In January, the Breakthrough Institute published its report, "Planes, Trains, and Car Bombs," arguing that despite warnings from politicians and terrorism experts that terrorists will pursue "exotic weapons and targets," al Qaeda continues "to carry out the same sorts of attacks they executed in the decades before 9/11." In the past decade, hirabis have not used biological or chemical weapons, nor have they targeted dams, our food supply, or the Internet. Instead, "al Qaeda directed, financed, or inspired attacks have targeted planes, trains, buses, government and symbolic buildings, and western hotels with bombs (and sometimes assault weapons)."

Now, in a Breakthrough debate, terrorism experts John Mueller, Brian Fishman, and Tom Parker weigh in over the assessment of the terrorist threat, the importance of language when discussing terrorism, and whether we're simply playing into terrorists' hands. More...

We can overcome this century's formidable environmental problems only by embracing modernization and technological innovation, Michael Shellenberger and Ted Nordhaus argued in their Breakthrough Journal essay "Evolve." In a new Breakthrough Debate, two scholars lend criticism to this new "modernization theology." "The troubling history of modernization gives us every reason to be deeply suspicious of anyone who suggests we should simply take it on faith," writes Jon Christensen. Leslie Paul Thiele, meanwhile, argues against a "black and white" view of technology. "The issue is not about being for or against technology," he writes, but using it wisely. More...

Environmentalists chastise humanity for transgressions against Nature. We are told that by creating technologies, we have sinned. But if humanity has sinned, it is not through the act of creation. Instead, we sin when we fail to care for our technologies. We should not stop creating; rather, our goal should be to never stop innovating, inventing, creating, and intervening. Instead of turning our backs on modernization, we must learn to modernize modernization. This challenge demands more of us than simply embracing technology and innovation. It requires exchanging the modernist notion of modernity for one that sees the process of human development as neither liberation from Nature nor as a fall from it, but rather as a process of becoming ever more attached to, and intimate with, a panoply of nonhuman natures. More...

Response: Clive Hamilton, author of Requiem for a Species: Why We Resist the Truth About Climate Change argues that the "deep greens" have become scapegoats, blamed for the "destabilization the social order, when their only crime is to alert us to it. "But sacrificing them "can only ever give the appearance of preserving the social order... To save ourselves we must learn to love our scapegoats."

Liberal devotion to scientific justification for social intervention seemingly knows no end. And yet, time and again, scientific rationality has proven to be a terrible foundation for progressive politics. By focusing on rationality above all, liberalism has pursued policies that are, in fact, anathema to liberal values. At the same time, liberals have increasingly turned away from technology, which, as opposed to science, might actually be the best way to advance our aspirations for a more equitable society. Indeed, for the Left to truly achieve liberal values, liberalism may have to give up the mantle of science and learn to embrace technology and the fruits therein. More...

Response: Sarewitz is mistaken in diagnosing liberalism's ills, says Mott T. Greene, professor of Science and Values at the University of Puget Sound. The problem with Sarewitz's argument is that liberalism no longer exists.

In a sweeping intellectual history, Mark Sagoff traces the birth of ecological economics in the 1980s through the field's demise in its attempt to mathematize religious views of nature. The rise and fall of ecological economics is a cautionary tale. In their obsession to model and monetize nature, ecologists and environmentalists lost their way, draining away the very moral power that once sustained environmentalism. More...

Response: Daniel Bromley, professor emeritus of the University of Wisconsin-Madison, agrees with Mark Sagoff's criticism of ecological economics. But Sagoff falters when he claims that environmentalists need to help society achieve pre-existing goals. "Societies do not have goals -- they have histories, out of which are crafted candidate families of possible futures."

Has humanity crossed a so-called "planetary threshold"? Will the Earth soon be no longer capable of supporting humanity? Or do such limits even exist? As a growing consensus among scientists has recognized the onset of the Anthropocene -- in which humans have become the dominant ecological force on the planet -- some have expressed concern that human civilization is fundamentally unsustainable. In his Breakthrough Journal essay "Planet of No Return," environmental scientist Erle Ellis argued that this view was at odds with science and human history -- it has been human limits, not natural ones, that have shaped human development. Not everyone agrees. Now, in a new Breakthrough Forum we publish today -- featuring responses from Bill McKibben, Nils Gilman, Robert Dello-Russo, Ronnie Hawkins and Francisco Seijo, as well as a reply from Ellis -- the debate over what the Anthropocene means, and how we ought to respond in the coming decades, takes center stage. More...

On March 26, 1974, dozens of women from the small village of Reni in the Uttarakhand Himalayas confronted a crew of out-of-town loggers. The women successfully prevented the loggers from chopping down the trees and, in the years that followed, the Chipko movement would become an international media sensation. "Tree hugger" entered the lexicon as an all-purpose signifier for environmental sympathies. But the Chipko movement became iconic in rough proportion to the degree to which it became detached from the actual events that transpired in Uttarakhand. From the start, Chipko was driven by a desire among villagers for local autonomy and economic opportunity. More...

Response: Shome's "reductive" take on the Chipko movement neglects previous research and unwittingly reproduces the same simplistic oppositional categories he supposedly critiques, writes Haripriya Rangan, author of Of Myths and Movements: Rewriting Chipko into Himalayan History.

Over the last decade, the idea that we have entered the Anthropocene has become inappropriately entangled with the belief that human civilization is fundamentally unsustainable. Yet the history of human civilization is also one of changing nature to support human populations. Just as the Stone Age did not end due to lack of stones, hunting-and-gathering was not displaced for lack of wild animals and foods, but due to the superiority of agriculture. Humans have no more reason to return to the Holocene than early agriculturalists had to return to the Pleistocene. The true significance of the Anthropocene is not that we must return to the Holocene, but that the continuation of Holocene-era nature depends on human civilization. More...