I have read somewhere that the main difference is that now we have 10 times more accumulated methane in the form of methane hydrates on ocean floor and permafrost. Methane is strong green house gas, like 100 times stronger than CO2. But as it lives only 6 years in atmosphere, the main difference would be not its amount, but the speed which which it could be realised from permafrost. This depends of speed of CO2 accumulation (which is now very high, while the total level is still low). The last thought is mine conclusion from what I read.
Geochemical situation also changed as we had several ice ages which are very good for methane hydrates accumulation and also because geography of Arctic ocean changed.
Anyway, I think that we runaway global warming may be easily prevented by artificial nuclear winter or some cloud seeding, if situation will be urgent. But AI situation is more complex.
I have read somewhere that the main difference is that now we have 10 times more accumulated methane in the form of methane hydrates on ocean floor and permafrost. Methane is strong green house gas, like 100 times stronger than CO2. But as it lives only 6 years in atmosphere, the main difference would be not its amount, but the speed which which it could be realised from permafrost. This depends of speed of CO2 accumulation (which is now very high, while the total level is still low). The last thought is mine conclusion from what I read.
Geochemical situation also changed as we had several ice ages which are very good for methane hydrates accumulation and also because geography of Arctic ocean changed.
Anyway, I think that we runaway global warming may be easily prevented by artificial nuclear winter or some cloud seeding, if situation will be urgent. But AI situation is more complex.