The state of humanity is getting better every day. On the whole, people are richer, healthier, and living longer than ever before. We are also a less violent species, it seems. Statistically speaking, my two boys, born in 2004 and 2007, can look forward to a nice long life. Several years ago, a Duke University demographer said:
It is possible, if we continue to make progress in reducing mortality, that most children born since the year 2000 will live to see their 100th birthday -- in the 22nd century.
There's just one problem. The planet they live on is going to be hotter, stormier, and possibly an ecological wasteland. At least that's what scientists have lately been projecting. The state of the environment, they say, is lousy: Earth is nearing or on the verge of a dangerous tipping point. (See what you have done, Malcolm Gladwell?) As some have noted, there is an unfortunate disparity between the outlook for humanity and the outlook for the planet. But what if we're getting a little ahead of ourselves here? What if this tipping points meme is a bit overwrought and not as imminent as we have been led to believe? That is essentially the argument five earth scientists have put forth in a study published this week in the journal Trends in Ecology and Evolution. Yes, the authors admit there are big red flags we need to pay attention to--the continuing loss of biodiversity, global warming, deforestation, etc--but they argue:
Even where tipping points have occurred on local and regional scales, there is empirical and experimental evidence to suggest that many ecosystems are able to recover even after heavy disturbance by humans.
The paper is a direct challenge to the influential Planetary Boundaries thesis, which was published in Nature in 2009. There, a number of prominent scientists had suggested that the massive imprint of humanity (our agriculture, cities, carbon emissions) was overrunning the earth's ecosystems, even pushing it past (or approaching) points of no return. Unless we got a handle on this, they said, humans would be in for quite a bumpy ride on a permanently damaged and dysfunctional planet. The fresh critique of this assertion in a reputable journal is sure to stir debate between the two camps that have staked out their positions on the Planetary Boundaries concept. Some of that is already starting to play out. Meanwhile, the idea of ecological and climate tipping points--the earth being pushed over a precipitous edge--has firmly taken root in environmental discourse.
