As population rises, so do the number of reporting stations, particularly reports from ships at sea given that ocean shipping has doubled in the last 20 years. Also the technology of data collection is far better than fifty years ago.. The data collected in just the last decade exceeds all of the data collected in the proceeding 100 years. Today we have ultra-super computers dedicated to climate research. Fifty years ago we didn't even have super computers... we had punch card computers at best. Prior to WW2 we had no knowledge of the jet stream and it's effect on climate change. or the effect of climate change ON the jet stream. The actual physics of what we now call climate change was still at the hypothesis stage fifty years ago...who knew?
The point here is that we now know 'stuff' that wasn't known fifty years ago and we collected more data every day. Technically, given what we 'know' science does know the effect of 1000ppm of CO2 in our paper thin atmosphere. At this point it's not 'perfect knowledge', but within a 95% probability a 1000ppm value would mean lights out for most human civilization above ground. We also 'know' within the same 95% certainty that at 450ppm we enter the foothills of a runaway greenhouse effect. Today we're close to 400ppm... we add about 15ppm per decade. You can do the math... your answer will have a 95% certainty... that's frightening.... no Al Gore required!
there's nothing precise about it. You're talking about making predictions based on modeling an entire planetary atmosphere and weather system.
Which is a completely chaotic system, by the way, meaning that, for practical purposes, no matter how many data points you can acquire there's always going to be a lot of significance in the ones in between that you don't have
I don't think there's any doubt that increased levels of greenhouse gases are not going to be a good thing, but exactly how that will shake out in practice is not something that I think is so certain.
There's lots of fun scenarios you can scare yourself with though. The idea of a runaway greenhouse effect for example, turning earth into something a lot like venus. I'm sure that will never happen though. You have my word on it.
as CO2 goes up , so does global temps . earths hottest period was the 100 million year carboniferous epoch when even the arctic was tropical , CO2 levels went as high as 363 ppm . on 12 21 12 atmospheric CO2 hit 400 ppm . this is passed the point of no return . the earth WILL go into an irreversible , permanent greenhouse effect . it will happen pretty fast . we have a few decades left , at best .
No one knows. We were supposed to have a point of no return at 350. Didn't happen. Then we were supposed to have a point of no return at 400. Didn't happen. Besides the CO2 level has risen during the last decade all the while the earth's temperature has gone down. Tsk. Tsk. Tsk.
1000ppm would be 1.3 doublings from now or 1.9 doublings from its natural state, which is 270ppm. Climate sensitivity is probably between 2-4C. That would make a world with 1000ppm carbon dioxide between 2.6C and 5.2C warmer than now.
reasonably. the gloal average should be about 88F as it was 35million years ago. we are at about 61,so a 27 rise.
http://blogs.nicholas.duke.edu/thegreeng...
some places like the sahara are already dangerous. upping the average adds more places.
According the the IPCC, that would require multiplying mankind's contribution by orders of magnitude - and would add a couple degrees.
Not precise at all. In fact the AGW premise has been largely debunked.
