I guess the models and estimates changed. Science is like that: it responds to new discoveries. It's only a minor difference in the time scale though: whether it's 2013 or 2030, we're in serious trouble now.

His actual statement:

He added: “Some of the models suggest to Dr [Wieslav] Maslowski that there is a 75% chance that the entire north polar ice cap during some of the summer months could be completely ice-free within the next five to seven years.”

Gore cited findings from climatologist Dr Wieslav Maslowski, a research professor at the Naval Postgraduate School (here).

However, it appears he mis-stated the forecast, according to reporting at the time.

In an interview with The Times published on Dec. 15, 2009 (here), Dr Maslowski said: “It’s unclear to me how this figure was arrived at. I would never try to estimate likelihood at anything as exact as this.”

According to the report, Gore’s office acknowledged after his speech that the 75% figure was used by Dr Maslowski as a “ballpark figure” in a conversation with the vice president several years before COP15.

https://climate.nasa.gov/vital-signs/arctic-sea-ice/

Pretty amazing to see all these downvotes on a purely factual statement. Watch it yourselves:

https://youtu.be/7hI5t3Uwfkk?t=1619&si=XtZDhtXoLyoczEG0