Some Opuntias can survive a lot of winter. They have been in the wild (and spreading on their own) in Hungary too. Lack of rain might be an even bigger problem than rising temperatures, as long dry periods might give the cacti an advantage over the native flora.
Wonderdull t1_j84rpws wrote
Reply to Cacti replacing snow on Swiss mountainsides due to global heating by TwoMoreDays
Some Opuntias can survive a lot of winter. They have been in the wild (and spreading on their own) in Hungary too. Lack of rain might be an even bigger problem than rising temperatures, as long dry periods might give the cacti an advantage over the native flora.