"The problem is there is no real consensus on global warming." - Anony Mous
Define consensus. I hear this a lot and it is generally from people who think science is decided by consensus.
"The pro-GW people pull out data from the last 1000 years which indeed shows a significant trend upwards. The anti-GW people pull out data from the last 2M years which shows that this is just a cycle." - Anony Mous
It is the rate of increase that is a problem, not so much the fact of temperature rise. By analysing our atmosphere we can work out where the carbon has come from and prove that the carbon is coming from us burning fossil fuels. By analysing the composition of the atmosphere over periods of thousands of years we can work out what was happening many years in the past and contrast that with today. Long story short, the evidence is there that this is an unnaturally fast rate of increase and the reason is the release of carbon from the geosphere (carbon that was taken into the rocks over millions of years is being released far faster than it can be put back in).
"The fact is that earth has been warmer and is currently still recovering from a very recent ice age (we're still at -3 degrees from the time humans initially came on the scene)." - Anony Mous
It's the rate of increase that is the danger... Our ecosystems have adapted to our current climate conditions over hundreds of thousands of years. If you change those conditions in a few decades then the biosphere cannot adapt quickly enough and we face mass extinctions. It is the rate of change that is the danger. It is the rate of change that is now troubling our world. It is the one thing that Conspiracy theorists never mention...