I can see how consumption plays a bigger role than population but like you said, more and more people seek that highly consumerist lifestyle. Especially in the US, where population is over increasing. And I don't think the people here are going to give up their consumption of beef and pork anytime soon. However, I won't deny that Africa does have a less impact on the environment than the US, but wild animals in Africa are on decline some even close to extinction due to poaching, trophy hunting, and other sports game that involve killing of rare and exotic animals. Also poor nations are willing to increase their economic growth at a price of wrecking forests to supply other nations with palm oil, wood pulp, soya beans, cattle, and cocoa. So about 25% of illegal deforestation in the tropics is therefore related- either directly or indirectly- to the exportation of consumer goods. Lets not forget more people in poor countries are migrating to other nations to live that highly consumerist lifestyle. I don't see majority of the population changing to protect the environment. So then overpopulation does become a problem.
Green fuel is not environmental friendly since palm oil is in it. But nuclear energy is considered as one of the most environmentally friendly source of energy as it produces fewer greenhouse gas emissions during the production of electricity as compared to traditional sources like coal power plants.
I haven't seen any updates on the polar bears. But I've read that the people there will have to burn all the rubbish to prevent polar bears from reaching in town in mass numbers.
No updates on the relocation of polar bears.