or gets eaten. This balance has kept your air stable for a very long time.
Temperature respiration increase is the scary part of this story for your warming world. The Q10 rule means respiration roughly doubles for every 18°F (10°C) rise in temp. As your planet heats up, plants breathe out CO2 faster than before. Photosynthesis doesn't speed up as much, so the net capture shrinks. Warmer temps could turn your forests from carbon sinks into carbon sources.
Heat waves already push this system toward trouble in many forests around your world. In my reading about the 2023 summer heat, I found that some forests released more CO2 than they absorbed for weeks. The trees kept respiring at high rates while stomata closed to save water inside their leaves. Food making slowed down while breathing stayed fast.
Crop plants add their own share to this global carbon cycle plants are part of on your farms. Farm fields release about 8 billion tons of CO2 per year through crop respiration alone. Most of that came from the air just months before through photosynthesis in those same crops. But the timing matters for how much ends up in your air versus stored in soil and food.
Your backyard garden won't fix climate change on its own no matter how many trees you plant. The scale of the problem is just too big for one person to solve alone in their yard. But knowing how plants fit into the carbon cycle helps you see why healthy forests matter so much. Every tree that stays standing keeps carbon locked away instead of floating in your air.
You can support the global effort by keeping your own patch of green healthy and growing strong all year. Healthy plants with good photosynthesis lock up more carbon than stressed plants do in your garden. Avoid removing big trees from your yard since they store the most carbon of all. What feels small in your garden adds up when millions of people do the same thing.
Read the full article: Respiration in Plants: The Complete Process Guide
