Excerpt from The Green Travel Guide, published by White Ladder during 2008. (Written together with Christine Smith.)
Chapter Two. Travel and climate change – the truth
Facts you need to know:
Global warming is a fact not a theory – if it wasn’t for global warming the Earth would be uninhabitable.
For centuries the degree of global warming was relatively stable.
But in the last few decades global warming has increased – and at an accelerating rate.
How far you travel on holiday could affect global warming.
Where you go on holiday will be impacted by global warming.
As we saw in the last chapter, the part of your holiday that’s likely to consume the most energy is getting to and from the destination. Why does that matter? Because, in the first place, when you burn fossil fuels you’re depleting a resource that’s in increasingly short supply. And, secondly, burning fossil fuels also creates pollution.
There’s been a huge amount of controversy about the role of pollution in climate change. Here we’re not going to give you opinions. We’ll just give you the facts and you can decide for yourself.
Is there global warming?
The first thing to sort out is whether or not there actually is any global warming so far. Well, as the table below shows, the five warmest years in more than a century have all occurred during the past decade or so.
The five warmest years worldwide since the 1890’s
Of course, that doesn’t tell us what caused the warming. And it certainly doesn’t prove that the warming will continue. But, unless you dispute the figures, it tells us that there has been a period of warming.
What kind of temperature increases are we talking about? Well, the Intergovernmental Panel on Climate Change (IPCC), created in 1988 by the World Meteorological Organization and the United Nations Environmental Programme, found that global average surface temperatures increased by 0.6 degrees C (plus or minus 0.2 degrees C) over the 20th century. That may not sound a lot but, as we’ll see in a moment, it’s highly significant. But the most ominous thing is that over the past 30 years the pace of warming has accelerated.
Aren’t these temperature measurements inflated by “urban heat islands”?
Scientists can make mistakes just like anybody else but that one is just too obvious. The higher temperatures in cities – your so-called urban heat islands – are discounted when the average surface temperatures are calculated.
It’s important to recognise that these are average figures. Some parts of the globe have warmed more and some have warmed less. Over the past 50 years the largest annual and seasonal increases have occurred in high latitudes, especially Alaska, Siberia and the Antarctic Peninsular.
The second warmest year of the past century – 1998 – occurred when there was a strong El NiÃ±o effect. So that might explain that one. But the warmest year so far happened without the help of El Nieto.
What’s El Nieto?
El Nieto is a regular though infrequent climate quirk which increases the surface temperature of the tropical Pacific. Amazingly, this in turn can lead to wind changes throughout the whole world causing hurricanes, flooding and drought.
The opposite is La Nieta, a less common cooling effect which, while it reduces extreme events in the Gulf of Mexico and the Caribbean, can nevertheless lead to increases in tropical storms and hurricanes in the Eastern Pacific.
Is there any link with global warming? The jury is out on that one. But it’s for sure that the droughts caused by El NiÃ±o lead to brush and forest fires (especially in Australia). In turn, those fires both produce carbon dioxide and reduce the planet’s ability to absorb it.
Will the global warming continue?
The only way to predict the future is to use climate models. Different scientists use slightly different models and come up with slightly different results. The range of mainstream predictions at the moment is that temperatures will increase by between 1.4 degrees C and 5.8 degrees C over the next hundred years – that’s roughly two to ten times more than in the past hundred years.
How good are these climate models?
At the moment the perfect model doesn’t exist, but the scientists realise that, of course. That’s why they always give a range of possible error with their predictions.
A good model would be one that if you fed into it the climate data for, say, 1990 and then asked it to forecast 10 years ahead, it would come up with exactly the figures that we know with hindsight were the correct ones for 2000. Which is exactly what Doug Smith and his colleagues did at the Hadley Centre in Exeter, England. So the Hadley Centre has a pretty good forecasting programme.
And what it tells us is this. The years 2008 and 2009 will be relatively cool (like 2007) but between 2010 and 2014 three years will set new records.
Won’t global dimming counteract global warming?
Gerald Stanhill designed irrigation systems in Israel. Not just any old irrigation systems. His systems delivered the perfect amount of water. Enough for the plants to thrive but not one wasteful drop more. And for that he needed to know exactly how much sunlight fell on the plants. In the first few years he noted nothing odd but as the years turned to decades he began to notice something strange. The amount of sunlight falling on Israel was going down. Together with a colleague, Shaptai Cohen, he published a scientific paper describing the discovery of what they called ‘global dimming.’
Global dimming is one of the great unknowns in the climate debate. The problem is we just don’t have enough radiometers – light measuring devices – set up around the world to know exactly what’s going on. But where there are reliable records they all point to a 10 per cent reduction in the amount of sunlight reaching the Earth. And that’s in just 30 years!
What’s going on? One plausible theory is that pollution is putting aerosols into the atmosphere, which reflect sunlight back into space. That fits with some of the data but not all of it. For example, it would explain why temperatures didn’t rise as much as they should have done during the 1950s, 60s and 70s. But China is a country that does have solar radiation figures and they show a ‘global brightening’ since the mid-1980s, despite China’s vastly increased air pollution.
So the picture is far from clear. But whatever is going on with global dimming, global warming is carrying on regardless.
Okay, but where’s the evidence that global warming is due to the greenhouse effect?
When we first heard about global warming we asked the same question as everybody else. Is this for real? Then we discovered something that puts the whole subject into perspective. The greenhouse effect is definitely not a theory. It’s not new. And contrary to what you may have heard, it’s not disputed by any scientist at all. The fact is the greenhouse effect has existed for eons and without it the average temperature of the planet would now be minus 18 degrees C. In other words, about 33 degrees C lower than it is now. We wouldn’t be writing this and you wouldn’t be reading it, if it wasn’t for the greenhouse effect. None of us would exist. Thank goodness for it.
The greenhouse effect works like this. The main constituents of the atmosphere – nitrogen and oxygen – are transparent to heat radiation. If they were the only gases in the atmosphere, the heat generated on Earth by the sun would be radiated back into space. But, fortunately, there are additional gases present in small quantities – water vapour, carbon dioxide, methane and others – which can trap some of the heat. And it’s lucky for us that they do. You’ve probably noticed the effect for yourself. When the sky is clear the night-time temperature falls more than when it’s cloudy. That’s because the clouds – water vapour – are exerting their greenhouse effect.
All this has happened naturally – that’s to say, without any man-made intervention – which is why scientists call it the natural greenhouse effect. As we stress, it’s not a theory. The ability of carbon dioxide, methane and various other gases to absorb long-wavelength radiant heat energy emitted by the Earth has been demonstrated in practical experiments.
Essentially, greenhouse gases operate like insulation round the Earth. Think of it like this. When you turn on a heater in your home the room warms up. When you turn it off the room stays warm for a time because the walls stop the heat escaping. That’s the same as the greenhouse effect on the planet. Now imagine taking the heater out into the garden on a cold night. Stand in front of it and you’re warm. But the moment you switch it off you’re instantly cold. Why? No insulation.
We can see the mechanism at work all around us in the universe. To give you an idea, the atmosphere of Venus, which is almost exactly the same size as the Earth, is composed almost entirely of carbon dioxide. So if the global warming theory is correct Venus should be an extremely hot place. And, you know what…it is. It’s 460 degrees C, in fact. No life, as we know it, could exist there.
Aha! say the sceptics. You’re overlooking the fact that Venus is much nearer the sun than the Earth is. At first sight, it seems like a reasonable point to make. But then take a look at Mercury. Mercury is very roughly half as far from the sun as Venus and so if distance from the sun were the only factor at work it should be hotter still. But the temperature of Mercury is very curious. On the sunny side, yes, it’s hot but not as hot as Venus. It’s 427 degrees C. While on the night-time side the temperature is…wait for it… minus 173 degrees C. Why? You’ve guessed it. Mercury has no carbon dioxide. In fact, it has no atmosphere at all. So there’s nothing to trap the sun’s heat. Where it shines, the planet rapidly heats up. Where it doesn’t shine, the planet rapidly cools down. Comparing Venus and Mercury gives a pretty clear picture of carbon dioxide at work.
Your own greenhouse gas experiment
If you’ve never particularly noticed the effect of night-time cloud cover then now is a good time to do a little experiment of your own. All you need are:
An atmospheric thermometer with maximum and minimum readings
Set out your notebook like this:
Day 1 Day 2 Day 3 Day 4 Day 5……..
Maximum daytime temperature
Minimum night-time temperature
Night-time cloud cover
(for example, none, light, thick etc)
You’ll find that when the skies are clear at night the temperature difference between night and day is generally greater than when there’s thick cloud at night. You’ll have proved for yourself that the greenhouse effect exists. In this case it’s due to water vapour. But carbon dioxide, methane and certain other gases work in the same way.
So far so straightforward. The pre-industrial concentration of carbon dioxide in the Earth’s atmosphere was 280 parts per million (ppm). Today the level stands at 380 ppm. Those who dispute human influence on global warming have got to explain why carbon dioxide does warm the planet at concentrations up to 280 ppm but exerts no further warming effect at higher concentrations. That’s a difficult trick to pull off. It would be the same as trying to argue that one centimetre of insulation in your home keeps the temperature up but two centimetres doesn’t make any difference. It’s just not logical.
But how do we know carbon dioxide is responsible?
So far we’ve concentrated on carbon dioxide but, yes, there are other gases that trap heat. Here are the main ones, compared with carbon dioxide:
Lifetime in the Pre-industrial Concentration
Atmosphere concentration in 1998
Carbon dioxide 5 – 200 yrs 280 ppm 365 ppm
Methane 12 yrs 700 ppb 1,745 ppb
Nitrous Oxide 114 yrs 270 ppb 314 ppb
Chlorofuorocarbon-11 45 yrs 0 268 ppt
Hydrofluorcarbon-23 260 yrs 0 14 ppt
Perfluoromethane 50,000 yrs 40 ppt 80 ppt
Ppm = parts per million; ppb = parts per billion; ppt = parts per trillion.
As you can see, carbon dioxide is the most abundant greenhouse gas but it’s not, in fact, the most powerful. If its global warming potential is given a value of 1 then, over a 20 year period, methane is 62 times stronger and over the course of a century nitrous oxide is almost 300 times more powerful. However, because of its abundance, carbon dioxide is the single largest contributor to what scientists call radiative forcing – the process by which human activities intensify the natural greenhouse effect.
The most frightening figures are those in the first column. Even if all man-made emissions are stopped now – which would be impossible – the planet would still heat up because it takes years, and even centuries, for these gases to disappear from the air.
If that’s right, why are so many people unconvinced?
In 2007 315 financial institutions together controlling around $40 trillion in funds sent out a joint letter. It was addressed to the 2,400 largest firms in the world. Basically, the institutions wanted a straight answer to a very important question: What are you doing about global warming?
Now, the heads of these financial institutions are, no doubt, very nice, concerned people. But they don’t normally waste their professional time on altruistic deeds or wild goose chases. Their job is to make money. So why did they put their names to the letter? Two reasons. Firstly, they believe man-made global warming is a reality. Secondly, they believe it could seriously impact their investments.
Of course, that itself doesn’t make them right, and we’ll be looking at some of the opposite scientific arguments in a minute. But that’s the measure of how seriously the business community now takes global warming.
What about sunspots?
Sunspots show cyclical patterns of 11, 90 and 180 years. Scientists have known about them for a long time and during the so-called Little Ice Age (1650 – 1750) very little sunspot activity was observed. So there could be a connection between the Earth’s climate and sunspots. But when you look at a graph of the Earth’s surface temperature over the past thousand years the Little Ice Age appears quite trivial when compared with the much greater temperature change we’re now experiencing. Sunspots just can’t explain it.
What about changes in the Earth’s orbit round the sun?
This is the so-called Milankovitch Theory. It proposes that cyclical variations in three of the Earth’s orbital characteristics affect climate. The first is eccentricity, that’s to say, the change from an elliptical orbit to a more circular one. But that takes place over a period of 100,000 years. The second is the wobbling of the Earth on its polar axis, a phenomenon more technically known as the precession of the equinox. But that cycle takes place over 26,000 years. It means that in 13,000 years from now, the northern hemisphere will experience greater seasonal variations – hotter summers but colder winters.
Then there are changes in the Earth’s tilt or obliquity. But that cycle is 41,000 years.
So although all of these things undoubtedly affect the Earth’s climate, none of them can explain the rapid increase in global temperatures over a timescale of a few decades.
But aren’t there scientists who disagree?
George Monbiot has made an exhaustive study of this subject in his book Heat and we recommend that you read it. To summarise Mr Monbiot, many of the contrary opinions emanated from a body called the Science and Environmental Policy Project (SEPP) run by Dr S. Fred Singer. They were extensively quoted on the internet and then requoted by many journalists. But according to Mr Monbiot, SEPP was funded by ExxonMobil, the oil company, as were more than 100 other organizations, all following the line that ‘the science is contradictory, the scientists are split, environmentalists are charlatans…’
It seems to have been a very successful campaign of misinformation. Against Dr Singer and the small number of other contrary voices are ranged, for example, the many scientists whose research has been carefully examined by the Intergovernmental Panel on Climate Change (IPCC).
The IPCC was set up by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) and it’s important to stress that it doesn’t carry out its own research but, rather, reviews and amalgamates the research by scientists all over the world. So it’s not just one voice by the combined voices of thousands of scientists from every part of the globe.
It’s worth pointing out that the IPCC won a Nobel Prize in 2007 for ‘efforts to build up and disseminate greater knowledge about man-made climate change.’ You can read the details of the IPCC findings at:
So what’s the impact likely to be?
The following changes won’t happen instantly a certain temperature increase is reached. The melting of glaciers and icecaps, for example, is a process that will take many years. But the changes will then be inevitable.
One degree of global warming
What it will mean for the planet
One degree would take us back to the way the Earth was six thousand years ago. In the Western USA it would be worse than the dustbowl years of the 1930s, when thousands of American farmers and their families became refugees. By 2100 it would mean there would be no fresh water anywhere on one-third of the world’s land surface. The melting of sea ice will accelerate, sea temperatures will rise, and hurricanes will increase in frequency and intensity.
What it will mean for your holiday
You might prefer to avoid destinations such as the south of Spain, Greece and Turkey in high summer – temperatures well into the 40s C (over 100 degrees F) will be the norm. You might have to forego low-lying destinations such as the Maldives – they won’t exist any more. And you’ll need a gondola to navigate not just the canals but also the streets of Venice.
Two degrees of global warming
What it will mean for the planet
Coastal towns – Manhattan, London, Bombay, Shanghai, to name a few – will be flooded. You’ll no longer need snowshoes for a visit to Greenland – it’ll live up to its name and be green, not white. And India will be a drought zone.
What it will mean for your holiday
You certainly won’t be taking Mediterranean summer holidays any more. Apart from the fact that it will be too hot, all the existing coastal infrastructure will become submerged. The Caribbean in the hurricane season will be a no-go area. And you can forget skiing.
Three degrees of global warming
What it will mean for the planet
The last time the planet was this hot was about three million years ago. Sea levels were then a staggering 25 metres higher than today, so today’s coastal towns just won’t exist and hundreds of millions of people will be displaced.
What it will mean for your holiday
You certainly won’t need to leave the UK to get a suntan, to put it mildly. In fact, summer temperatures will consistently be in the mid-40s C (over 100 F). Nor will you need to travel to Greece to enjoy a collection of islands because that’s what Britain will have become. Australia will no longer be on the itinerary, nor the game parks of Kenya or Tanzania. You’ll probably be heading, instead, for the Arctic.
All right, but it’s going to take a long time and by then we’ll be able to go to another planet, won’t we?
No to both questions. Sea levels won’t rise 25 metres on the very first day that global average temperatures reach three degrees higher. But life could become very unpleasant as early as 2050 and we’re talking in terms of sea levels rising a metre in the next century.
As to other planets, there are none in the solar system that are capable of supporting us, even if we had the technology. We’ve already ruled out Venus and Mercury. Mars looks more promising. Life on its equator wouldn’t be too bad, varying between minus 20 degrees C and plus 30 degrees C. But as to the rest of it, well, the average surface temperature is minus 65 degrees C. So not much room there. And all the other planets are colder still.
Earth alone in our solar system has a climate that can support us. And, in fact, when you think about it, only a small fraction of the Earth is actually comfortable. Seven-tenths of the planet is covered by water so we can’t very easily live there. Of the remainder, vast areas are either too cold, too icy, too hot, too desertified, too steep, too high or have too great a flood risk to make congenial places for humans to live. In other words, in the whole of the solar system there’s just between one and four acres per person, to live on and to supply all our needs – houses, gardens, farmland, roads, railway lines, factories, shops and all the rest. If that were to be reduced because of climate change it would be a catastrophe.
What sort of cuts in carbon dioxide emissions will we have to make to avoid all this?
As mentioned in the previous chapter, some experts are calling for cuts of 90 per cent. Which, with present technology, would mean things like an end to flying and almost completely banning private cars.
Is there another way?
This is where things get really controversial. We believe there is. For two reasons. Firstly, because the amount of carbon dioxide already in the atmosphere will mean global temperatures going up by between a half and one degree Centigrade. And as we’ve just seen, that will already be pretty serious. That scenario, remember, is with the carbon dioxide we already have. And more is being added to it every second. If we don’t like the one degree scenario – let alone anything worse – we have to use our ingenuity, either to extract the carbon dioxide from the atmosphere or to offset its impact.
That brings us to the second reason. An alternative just has to be found. Because, no matter how sensible it might be from the environmental viewpoint (and, indeed, the personal survival viewpoint) to ban planes and severely restrict cars and so forth, it isn’t going to happen. It just isn’t. By the time we all accept the case for such severe changes in lifestyles it will be far too late.
We might be accused of wishful thinking but necessity has always been the mother of invention and it will be again. The race is on for new technologies.
One approach is to reflect some of the sun’s heat back into space. How? Well, snow is pretty good at it. Which is why the loss of sea ice, glaciers and snow in winter is so serious. It’s not just a question of no more skiing. All those chocolate-box snowscapes were actually helping maintain the planet at an agreeable temperature.
A technical way of achieving a similar result would be to fire tiny drops of seawater into the sky to create highly-reflective, low-lying marine cloud. Stephen Salter at the University of Edinburgh has designed an unmanned ‘ship’ to do just that, using nothing more than wind power. According to his calculations, 50 such ships, costing a few million pounds each, would take care of one year’s carbon dioxide emissions. What they’d do to the weather isn’t clear but building an experimental ship sounds like a good idea. And urgently.
Another idea is to spread tiny particles in the upper atmosphere. This already happens to some extent both naturally and unnaturally. The natural way is a volcano – like Mount Pinatubo – whose 1991 eruption caused measurable global cooling. The unnatural way is sulphate pollution from industry. Nobody wants pollution and in the last decade or so clean air legislation has reduced it. So it would be ironic if another form of pollution turned out to be part of the solution.
The most expensive and exotic idea so far is to launch tiny, reflective spacecraft -no more than a metre across – to the inner Lagrange point. That’s a spot between the Earth and the sun where the forces should hold a spacecraft locked in position. Unfortunately, several million would be needed at a cost in the trillions of dollars.
Other more easily attainable ways of reflecting sunlight could include reflectors in the desert (possibly combined with solar cells) and, quite simply, painting the roof of every house and building white. Los Angeles is already seriously considering this, not just to help slow global warming but to reduce local warming – big cities get hotter than the countryside.
But perhaps the most logical approach is to remove the excess carbon dioxide from the atmosphere. After all, we put it in. So we should be able to find a way to take it out again. Algae are good at scrubbing carbon dioxide and could be encouraged to do more. One idea, already being tested, is to seed the oceans with iron, which stimulates the growth of algae. Another is to float 100 metre tubes vertically in the water, equipped with non-return valves. The movement of the tubes by the waves would draw cooler water up and improve conditions for the algae, which are now suffering in today’s warmer oceans.
Yet another idea is to build structures looking rather like cooling towers. Upward-flowing air inside would pass through a cloud of sodium hydroxide, causing the carbon dioxide to fall to the bottom.
Have we reached peak oil?
Once we’ve passed peak oil so production levels will decline…and decline…and decline. Which means carbon dioxide emissions from that source will also inevitably go down.
In 2007 demand was around 86 million barrels a day and still going up, largely due to China and the other emerging economies.
But have we now reached peak oil? And will we all be forced to change our ways, whether we like it or not? Well, at the time of writing, oil prices have set new records and oil companies, big and small, are out there scouring the planet for new fields. But they’re not finding them. New wells in existing fields, yes, but completely new fields are rare.
As a ball park figure, the output of an average oil field declines almost five per cent a year. US production, for example, is already past its peak. That was back in 1973.
Some experts say we’re at the global peak now. Some say we’re already past it. The most optimistic put it at 50 years.
The strange case of Robert Preston
It was one of the most astonishing cases in legal history. Robert Preston had been doing nothing more than standing in the high street of the small country town where he lived when a man approached, raised his arm and fired a shot. What happened next has been the subject of controversy ever since. Onlookers described seeing Mr Preston clutch his chest and fall to the ground. While an off-duty nurse tended him, three courageous bystanders heroically decided to have-a-go. But, the curious fact is, the gunman offered them no resistance and when the police arrived he even laughed.
Mr Preston died and the gunman was put on trial for murder. His defence was unusual. He didn’t deny firing the gun. He simply argued that Mr Preston had died for a completely different reason. Mr Preston, so the gunman claimed, had died of a heart attack before the bullet hit him. Therefore, the shooting had nothing to do with it. It was merely a coincidence. He even called two eminent scientists in his defence and they confirmed the gunman’s case. Meanwhile, although the forensic scientists called by the prosecution were initially adamant that Mr Preston died from the bullet, under fierce cross-examination, they all had to admit they couldn’t prove beyond doubt that Mr Jenkins hadn’t died of a heart attack before the bullet smashed into his chest. And, indeed, it emerged he had suffered heart attacks before.
When the jury came back the foreman, who was in fact the editor of a respected newspaper, pronounced: “Not guilty!” The courtroom was in an uproar. The judge then handed down his now famous ruling. Subversive forces, he said, wanted us all to believe guns were dangerous when there was insufficient evidence. Until such time as it could be conclusively proven that people who had been shot had not died of prior heart attacks, it would be permissible for anybody to shoot anybody else.
You think we’re making that up, don’t you? But we’re not. All we’ve done is change the names. Instead of Robert Preston read “the atmosphere of the Earth.” And instead of the bullet read “man-made carbon dioxide”. Otherwise the scenario is the same.