Yes, of course “sustainable development” is still relevant. I would argue it is even more relevant now than when the concept was first talked about in 1987. “The World Commission on Environment and Development, commonly referred to as the Brundtland Commission, defined the concept as development ‘that meets the needs of the present without compromising the ability of future generations to meet their own needs’, and at the same time takes into account the needs of the poor in the developing world.”
Since 1987 we have added more than 2 billion people to the planet and while our arguing about global climate change is new, we are still arguing over many of the same issues that were being discussed in 1987. So sad!