We usually justify our claims to mitigate climate change, to preserve nature, and to consume fewer resources by talking about the rights of future generations. We typically refer to the Brundtland Commission's definition of sustainable development, which explicitly points out our obligation to future generations.
Often, environmentalists take this definition to mean that we must maintain or protect the current state of the world for future people, that we need to save the planet from global warming or slow the rate of species decline so that future people can live like we do (or better than we can).
Through some lengthy philosophical reasoning, philosopher Derik Parfit concludes that "every single person alive 100 years from now will be an entirely different individual from the person he or she would have been had we not intervened in the environment." (Read it summarized by another guy – Anthony Damato – here).
And for the big Q: "How can we owe a duty to future persons if the very act of discharging that duty wipes out the very individuals to whom we allegedly owed that duty?" In other words, by preserving the environment, we would make "future generations" worse off than if we had not acted at all because we would deny those "future generations" existence.
What a paradox.
Even though it appears that we do not have an obligation to future generations to preserve the environment, that does not mean we have no moral obligation at all. Perhaps we have no obligation to future generations, but rather obligations to the ideals themselves.
We could continue to explore this question in a philosophical manner or we could change the discussion entirely, which is what we all need to do.
The conversation about rights for future generations is now moot, realistically, because we are seeing the effects that humans have on the environment first hand (erratic climate and weather patterns, sea level rise, changing ecosystems, increased air pollution, etc.). There is no need to talk about "future generations" anymore, because we are the "future generations" that the definition was based upon. And adding time lag to the equation, we have yet to see some of the effects that we have already caused, let alone the effect of our actions yet to come.
So, we can no longer talk about the rights of future generations; rather, we need to shift the conversation to protecting our current generation. Sure, future generation and long-term sustainability matter, but sustaining our world for current generations is a much more compelling motive to protect all of our vital ecosystems and fascinating species.
When we cut down forests for agriculture, for example, there are immediate repercussions. Not only do we disturb the habitat for many species, but we also destroy the soil.
And according to the poverty-environment thesis, "the poor are both the agents and victims of environmental degradation." Sixty percent of the world's poor relies on natural resources, such as hardwood forests, for their livelihood. Even though it is not a sustainable cycle, it puts food on the 60 percent's table today. Let us practice environmental protection for them, not for the people 100 years in the future.
There are many, many organizations (e.g., Heifer International) working to do just that – fight poverty, food insecurity, and environmental justice, among many other organizations. There are also many businesses, institutions and individuals who are fighting for sustainability. We just need to get everyone on board and on the same page.