Environmental journalism, by and large, reflects not just news of the day (and an underlying theme) but also the zeitgeist. For example, when I made ecology my beat in the late 1990s, stories about the biodiversity crisis were prevalent in mainstream media and in environmental magazines--one of which I worked at through most of the 2000s. In my current feature story on the divide in the conservation community, I have a historical section on the roots of environmental conservation. There, I talk about a progression in ecology--evolving primary concerns over a 100-year period, from wilderness preservation and endangered species to biodiversity and ecosystem services. Of course, ecology is a huge field with many sub-disciplines. What I'm referring to are issues that were picked up in the media and frequently covered, which helped them gain traction as popular causes. This does not happen in a vacuum. Influential thought leaders and vocal scientists play an instrumental role. For instance, if you want to understand how biodiversity became a huge story in the 1980s and 1990s, read "The Idea of Biodiversity," by David Takacs. This 1996 book is also mentioned in a recent paper published in the journal Ethics, Policy, and the Environment. The authors argue:

We suggest that biodiversity is only the most recent in a long line of scientific "proxies" promoted to the public as a basis for conservation values. Such proxies gain widespread popularity due to their veneer of empirical objectivity, which encourages the public and policy makers to believe that decisions made on the their basis are value-neutral and free from any ideological commitments.

Be sure to read the whole paper, for the authors do not aim to de-legitimize the concept of biodiversity. Indeed, towards the end, they write:

The public promotion of biodiversity as a rallying point for conservationists since the 1980s has been well-intentioned, both in its aim to build public awareness and support for environmental causes on a solid scientific foundation, and in its desire to reduce anthropogenic species loss and stave off the prospect of a mass extinction event. These conservation goals, which are even more pressing in the light of climate destabilization, certainly deserve our full attention. Furthermore, empirical research in the diversity of life at every scale, which will undoubtedly shed new light on what we value in nature and prove useful for conservation purposes, should continue unabated.

Still, you need to keep reading past that section, too, to where they explain how, "as with previous concepts drawn from scientific ecology and promoted to the public as empirical foundations for nature's value, biodiversity operates with a veneer of objectivity that appeals to those who wish to avoid seeming subjective or ideological." As the authors go on to note:

In the conservation arena, this has happened repeatedly with concepts drawn from the science of ecology, including the "balance" and "harmony" of nature, ecosystem health and integrity, ecological interdependence, keystone species--and even "ecology" itself, the popular understanding of which has long contrasted with the term's scientific meaning...While this practice may have strategic value for influencing public opinion, it is disingenuous; policy decisions necessarily involve value judgments, and the role of these judgments is obscured when decisions are presented as following automatically from empirical evidence. It can be difficult in such contexts to identify precisely where facts end and value judgments begin, with potentially problematic consequences for the transparency and democratic inclusiveness of the decision-making process.

It is in such contexts that environmental and science journalists should play a more critical role, closely examining the space where facts end and value judgments begin. ** Check back tomorrow Friday for further elaboration on themes discussed in my Issues in Science and Technologystory.