A number of studies indicate a clear connection between increasing extreme weather and climate change.2 One, by climatologists at the U.S. National Center for Atmospheric Research in Colorado, looked at rising global atmospheric and sea surface temperatures, which have increased water vapor in the atmosphere by about 5 percent since the 1950s. According to the 2015 paper, published in Nature Climate Change, “This has fuelled larger storms, and in the case of hurricanes and typhoons, ones that ride atop oceans that are 19 centimetres higher than they were in the early 1900s. That sea-level rise increases the height of waves and tidal surges as storms make landfall.”
Because of the way the planet and its systems balance energy, extreme precipitation in some areas is increasing more quickly than overall rainfall. Rain is caused by water vapor cooling enough to condense into liquid when the atmosphere cools. But with more greenhouse gases warming the atmosphere, water vapor can build up, leading to heavy rain and snow events that are increasing in frequency and severity. With more moisture and energy in the atmosphere, and warmer oceans, the world can also expect more intense hurricanes. Besides flooding, extreme precipitation can cause crop damage and loss, soil erosion, water contamination, and more. Because water vapor is often held for longer by a warmer atmosphere, and released in extreme events over smaller areas, other areas often get less overall precipitation than before, leading to droughts in some places.
A Stanford University study found “accumulation of heat in the atmosphere can account for much of the increase in extreme high temperatures, as well as an average decrease in cold extremes, across parts of North America, Europe and Asia” but also concluded the influence of human activity on atmospheric circulation, another factor in climate change, is not well understood.3
What scientists do know is that moist air rises as it is heated near the equator. Once it is high enough to cool, the moisture falls as tropical rain. The dry air then moves north and south, normally dropping at the subtropics. With a warmer planet, it travels farther, causing drying conditions farther north and south. This could help explain ongoing drought conditions in California and other parts of the U.S. Southwest. A 2016 paper published in Nature Climate Change examined the effects of atmospheric circulation and increased water vapor on storms and flooding in England during winter 2013–14.4 The researchers used model simulations and found that the historic precipitation and flooding were caused not just by increased moisture in the air but also by increases in the number of January days with westerly flow.
The damage that climate change is causing, which will get worse if we fail to act, goes beyond the hundreds of thousands of lives, homes, and businesses lost; ecosystems destroyed; species driven to extinction; infrastructure smashed; scarce or polluted food and water in many areas; and people inconvenienced. It will even devastate the one thing that many corporate and government leaders put above all else: that human creation we call the economy—the very excuse many of our leaders use to block environmental protection and climate action.
The U.S. Environmental Protection Agency (EPA) reported, “Between 2011 and 2013, the United States experienced 32 weather events that each caused at least one billion dollars in damages.” According to Hansen, the Texas drought in 2011 alone caused $5 billion in damage. Repairing the damage from Hurricane Sandy in the U.S. is expected to cost at least $50 billion. And as former World Bank economist Nicholas Stern has pointed out, slowing climate change will cost us, but doing nothing will cost far more.
Earth is clearly experiencing more frequent extreme weather than in the past, and we can expect it to get worse as we burn more coal, oil, and gas, and pump more carbon dioxide and other greenhouse gases into the atmosphere. This can have profound and costly impacts on everything from agriculture to infrastructure, not to mention human health and life.
Increasing extreme weather threatens global water supplies and food security. We’ve already seen prolonged droughts affecting food supplies in what were once productive food-growing areas, such as California, parts of Africa, and elsewhere in the world. Flooding also destroys crops and degrades and erodes soil, and changing weather patterns—altered growing seasons, less predictable conditions, and shifting climate zones—are making food production a challenge. Melting glaciers and changes to the earth’s hydrologic cycles will affect the availability of water for drinking and growing food. As the world has come to depend more and more on globalized food delivery, climate change will also put pressure on the ability to rationalize these systems. Transporting food over long distances will become increasingly difficult, unless we can find ways to ship products without burning large amounts of some of the most polluting fossil fuels. That means shifting to more local food production, but that is threatened by the difficulty many areas are experiencing, and will experience even more as the world continues to warm, to produce food for local populations. Increasing degradation and loss of productive soils because of industrial agriculture practices and climate change add to the problem.
As water and food security are compromised, disease can start to spread. Climate change isn’t just a matter of more unpredictable weather or increased storms, precipitation, and heat waves; it threatens the basic elements we need to survive and be healthy.
What Can We Learn From Arctic Ice?
THE ARCTIC MAY seem like a distant place, just as the most extreme consequences of our wasteful use of fossil fuels may appear to be in some distant future. Both are closer than most of us realize.
The Arctic is a focal point for some of the most profound impacts of climate change. As we saw in Chapter 1, much of our understanding of global warming comes from studies of the Arctic, where changing conditions can trigger feedback cycles that affect the entire planet. One of the world’s top ice experts, Peter Wadhams of Cambridge University, calls the Arctic situation a “global disaster,” suggesting ice is disappearing faster than predicted and could be entirely gone in the near future.5 “The main cause is simply global warming: as the climate has warmed there has been less ice growth during the winter and more ice melt during the summer,” he told the Guardian.6
Over the past thirty years, permanent Arctic sea ice has shrunk to half its previous area and thickness.7 As it diminishes, global warming accelerates. This is caused by a number of factors, including release of the potent greenhouse gas methane trapped under nearby permafrost, and because ice reflects the sun’s energy, whereas oceans absorb it.
Because of albedo feedback (which refers to the ability of a surface to reflect solar energy), ice-covered regions like the Arctic are affected to a greater degree than other areas by even small changes in global temperatures. Researchers say the Arctic is warming twice as fast as the rest of the planet. Fresh Arctic snow and ice can reflect as much as 80 percent of the sun’s energy back to space, and melting ice in summer can reflect 50 percent. According to the U.S. National Oceanic and Atmospheric Administration, ocean water only has an albedo of 10 percent.8 Even small amounts of warming cause ice and snow to melt, reducing the surface area that reflects solar energy. As more dark ocean and land surfaces are exposed, more energy is absorbed, which causes further warming, and further melting, and so on. These feedback loops in the Arctic are complicated, because the Arctic receives little or no sunlight during winter, but up to twenty-four hours of sunlight during summer. But warming during spring, summer, and fall causes spring melt to arrive earlier and fall freezing to start later, meaning the period during which solar radiation can be absorbed rather than reflected lasts longer. And because the oceans absorb more heat during summer, they release the heat during fall and into winter, causing the atmosphere to warm even more. Because the atmosphere over the Arctic is quite stable, the heat stays near the earth’s surface, leading to amplification of warming in the area.
The increase in warming rates in the Artic regions sets off another feedback loop, as CO2 and methane, a greenhouse gas many times more potent than CO2, are released from oceans, permafrost, and soils that are no longer frozen. This causes more warming and more melting, and so on.
According to the IPCC, Arctic warming