This is the Motte and Bailey fallacy.
You made a claim. When challenged on its accuracy, you retreated to a different (defensible) claim, rather than admit defeat.
The claim you made was:
... and the appropriate response from an honest person when shown that this is false would be to admit that you were wrong.
Instead you shifted to the different (and less easily disproven) claim that there's no evidence that the decline in life expectancy has climate change as a cause.
That might impress the foolish partisan mouth-breathers on denialist websites, but around here it just makes you look shifty, unreliable and untrustworthy. If you refuse to acknowledge, admit, and (most importantly) discard those claims that are demonstrated to be false, then why would anyone take seriously any future claims you make?
... philosopher Nicholas Shackel coined the term “motte-and-bailey” to describe the rhetorical strategy in which a debater retreats to an uncontroversial claim when challenged on a controversial one. The structure goes something like this:
First, someone makes a controversial statement from what blogger Ash Navabi calls the “courtyard of ideas.” Then when that statement, the bailey, is attacked, the speaker retreats to the motte, the place of “strict terms and/or rigorous reasoning”—falsely claiming that she was just making an obvious, uncontroversial point, one that could not possibly be challenged by any right-minded individual. Finally, when the argument has ended, she will go back to making those same controversial statements—the argumentative bailey, having successfully fended off all attackers. The point is to defend a controversial idea by systematically conflating it with a less easily-assailable one.
(
Source)
