Finally, the really good news is that every single one of the required technologies already exist and are being used in various parts of the world. For example, Senegal has "switched virtually its entire population from traditional stoves to modern ones, so it can be done," climate scientist Drew Shindell of NASA's Goddard Institute for Space Studies, lead author of the study, wrote in an e-mail. It is simply a matter of global adoption or, as the United Nations Environment Programme put it in a similar analysis last year, "much wider and more rapid implementation is required to achieve the full benefits."
In addition to saving lives, stopping soot may also preserve endangered ecosystems, such as the mountain glaciers of the Himalayas and Karakoram or Arctic sea ice. In fact, the computer modeling suggests cutting black carbon could forestall as much as two thirds of the warming in the Arctic—the fastest warming region of the globe—over the next 30 years. Even more significantly (from the human perspective), eliminating the atmospheric smut known as the "Asian brown cloud" could help maintain the monsoon patterns that bring water to India while reducing drought risk in places like the Sahel.
This doesn't mean that humanity would not have to deal with CO2 emissions—and would not be storing up future trouble by continuing to emit at our present pace—but it would buy time and, perhaps even more importantly, significantly reduce the chances of catastrophic climate change. Adding in cuts in yet more non-CO2 greenhouse gases—like the hydrofluorocarbons currently being phased out under the terms of the Montreal Protocol to eliminate the ozone hole—will also help. "These are things to do in addition to but not instead of reducing CO2 emissions," Shindell emphasized.
So why isn't this happening already? First and foremost, it is—in some parts of the world, at least. But short-term cost considerations, institutional structures and even societal priorities can stand in the way. For example, limited budgets might keep a municipality from installing methane capture at the local landfill in the U.S. Or an oil company might refrain from investing in similar methane capture at its wells because it can make more money investing in opening a new field instead. "In poor places, it really can be a lack of the upfront costs," Shindell added. There's also the not insignificant challenge of implementing such solutions globally—otherwise known as the problem of scale—as well as overcoming the reasons of engaging in traditional practices, such as burning the residue in agricultural fields to increase fertility, in the first place.
But there's a more fundamental reason for the inertia, according to the researchers, who note that "the benefits would not necessarily accrue to those incurring costs." That also explains our inaction on climate change generally. Or as Shindell noted "It's not trivial to get this done—even if it's beneficial for society as a whole."