The rising public awareness of climate change, says MIT President Susan Hockfield, comes with a price. “The public dialogue has evolved from nothing is wrong, so we need to do nothing, to everything is so wrong, that there’s nothing we can do.” Citizens are “starving for a sense of focus, clarity and direction,” and with that in mind, MIT and other organizations “need to speak louder,” declares Hockfield, by elevating the public debate, telling the truth about the power and limitations of technology, and focusing on the harsh reality that the scale of a proposed solution can “doom a clever idea to nothing more than a dilettante’s distraction.”

Here’s Rajendra K. Pachauri’s panic-inducing assertion: We have a window of seven years to stabilize CO2 at today’s levels if we are to limit our global mean temperature increase to around 2.40C. A world this hot would be a very unpleasant place to be. Pachauri lays out unequivocal” evidence of climate change, and describes how extreme precipitation events, heat waves and other natural catastrophes will become more frequent, endangering vast swaths of humanity. We stand to lose 20-30% of species if warming exceeds 1.5 to 2.5 0C. Pachauri also notes this “scary prospect”: the rapid loss of ice sheets on polar land, leading to sea level rises of several meters, and the flight of large populations in response.

Pachauri describes the kinds of adaptations humanity must make to the changes already underway, including protection from flooding; preventing water scarcity; and retooling agriculture. Developed nations have a head start in these, and must help out developing nations, or risk global conflicts. Yet adaptation alone “cannot cope with all the projected impacts of climate change,” says Pachauri, so greenhouse gas mitigation efforts are urgent. In the midst of this desperate panorama, Pachauri holds out some hope: “Anyone who says, what’s the point, why take action—if we start today, we can really make a difference in the next two to three decades.”

What’s more, we have at hand a portfolio of technologies that are currently or soon to be available that could achieve significant mitigation, he says. If we invest in public transport and efficient vehicles, the right kinds of R&D, technology transfers and incentives, we could achieve our goals. And he notes, the cost of taking such actions “are not high at all.” To stabilize CO2 at around 500 PPM, the costs in 2030 would be less than 3% global GDP, which amounts to a minuscule .12% annually.