1) Checking the air locked in icebergs shows CO2 level cycles.
They show that the high levels of CO2 in our atmosphere aren't the highest in history, and perhaps they are a result of a natural cycle and not just our air pollution.

2) No one managed to agree if the high CO2 levels came before Ice-period or after.

That means there are 2 valid propositions - one is that high co2 levels raise the temperature and thats what stopped the ice-age. In this case we are in trouble. The other means that high co2 levels can be something that happens naturally when earth is nearing an ice-age and it may be what is happening now.

"Natural" is a loaded word.

Lets say: Effects caused by advanced technology?

What about effects caused by unco-ordinated grazing? Notice how greener fenced areas are in the Arava than the un-fenced ones.

There is an alternative theory called "The Urban heat sink"

They claim that cities are much darker than forests (a questionable claim at best IMO)
And that the heat captured by the dark surfaces of cities and roads changes the climate.

Anyone would like to manufacture white asphalt?