When it comes to sustainability, 2015 was a landmark year. The international community signed on to the Sustainable Development Goals (SDGs) and adopted the Paris climate agreement, under which more than 190 countries have committed to reducing greenhouse-gas emissions (GHGs). In that year and the next, there were complementary agreements on finance, cities, and biodiversity. Taken together, these accords established a clear global agenda.
The challenge now is to deliver on that agenda, which requires clarity on both the objectives and on strategies to achieve them. Sustainability is about ensuring that future generations have opportunities that are at least as good as those available to the current generation, assuming they behave similarly to those that follow. Much, then, will depend on the assets we leave to those who come after us. Some assets take the form of physical capital, such as infrastructure, or human capital, including health and education. But it has become ever clearer that opportunities for future generations depend critically on natural capital (water, air, land, forests, biodiversity, and oceans), and social capital (public trust, strong institutions, and social cohesion).
This implies that it makes no sense to invest in physical capital that is harmful to public health, the natural environment, or social trust and cohesion. Sustainability demands that we invest in and protect all four forms of capital simultaneously. It requires that we incorporate such principles into our economic theories and development models. Only by changing how we think about progress can genuine progress be made.