CO2 surplus also takes 15 to 25 year to go up to the high mesosphere. That mean that a climate drift we experience today is not to consequence of the CO2 we put in the atmosphere last year, but the carbon we put in year 2000. You will never see the 2020 climate again, neither will your children or grandchildren.
If we did act today, drastically (we won't), maybe we will stabilise 2040 climate over a long period of time. in 2040 wet-bulb temperature is only reached a dozen day a year in a few 3rd world countries, nothing to worry about if you don't have familly in SA, West Africa, India or Indonesia. 2060s climate will be sightly harsher if you have family in Florida, but as long as their air conditioner doesn't fall apart and they don't go out for more than an hour, they should survive. Maybe by 2080 we will have stabilized the climate.
The other issues might be non-factor with enough technology (crop failing can be managed better, sea rise can be handled). If we don't follow though, this will be harsher than wet-bulb temperature in few area of the world.