and this may not seem like a lot -- less than 1ºc -- but the thing to know about it is these greenhouse gases we throw up stay in the atmosphere for a very long time, there are very long time lags involved here so this 0.8º temperature rise is a response to what we were doing 50-100 years ago, and what we see in the first half of this century will be a response to what we've done in the last 50 years and what we'll see in the latter half of this century will be a response to decisions we make today.