However, even if human activity is having little or no effect on global warming, but science shows nature is leading us into a hotter global climate that will make human survival harder, should we ignore it or not try to ameliorate its effects?
Why would it make human survival harder? Like they say about alleged global warming, it will be warmer someplaces, and cooler in others. By the same token, it will make survival harder in some areas, easier in others. But the time frame of change is so long, that generations will have time to adapt.
As far as countering the trends, we don't yet know enough about the causes, how to extrapolate to the future, or even the technology to change the conditions. There is also the very real danger that we will amplify an undesirable oscillation. Have you ever driven one of those bumper-cars at the carnival where it tended to go left, so you turned hard right, only to have it veer too rapidly to the right, so you turned even harder to the left.