THE scene is the top of Mount Everest and a prominent sign advertises the "climate change summit 2040". "Good news," says a suited figure at a podium above a group of attentive delegates. "We finally have a binding international agreement to control greenhouse gases!"
Behind him rears a Noah's Ark crammed with pairs of animals, about to set sail as the rising waters threaten even to engulf the highest point on earth. The cartoon is the take of The Economist, one of the opinion-forming magazines of the business elite, on preparations for what is being billed as the most important gathering of world leaders – in Copenhagen in nine days' time – since the Second World War.
Like many cartoons, it tackles extremes with an undercurrent of the truth. Millions of homes engulfed by flood water, whole countries struck down by famine and crop failure, and supplies of drinking water drying up – these are the outcomes level-headed scientists believe are inevitable unless urgent action is taken to rapidly bring down greenhouse gas emissions across the planet.
It's not just theorising about the future either. That the planet is getting gradually warmer was confirmed last week with a forecast from the Met Office's Hadley Centre that next year will be the hottest on record.
In fact, the forecast for the decade is that at least half of the years up to 2019 will be hotter than the hottest year so far – 1998. That means a 0.55C climb above the average over the decade – and if trends persist it will reach 0.7C by 2015. This is well on the way to the 2C rise on which there is scientific and political consensus that there will be dangerous consequences for the planet and its growing population.
Last month, a survey by the Polar Ocean Physics Group at Cambridge University predicted that, if the Arctic ice sheet continues to melt at the present rate, ships will be able to sail in open water to the North Pole by the summer of 2020. Similar forecasts are also being made for the rapid retreat of the ice in Antarctica, with untold consequences for rising sea levels.
At the same time, an Australian parliamentary report warned that 84billion worth of property was at risk from rising sea levels and more frequent storms in the area of the famous Bondi Beach in Sydney. Each centimetre rise in sea level is expected to carve a metre or more off the Australian shoreline.
Meanwhile, deforestation of the planet's tree resource in regions such as the Amazon basin – a process which accounts for 17 per cent of carbon emissions every year – moves on apace.
The Hadley Centre is convinced that unless there is agreement at Copenhagen that leads to drastic cuts in CO2 emission, the earth is currently on course for a 4C rise in global temperatures as soon as 2060, and 6C by the end of the century.
If temperatures were to rise by 4C, say Hadley scientists, 150 million people living in low-lying areas would be flooded every year. Three-quarters of those would be in Asia, although other parts of the world would also be affected – such as the south-east of England and Scotland's low-lying islands. Crop yields would drop by 40 per cent in parts of the world, forest fires would become common and water supplies will dry up by 70 per cent in parts of Africa, South America and in Mediterranean countries.
The hottest days of the year in Europe would be as much as 8C warmer, meaning that devastating summers – such as that of 2003, which killed tens of thousands of people from heat-related illnesses – would become the norm.
Professor Kevin Anderson, research director at the Tyndall Centre for Climate Change, thinks the prospect of a 4C temperature rise is "terrifying" and that although small pockets of people would probably survive, humanity as a whole would be devastated.
He envisages a battle for land as populations flee to areas where conditions will still provide the resources to survive.
This means, although Scotland may not be directly affected by the severe droughts, floods and famines predicted for some other parts of the world, it will by no means escape their impact.
"People won't sit still in that situation," says Anderson. "When push comes to shove, people don't respond in a nice, neat manner. We turn to other ways of getting what we need, through violence or mass migration."
He adds: "The other thing to remember is that 4C is a global average. It's probably nearer 5C on land, and would be up to 15C in some areas.
"There's no evidence to suggest that humanity can actually survive at this sort of temperature. Small pockets of human beings might continue to exist but I don't consider that to be a success."
However, the urgency of the crisis has not yet translated into significant progress on cutting emissions, even in countries, such as the UK, which are taking the lead.
Data from the Department of Energy and Climate Change shows that, on average, emissions dropped by just 0.95 per cent a year in the UK between 2003 and 2007.
For even a 50 per cent chance of keeping within the 2C limit, all rich nations need to cut emissions by about 40 per cent by 2020, on 1990 levels. This means the 0.95 per cent average needs to rise to at least 3 per cent.
Anderson is pessimistic about whether global temperature rises will be kept below the crucial 2C level.
"My view is that we have to stay below 2C," he says. "That's what we have to do. It's morally incumbent on us to do that but I think we will fail. That is no reason not to do everything we can now."
Dr Vicky Pope, head of climate change advice at the Met Office, explains why sticking within 2C is so challenging.
She says: "A backlog of emissions is already committing us to a 0.6C rise so even if we stopped emissions today it would already go up by that much. Then we have already previously had another 0.8C, so that takes you to 1.4C."
Pope says it is important to remember the human consequences of the statistics.
"I was thinking that, by the time my son is my age, we will have the type of summer we had in 2003 (the third hottest recorded] every second year," she says. "As scientists it's very easy to get a bit detached, but that makes it more personal for me."
Despite a consensus of opinion among the scientific community – from the Met Office to the Royal Society – as well as among governments worldwide, latest polls have highlighted that scepticism about the consequences of climate change is still strong.
A Populus poll suggested just 41 per cent of adults in the UK accept as an established scientific fact that global warming is taking place and that it is largely the result of human activity. Sceptics point out that, since 1998, temperatures have not risen dramatically.
However, Pope says: "Temperatures haven't gone up very much because of natural variability. We had a very strong El Nio (the cyclical meteorological phenomenon involving a substantial warming of the waters of the east Pacific Ocean] in 1998 that led to a very warm year. We haven't had such a strong El Nio since, although we've got one now, so this year is warmer. It is important to look at the long-term trends."
A graph of the trends over the past century shows a steady increase in temperatures since the Industrial Revolution began. The ten warmest years on record have all occurred in the past 12 years.
But is human activity, in particular the burning fossil fuels such as oil, to blame? The Intergovernmental Panel on Climate Change said, in its 2007 assessment, there was 90 per cent certainty humans were responsible.
Dr David Reay, a senior lecturer in climate change at Edinburgh University, says he is as sure as it is possible for a scientist to be that humans are fuelling climate change.
"As a scientist you can never be 100 per cent certain of anything." he says. "There are no absolutes. But in terms of the evidence, I can say it is almost absolute."
He thinks people do not want to believe there is a problem. "We don't want to change our lives radically and that's what climate change means for most of us in the developed world. It's not a message that we particularly want to believe because then we need to do something about it."
Reay believes it is time to stop questioning if climate change is happening, and being caused by humans, and to start finding ways to tackle the problem.
Political leaders must plan now how to cope with the devastation that will be wrought by a 4C rise, while at the same time doing everything possible to keep it below 2C, he argues.
"It doesn't look great for Copenhagen itself delivering the mechanisms that will keep us below that degree of warming," he says. "At the very least it needs to happen early in 2010. We have really got a very limited time. If emissions go on as they are past 2015, then there's absolutely no way we can cut emissions enough to keep them below 2C."
Sceptics pressure scientists over e-mail cover-up
LAST week, they reared their heads across the globe. A loose alliance of climate-change sceptics – including academics, right-wing commentators, a British Lord and an American "shock-jock" – emerged to claim that leaked e-mails written by scientists were evidence of a massive, sustained cover-up.
The e-mails, some written 13 years ago, were retrieved by so far unknown hackers from the computers at the climate-change research unit at East Anglia University and spread rapidly across the internet.
They supposedly showed scientists made snide comments about climate sceptics, and revealed exchanges about how to present the data to make the global warming argument look convincing.
In one e-mail, confirmed by the university as genuine, a scientist jokingly referred to ways of ensuring papers which doubted established climate science did not appear in a report being compiled by a UN body.
Professor Phil Jones, the unit's director, said the suggestion that there was a conspiracy to alter evidence to support a theory of man-made climate change was "absolute rubbish". Nevertheless, the furore gave an unexpected boost to global warming sceptics on both sides of the Atlantic.
What it also did was provide a high-publicity platform for the launch of a new "high-powered" thinktank on climate change by Lord Nigel Lawson, the former Tory Chancellor and global warming critic. Although he denies he is an out-and-out sceptic, he says he is doubtful about the international policy response.
His colleagues include Benny Peiser, a social anthropologist at Liverpool's John Moores University, who has argued concern about climate change has reached "near hysteria" and its trustees include Lord Barnett, a former BBC vice-chairman who voted against the government's Climate Change Bill, and the Bishop of Chester, who has argued there was no consensus among climate-change scientists.
The joy among US climate change contrarians – where the sceptics' arguments have a deeply-entrenched following – about the e-mails row was unrestrained. Republican Senator James Inhofe said: "They cooked the science to make this thing look as if the science was settled, when all the time of course we knew it was not."
Influential radio host Rush Limbaugh was exultant, saying: "I've instinctively known this from the get-go, from 20 years ago."
Their counter arguments are well rehearsed. On evidence that the Earth is getting warmer, they say most long-term data comes from surface weather stations and many of these are in urban centres which have expanded in both size and energy use. When these stations observe a temperature rise, they are simply measuring the "urban heat island effect".
Computer models, the main method of forecasting future climate change, are unreliable, they say. Although the models predict that the lower levels of the atmosphere should be warming faster than the Earth's surface, measurements, say the sceptics, show the opposite. So either this is a failing of the models, or one set of measurements is flawed, or there are holes in our understanding of the science.
The sun, they contend, is the main influencer of climate with historical records showing the Earth's weather patterns have regularly responded to cyclical changes in the sun's energy output.
Meanwhile, data on the size of the polar ice caps – mainly gleaned from satellite images – does not go back far enough to justify claims there is anything exceptional about the apparent shrinkage in Arctic ice over the last few decades.
Water vapour, they say, is the major greenhouse gas while carbon dioxide is relatively unimportant.
Even if it is real, man-made climate change is just one problem among many facing the world, the critics add. They urge that governments and societies should respond proportionately, not pretend that climate is a special case. Some economists believe that a warmer climate would, on balance, improve lives.
But, for now, and certainly for the next month while the scientists and politicians gather in Copenhagen, such arguments are likely to receive short shrift. In Congress, even the most determined opponents of climate-change legislation now frame their arguments in economic terms – the impact on big business if punitive measures area taken – rather than on the science.