of methane and carbon dioxide, meaning that global warming spirals upward.
Five degrees
Earth hotter than at any time for 55 million years.
Desert belts expand from the subtropics into temperate regions. Civilization collapses as humanity is unable to cope.
Methane hydrate is released from underneath the oceans, sparking tsunamis in coastal regions and pushing global warming into an unstoppable spiral.
Much of the world is uninhabitable.
Six degrees
Mass extinction scenario: the end-Permian mass extinction 251 million years ago was associated with six degrees of warming, and wiped out 90% of life on earth. No one is sure what happened, but a combination of volcanic CO2 releases and methane hydrates may have been the cause. (This was much worse than the end-Cretaceous mass extinction, 65 million years ago, which wiped out the dinosaurs.)
Huge firestorms sweep the planet as methane hydrate fireballs ignite.
Seas turn anoxic (without oxygen) and release poisonous hydrogen sulphide.
Humanity’s very survival as a species is in question.
(Note: this list is a very potted summary of a book called Six Degrees, also by Mark Lynas, published in March 2007 by Fourth Estate.)
If none of this sounds very appealing, then you’re reading the right book. This guide aims to show how you can help to avoid these disasters by reducing your personal contribution to global warming. The table on page 29 indicates the changes that are needed on a global scale to avoid each successive degree of global warming.
TWO DEGREES – THE TARGET
You might have noticed from the discussion above that there are certain ‘tipping points’, after which global warming could become unstoppable. Several of these could be reached if temperatures cross the two degrees threshold, because at this level of warming, greenhouse gas releases from the soils and forests could take on their own unstoppable momentum. That would leave humanity powerless to intervene as our planet began cooking. For this reason, many environmental groups and even governments (including the European Union) have begun to fix on the target of two degrees as a danger level that must not be crossed.
The graph on pages 20-1 shows how high temperatures might rise, in comparison to their levels over the last millennium. Note that the two degrees danger line is well below most of the scenarios for temperature change by 2100.
Staying below two degrees with any level of certainty would require global greenhouse gas emissions to peak by 2015 – quite a tall order, especially given the reluctance of many people and nations to face up to the scale and urgency of the problem. However, even if we overshoot this target, any cuts we do make will still help to slow the rate of change. At the very least, this gives human societies and natural species more time to adapt to rising sea levels, harsher weather and shifting climate zones. So it’s not too late to act, but time is rapidly running out, and the era of procrastination is definitely over.
WHAT IS A CARBON FOOTPRINT?
In short, a carbon footprint is a measure of an individual’s contribution to global warming. Almost every energy-consuming activity we engage in has a carbon cost. Sometimes this carbon expenditure is obvious, such as the exhaust belching out of the back of a ‘Chelsea tractor’ 4x4 on the morning school run. At other times it is less obvious, like the ‘food miles’ inherent in imported produce we might buy at a
supermarket. Your carbon footprint will be impossible to pin down exactly, but getting a general idea will help you to reduce your impact on the climate.
Many people (especially those who work in the fossil fuel industries) suggest that getting to grips with climate change will require terrible wartime-style sacrifices, where we all have to sit shivering around a single candle all winter while wearing five jumpers. But actually, reducing your carbon footprint is surprisingly easy, and not only does it not require hair-shirt sacrifices, it will probably increase your quality of life substantially. Cycling or walking rather than driving, eating local produce rather than supermarket junk and having some solar panels on your roof are hardly going to bring your world to an end. Sandals are, of course, optional.
Some comparisons between countries
We’ve all heard the cliché that Americans are greedy polluters, while Africans have a much lighter impact on the planet. But is it true? Different countries have radically different carbon impacts, depending on their pattern of development and the lifestyles of their citizens. America is in fact quite near the top of the global warming polluters’ league table, with almost 20 tonnes of carbon dioxide emitted per person. But the United Arab Emirates and Qatar, with their oil-rich economies, have twice the per-person impact of the US.
European countries tend to have about half the per capita emissions of the United States: the UK, for example, has 9.4 tonnes to America’s 19.8. So our carbon footprints are only half as large as those of the average American. But they are still big on a global scale – each Brit produces ten times as much CO2 as each Vietnamese. Global warming naysayers are fond of pointing the finger at China and India, as if they are to blame for the problem. But China’s emissions are only 3.2 tonnes per person while India’s are 1.2 tonnes per person.
Africa is often forgotten altogether, and African per capita emissions are indeed minuscule in comparison to ours. Tanzania’s people emit only 0.1 tonnes each – one hundredth of our per-person total – while Chad
Tip: At the moment it is not possible to say when each degree of temperature rise will be reached – because that depends on decisions we have all yet to make. If we continue to increase carbon emissions, we might reach two degrees as soon as 2030. But if we cut back our greenhouse gas emissions sharply, we may avoid two degrees altogether.
and Mali have emissions so low that they are not even measurable. It is interesting to note how African people are often blamed for environmental damage such as deforestation and the hunting of wildlife, but in global warming terms they are greener than green. The only exception is highly developed South Africa, which, with 7.8 tonnes per person, is nearly up to European standards. Anyone who has travelled around Johannesburg’s traffic-choked motorways will quickly understand why.
Of course, because developing countries have such huge populations, their global impact is considerable. China is the second-largest emitter in the world (after the United States, of course), with 14.5% of the world total. India is number four in the list, with 5.1% of the total, while the UK is seventh, with 2.3%. Because of their large total impact and the rapid scale of their economic development, it is clearly true that global
Tip: The UK often claims to be doing most towards bringing down greenhouse gas emissions, and the government projects that we are on target under the Kyoto Protocol to meet our reduction of 12.5% by 2012. However, a tougher government target of 20% reductions by that date has now been quietly dropped, and emissions are currently rising again – thanks mostly to the general public driving and consuming more.
