Gulf stream is a tough issue because of the uncertainty around when it may happen and what its effects will be. Some research I’ve seen suggests the biggest temperature effects will be confined to coastal northern Europe but I’m not sure how certain that is. Hopefully research over the coming years will clarify that issue. In the meantime, two approaches may have merit. Species that tolerate a wide range of environments will be useful. And then on a broader scale, diversity will be important in case some species become unsuitable, others will endure.