If putting up sunscreen means "inject our atmosphere with a chemical species of which we know it also has several adverse effects besides blocking solar radiation", I'm not buying that. I do not favour the analogy of comparing the earth's climate with a human's illness, but in this case: it's chemo-therapy - it doesn't work on the long run, and the side-effects aren't pleasant either. Focus on the $WHATEVER instead.

There is quite some reason to doubt that significant global warming occurs, that it is human made if it occurs and that it is catastrophic if it occurs.  Don't insult the few people who still approach the topic scientifically.

Hopefully I am one of those in that group, but I can't completely agree there either. Global warming is pretty much undeniably there - even when there is discussion left at what scope. I'd join you if you were to state there is still uncertainty at how much of the warming can be contributed to CO2, how much to other anthropogenic influences and how much to influences outside our grasp. Also the estimates surrounding 2x[CO2] are still up in the air.

As you may know, I've been previously busy at ET to show that CO2 reduction may not necessarily be the magic bullet to solve the global warming increase - but it sure won't hurt our planet either.