Allow me to quote from your link:
"Scientific evidence for warming of the climate system is unequivocal.
- Intergovernmental Panel on Climate Change"
Ok, great... how much of that is man-made change?
You could read the report
for yourself or you can look at a pretty graph that summarizes the findings.
What can we do about it if so?
There are a variety of strategies that we could try but the simplest, easiest, and cheapest solution is to apply a price to carbon emissions. Any economist can tell you that charging for emissions will reduce them.
Very little, many of the economies with carbon emission taxes are outperforming their neighbours, who don't have emission taxes.
What does it cost to adapt to it rather than try and change it the other way?
Generally speaking, estimates of adaptation costs that have them running around 2-4 times as much as mitigation are considered to be low-balling the costs.