It has taken me awhile to figure out how to call attention to some really scary climate news while keeping to my goal of publishing posts that are 50 percent positive. Some news, such as the record high temperatures across the US this spring, I can balance with a good-news story: the US has cut its carbon emissions significantly and is on track to hit President Obama’s commitment to reduce global warming pollution between 2005 and 2020 by 17 percent. But in the case of the June 6 paper published in Nature warning that Earth may be fast approaching a tipping-point, a shift to a much-less-hospitable ecosystem, it takes work to be optimistic. And so I follow the lead author of the study in viewing the warning itself as good news. As Anthony Barnosky, a paleoecologist, told an interviewer from Wired, “There have been big, planetary shifts before.” The difference is, we know that one is imminent. Unlike us, “the dinosaurs couldn’t see it coming.”
The study, in which 22 scientists warn of impending and irrevocable major changes in the biosphere, is behind a paywall, but summaries abound in blogs. I recommend starting with David Roberts’ post on Grist or the Wired write-up, or one of the few front-page news stories, in the San Francisco Chronicle (probably because Barnosky is from nearby UC Berkeley). Most accounts refer to a tipping point for Earth, but the paper itself uses the term “status shift”–an irreversible transition of an ecological system from one state to another. Many such transitions are localized, but there have been global ones, such as the end of the last ice age about 14,000 years ago. It’s not just the warming of the planet that is leading to a status shift, say the scientists; it’s the explosion of population, which means ever-more resources for the extra billions to consume. More people means habitat destruction, the disappearance of plant and animal species, over-exploitation of energy resources, and more carbon emissions, producing more warming.
Here’s a video of lead author Anthony Barnosky, of UC Berkeley, on the findings:
James H. Brown, a macroecologist who is one of the authors, is quoted in the Times‘s Green blog as saying, “We’ve created this enormous bubble of population and economy. If you try to get the good data and do the arithmetic, it’s just unsustainable. It’s either got to be deflated gently, or it’s going to burst.” How we can gently deflate the bubble is what the commentators explore in the posts. Common to all the scenarios for avoiding the brink are the need to dramatically slow population growth, get off fossil fuels and onto alternative forms of energy, develop more efficient food production, and practice better ecosystem management.
The analysis includes reaction from climate scientists with different perspectives, such as those who would greatly expand the time frame of these changes (the paper warns that they may occur within a few generations), To keep away from what would tip this blog toward doom and gloom I seized on the judgment of those who say this shift is neither imminent nor inevitable, which echoes Barnosky’s belief expressed in the video and in interviews that humanity can pull together and avoid the doomsday scenario. In an interview with the Green blog’s Justin Gillis, Barnosky pointed out that “while many species are threatened directly and indirectly by human activity, the number actually driven extinct in the last 200 years is estimated to be only 1 to 2 percent of all species on earth. ‘We still have almost all the species that we regard as valuable out there to be saved. . . . We as people have it in our power to do that.’”
I’ll give the final word in this post to David Roberts, in a June 11 post in Grist, who stated the goal in larger terms–namely, that we have to conceive of ourselves as global citizens, not just as members of a family, or a tribe, as Thunder or Heat fans. Even thinking of ourselves as North Americans isn’t enough. We are “those who live on Earth”; our fellow tribe members are all human beings. Only in this way will we be able to “envision a world in which we slow our degradation of ecosystem services, avoid global tipping points, and develop technology that is regenerative, working with nature, like nature, rather than clumsily trying to replace it.” By this, I take him to mean we ought to go beyond technological fixes like geoengineering, which has recently become a hot topic. More about this in upcoming posts.