Yes, I am aware that this is the temperature change that a doubling of CO2 would have in a scenario with no feedbacks- a blackbody.
It is likely that there are negative feedbacks that act to supress the warming even further.
There is only one negative feedback that has been clearly demonstrated and that is the simple fact that objects at higher temperatures radiate very much faster than those at lower temperatures. In other words the hotter something is the faster it cools down. For example you might want to claim that clouds are a negative feedback, but if we look at Venus which has a 100% more cloud cover, and lower a total for incoming radiation, yet it has a much higher surface temperature than earth.
On the other hand there are numerous positive feedbacks. Particularly that higher temperatures increase the amount of water vapour in the air (7% per 1 deg C) which is again a stronger GHG than CO2. Loss of ice cover over the sea changes the surface from reflecting 90% of the radiation to absorbing in excess of 80%.
Higher temperatures of themselves also increase the amount of carbon based GHGs in the atmosphere EG forest fires, increased methane emission's from tundra and peat areas
You are a bit confused here cell phones generate heat due to potential energy being released in to the cell phone circuits. All objects that are above 0 Deg K radiate and absorb radiation, an equilibrium is reached with its neighbours, when the radiation in is in balance with the radiation out.
You missed my point.
The point is, just because that we know something impacts the surroundings, does not mean it is a large factor by any means.
No you don't get it that just because the size of something is small does not mean that it can't have a big impact for example a catalyst can completely change the outcome and speed of chemical reactions even though they may be present in very small quantities. On the other side of the coin nitrogen has fairly minor effects on the atmosphere despite being the largest component.
In the case of your cell phones if the heat from them is not allowed to escape the room, the temperature will rise, but the reality is this becomes harder and harder as the temperature rises. As a simpler example buildings have been designed which are heated only by the heat from the occupants.
This is quite correct but unfortunately the minor effect of CO2 causing 3 or 4 deg C increase in temperature is going to be a major problem for nearly all life on earth.
I still can not believe how some people can believe sensitivities that high.
In order to believe a 4 Degree sensitivity, you would have to believe that the increase in CO2 has caused a 1.6 Degree C temperature change over the 20th Century, which we haven't even come close to.
The figure is 1.3 deg C based on sensitivity of 3 deg C.
The equivalent of 0.4 Deg C ended up in the oceans and 0.9 Deg C in the atmosphere. Bear in mind that the ocean increase in temperature is in fact much less as water has a much higher heat capacity than air. Just be patient we are getting there.
If you do not accept that level of sensitivity then how are you going to explain the ice ages of the last 4 million years or for that matter how the earth was much hotter than today, 100s of millions of years ago, despite the fact that the sun was not emitting as much heat as today.
You would then need to prove that something is so strong that it would create a cooling of 0.8-0.9 Degrees C to give us the 0.7-0.8 Degrees C of warming we have observed during the 20th Century.
Ah you don't understand that the warming caused by other GHGs in the atmosphere such as methane and NO2 etc are balanced by the aerosol cooling effect.
If it were aerosoles, we would see the Northern Hemisphere warming the slowest, and the cities would be seeing enormous temperature drops to get the global value of nearly 1 Degree C cooling, since the impacts of aerosoles are short lived and very local.
We don't see either of these.
The southern hemisphere is warming faster than the northern hemisphere when you take into account the deference in proportions of land and sea.
The temperature of a city is strongly influenced by local weather conditions ie how windy it is and its latitude. The major effect of Aerosols is to increase cloud cover and to make clouds more reflective therefore it is reasonable to assume that the effect lasts several days by which time the airmass may well have gone 1/4 of the way round the globe.
You can argue as much as you like but the people who thoroughly understand the science say you are wrong.
There are many people who are skeptical who would argue that you were mistaken yourself.
There is nothing wrong with being skeptical but it must be tempered by the current state of our knowledge and the level of understanding of those people making various claims.
I am not wrong or right I simple accept that the vast majority of climate scientists have made a convincing case that the current and future levels of GHGs will lead to higher surface temperatures. Whereas those who claim this is not the case have not, and is best summed up by the saying " The devil can quote scripture for his own purposes"