The temperature averaged 62F in 1997...what changed
You already posted the answer to that in your Op which you pretend to be too stupid to understand so you can continue to lie.
From your OP:
Please note: the estimate for the baseline global temperature used in this study differed, and was warmer than, the baseline estimate (Jones et al., 1999) used currently. This report has been superseded by subsequent analyses. However, as with all climate monitoring reports, it is left online as it was written at the time.