Europeans are not concerned much abut climate change, whatever that means but mass immigration is an existential threat, well, maybe that is exaggerating, but, still a threat:
https://www.dw.com/en/migration-more-worrying-than-climate-change-for-europeans-survey/a-49904437
“While climate change is growing in the public consciousness, migration is still the major issue for more EU citizens, according to the results of the European Commission's biannual Eurobarometer public opinion survey. Migration remains the top concern across the European Union, according to an EU public opinion poll, although the importance of climate change is growing. Thirty-four percent of respondents in the new Eurobarometer survey view immigration as the most pressing problem, down six percentage points from last year. However, the issue topped the list of issues in 21 member states, with Malta, the Czech Republic, Estonia, Slovenia and the Netherlands having the highest proportion of respondents ranking it most problematic. For the first time, climate change jumped to the second most important concern, with 22% of respondents mentioning it, according to the biannual poll conducted by the European Commission."
Even if climate change was real, not saying that it is, there is unlikely to be much that humans could do about it, whatever its causes. China will press ahead with growth, whatever the cost. And, as the left say, how can we in the West tell the rest not to grow, when we have had the goodies? Sure, just accept that you can kiss your sacred environment goodbye if you are right. But, immigration is real and population pressure is a far greater destructive force than climate, and in any case impacts upon climate in various ways. Thus, real environmentalists should be immigration restrictionists.