blockski wrote:No one - absolutely no one - is saying that CO2 is the only reason the world is warming. However, this chart (from a 2010 paper - https://agbjarn.blog.is/users/fa/agbjar ... -years.pdf ) is not claiming that the temperatures in the past were the same, so everything is fine. It's also a paper focused solely on the historical record. We know how much we've changed the atmosphere since we started burning fossil fuels. CO2 in the atmosphere over the last 800,000 years (homo sapiens has only been around for the last 300,000 years, btw) was never more than 300 parts per million, and we just shot through 407 ppm.
There's no evidence that the cooling will just happen. Saying 'yes most likely' is a statement completely without evidence.
The broad outlines are all there: we know CO2 is a greenhouse gas; we know we're emitting lots of it; we know this will warm the planet. We expect to see all of these things, and that's exactly what the instrument observations show.
Sorry but Homo Erectus lived in 650 ppm, and there's no evidence to say we'll be in trouble if we reach that point, as long as O2 remains within +/- 10% of where it is today (though, with obesity rates rising we may very well see boatloads of unhealthy people die of asphyxiation at the extreme end of that, which isn't necessarily a bad thing from the evolutionary standpoint). What we really need to watch is where the O2 is going, along with NOx.
There's outstanding evidence that the cooling will "just happen" as readable from my previous sources, directly from the 1999 paper the IPCC keeps trying to bury without counter evidence.