Jeremy Berg in Science:
Our planet is in a perilous state. The combined effects of climate change, pollution, and loss of biodiversity are putting our health and well-being at risk. Given that human actions are largely responsible for these global problems, humanity must now nudge Earth onto a trajectory toward a more stable, harmonious state. Many of the challenges are daunting, but solutions can be found. In this issue of Science, we launch a series of monthly articles that call attention to some of the choices we can still make for shaping tomorrow’s Earth—commentaries and analyses that will hopefully provoke us to making thoughtful choices (see scim.ag/TomorrowsEarth).
Many of today’s challenges can be traced back to the“Tragedy of the Commons”identified by Garrett Hardin in his landmark essay, published in Science 50 years ago. Hardin warned of a coming population–resource collision based on individual self-interested actions adversely affecting the common good. In 1968, the global population was about 3.5 billion; since then, the human population has more than doubled, a rise that has been accompanied by large-scale changes in land use, resource consumption, waste generation, and societal structures. Science‘s “State of the Planet” articles (published between 2003 and 2008; see scim.ag/StateofthePlanet) articulated the stresses and possible solutions to these growing human-induced impacts on the Earth system. Donald Kennedy, then Science‘s Editor-in-Chief, aptly asserted: “The big question in the end is not whether science can help. Plainly it could. Rather, it is whether scientific evidence can successfully overcome social, economic, and political resistance.”
Through collective action, we can indeed achieve planetary-scale mitigation of harm. A case in point is the Montreal Protocol on Substances that Deplete the Ozone Layer, the first treaty to achieve universal ratification by all countries in the world. In the 1970s, scientists had shown that chemicals used as refrigerants and propellants for aerosol cans could catalyze the destruction of ozone. Less than a decade later, these concerns were exacerbated by the discovery of seasonal ozone depletion over Antarctica. International discussions on controlling the use of these chemicals culminated in the Montreal Protocol in 1987. Three decades later, research has shown that ozone depletion appears to be decreasing in response to industrial and domestic reforms that the regulations facilitated.