The following is an excerpt from the new book The Madhouse Effect by Michael E. Mann & Tom Toles (Columbia University Press, 2016):

The most unfortunate part of the societal debate over climate change has been the ease of imagining a warming climate as an essentially unthreatening occurrence, the status quo. “Global warming” sounds almost pleasant. Like a day in springtime. You may have heard someone say in response to a nice day in winter, “If this is global warming, I’ll take it!” A smooth, comfortable adjustment in living circumstances, not unlike turning up the thermostat by a degree or two. Not to worry! [[{“type”:”media”,”view_mode”:”media_large”,”fid”:”617133″,”attributes”:{“alt”:””,”class”:”media-image”,”height”:”428″,”typeof”:”foaf:Image”,”width”:”480″}}]] This response is entirely understandable. Unfortunately, it is also entirely wrong. Although the increase in CO2 in the atmosphere is gradual and steady, the results of that increase will be anything but. People assume that noticeable effects will be far off in the future, but they are showing up right now. Relentlessly. And if you think the effects will be felt only in some faraway corner of the globe where only polar bears and penguins live, think again. The consequences of a changing climate are occurring everywhere and, yes, likely right near you, affecting you, your family, your friends, your community. Be it national security, food, water, land, or health—ours and our planet’s—the specter of climate change is upon us.

Dreams of slowly adapting to climate change will have to be replaced with the hard reality of an ever-escalating pace of disruption and unpredictability. In what ways will the effects of climate change be felt? In nearly every way.

Security You don’t have to be driven by ethics, morality, religion, or altruism to recognize the threat posed by climate change. Being a national security hawk, for instance, is more than adequate. In the lexicon of the national security community, climate change is the ultimate threat multiplier—it takes existing tensions and conflicts and amplifies them. A thawing Arctic Ocean means a new coastline to defend. It means open competition among the bordering nations of North America, Europe, and Asia for oil-drilling rights in the Arctic—rather ironic, since oil drilling is part of what got us into this mess in the first place. Climate change will create more competition among a growing global population for less food, less water, and less land—a prescription for a perfect storm of global conflict. That storm is already brewing. A compelling case can be made that the historic ongoing drought in Syria was made worse by the aggravating effects of climate change and played a key role in the civil unrest and societal instability that ultimately led to the civil war there, the reverberations of which continue to be felt around the world. To understand how increased conflict might arise throughout the world, let’s consider how climate change will affect the underlying contributing factors. Let’s examine how climate change will have an impact on all sectors of our lives. Food The global population is currently around 7.3 billion and growing. It is projected to reach 9 billion by the middle of this century and could grow to 11 billion by the end of the century. Malnutrition and hunger currently afflict more than 800,000 people, according to the World Food Programme. That number will only get larger without a concomitant increase in food production. Yet climate change will likely lead to a decrease in global food production.

In the tropics, temperatures are already close to optimal for growing cereal crops such as rice, corn, and sorghum. That might sound good, but it’s actually very bad. It means that even modest warming will lead to precipitous drops in yields due to the rapid descent down the far side of the productivity peak. That descent translates to a substantial decline in the cereal crops available to feed a large, growing, and too often malnourished population. In the extratropics, the situation may seem better. Growing seasons will potentially get longer, and crops will potentially be grown at higher latitudes. That’s the good news. Now the bad news. Any resulting gains could be more than offset by increases in damaging weather, more widespread and destructive wildfires, and longer and more frequent drought. Think about the summer of 2012, when our nation’s breadbasket was decimated by record heat and drought. Or think about the past five years, during which the unprecedented ongoing drought in California has threatened 33 percent of our total supply of fresh produce. In 2010, climate-related factors led to a 33 percent drop in wheat production in Russia, a 19 percent drop in Ukraine, a 14 percent drop in Canada, and a 9 percent drop in Australia. Less grain means less feedstock for livestock, and extreme summer temperatures mean greater heat stress on livestock, less water for them to drink, and fewer days and hours that farmers and ranchers can work the land. Ranchers in Oklahoma and Texas lost nearly 25 percent of their cattle during the record drought in 2011. Well, at least we’ll still have plentiful seafood, right? Alas, no. The disruption of ocean currents such as the North Atlantic Drift could impact the productivity of the North Atlantic, a critical source of fish and seafood. Meanwhile, we have seen massive die-offs of salmon in the Pacific Northwest in recent years due to scorching-hot waters, and West Coast oyster farms are getting hammered by global warming’s twin brother: ocean acidification. Rising CO2 levels are likely to further exacerbate the threats to fish and shellfish stocks already threatened by overfishing, water pollution, and other human-caused threats.

Water We human beings need food. But we can go without it for weeks. Water, however, we can go without for only a few days. And climate change means that there will be less of it—less freely available freshwater over a large part of the globe—to quench the collective thirst of a growing global population.

As the jet streams migrate poleward in a warmer planet, the dry subtropics will expand into the middle latitudes, leading to a wider zone of semiarid conditions. Now, that shift may seem to be balanced by other changes: the subpolar regions will likely receive more rain and snow, and the deep tropics, lying within the band of rising air currents known as the Intertropical Convergence Zone (ITCZ to weather nerds), may get even wetter as a warmer atmosphere produces greater amounts of rainfall. It sounds like a zero-sum game. Isn’t the challenge just to move the water from where there is a surplus to where there is a deficit? Well, if that were all, then, yes, but the task would be extremely difficult and expensive, requiring massive investments in infrastructure. An ounce of prevention—in this case, cutting greenhouse gas emissions—is worth a pound of cure.

But there is a further complication. Just because more water falls doesn’t mean that there is more moisture in the ground. Warmer soils and vegetation evaporate more moisture from the ground into the atmosphere. The current drought in California coincides with the warmest year (2014) on record there. That isn’t a coincidence. For the semiarid American West, the diminishing water supply and the growing population are on a collision course. To be sure, there are some workarounds. For coastal regions, there is large-scale desalinization. But that solution is, once again, costly. Yet letting Los Angeles and San Francisco wither away would be an even more expensive prospect. For inland cities such as Las Vegas and Phoenix, the prospects are more daunting, especially as we factor in the steadily decreasing snowpack-fed river and stream flows, a key source of freshwater for human consumption and irrigation throughout the American West. Even the less-arid Pacific Northwest, with its populous cities Portland, Seattle, and Vancouver, isn’t immune—it, too, is starting to face significant water-resource pressures. Meltwater from mountain glaciers and snowpack is a major source of freshwater in arid and semiarid regions around the world. As we lose Ernest Hemingway’s “snows of Kilimanjaro” (the ice fields of Kilimanjaro, to be more scientifically precise), so too do we lose a key source of year-round freshwater for the people of eastern equatorial Africa. Glacial meltwater from the Himalayas feeds the Ganges, Indus, Mekong, Yangtze, and Yellow Rivers, which provide drinking water and irrigation for large populations throughout China, India, and other Asian nations. As we lose the Himalayan glaciers, we lose a primary source of freshwater for more than 1 billion people. A similar threat holds for many other regions around the world.

Then there is groundwater and the aquifers that feed it, accounting for as much as 40 percent of all drinking water and widely used for agriculture in semiarid regions. The Ogallala Aquifer, which lies below the Great Plains of the United States, is among the world’s largest aquifers, occupying nearly 200,000 square miles (322,000 square kilometers). It provides nearly 33 percent of the groundwater used for irrigation in the United States and more than 80 percent of the drinking water for the approximately 2 million inhabitants of the region. Unfortunately, the Ogallala Aquifer—like many aquifers—is living on borrowed time. It is being depleted by several percent per decade, with the total depletion to date exceeding the annual flow of eighteen Colorado Rivers. Some estimates have it being completely depleted by 2028. The aquifer consists largely of relict meltwater from the end of the most recent ice age. Once it is depleted, it will take more than 6,000 years to replenish naturally through rainfall (which amounts to about 0.1 inch [0.254 centimeter] per year). The Food–Water–Energy Nexus Food, water, and energy are now inextricably linked. The choices we make about one have profound consequences for the others. Consider again the Ogallala Aquifer, which provides drinking water in the semiarid High Plains of Texas. Water from the aquifer is being tapped not only for irrigation of crops but also for hydraulic fracturing (“fracking”)—a process used to free natural gas trapped in bedrock. This is potentially problematic on several levels. First, it means that in some communities, people are forced to take the costly measure of trucking in drinking water because agricultural and fossil fuel interests are competing for the diminishing available groundwater. Adding insult to injury, the mix of toxic chemicals used in fracking can potentially contaminate the groundwater that remains.

Consider also the controversial Keystone XL pipeline, a project to deliver low-quality, heavy oil (bitumen) extracted from the Athabasca oil sands in Alberta to the global market by way of the Great Plains. The pipeline would travel through a large region underlain by the Ogallala Aquifer. If the pipeline were to erupt, its contents could potentially contaminate that critical supply of freshwater. Although the project is currently on hold after being rejected by the Obama administration, there is no guarantee against this scheme or similar efforts moving forward in the future. Water is also needed for other sources of energy. Obviously, it is necessary for hydropower and hydrothermal energy generation. But a steady source of running cool water is also needed as a coolant for the production of nuclear energy, hence the location of nuclear power plants near rivers (for example, Three Mile Island is located on the Susquehanna River). Climate change is a major source of vulnerability here because it could lead to reduced or more intermittent stream flows. The same stream flows are needed to cool coal-fired power plants. The continued burning of coal—the most carbon-intensive form of fossil fuel burning—is, of course, a substantial contributor to climate change. And climate change is, as we now know, reducing river flows (or making them more intermittent) in many regions, which, ironically, is adverse to the continued operation of coal-fired power plants. Perhaps we have identified here one key negative (that is, stabilizing) climate change feedback loop? Now, back to the food part of the nexus. Obviously, we have a finite amount of land available for agriculture and livestock. Food production currently utilizes roughly half of Earth’s total land surface area and is rapidly consuming what fertile land remains. If we allow an increasing share of the arable land to be used for growing biofuels such as switchgrass, then we are trading off agriculture for energy. Indeed, the trade-off is even more obvious when we consider growing crops such as corn (which could potentially be feeding the world’s hungry and malnourished) for the fuel (ethanol) they can provide. The “food for energy” road is an ethically perilous one, and we appear to be proceeding down it headlong. We are reminded that there is no free lunch, figuratively or literally, when it comes to the trade-offs in the food–water–energy nexus. Land Regions such as the Sahel of Africa are becoming uninhabitable for climate-related reasons. It is estimated that 80 million of the 100 million people living in the Sahel are dependent on rainfall for their survival. Sustained drought and the growing intermittency and unpredictability of rainfall, however, have rendered the region unfavorable for farming and herding. Villagers are left with no choice but to abandon their land in search of more favorable lands. There is a name for this phenomenon: environmental refugeeism. The potential conflict between the environmental refugees and the native inhabitants of the lands to which they are fleeing is a very potent ingredient in the mix of factors leading national security experts to fear a future global conflict crisis. Health