Metformin, the big new "anti-aging" drug, explained

Considering all the issues with climate change, biodiversity loss and our society reliance on non-renewable resources, I have trouble being enthusiastic about the prospects of humans living longer. It will already be difficult for everyone to live a decent life with 11 billion people by 2100. If we find ways to extend human life by several decades, a new kind of demographic transition will start with a new equilibrium much higher. While it is difficult to argue that at an individual scale it would be awesome, I am very concerned of the consequences of such discoveries at a global scale.