First a bit of framing: It’s a pity, but two of the things human beings do very poorly are calculate future risk and take seriously anything that isn’t happening right now. That means that bad things could happen to us a thousand years from now, or in even a few decades, but they don’t seem real. That doesn’t mean the dangers aren’t real, just we generally don’t believe it. That makes us fallible, capable of making errors, even own-species-eliminating errors. The two fallibilities go together, don’t they? The imprecision of our long-term risk analysis and our ability to react mainly to things with immediate impact are related. We are for the most part creatures of the here and now. The trendy thing to say is that this is ‘hard wired’ into us, built into our DNA, a product of inexorable evolution from surviving the last three million years or so.

I bring this up because as most people know, there is a climate change controversy. Roughly 98% (or more) of the scientists who study the Earth’s climate, atmosphere, oceans and history are saying that our globe’s climate is changing, growing warmer, and the results will not be good for humanity. Most of these same scientists also say we human beings are the principle cause, mainly through increasing the carbon load of our atmosphere. Of course, there is opposition to this scientific consensus, call it climate denialism or what you will. This opposition is fed by two big factors, financial support from those who have a stake in managing the use of energy and profiting from it, and the factor I mentioned above, the difficulty for most people to consider long term risk and non-immediate threat as real.

The point of this framing is to bring up a newly released review paper in the journal Nature [07 June 2012, paywalled, Approaching a state shift in Earth’s biosphere]. Nature is one of the premiere science publications, so when the June issue appeared with the cover story “Second Chance for the Planet,” to no surprise many of the stories in that issue were picked up by media all over the world. You may have caught some of it, with headlines running toward the apocalyptic and using the words “tipping points.” The tipping points part comes from the review paper. Unfortunately, no…stupidly, the paper is behind the journal’s paywall, so it isn’t widely available. I guess making money from apocalypse is more important.

Editorializing aside, the paper grew out of conference held in 2010. A group of scientists decided they were less concerned about trends, which are relatively well understood, than they were concerned about tipping points. You’ve heard the phrase, “It was all good, until it wasn’t.” That embodies a tipping point. Like overfilling a dam, there’s no problem until the dam is over capacity, but at some (tipping) point, it can hold no more and the dam bursts, resulting in a flood. Only that’s an analogy about a human thing – dams can be rebuilt and water put back in the reservoir. Natural tipping points are less repairable, if at all. More importantly, unlike a dam, tipping points in nature are often difficult to see or measure. How much carbon dioxide in the atmosphere is too much? At what point will the global climate change and can’t be changed back? Tipping points are very serious, often irreversible, and probably devastating to humanity; but they’re very hard to predict or even to assess the risk. Nevertheless, this group of scientists – the paper is co-authored by 22 people from many disciplines and from around the world – believe that we must pay more attention to tipping points, perhaps even more than we do to trends, because once we reach tipping points, well as they say, that may be all she wrote.

The paper was built on reviewing entire bodies of work, meaning hundreds of research papers across a wide range of disciplines. This review highlighted several points:

- Human-generated pressures, such as carbon emissions from vehicle traffic, are changing Earth’s atmosphere, oceans and climate so rapidly that entire ecosystems and the biodiversity of the planet will reach critical survival thresholds within our lifetime.
- Human resource consumption, coupled to population growth, is transforming the planet, fragmenting almost every aspect of Earth’s biology, including our own.
- The rate of change, especially in climate, exceeds that of periods when the Earth transitioned from a glacial to inter-glacial state.

In the words of one of the authors, Arne Mooers, professor of biodiversity at Simon Fraser University (Vancouver, Canada):

The last tipping point in Earth’s history occurred about 12,000 years ago when the planet went from being in the age of glaciers, which previously lasted 100,000 years, to being in its current interglacial state. Once that tipping point was reached, the most extreme biological changes leading to our current state occurred within only 1,000 years. That’s like going from a baby to an adult state in less than a year. Importantly, the planet is changing even faster now.

The odds are very high that the next global state change will be extremely disruptive to our civilizations. Remember, we went from being hunter-gathers to being moon-walkers during one of the most stable and benign periods in all of Earth’s history.

Once a threshold-induced planetary state shift occurs, there’s no going back. So, if a system switches to a new state because you’ve added lots of energy, even if you take out the new energy, it won’t revert back to the old system. The planet doesn’t have any memory of the old state.

[Source: EurekAlert]

The point of the review turned out to be not just another warning that global climate change is a bad thing. The problem is far more than climate change. It’s all the things that are changing the Earth due to human activity. The authors of the paper decided on two points: One, overall change is happening faster than we thought, and two, it could happen suddenly at a tipping point. The scientists put some numbers to this second poinnt as an example, currently about 43% of the Earth’s surface is in human use, if we reach 50%, then all bets are off for the Earth as a whole. This is an odd thing to say, as if surface use was somehow a decisive indicator. What the paper really shows is that we need more research into the nature and probability of multiple tipping points. Science doesn’t know with any precision what those tipping points are. There will be many tipping points, for species, for resources, for land area, for climate, for the ocean – and so forth. They all need more research to put some facts and figures behind the risk estimation of a global tipping point.

As I wrote above, human beings are not particularly good at risk assessment – even scientists. It’s a good thing that an interdisciplinary group of respected scientists have come to the conclusion that we need to know much more about global tipping points (risk assessment). I get the influence of popular authors such as Malcolm Gladwell has made the phrase useful. Unfortunately, in using ‘tipping points’ the scientists still don’t have a convincing story. The validity of tipping points – one or many – is not obvious. Most people will not believe the predictions for the relatively distant future. And so I’m afraid a very serious effort by a very concerned, even frightened, group of people (who are also scientists most involved with the issues) is dismissed; first by the media and then by most of the public. “Yet another group crying wolf!” says the Fox Network, for example.

I like the symbolic value of the phrase ‘tipping points.’ It’s easy to make analogies and most people can intuitively understand what is meant. However, there is a problem with the science of tipping points. It’s quite possible we won’t know many (or even any) of the tipping points until after they’ve happened, and they probably won’t happen fast enough to make the kind of story people believe. We know the trends that lead to tipping points, but the trends are undemonstrative for the average person because they take too long and tend to go up and down. In fact, they’re based on research, which can be debated just like any other scientific endeavor. We know that a great deal of money will be spent in continuing the debate.

If science and scientists are going to use ‘tipping points’ then, indeed, more research is needed; more than that, the story behind ‘tipping points’ needs to be far more robust. For example, are we talking about a ‘global tipping point’ for the Earth? One tipping point? Or are we talking about many tipping points that add up to a global tipping point? Even this basic distinction is missing from the way the term is currently used. No wonder the media and the public find it to be rather empty verbiage.

It’s frustrating for scientists who feel deep in their bones how bad, how desperate, their research makes them feel – but they can’t get it across to the public, at least not in those countries where the opposition is well funded and organized. Latching onto the term tipping points reflects that frustration, but it also illustrates that the framing of the scientific story still needs a lot of work.