Climate change chain reactions, bad and good

When Hurricane Matthew rampaged through parts of the Caribbean and the southeastern United States last month, its immediate effects were devastating. But its longer-term effects could be just as bad. The hurricane killed more than 1,000 people in Haiti, but flooding also triggered a resurgence of cholera that could ultimately kill even more. In North Carolina, after the initial damage of the storm’s arrival, Hurricane Matthew left many people without clean drinking water or power for weeks, and floodwaters spread a contaminated brew of waste and chemicals that threatened human health. And in Florida, which reported 185 cases of non-travel-related Zika virus infections as of November 1, the hurricane boosted the mosquito population, according to officials in at least one county.

Hurricane Matthew is just one example of a climate event setting off a chain of negative reactions such as flooding, soil erosion, dune destruction, crop damage, and other problems that contribute directly to human misery. In a warmer world, we can expect not only fiercer storms but also longer periods of drought, which can lead to food shortages, soaring prices, and political instability.

Climate change isn’t something that just inches along incrementally at the pace of slowly rising mercury. Like a nuclear or chemical chain reaction in which a single event sets off subsequent reactions that are irreversible and potentially catastrophic, warmer temperatures can explode into a series of other changes affecting water, food, ecosystems, and human health around the world. Many of the solutions proposed for climate change focus on the endgame—removing carbon dioxide from the atmosphere at some later date when the situation is more dire than today. But the best solutions are those that begin soon and have cascading effects far into the future: good chain reactions.

Hurricanes from hell. Climate models predict that as our planet warms, tropical storms will become fewer in number but more intense—with longer durations, stronger winds, and heavier rainfall. And because the sea level is rising as a result of global warming, big hurricanes are increasingly likely to cause lethal storm surges and inland flooding. The sea level has already risen about 2.5 inches since Hurricane Andrew hit Florida in 1992, and that seemingly small rise has big consequences for Florida and other relatively flat coastal areas.

Scientists have long known that global warming can set off a sequence of events, some of which make the warming even worse. For example, as Arctic sea ice melts, the dark underlying ocean waters absorb even more heat than the sun-reflecting white ice once did—causing any remaining ice to melt even faster. On land, rising temperatures in places such as Alaska and parts of Canada can cause extended droughts, making peat bogs more susceptible to wildfires—which can release heat-trapping carbon dioxide into the atmosphere and raise the global temperature still further. Thousands of fires in drained peatlands made Indonesia the world’s fourth-largest emitter of carbon dioxide last year.

Climate change’s cascading effects can be complicated and difficult to anticipate. For example, a team of researchers in Japan and Russia recently studied the effects of simulated climate change on the gut of an insect called the southern green stinkbug; they discovered that rising temperatures are likely to suppress a type of bacteria that lives in the stinkbug’s gut—and on which it depends for growth and survival. While weaker stinkbugs might be cause for celebration in some circles, the bigger-picture worry is that anything that kills off “good” bacteria in the guts of insects could also be bad for the animals that feed on those insects—and in turn for the humans who eat some of those animals. In other words, global warming might not only give stinkbugs a bellyache, but also give humans a food crisis.

One-dimensional solutions. We can learn a lot by studying complex natural systems like the stinkbug and its food chain. Instead, though, policymakers and engineers typically focus on one-dimensional solutions that don’t actually solve the climate problem—and might even be making it worse. For example, the construction boom in solar panels and wind turbines still has not led to the closure of a single fossil-fuel-burning power plant. As one recent study reported, “over the past 50 years, reducing the carbon intensity of the energy supply has been connected with higher energy use and electricity production.” In other words, the mad dash to build renewables is merely adding energy to the existing dirty supply, rather than replacing it—in much the same way that the spread of computers led to more paper use, instead of less.

A recent paper in the journal Science warned that putting too much faith in technical solutions could make people feel that a quick fix is possible—and that they therefore have a moral license to continue polluting for now. The paper’s authors pointed out that achieving the toughest requirements of the Paris Agreement would require a massive deployment of “negative-emission” strategies—methods for removing carbon dioxide from the atmosphere. Many of these strategies are unproven or barely demonstrated—for example, injecting carbon dioxide into basalt rock deep underground, or burning biomass in combination with carbon capture and sequestration.

Embracing complexity. There is at least one negative-emissions strategy, though, that is not only proven but also has a cascade of positive effects: planting trees. Planting fruit and coffee trees in areas devastated by the hurricane in Haiti, for example, would not only remove carbon dioxide from the air but also help farmers and the local economy, improve food security, provide shade, and stabilize soils. And in urban areas, trees not only help clean the air and reduce the need for air conditioning, but also raise property values and reduce stress. A study just released by the Nature Conservancy found that spending four US dollars per resident on planting trees in 245 of the world’s largest cities could improve the health of millions of people.

Planting trees does not eliminate the need to act quickly to reduce carbon emissions, of course. Too much attention has been focused on creating clean energy, and too little on keeping dirty energy in the ground. For immediate and cascading effects, nothing beats a carbon tax—and no new technology is required. Carbon taxes have already been successfully adopted in several countries and are being actively considered in others, but in the United States a carbon tax is on the ballot in only one state.

Washington state’s proposed carbon tax would do more than just encourage energy conservation and a switch to cleaner energy sources and processes. It would also reduce the state’s sales tax and provide tax credits to 460,000 low-income households. And a carbon tax would have all sorts of “co-benefits” unrelated to climate change, such as reducing respiratory problems and premature deaths by reducing air pollution, and improving fitness by giving people an additional financial incentive to walk or bike instead of driving.

Unfortunately, policy makers and engineers still fail to appreciate the urgency and complexity of the climate problem, and continue to be attracted to technological solutions that don’t work as intended. They still fail to understand the underlying social and economic processes that thwart simplistic solutions. They still think they have 30 or 40 years to prepare for a climate storm that has already made landfall and is quickly growing worse than anyone imagined.