For the past 10,000 years or so, humans have enjoyed a fairly stable and benign climate regime, that has allowed the emergence of agriculture and civilization. This is largely because atmospheric CO2 levels stayed between about 180ppm and 280ppm.
This time period, or epoch, is called the Holocene. We are essentially forcing the end of the wonderful Holocene. On our current path, we will have created a world that humans have never experienced, by the end of this century, or early in the next.
We have increased CO2 to 392ppm in about 100 years. That is a 40% increase.
By about 2080, we will have doubled the pre-idustrial 280ppm to 560ppm.
CO2 levels have not been this high in at least 400,000 years, twice as long as modern humans have even existed. And there is evidence CO2 hasn't been this high in 800,000 years
We are increasing atmospheric CO2 10 times faster than at the PETM. (Paleocene-Eocene Thermal Maximum) 55 million years ago.
This was 10 million years after the dinosaurs died off. They lived in a much hotter world than humans have ever experienced. At the PETM, these already high global temperatures soared by another 5C to 6C, from the greenhouse effect, after a big surge in CARBON DIOXIDE.
It took 200,000 years for rock weathering and other slow forcings to remove enough CO2 from the atmosphere to cool the earth back down.
CO2 levels at the PETM were much higher than today, but it took 5,000 to 10,000 years to get there. The poles warmed by 10 C to 20 C. That's 18 F to 36 F warming. But it isn't just the magnitude of the warming, but the speed of today's warming that is dangerous. Species had thousands of years to adapt or evolve during the PETM. We don't.
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For the past 10,000 years or so, humans have enjoyed a fairly stable and benign climate regime, that has allowed the emergence of agriculture and civilization. This is largely because atmospheric CO2 levels stayed between about 180ppm and 280ppm. This time period, or epoch, is called the Holocene. We are essentially forcing the end of the wonderful Holocene. On our current path, we will have created a world that humans have never experienced, by the end of this century, or early in the next. We have increased CO2 to 392ppm in about 100 years. That is a 40% increase. By about 2080, we will have doubled the pre-idustrial 280ppm to 560ppm. CO2 levels have not been this high in at least 400,000 years, twice as long as modern humans have even existed. And there is evidence CO2 hasn't been this high in 800,000 years We are increasing atmospheric CO2 10 times faster than at the PETM. (Paleocene-Eocene Thermal Maximum) 55 million years ago. This was 10 million years after the dinosaurs died off. They lived in a much hotter world than humans have ever experienced. At the PETM, these already high global temperatures soared by another 5C to 6C, from the greenhouse effect, after a big surge in CARBON DIOXIDE. It took 200,000 years for rock weathering and other slow forcings to remove enough CO2 from the atmosphere to cool the earth back down. CO2 levels at the PETM were much higher than today, but it took 5,000 to 10,000 years to get there. The poles warmed by 10 C to 20 C. That's 18 F to 36 F warming. But it isn't just the magnitude of the warming, but the speed of today's warming that is dangerous. Species had thousands of years to adapt or evolve during the PETM. We don't.