Or perhaps the stated premise is untrue or at least exagerated. Perhaps the “worldwide temperature increase . . . over the last 100 years” is not as significant as we have been led to believe.
My take is that the data has been manipulated, and we have been lied to. The whole AGW scare is one giant fraud whereby insiders make money, and everyone else in the world suffers.
Or perhaps, given the equipment used of the last 100 years, the margin of error is greater than the predicted change.