It is necessary to understand the capabilities and sentience of animals in order to place obligations upon ourselves. Even though we cannot know exactly what future people will be like, I disagree with the idea that we do not know what humans will be like and what they need. It seems completely ignorant to think that the preferences of future generations will be completely different from the past. It is clear that the destruction of the environment, flooding of lands at low sea levels, cannot benefit humanity. Obligations to future people should not differ much from obligations to other humans. This is still in line with the first premise, as it is understood what humans are like and what they desire, and it is the denial of that understanding in future generations that leads to the conclusion. There are certain things humans need to survive and prosper, these likely will not change much and to assert there is no obligation because there is no way to know seems ignorant and extremely damaging to future generations.