Since 2001, there has been a torrent of new scientific evidence on the magnitude, human origins and growing impacts of the climactic changes that are under way. In overwhelming proportions, this evidence has been in the direction of showing faster change [and] more danger.
—John P. Holdren, president of the American Association for the Advancement of Science, quoted in The New York Times, February 2, 2007
It’s only now that we are beginning to face up to the reality of the impact that our everyday science and technology has had on the environment. You don’t need to look at some evil weapon of mass destruction conjured up by a mad scientist—our transport, housing, industry, and consumption in general are having a direct effect on the world we live in. Climate change is already under way. Just a few degrees of global warming would be enough to bring worldwide civilization to the verge of collapse.
This is the most insidious way that science can present a threat to humanity. We have all benefited hugely from the mechanization of civilization. We can achieve actions that once would have seemed incredible—like flying from one side of the planet to the other—with very little personal effort. But we are just beginning to realize the impact that our life-enhancing science and technology is having on the planet.
It would be fair to say that until recently, the threat from climate change was not well understood. In my Oxford Dictionary of Scientific Quotations, published in 2005, there is no reference to global warming and only one mention of climate change—and this is unconnected with the threat with which we are now concerned. Just take a look at that quote from the American atmospheric chemist Richard P. Turco, made in 1983, to see how much things have changed.
Global nuclear war could have a major impact on climate—manifested by significant surface darkening over many weeks, subfreezing land temperatures persisting for up to several months, large perturbations in global circulation patterns, and dramatic changes in local weather and precipitation rates—a harsh “nuclear winter” in any season.
In a world still living under the threat of imminent nuclear war, it seemed that humanity’s main impact on the climate could be nuclear winter. The vast amount of smoke and debris from the explosions of atomic bombs would, like Krakatoa’s haze of dust writ large, act as a sunshade in the atmosphere long enough to seriously chill the planet, perhaps even bringing us to the apocalypse of a world undergoing a massive ice age that would wipe out life on the planet in all but a narrow equatorial band.
As the threat of atomic devastation has become less significant, a very different, much more subtle type of climate change has reared its head. This is the kind of change portrayed in Al Gore’s movie, An Inconvenient Truth. For a long time this has been played down or even dismissed by the press and those with vested interests in ignoring climate change. And it’s true that portrayals like An Inconvenient Truth have not always helped, because they have tended to be a little careless with the facts in their enthusiasm to get the message across. But we shouldn’t take this as meaning that climate change is not happening, nor that its impact on human life will be insignificant.
The obvious sources of opposition to the findings of environmental science are companies benefiting from products and services that threaten the environment. It’s not a simple equation that everyone involved in a polluting company is necessarily a bad guy. The executives of these companies are human beings with children—they may well want to help the environment. Yet history has shown that commercial organizations are very good at ignoring the negative aspects of their products until they are forced to take them into account. The past actions of cigarette manufacturers make it clear that companies are prepared to ignore evidence until the last possible moment, and to try to manufacture opinion that supports their business objectives.
Time and time again those who have a motive to suppress the bad news about climate change have ignored evidence and tried to counter expert views. Often such actions are done through third parties—organizations and individuals that present the anti–global warming message in an apparently independent manner, but whose funding can be traced back to energy companies and others businesses that find climate change a commercially irritating concept.
In early 2007, Senator Barbara Boxer, chair of the U.S. Senate’s Environment Committee, had a meeting with the head of the Intergovernmental Panel on Climate Change (IPCC), the body set up by the World Meteorological Organization and the UN to provide scientific evidence to governments around the world. At this meeting, Senator Boxer was given an unequivocal message that climate change was real, and there was a very high probability that the burning of fossil fuels was a major contributor to the problem. As she left the meeting, one of Senator Boxer’s staff pulled her to one side. She was told that a conservative organization, funded by an oil company, was offering scientists $10,000 to write articles that attacked the IPCC report and the models that had been used to produce its gloomy predictions.
This was organized resistance. Former senator Tim Wirth, onetime Democratic spokesman on the environment, drew a parallel with the tobacco industry at its height. “Both figured, sow enough doubt, call the science uncertain and in dispute. That’s had a huge impact on both the public and Congress.” The result has been to produce significant doubt and confusion in the public’s mind. The message the public has received from much of the media is that scientists and science are divided on whether or not human-caused climate change exists.
Those who feel that the whole idea of a covert alliance attempting to dismiss global warming smacks too much of conspiracy theory might be shocked to learn that as long ago as 1998, a group including representatives of well-known organizations that argue against global warming met with representatives of oil company Exxon at the hardly unbiased American Petroleum Institute to discuss a campaign to train twenty scientists to become media representatives for their viewpoint. (This campaign was quietly dropped when memos from the meeting were leaked.)
ExxonMobil seems finally to be losing its will to keep fighting the anti–global warming fight. After being rapped on the knuckles by the U.S. Senate for spending over $19 million on anti–global warming organizations producing, as one senator put it, “very questionable data,” the company has publicly announced that it accepts the risks posed by climate change. These could be weasel words, and there are still senior Republican politicians who have been unable to shake off the anti–global warming view—but the United States seems to be finally turning the corner on climate change.
Part of the problem with understanding the likely consequences of continuing to abuse the environment on the scale that we do is that the threats don’t always sound particularly scary. In worst-case scenarios there is talk of temperatures rising as much as five degrees Celsius (nine degrees Fahrenheit) by the end of the century. This doesn’t sound particularly scary. Those of us who live at chillier latitudes may even think a few degrees warmer wouldn’t be a bad thing. But there’s a wealth of unpleasant detail hiding beneath those small numbers.
First, the numbers are averages. A rise of a few degrees in the average temperature can mean peak values that soar far above current levels. Averages are useful to get a broad picture of what is happening but can be extremely misleading when we try to understand what we experience. Just consider the difficulty of making deductions from averages. The average person has fewer than two legs (because some are missing a limb, the average is below two). Does this mean that shoe stores should stop selling shoes in pairs? It would be a ridiculous act—but that’s what would happen if you only considered averages. We don’t live the averages; we live through the peaks and troughs—however extreme they may be.
And then there’s the wider impact of climate change. It’s not just about the temperatures rising. Accompanying warming of this scale are impacts like droughts, the sort of wildfires that have swept California in the past occurring much more frequently, and sea-level rises from melting ice that could see whole low-lying swaths of real estate left useless. Think of what happened in New Orleans after Hurricane Katrina struck in 2005, repeated on most of the low-lying coastal areas around the world.
We are reluctant to do anything about climate change, because preventing it is expensive, and it requires us to suffer financial pain now to deal with a future problem that can’t be exactly quantified—a difficulty that became doubly problematic as the world sank into recession in 2008 and 2009 and most governments decided that getting the economy going again was more important than thinking about the planet. We saw, for example, programs to encourage us to go out and buy more cars. This was great for jobs, but not so great for the planet.
It’s shocking how long it has taken for there to be widespread acceptance that climate change is really happening. It shouldn’t be news. The U.S. National Academy of Sciences made its first study of global warming back in 1978. Although widespread acceptance that there is a serious problem took time to develop, the impact of climate change has now been studied for a good number of years—and the vast majority of scientists accept that this change is strongly influenced by human activity.
The UN added its support in the form of the 2007 report from the Intergovernmental Panel on Climate Change, stating that global warming is a fact, and that most of the rise in temperature since 1950 is most likely (with a better than 90 percent confidence) to have been caused by human intervention. “February 2 [of 2007] will be remembered as the date when uncertainty was removed as to whether humans had anything to do with climate change on this planet. The evidence is on the table,” said Achim Steiner, executive director of the UN Environment Programme.
Even the few scientists who don’t accept a man-made component to climate change admit that we are undergoing global warming. According to the IPCC, the world can look forward to centuries of climbing temperatures, rising seas, and disrupted weather. The ten warmest years on record have all occurred since 1990, and most of those were in the last decade. All the evidence is that the world is warmer now than at any time in the past two millennia—if current trends continue, by the end of the century it will be the hottest it has been in 2 million years.
There is a lot of talk about action to prevent climate change—but, realistically, this is not likely to have enough effect. It will almost certainly be a matter of too little, too late. Even if we persuaded the Western world to give up its love affair with the SUV and cheap flights, the economies of China and India are gearing up to rival those of the West. It has been argued that the only way to prevent climate change passing through a tipping point where warming will accelerate beyond our control is to reduce greenhouse gas emissions by 90 percent by 2030. No politicians are suggesting cuts that will achieve anywhere near this level of reduction.
We don’t have to reach that tipping point to see climate change accelerating. Already the trends are getting worse. As New Scientist magazine said in February 2007, “The [IPCC] authors acknowledge that they were being conservative. There is, though, a fine line between being conservative and being misleading, and on occasion this summary crosses the line. It omits some real risks either because we have not pinned down their full scale or because we do not yet know how likely they are.” Every week brings new revelations that global warming will hit us harder and sooner than was previously thought.
Apart from a relatively small impact from the heat of the Earth’s core, the world’s warmth comes from the Sun. Without the energy of sunlight, the surface of the Earth would be similar to that of a distant planet in the solar system with a temperature hovering below -240 degrees Celsius (-400 degrees Fahrenheit). The Sun’s warmth is essential to preserve life—but it is also the Sun that pushes us into global warming. Normally a fair amount of the Sun’s energy is reflected back off the Earth out into space. The more of that energy that is absorbed by the atmosphere and the planet, rather than reflected, the more Earth’s temperatures will rise.
The greenhouse effect, which we’ve heard so much about, modifies the amount of the Sun’s energy that escapes back through the atmosphere. Again, like the Sun, this isn’t a bad thing in itself. If there were no greenhouse effect, the Earth would be an unpleasantly chilly place, with average temperatures of -18 degrees Celsius (zero Fahrenheit), around 33 (60) degrees colder than it actually is. But living in a gaseous greenhouse can be just as troublesome as not having its protection.
The greenhouse effect is caused by water vapor and gases like carbon dioxide and methane in the atmosphere. Most of the incoming sunlight powers straight through, but when the energy heads back into space as infrared radiation, some of it is absorbed by the gas molecules in the atmosphere. Almost immediately the molecules release the energy again. A portion continues off to space, but the rest returns to Earth, further warming the surface.
We only have to look into the sky at dusk or dawn when the planet Venus is in sight to see the result of a truly out-of-control greenhouse effect. Venus is swathed in so much carbon dioxide (around 97 percent of its atmosphere) that relatively little energy ever gets out. Admittedly our sister planet is closer to the Sun than is the Earth, but it’s this ultrapowerful greenhouse effect that results in average surface temperatures of 480 degrees Celsius (900 degrees Fahrenheit)—hot enough for lead to run liquid—and maximum temperatures of around 600 degrees Celsius (1,100 degrees Fahrenheit) making it the hottest planet in the solar system.
No one is suggesting that the Earth’s atmosphere is heading for Venus-like saturation of greenhouse gases, but there is no doubt that the concentration of carbon dioxide, methane, and other gases that act as a thermal blanket is going up. Each year we pour around 26 billion tons of carbon dioxide (CO2) into the atmosphere. Around a quarter of the CO2 we produce is absorbed by the sea (though this process seems to be slowing down as the oceans become more acidic), and about a quarter by the land (much of it eaten up by vegetation), but the rest is added to that greenhouse gas layer.
Looking back over time—this is possible thanks to analysis of bubbles trapped in ancient ice cores from Antarctica and Greenland, where the further down we drill, the further back we look in time—the carbon dioxide level was roughly stable for around eight hundred years before the start of the Industrial Revolution. Since then it has been rising, and even the rate at which it rises is on the increase—not only is the level of CO2 in the atmosphere growing; the growth is accelerating.
In preindustrial times, the amount of carbon dioxide in the atmosphere was around 280 ppm (parts per million). By 2005 it had reached 380 ppm, higher than it has been at any time in the last 420,000 years. It’s thought that the last time there was a consistent comparable level was 3.5 million years ago in the warm period in the middle of the Pliocene epoch, well before the emergence of Homo sapiens, and it’s likely that levels haven’t been much higher since the Eocene epoch, 50 million years ago. The Intergovernmental Panel on Climate Change predicts that if we don’t change the amount of CO2 we generate, levels could be as high as 650 to 1,000 ppm by the end of the century. The Goddard Institute for Space Studies (GISS) model, one of the best computer simulations of the Earth’s climate, which reflects the impact of these changes on water patterns, predicts that most of the continental United States will regularly suffer severe droughts well before then.
Current predictions are that by the end of the century, the tropics will live through droughts thirteen times as often as they do now. Drought is already on the increase. A 2005 report from the U.S. National Center for Atmospheric Research notes that the percentage of land areas undergoing serious drought had doubled since the 1970s. Southwestern Australia, for instance, is facing a steady reduction in rainfall, leading to both potential drought and increased chances of bushfires.
As drought conditions spread, availability of water becomes restricted. Significant decreases in water output from rivers and aquifers are likely in Australia, most of South America and Europe, India, Africa, and the Middle East. Across the world, drought will be dramatic. The 2007 report of the UN Intergovernmental Panel on Climate Change predicted that by the last quarter of the century between 1.1 billion and 3.2 billion people will be suffering from water-scarcity problems.
Most historical droughts have been relatively short-term. Caused by statistical blips in the climate rather than marked permanent change, they cause devastation and disaster, but can be recovered from. A long-term drought provides no way out. Where these have happened in the past, civilizations have simply disappeared. After three or four years, the inhabitants of the drought area are faced with a simple choice: evacuation or death. A couple of years later and you have an abandoned region, littered with ghost towns and dead villages. Drought is no minor inconvenience.
At first glance, the whole concept of running low on water is an insane one. Looked at from space, the defining feature of the Earth when compared with the other planets in our solar system is water. Our world is blue with the stuff. In round figures there are 1.4 billion cubic kilometers (a third of a billion cubic miles) of water on the Earth. This is such a huge amount, it’s difficult to get your head around. A single cubic mile (think of it, a cube of water, each side a mile long) is around 1 trillion gallons of water.
Divide the amount of water in the world by the number of people and we end up with nearly a tenth of a cubic mile of water each. More precisely, 56 billion gallons for everyone. With a reasonable consumption of 1.3 gallons per person per day, the water in the world would last for 116,219,178 years. And that assumes that we totally use up the water. In practice, much of the water we “consume” soon becomes available again for future use. So where’s the water shortage?
Things are, of course, more complicated than this simplified picture suggests. In practice, we don’t just get through our 1.3 gallons a day. The typical Western consumer uses between 1,500 and 3,000 gallons. In part this happens directly. Some is used in taking a bath, watering the lawn, flushing the toilet—but by far the biggest part of our consumption, vastly outweighing personal use, is the water taken up by manufacturing the goods and food that we consume. Just producing the meat for one hamburger can use 1,000 gallons, while amazingly, a one-pound can of coffee will eat up 2,500 gallons in its production.
However, even at 3,000 gallons a day, we still should have enough to last us over 57,000 years without even adding back in reusable water. So where is the crisis coming from? Although there is plenty of water, most of it is not easy to access. Some is locked up in ice or underground, but by far the greatest majority—around 97 percent of the water on the planet—is in the oceans.
For countries with a coastline, like the United States, this is not particularly difficult to get to, but it is costly to take seawater and make it drinkable. The fact that nations with coastlines are prepared to spend huge amounts of money on reservoirs to collect a relatively tiny proportion of fresh rainwater, rather than use the vast quantities of sea that border them, emphasizes just how expensive is the desalination process required to turn seawater into drinkable freshwater.
Water shortages, then, come down to a lack of cheap power. If we had unlimited extremely cheap power, there would not be a water shortage. More indirectly, the price of power also limits our access to food. Drought makes food harder to grow, since we must rely more on expensive irrigation; but with sufficient power, irrigation should not be an issue. On the world scale, as climate change bites, limits on power availability make it harder to provide irrigation and to transport food around the world to meet global need.
Even where there is not the immediate threat of drought, the rise in temperature can push previously lush areas into decline. Many areas that are currently tropical forests—the Amazon rain forest has to be the best known example—are predicted to change to savannah, grassland, or even desert as carbon dioxide levels rise and a combination of lack of water and wildfire destroy the woodland. The Amazon, long touted as the lungs of the world, has already become an overall source of carbon dioxide, pumping over 200 million tons of carbon from forest fires into the air—more than is absorbed by the growing forest. If things continue the way they are, the expectation is that the Amazon rain forest will be just a memory by the end of the century.
This change of the environment from carbon sink—a mechanism to eat up carbon dioxide from the air—to carbon source is a feature of not just tropical forests. In 2005, scientists in the United Kingdom reported that soil in England and Wales had switched from being a carbon sink to being a carbon emitter. As average temperatures rise, the bacteria in the soil become more active, giving off more CO2. Remarkably, in 2005 this was already proving enough of a carbon source to cancel out all the benefits from reductions in emissions that the United Kingdom had made since 1990.
A combination of decrease in rainfall over areas like the Amazon rain forest with increase in temperature is expected to result in a massive die-off. There is a similar expectation that temperate and coniferous forests in Europe and parts of North America will be drastically reduced. The picture isn’t uniformly gloomy—there is some expectation of a northern expansion of forest in North America and Asia—but even so, the overall effect is that vegetation that has been soaking up carbon will, in our lifetimes, reverse to being an overall source of carbon, kicking the greenhouse effect into positive feedback. And positive feedback is the worst possible news about climate change.
The best-known example of positive feedback is the howl from a sound system when a microphone is brought too close to the speaker. Tiny ambient sounds are picked up by the microphone, come out of the speaker louder, are collected again by the microphone, and are reamplified, getting louder and louder until they become an ear-piercing screech. One of the most worrying aspects of climate change is that the global climate also features a number of positive-feedback systems, where a change reinforces the cause of the change, making the change happen faster, which reinforces the cause more, and so on.
Positive feedback has often been omitted from predictions. As New Scientist put it in February 2007, “The rising tide of concern among researchers about positive feedbacks in the climate system is not reflected in the [IPCC report] summary…. One clear need is to get to grips with the feared positive feedbacks.”
It’s not just the Amazon rain forest and the Australian bush that are tipping into positive feedback, adding to the greenhouse effect. Other forests around the world are being taken out of the carbon-sink equation as temperatures rise. For example, a combination of the increased temperature and the spread of pests is having a devastating effect on some Canadian forests. In one year, British Columbia lost nearly one hundred thousand square kilometers (forty thousand square miles) of pine trees (over half the land area of the state of Washington) to a combination of forest fires and disease. The local government estimates that 80 percent of the area’s pines will be gone by 2013.
Wildfires, destroying thousands of hectares of land and properties, are becoming increasingly common. In 1998 fires destroyed 485,000 acres in Florida and 2.2 million acres in Nicaragua. This is happening more and more frequently. More than 600,000 acres were destroyed on the Florida/Georgia border in 2007. Even in previously temperate areas like the United Kingdom, wildfires now pose a threat.
Agriculture will be forced to undergo major changes. Traditional crops of hot countries will take over in previously temperate regions, while areas already growing such high-temperature crops will find it increasingly hard to provide any food. The 2007 IPCC report that forecast huge water shortages also predicted that as the twenty-first century progresses, up to 600 million extra people will go hungry as a direct result of climate change.
If things get too drastic, perhaps our only hope will be a “Noah’s ark” of food—the vault being built by the Global Crop Diversity Trust in the permafrost of the Svalbard Archipelago near the North Pole, which will contain 3 million batches of seeds from all current known varieties of crops as a defense against the impact of global catastrophe.
There is an even more insidious effect of global warming that provides another, particularly dramatic, positive-feedback loop in the climate system—the melting of the Siberian permafrost.
In western Siberia lies a huge peat bog, around 900,000 square kilometers (350,000 square miles) in area—the size of Texas and Kansas put together. Peat, the partly decayed remains of ancient moss and vegetation, is a rich source of methane, a gas that contributes twenty-three times as much to the greenhouse effect weight for weight as does carbon dioxide. The methane from the bog is frozen in place by the permafrost—a solid mix of ice and peat that never melts. At least, that never melted until now. That permafrost is liquefying, discharging a huge quantity of methane into the atmosphere. By 2005 it was estimated that the bog was releasing 100,000 tons of methane a day. That has more warming effect than the entire man-made contribution of the United States. And thanks to positive feedback, the more the bog releases methane, the faster it warms up, releasing even more.
The impact of increasing temperatures is even worse for our city dwellers than for the rest of the population, thanks to the urban heat island effect. In a normal environment, summertime temperatures are kept under control by nighttime cooling. Without energy from the Sun hitting the dark side of the Earth, the planet can only lose heat, and where there are clear skies this can happen surprisingly quickly, providing the biting cold nights of the desert. But something goes wrong with this natural cooling process in a city. The sidewalks and canyonlike streets act as storage heaters, absorbing energy that will keep temperatures relatively high at night.
This is the reason that many of the casualties of the European heat wave of 2003 were in cities. It’s not a sudden, short snap of heat that is a large-scale killer; it’s sustained heat that goes on day after day, and particularly that carries on through the hours of darkness. In the 2003 heat wave, it never got cool enough at night for relief. On August 12, 2003, Paris suffered a nighttime temperature that never went below 25.5 degrees Celsius (78 degrees Fahrenheit), stifling for the majority of city-center households without air-conditioning. Thousands died from the impact of the relentless heat held in place by the city streets. The final European death toll was over thirty-five thousand from the heat and up to fifteen thousand more from the pollution that built up, particularly over cities, in the warm still air.
Europe isn’t alone in suffering the impact of sustained heat. Even though air-conditioning is much more widespread in the United States, hundreds died in Chicago in July 1995 when a heat wave of such sustained ferocity hit the city that on two successive nights the thermometer never dropped below 27 and 29 degrees Celsius (80 and 84 degrees Fahrenheit) respectively. To make matters still worse, warm air rises. The temperature difference between the ground floor and the top floor of a building can be enough to make the difference between comfort and trying to sleep in a virtual oven. Older high-rise buildings without air-conditioning but with relatively good air flows are particularly susceptible to roasting inhabitants on upper floors.
The urban heat island effect is real, and because it is factored out of climate change calculations to avoid confusing the impact from greenhouse gases, it means that cities are likely to fare significantly worse than the predictions of temperature rise given by the climate change models. It has been shown that urban heat islands don’t contribute particularly to the overall warming of the planet (this can be seen because there is no real difference in global temperature between still days in the city, when the effect arises, and windy days)—but that really doesn’t matter to the person in the city apartment. She will still suffer much more than the models predict.
That’s just how things are now. Killer heat waves like the one that struck Chicago in 1995 currently might be expected every twenty years or so, but are likely to be annual occurrences by the end of the century according to our best predictions. It is quite likely, according to today’s forecasts, that a summer with such temperatures would be average by 2040 and could be typical of the coldest summer of the decade by the 2060s. The one mitigating factor that might benefit some northern areas is the slowing down of the thermohaline circulation, the complex system of ocean currents that transport large amounts of heat from the tropics to northern latitudes. The section of this ocean conveyor system that runs in the surface layers of the Atlantic, stopping the northeastern coastline of the United States and northern Europe from being more like Siberia in temperatures, is the Gulf Stream.
There is some evidence that climate change could produce a reduction of strength in this ocean conveyor, because of the impact of freshwater from melting ice sheets. The collapse of the conveyor was the scenario dramatized in the movie The Day After Tomorrow, but this hugely overemphasized both the speed of the change and its impact. Early attempts to model the impact of climate change on the conveyor suggested that it might shut down entirely over this century, but current best estimates predict a decrease in strength of around 25 percent. This will help mitigate the heat impact of climate change in the areas warmed by the Gulf Stream, but will not totally counter it.
As the planet warms up, the delicate balance of coastal life will be devastated. Increasing temperatures inevitably result in sea-level rises. This is not just a case of irritating the coastal wildlife. Many of the world’s great cities from New York to London, and major sections of low-lying countries like Bangladesh, are at risk of destruction by relatively slight increases in sea level. In the storm surge of 1998, 65 percent of Bangladesh was inundated. It would not take much of a rise to make this a permanent state.
Climate change has a double impact on sea level. The headline-grabbing cause is the melting of vast tracts of ice, increasing the volume of water as they plunge into the sea, but there is a more direct effect too. As liquids get warmer they expand, and with the huge volume of water in the oceans this has a significant effect. Just a few degrees’ increase in temperature is enough to push the sea level up several feet from expansion alone. But the melting ice isn’t just featured more often in the news because it looks more dramatic on the TV screen. Though currently expansion is responsible for more rise than melting, the situation with the world’s frozen supplies of water is heading for potential catastrophe.
A very visual illustration of the impact of climate change is the way that ice is disappearing from the North Pole in the summer. Not only is this happening on a large scale, but also Arctic ice is melting much faster than was expected only a few years ago. NASA satellites have revealed that between the winters of 2004 and 2005, three quarters of a million square kilometers (280,000 square miles) of ice that was normally permanently frozen melted: this is without historical precedent. The summer low of 2005 had a polar ice cap with 20 percent less area than that of 1978. At least once in the last few years, the North Pole itself has disappeared. This can happen because the Arctic isn’t a landmass but a floating sheet of ice.
The good news here is that melting Arctic ice doesn’t contribute to an increase in sea levels. Floating ice is already displacing water just as a ship does—if the floating ice melts, the overall water level doesn’t rise. But that doesn’t mean the disappearing Arctic summer ice is a good thing. Not only is it a disaster for wildlife like the polar bear; it also has a direct impact on global warming. Melting ice drives another of the positive-feedback loops that are so common in the climate change world.
As we’ve seen, it’s the Sun’s energy that heats up the world. But not everywhere is equal when it comes to solar warming. The lighter in shade a surface is, the more energy is reflected back out to space (greenhouse gases permitting). The glittering whiteness of an ice sheet is ideal to flash back a good portion of the energy, while the dark waters of the ocean absorb significantly more. Water takes in more heat from sunlight than does ice. So the more the Arctic ice melts, the more energy is absorbed, melting even more ice—positive feedback. And even though the Arctic melting doesn’t contribute directly to sea-level rise, because of this positive feedback, it does contribute further to global warming.
Much more worrying than the Arctic from the point of view of ocean levels is Greenland. If we think of Greenland at all, it tends to be either as a cold little place between Europe and America, or as the first example of dubious advertising, when it was optimistically given a name that implied verdant pastures in an attempt to attract gullible Norse settlers. But in climate terms, the interesting (and potentially frightening) thing about Greenland is its ice sheet.
More accurately, this is no mere ice sheet, but an ice mountain range. The Greenland ice sheet covers over one and a quarter million square kilometers (half a million square miles)—think Texas, California, and Florida combined—and is mostly over 1.6 kilometers (a mile) high. At its thickest, the ice sheet is nearly two kilometers (ten thousand feet) high, half the height of the tallest mountain in the United States, Mount McKinley.
According to NASA, through the 1990s the ice sheet was shrinking by around fifty cubic kilometers (twelve cubic miles) a year. That’s a lot of ice—but it would still take between one thousand and ten thousand years for the Greenland ice sheet to melt completely. There’s no room for sighs of relief, though. As Jim Hansen, director of the Goddard Institute for Space Studies and George Bush’s top in-house climate modeler, graphically put it, “[Greenland’s ice is] on a slippery slope to hell.” By 2000, the rate the ice sheet was melting had accelerated so much that it was already losing vastly more than had been estimated just ten years before. The assumption had been that the ice would gradually melt from the surface downward, trickling its way to the sea as runoff water. But what is actually happening is startlingly different.
Lakes of water are forming on top of the ice sheets. These sheets aren’t always uniformly solid. If there’s a crack in the ice below a lake, the water can rush down, opening up the crevasse further as it flows until it has passed through the entire sheet to its interface with the rock below, where the water flow can eat away from beneath, enabling huge swaths of the ice sheet to float off the land. “[If] the water goes down the crack,” says Richard Alley of Pennsylvania State University, “it doesn’t take 10,000 years [to reach the base of the ice sheet], it takes 10 seconds.” If the entire Greenland ice sheet were to end up in the ocean, it would raise sea levels by seven meters (twenty-three feet). And this is without considering the impact of the melting of the Antarctic ice cap, which is on land, and so also contributes to the rise in sea level.
If the disappearing ice sheets weren’t enough, there is also plenty of evidence that the glaciers around the world are also disappearing with unprecedented speed. Not only do these contribute to sea-level rise (the glaciers of Tajikistan alone hold eight hundred cubic kilometers, or two hundred cubic miles of water), but water from glaciers is essential for the irrigation and drinking water of many countries.
Around 10 percent of northwestern China’s water supply comes from glacier meltwater, for instance, and there are higher percentages elsewhere. Loss of glaciers will have a devastating effect on the economy and social well-being of a number of countries.
Sea-level rises are real and are happening. The Carteret Islands in the South Pacific are already being abandoned, their two thousand inhabitants displaced by the rising ocean. The current best guess suggests the islands will be totally submerged by 2020. Perhaps even more striking is the fate of Tuvalu, another collection of islands in the South Pacific, which forms a nation in its own right. The ten thousand people of Tuvalu are also having to give up their homeland. Before long that country will be a small modern-day equivalent of the mythical Atlantis, disappearing under the waters.
Many of the world’s great cities are on coastlines and would have to be abandoned if sea-level rises reach a fraction of the levels that now seem entirely feasible. The timescale for this is uncertain.
Conservative estimates put the rise by 2100 at half a meter (1.6 feet) but this is without the impact of positive feedback and the unexpected behavior of the Greenland ice sheet. The change in the Arctic perennial ice in 2007 was eighteen times faster than was predicted just ten years ago. By February 2007, sea-level rises were happening twice as fast as was predicted in 2001. Without a transformation in approach to climate change, the five meter (sixteen feet) mark could easily be reached in our lifetime. It would take only an extra 2.7 degrees Celsius (5 degrees Fahrenheit) to take the world to the conditions of the mid Pliocene, when sea levels were 80 feet higher than today. Imagine the New Orleans flood, but massively deeper and never abating. Cities like New York and London would not stand a chance.
Global warming will change the shape of the inhabited world. Over 20 percent of the world’s population lives within thirty kilometers (twenty miles) of the coast, and the number of people living in these at-risk areas is growing at twice the average global rate. Rising seas would mean that most of the U.S. eastern seaboard would have to be abandoned, along with half of Florida, as would low-lying shore areas inhabited by hundreds of millions around the world. And this is not the limit.
As we’ve seen, if the Greenland ice sheet melted, sea levels would rise seven meters (twenty-three feet.) The collapse of the fragile West Antarctic ice sheet would raise levels by up to another six meters (twenty feet), while the whole of the Antarctic ice cap melting would precipitate an extra sixty meter (two-hundred-foot) rise (though this is thought unlikely to happen with temperature rises of less than around 20 degrees Celsius (36 degrees Fahrenheit).
Any figures for sea-level rise also need to include the impact of storm surges. In some areas—around the New England coast, for example—when the storms are at their height there are expected to be sea-level rises of around three feet more than are otherwise predicted, well before the end of the century.
We might be dependent on energy coming in from the Sun, but in terms of matter, the Earth is largely a closed system. Extra droughts in some parts of the world mean more wetness elsewhere. As well as the impact of sea-level rise, some parts of the world can expect increased rainfall, and particularly more heavy storm rain. At the moment the increase is relatively slight—in 2001, the IPCC estimated increased precipitation of between 5 and 10 percent in the Northern Hemisphere over that of the previous hundred years—but there’s more to come.
A significant fear is that global warming will produce more hurricanes like Katrina, the storm that devastated New Orleans and the surrounding coast in 2005. There is no certain evidence that climate change was behind the significant rise in numbers of hurricanes in 2005. As the oceans heat up, it should be easier for hurricanes to form, but there are other factors that come into play, and scientists are reluctant to commit themselves to saying that hurricane formation is on the increase. (This is a reassuring counter to those who think climate change scientists have a hidden agenda and make predictions that show that man-made climate change is responsible for everything that goes wrong with the weather.)
However, even if the increase in numbers of hurricanes in 2005 was a blip, it does seem true that there is a rise in the power of the type of tropical storm that can cause so much damage. Two studies in 2005 both showed that the energy levels of hurricanes is on the rise, with twice as many storms at the highest category 4 and 5 levels as were recorded in the early 1970s. There shouldn’t be a similar effect with powerful tornadoes, though. The really big tornadoes are the product of a very special kind of thunderstorm that doesn’t seem to be influenced by global warming. The smaller, more common tornados may be on the rise, but equally it could be that we are just noticing and reporting them more.
As things get worse, there will be huge disruptions to normal services. Availability of electricity, gasoline, and natural gas will be increasingly restricted as the need to respond to climate change goes critical. At the same time, with stocks of nonrenewable fuels running short and sources of supply becoming more remote, there is a growing opportunity for disruption of supply by natural disasters and terrorists. We could see a regular or even permanent breakdown of these services that are essential for our everyday lives.
Climate change also contributes directly to power outages. Extreme summer temperatures are often responsible for failures of power systems, in part because of the heavy load from air-conditioning, and also when power lines expand and sag, coming into contact with nearby trees and causing blackouts. The dramatic weather systems generated by global warming, including tsunamis and hurricanes, can also wreak havoc with power distribution systems. In December 2006 around 1.5 million homes in the states of Washington and Oregon were blacked out, some for up to a week, as power lines were brought down by howling windstorms and heavy rains. In January 2007, storms in the United Kingdom left 300,000 households without power, many for several days. As the impact of climate change grows, these will become very familiar headlines.
It doesn’t help that the electricity grids of many countries are suffering from overload and age. As systems become more complex, their susceptibility to freak accidents and technical problems grows. In 2003 there were two large-scale electricity blackouts in Western countries. The Northeast blackout plunged a sizable part of Canada and the northeastern United States into darkness, leaving a total of 50 million people without power. The same year, an enormous power outage left the whole of Italy and parts of Switzerland without electricity, causing upheaval for a record 56 million people.
Of course, prediction isn’t an exact science. We can’t forecast the weather accurately for more than a few days out, so it seems optimistic to assume that we can know how the world’s climate will change over tens of years. But while there will always be varying interpretations as long as there are different scientists analyzing the data, the consensus is now hugely in favor of global warming being a real, growing threat.
Some skeptics still point out that the changes so far have been relatively slight, and may not have a huge impact before the end of the century, but they are missing two significant points. First, the impact has begun. If you doubt this, speak to a citizen who has lost his home to unprecedented wildfires or coastal floods. Second, it’s a mistake to assume that the change we see now will continue at such a relatively slow pace.
According to the Australian climate change expert Will Steffen, the world is not usually a place of gentle, slow drift. “Abrupt change seems to be the norm, not the exception,” says Steffen. On twenty-three occasions during the last ice age, for instance, air temperatures went through massive climbs, pushing temperatures up by as much as 15 degrees Celsius (28 degrees Fahrenheit) in around forty years. Around half of the entire warming between the ice ages and interglacial periods that followed—again, changes on the order of a huge 15 degrees Celsius—took place in just ten years.
When the Earth undergoes major change it tends to be in sudden, large steps—this is something that is a relatively recent discovery. Richard Alley, in a report for the U.S. National Academy of Sciences, concluded, “Recent scientific evidence shows that major and widespread climate changes have occurred with startling speed…. This new thinking is little known and scarcely appreciated in the wider community of natural and social scientists and policymakers.” We might be predicting a half meter (1.6-foot) rise in ocean level by 2100 (plus up to another 3 feet of storm surges) based on current, slow, steady rise, but we have to prepare for the possibility of a precipitate increase in temperature that will result in much faster rises in sea level.
Even without such a change, there is a real possibility that current predictions are underanticipating the impact because positive feedback may accelerate the process.
Sometimes, even our attempts to make the environment better can have an ironic and unexpected effect. Aerosols, the scientific term for suspensions of fine particles in the air, typical of much airborne pollution from smog to black smoke, are something that has been cut back significantly as we manage to clean up the air. But aerosols have a helpful effect where global warming is concerned.
Unlike greenhouse gases, they stop the Sun’s energy on the way in, and so have a cooling effect on the ground below. (This is reversed if soot particles, for instance, land from the aerosol on snow, darkening it and reducing reflection.) At the moment aerosols could be reducing the global-warming impact of greenhouse gases by up to half—but this contribution is liable to seep away as we achieve cleaner air.
Everyone from the most adamant denier of human-caused global warming to the greenest of scientists agrees that there’s a lot of uncertainty in the predictions of just how much the effect will be. That’s inevitable because they are dealing with a very complex and only partly understood system. Clouds, for example, have a big impact on the climate. Low clouds have a cooling effect; high clouds trap infrared radiation and warm us up. Different types of clouds make dramatically different contributions to heating or cooling. Attempting to include the feedback produced by clouds into climate models produces a huge range of variation.
This means that though the most likely predictions are still for a one or two degrees Celsius temperature rise within a century, it certainly isn’t impossible to be looking forward to a rise of 8 to 12 degrees Celsius (15 to 20 degrees Fahrenheit)—plenty to make the most dire predictions of the impact of climate change a reality in our lifetimes. The knowledge that there’s uncertainty doesn’t mean we can just cross our fingers and hope the threat goes away. It’s all the more reason to be ready, in case things head for the unpleasant end of the prediction range. And something we know for certain is that even if the predicted averages are true, we will experience worse, because as we have already seen, we don’t experience averages; we live through the peaks and troughs. The damage is caused by the worst the weather can throw at us.
Is total devastation of society as we now know it inevitable from climate change? Thankfully, no. There are three possibilities that could save us.
The first is that it could all be a big mistake. Only twenty-five years ago some scientists were forecasting a return to ice age conditions rather than global warming. The Earth’s weather system is immensely complex. We can’t make detailed weather predictions more than a few days ahead. Beyond that, chaos reigns, as very small changes now can make a big difference to weather in the future. While the urban myth that a butterfly beating its wings on one continent can cause a hurricane on another is not true, chaos theory assures as that we will never be able to give a 100 percent accurate weather forecast over as short a period as a fortnight.
The models used to predict climate change are immensely complex, and subject to a lot of doubt. However, what we can do is take the best picture from a range of forecasts; this is how regular weather forecasts have been improved vastly over the last ten years. And doing that, the prognosis is not good. We can also compare the predictions of the models from a few years ago with what has happened since. So far, practically every model has been too optimistic. Things seem to be getting worse faster than the models predict.
The theory could still be wrong, and that could still save us. We may find that the world’s climate surprises us and takes a whole different turn—but there is no good reason to assume that this is going to happen, and it’s a pretty weak basis to plan the future of the world on.
The second possibility to mitigate the impact of climate change is that we make enough changes to the way we act, reducing greenhouse gas emissions and improving the way we soak up carbon dioxide, methane, and other such gases, to be able to hold off the kind of temperature rises that are currently predicted.
The global financial difficulties of 2008–9 could help a little with this, as there was a slowing down at least of the rate of rise of emissions, though some initiatives to try to overcome the recession, like those encouraging consumers to buy more new cars, would have had a negative effect on the environment.
Perhaps most encouraging are changes to both power generation and transport. On the power-generation side we have seen attempts to clean up power station exhaust gases, an increasing use of “renewable” resources like wind and wave power, and carbon cap-and-trade schemes to encourage organizations and governments to reduce emissions. For cars and trucks we have seen the May 2009 initiative, which promises leaner, greener automobiles in the future, reducing emissions by about one-third by 2016, with the equivalent impact on emissions of taking over 100 million cars off the road.
However, great though these actions are, most climate scientists tell us it’s not enough to cut back on emissions. We need to get to a state where we’re actively taking greenhouse gases out of the atmosphere. This is one of the possibilities for the third wave of fixes for climate change—where science is used to reduce greenhouse gas levels in an active fashion.
The most straightforward approach is to get hold of greenhouse gases and lock them away. This is what trees do—but unfortunately, they’re much too slow at it for a tree-planting program to help with our short- to medium-term climate change problems. (And trees also have the problem that eventually they will die and rot, sending much of the carbon back into the atmosphere.)
We can already scrub the carbon out of the output of power stations, and with time could be able to do this with smaller emitters, like car engines. The carbon dioxide is captured, often by pushing it through solvents that latch onto it, then taken somewhere it can be stored long term. In theory this could just involve pumping CO2 into the deep oceans; but it would gradually escape, and doing this would also contribute to increased acidification of seawater, putting corals and other marine life at risk.
More practical is pumping the gas into underground fissures and disused oil fields. Carbon dioxide is heavier than air, and with appropriate capping, such stores could keep the greenhouse gas locked away for thousands of years.
The trouble with much carbon capture, whether it’s operating on car exhausts, your domestic boiler, or a power station, is that the processes involved can be energy intensive. The exhaust gases are bubbled through a liquid solvent that reacts with the CO2, pulling it into the liquid. You then have to either wastefully and dangerously dispose of the solvent, or use a considerable amount of energy getting the carbon dioxide back out of solution so it can be stored away.
At the University of California, Los Angeles, a location all too familiar with car exhaust gases, scientists have been developing new carbon-capture materials. These zeolitic imidazolate frameworks are collections of tiny crystals that are like traps for CO2. The crystals have pores in them that the carbon dioxide molecules can slip into, but find it difficult to get out of. Because the CO2 has not undergone a chemical reaction, it can be extracted from the crystals by simply dropping the air pressure, leaving the crystals fresh to be reused. The team at UCLA hope that they will be able to test the crystals live in a power station within a year or two.
Others are looking at ways to recycle the carbon from the atmosphere, actively reducing levels of greenhouse gases. There is a technique that can use solar energy to process carbon dioxide and hydrogen to produce hydrocarbons—the basic components of fuel oil and gas. Such carbon recycling could be used to actively reduce carbon levels, or simply to prevent them rising any higher by reusing the hydrocarbons produced this way, rather than burning fossil fuels.
These are the straightforward approaches that science can take, but others are more surprising, or more extreme. There are many suggestions; Here are three samples. One is to move from farming cattle and sheep to raising kangaroos. The reasoning here is that ruminants, grass-feeding mammals, are a major contributor to global warming. As an animal like a cow eats it burps up considerable amounts of methane. Although we don’t hear as much about methane as we do about carbon dioxide, it is a powerful greenhouse gas, as we’ve seen, with around twenty-three times as strong an effect as carbon dioxide. The output of such livestock worldwide contributes 18 percent of all greenhouse gas emissions (in terms of impact)—more than all forms of transport combined. But kangaroos are different. They don’t burp methane.
One possibility is to convert ranches to farming kangaroos, but a more likely approach is to look at what makes kangaroos different from cows and sheep. The kangaroos have a unique kind of bacterium breaking down plant matter in their stomachs. While the bacteria in cow and sheep stomachs pump out the greenhouse gas, the kangaroo equivalent doesn’t. It has been known for some time that a diet rich in clover will partially suppress production of methane, but efforts are also being made to vaccinate against the offending bacterium, or even to try switching cows’ stomachs over to the kangaroo bacteria.
A second idea that has been tried on a small scale is seeding the ocean with iron filings. These encourage the growth of algae, which take carbon dioxide from the atmosphere to build their cells, but (hopefully) don’t release it back when they die, as they sink to the bottom of the ocean. On a large-enough scale an increase in algae levels would have a noticeable impact on greenhouse gas levels, but we just don’t know what the result of dumping so much iron in the sea would have on other organisms, what the effect of a massive increase in algae populations would have on the marine ecology, or even how much the iron would really benefit the algae.
A final idea that is taken seriously in some quarters, despite seeming like a science-fiction fantasy, is to accept that there’s nothing we can do about the level of greenhouse gases, and instead to reduce the level of natural heating of the Earth to compensate for the global warming coming from the greenhouse gases. The Earth’s main source of heat is the Sun. So why not stop some of the sunlight from ever reaching the Earth?
The idea here would be to put an enormous screen in space that would cast a shadow over part of the Earth. This would have the immediate effect of reducing the Sun’s heating power, it’s true, but the cost and complexity of the idea are staggering. Ken Caldeira of the Carnegie Institution for Science of Washington, who has modeled the effects of a solar shield, has said, “We would need to be confident that we would not be creating bigger problems than we are solving. Therefore, it is important both to understand the mess we are in today—how close are we to making irreversible changes, how fast can we alter our energy system—and to understand what might happen should we try to avoid some of the worst outcomes by engineering our climate.”
Scientists approach ideas to tweak the environment back the other way, away from global warming, with real trepidation. We have already demonstrated how good we are at messing up the environment, and we are all too aware of other situations where attempts to play nature at its own game have failed. Often, for instance, when a predator from a different country has been introduced to control a pest it has resulted in an out-of-control population of the predators, lacking the situations that normally keep them in check. The burgeoning population of predators then takes on prey they were never intended to attack, and throws the whole ecosystem out of balance.
Similarly, but on a much larger scale, there is a concern that taking action to reverse the effects of climate change could either produce unwanted side effects, or could go too far the other way, resulting in equally undesirable climate change involving global cooling. There’s another, more subtle danger, too. If we give too much attention at this stage to possible future scientific solutions, we might be tempted not to do anything about cutting our emissions of greenhouse gases, assuming “we can just fix it”—when we have no evidence as yet that such a fix will ever be feasible.
What all now seem to agree on is that we can’t afford to wait until things go horribly wrong before we start to try out different “geoengineering” approaches in small-scale trials. Without doing this, there is little chance of being able to assess the risk involved. Yet those trials that should be enabling us to get a better idea of what’s feasible tend to come up against strong opposition from environmental groups, worried about the effects on local ecosystems where the trial is undertaken. We have to accept that we can’t protect everywhere and everything. If we are to be ready to help reverse climate change, we need some short-term sacrifices to help us along the way.
Once more we see here the huge difficulty of dealing with a global issue, using actions that will have local effects. It’s the inherent problem of that trite mantra “Think globally, act locally.” When we act locally to influence a global issue, like climate change, the result will be not a global change but a variety of local changes. You can’t practically turn down the temperature on the whole planet. Any geoengineering solution is likely to result in some areas dropping more in temperature than others—which will result in winners who get a better climate and losers who might experience drought.
The fact that impacts may vary by location has already come close to generating an international incident. In late 2005, Russian scientist Yuri Izrael attempted to persuade the Russian government to try releasing around 600,000 tons of sulfur particles into the atmosphere. Just as happens after a large volcanic eruption, this would result in reduced sunlight hitting the Earth and a reduction in global warming. However, it would be impossible to ensure that such an action would not cause droughts in some parts of the world.
This wouldn’t necessarily be seen as just an experiment gone wrong. There are United Nations agreements in place prohibiting military (or other hostile) uses of environmental-modification techniques. This ban was brought in after U.S. attempts to use seeded rain to make terrain difficult to cross in the Vietnam War. If such a particle-based sunshade did result in droughts or other weather conditions dangerous to life, particularly in a second country, it’s quite possible it would be considered an act of aggression—though it might be hard to prove the source of the problem. It’s clear that any attempt to engineer our way out of the problems of climate change other than by reducing emissions is fraught with difficulty.
All the initiatives to reduce our impact on the planet, and more like them, are great. And it’s just possible that option one is true, and we don’t have to do anything, because the models are wrong. But I am pessimistic. Even if the Western nations managed to become carbon neutral overnight, aspiring economies like China and India are continuing to increase their greenhouse gas outputs at an alarming rate. They are willing to talk about caps on emissions—but it is only natural that they feel they should be allowed to catch up a bit before they are set the same limits as those of us who already make huge contributions per head to global warming.
The other problem here is that almost all the solutions to climate change require long-term investments—but our whole political system is not set up to support long-term investment. Politicians like to see a quick fix, with plenty of bang for the buck. Climate change investment just can’t be like that.
As we’ve seen, for instance, we need to invest a lot more in nuclear fusion. This technology would enable us to generate power with very low emissions—and without the reliance on rare minerals and the production of large quantities of radioactive waste that go along with traditional fission reactors. However there is only one new experimental fusion reactor planned in the world. The United States, which you might expect to be leading such research, doesn’t have a single experimental fusion reactor, and has reduced its level of funding to the ITER because the project is too long term.
The result of this short-termism is that the political action being taken to reduce the impact of climate change is too little, too late. It will help mitigate the impact—and every little bit helps—but I don’t believe we will see real-world commitment to dealing with climate change until we have a state of near disaster in large parts of the globe.
It’s depressing. I wish it were different. But it isn’t. Green campaigners can jump up and down and predict doom as much as they like, but I think we should instead be thinking as much as possible about how can we mitigate the impact of climate change on human beings and our cities, because we aren’t going to change our ways until things have gotten really bad.
One aspect of climate change that isn’t always noticed is that the phenomenon is not a problem for the Earth. Green publicity material often accuses us of putting the planet at risk. But we aren’t risking the Earth with our actions, not in any way. Our planet will cope just fine. We might end up making it temporarily uninhabitable for many of the living creatures we are familiar with, ourselves included, but to the planet itself there will be little change. What’s more, bacteria will continue to thrive.
We tend to think of ourselves as the dominant species, but bacteria have been around a lot longer, and thrive in a much wider range of environments. In the next chapter we look at the uncomfortable relationship human beings and science have had with these smallest of living things, themselves possible bringers of mass destruction.