The above is the view of the IPCC for over 10 years.
Recently, the IPCC changed their view:
An ever-growing body of observation-based studies indicating that the climate sensitivity is in the range of 0.5 to 2.5°C with a best estimate of 1.5 to 2°C, and is very unlikely to be more than 2°C.
Anything at or below around 2.0 C of warming simply gets the world temperature back to what it was during the Holocene Optimum and won't cause the type of catastrophes that the alarmists have warned us about. Skeptics and luke warmers have long indicated that warming would likely be below 2.0 C due to a doubling of CO2. And many skeptics think it could be much below 2.0 C. The climate sensitivity range though of 0.5 to 2.5 C certainly is no longer very alarming.
And to get this not so alarming range of climate sensitivity, the IPCC is using the highest possible numbers to get the 0.5 to 2.5 degree C number. The temperature "adjustments" are also part of those estimates. If the temperature adjustments were removed, that alone would change the estimate down by as much as 40%. In other words, the temperature range that they are using is still too high. Reduce by 40% and it goes to 0.3 to 1.5 degree C. That range would not be controversial to most skeptics. My own estimate has been a doubling of CO2 may cause 0.2 to 0.6 degree C increase in temperature.