If the planet heats too fast, plants stop pulling CO2 from the sky and the climate spirals faster.
That is the stark warning from new research in Nature Communications that rewinds Earth’s last major heat shock 56 million years ago and finds vegetation simply could not keep up.
Back then global temperatures jumped by about 6°C in roughly 5,000 years as carbon flooded the atmosphere.
What followed was a climate event that refused to end lasting more than 100,000 years because many plants stopped functioning properly as carbon sinks.
Scientists modelled how ancient vegetation evolved moved and stored carbon then matched it with fossil pollen from Wyoming the North Sea and the Arctic.
The snapshots show mid-latitude ecosystems collapsed into smaller drought-tolerant species like palms and ferns as deciduous forests retreated.
Leaf mass increased soil carbon fell and the landscape lost the heft needed to lock away CO2.
That loss of carbon storage meant more CO2 stayed in the air which pushed temperatures higher and kept them there.
The vegetation that could regulate the climate took up to 100,000 years to recover.
The Arctic told a different story.
Warmer conditions there helped plants thrive with biomass increasing and subtropical species like palms holding on.
But the contrast only underlines the scale of the problem: huge regions simply could not adapt once warming crossed 4°C.
Today the world is heating about ten times faster than during that ancient shock.
Plants have far less time to adjust meaning the safety valve they normally provide could weaken in the coming decades.
If vegetation cannot rebuild its carbon-storing muscle quickly enough more CO2 will linger forcing temperatures even higher says the study.
The lesson from deep time is blunt. Ecosystems can stabilise the climate only within limits.
Push them past those limits and the planet loses one of its most powerful brakes.
Prehistoric lesson – if it gets too hot plants stop helping appeared first on Energy Live News.