If computer models were to disappear, we would still have the physical evidence. The only computer Svante Arrhenius needed was his brain.

We would still have the data that it is warming.

We would know that CO2 causes warming, from lab data.

We just would not know by how much.

What caused the warming in the Middle Ages? If it is happening now, how bad is the additional effect of CO2 on top of that?

None The dumba** dupes are constantly duped AND they are duped by amateur self proclaimed climate scientists like watts. nova and goddard none of whom ever studied climatology

Real time temp measurements prove beyond a doubt that the planet is warming in relation to CO2 rising

There would always be Al Gore to pick on.

If at all. And why are myths about this so popular with anti-science dupes?

U.S. National Academy of Sciences, 2010:

http://books.nap.edu/openbook.php?record_id=12782&page=1

“Climate change is occurring, is caused largely by human activities, and poses significant risks for a broad range of human and natural systems.”

http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=12877

“Choices made now about carbon dioxide emissions reductions will affect climate change impacts experienced not just over the next few decades but also in coming centuries and millennia…Because CO2 in the atmosphere is long lived, it can effectively lock the Earth and future generations into a range of impacts, some of which could become very severe.”

http://www.physics.fsu.edu/awards/NAS/

“The Academy membership is composed of approximately 2,100 members and 380 foreign associates, of whom nearly 200 have won Nobel Prizes. Members and foreign associates of the Academy are elected in recognition of their distinguished and continuing achievements in original research; election to the Academy is considered one of the highest honors that can be accorded a scientist or engineer.”

http://en.wikipedia.org/wiki/Global_warming

http://en.wikipedia.org/wiki/History_of_climate_change_science

http://www.aps.org/publications/apsnews/200602/backpage.cfm

http://en.wikipedia.org/wiki/Stern_Review

http://nas-sites.org/climate-change/qanda.html#.U2Afzsf75DS

http://www.skepticalscience.com/argument.php