Climate Conflict

How Global Warming Threatens Security and What to Do about It

Jeffrey Mazo

• Publisher: Routledge
• Year: 2010
• Topic: Politics & International Relations
• eBook ISBN:
  9781136776939
• Subtopic: Military & Maritime History
• Index: Politics & International Relations

Climate change has been a key factor in the rise and fall of societies and states from prehistory to the recent fighting in the Sudanese state of Darfur. It drives instability, conflict and collapse, but also expansion and reorganisation. The ways cultures have met the climate challenge provide lessons for how the modern world can handle the new security threats posed by unprecedented global warming.

Combining historical precedents with current thinking on state stability, internal conflict and state failure suggests that overcoming cultural, social, political and economic barriers to successful adaptation to a changing climate is the most important factor in avoiding instability in a warming world. The countries which will face increased risk are not necessarily the most fragile, nor those which will suffer the greatest physical effects of climate change.

The global security threat posed by fragile and failing states is well known. It is in the interest of the world's more affluent countries to take measures both to reduce the degree of global warming and climate change and to cushion the impact in those parts of the world where climate change will increase that threat. Neither course of action will be cheap, but inaction will be costlier. Providing the right kind of assistance to the people and places it is most needed is one way of reducing the cost, and understanding how and why different societies respond to climate change is one way of making that possible.

CHAPTER ONE
Global Warming and Climate Change

This book is intended to help answer a simple question: what are the implications of climate change over the next few decades for global security and international relations? While the question may be simple, the answer is not. It touches on such complex and interrelated topics as the historical interaction between human society and climate, the dynamics of state stability and state failure, and the nexus between conflict and resource scarcity. Later chapters will consider examples of historical conflicts and societal failures induced, accelerated or intensified by resource scarcity and environmental factors; assess the relative risks of internal and inter-state conflict in different parts of the world; and discuss the probable consequences of climate-related instability and its implications for security policy of states and transnational organisations.

But these discussions are moot if we do not face significant changes in global and regional climate. How do we know change is occurring? Just how robust are the projections? And how severe will the changes be?

Ice Ages and hockey sticks: climate past and present

The evidence for global warming over the last 150 years is unambiguous, and the evidence that a substantial part of it was due to human activity is almost as certain.¹ The basic concept behind this explanation – the ‘greenhouse effect’ – is straightforward: the Earth’s atmosphere retains heat because carbon dioxide (CO₂), water vapour and some other gases are relatively transparent to sunlight but less so to the frequencies at which energy is re-radiated from the warmed planet – analogous to the way a greenhouse retains heat. The mechanism is well understood; without it, the temperature of the Earth would be below freezing. The theory behind human-induced warming is that human activity – mainly the burning of fossil fuels, but also land-use patterns, farming and other practices – increases the concentration of these greenhouse gases in the atmosphere and thus reduces the amount of energy that is lost to space. In fact, it has been suggested that increasing human population and the spread of agriculture may go some way toward explaining why the last 5,000 years have seen a relatively mild and stable climate rather than a return to Ice Age conditions, as might have been expected on the basis of previous climate cycles.²

The IPCC’s working group on the physical science of climate change concluded in 2007 that it was very likely that the rate of increase in the climate impact of the most important greenhouse gases over the last century was unique compared at least to the last 10,000 years. Variations in greenhouse-gas concentrations over this span, up to the Industrial Revolution, were smaller and mostly due to natural processes. It is unlikely that temporary warming episodes during this period, whether one-off or cyclical, were global in scope rather than limited to particular regions; nor can cyclical elements explain most of the recent warming.³ The most visually compelling demonstration of the historical trends and the uniqueness of the present

Figure 1. The ‘hockey stick’ graph.

The year by year (dark grey curve) and 50-year average (black curve) variations of the average surface temperature of the northern hemisphere for the past 1,000 years as reconstructed from tree rings, corals, ice cores and historical records and calibrated against thermometer data since 1850. The year by year curve since 1850 is based on the instrumental record. The 95% confidence range in the annual data is represented by the grey region.

is the so-called ‘hockey-stick’ graph of reconstructed mean northern hemisphere temperatures over the past millennium (Figure 1). This shows temperatures as relatively constant until the twentieth century (the shaft) with an abrupt, steep rise thereafter (the blade). Although it generated much controversy and criticism after it was published in 1999, precisely because it was so iconic, more recent reconstructions have confirmed it in all important respects and extended it to global coverage and backwards in time.⁴ The graph is striking confirmation that the world is entering a historically unprecedented period of warming and climate instability.⁵

This is not to say that natural variations in climate are not important. Firstly, ‘climate’ by definition is simply weather averaged over at least several decades. The World Meteorological Organisation, for example, uses 30-year averages to identify climate trends.⁶ This is because the difference in weather – temperature or precipitation – from one year to the next can be substantially greater than any underlying climate change. Annual variation thus risks swamping evidence of climate change when looked at over too short a period. Random events such as volcanic eruptions can also have significant short-term cooling effects that can mask long-term trends.

Besides these random or chaotic fluctuations, there are also weather cycles on various time scales which themselves vary in length and severity, so climate must be considered over a period long enough to subsume several such cycles. The most important is the two- to seven-year cycle of fluctuation in the El Niño–Southern Oscillation (ENSO) system, a coupling of global-scale tropical and sub-tropical atmospheric pressure patterns with tropical Pacific surface temperatures. A period of unusually high sea-surface temperatures in the tropical Pacific is called ‘El Niño’ and its colder mirror image is ‘La Niña’. These can have widespread effects on temperature and precipitation patterns, including monsoons, and lead to droughts and floods. What some people argue has been a levelling-off of global warming since 1998 is merely an artefact of a strong El Niño effect in that year, a perfect example of the need to consider climate over periods of several decades. There is no consensus on whether the variations on the scale of centuries or millennia apparent in the original hockey-stick graph and its analogues are cyclical or random.

These sorts of uncertainties have been cited by some policy advocates and policymakers and in the media as reasons to dismiss the potential threat of climate change or to delay unpopular or expensive policy responses.⁷ But the conclusions of the IPCC – that there is no doubt that there has been global warming over the last 100 years, that it accelerated in the second half of the twentieth century and that most of it is very likely due to increased concentrations of man-made greenhouse gases – reflects the consensus of the international scientific community. A study of 928 scientific papers published between 1993 and 2003, designed to test the idea that the IPCC assessment reports (among others) might downplay legitimate dissenting views, concluded that any impression of confusion, disagreement or discord among climate scientists was incorrect.⁸ The very small number of vocal contrarian scientists, not all of them climatologists, does not belie ‘the basic reality [that] anthropogenic global climate change is no longer a subject of scientific debate’.⁹

A more recent survey found that 82% of Earth scientists and 97.4% of climatologists agreed human activity was a significant contributing factor in changing global temperatures. The authors concluded ‘the debate on the authenticity of global warming and the role played by human activity is largely nonexistent among those who understand the nuances and scientific basis of long-term climate processes’.¹⁰ Whether that consensus is correct is a separate question, which cannot be addressed by criticism or falsification of individual studies or data sets. Climate science, and hence the current consensus on anthropogenic global warming, is firmly grounded in a consilience of method, evidence and theory.¹¹

The IPCC is, if anything, prone to underestimate the likely human contribution to global warming and the severity of its impacts. The conservative and consensual assessment process guards against over-reliance on individual studies or personalities on either side of the debate.¹² The robust nature of the methods and conclusions is reflected in the reduction in uncertainty between the IPCC’s Third Assessment Report in 2001 and the Fourth in 2007. For example, the precision and margin of error in the estimates of the rise in global mean temperature in the twentieth century both improved, and a better and lower estimate of the contribution of changes in solar radiation to temperature change in the post-industrial period was also obtained.¹³ More generally, advances in detecting and attributing recent climate change, understanding climate processes, and modelling climate have all led to more robust results not just since 2001 but progressively since the first assessment report in 1990.¹⁴

The controversy over the hockey-stick graph exemplifies this process. Published in 1999, it was used to illustrate the Third Assessment Report and came to be an iconic symbol of the anthropogenic global-warming hypothesis. It thus became a lightning rod for climate-change sceptics, who argued it was based on bad data, was unreliable due to uncertainties associated with the wide range of proxy data (tree rings, pollen deposition, air bubbles in ice, etc.), and was a statistical artefact.¹⁵ It was the focus of two reports commissioned by members of the US Congress in response to the controversy. One, a peer-reviewed report from the National Research Council, generally affirmed its methods and conclusions; the other was sharply critical.¹⁶ Yet each of the criticisms levelled at the hockey stick has been independently rebutted and the original authors of the graph have refined and extended their work.¹⁷ After all this give-and-take it is now widely agreed that the hockey stick is consistent with the overall scientific consensus on past climate trends; it is one of 12 reconstructions compiled in the IPCC Fourth Assessment Report.¹⁸

The progressive refinement of the scientific consensus which can be seen over the course of the four assessments points to another inherently conservative aspect of the IPCC process. The complexity of the process, with hundreds of scientists involved in assessing thousands of published studies, meant the cut-off date for a study to be included was mid-2006, for a report approved in February 2007. The full report approved and published in November 2007 did not, therefore, take into account research published in the preceding year and a half. Although the assessment report is by intent and nature the most comprehensive and reliable summary of the state of knowledge about climate change, by early 2010 nearly four years of further work had been published. All the more recent evidence indicates that, if anything, the IPCC Fourth Assessment Report projections underestimated the amount, rate and impact of anthropogenic climate change.¹⁹

Projections and policy: climate future

In February 2007 the IPCC’s physical sciences working group reported that global warming, which had been averaging 0.13°C per decade over the previous 50 years, would continue over the next two decades at a rate of around 0.2°C per decade, regardless of which set of assumptions were taken for trends in the greenhouse-gas emissions responsible for the rise.²⁰ Even if the increase in concentrations of greenhouse gases in the atmosphere could be stopped entirely, warming would still continue at about half that rate. The best estimates of temperature change by the end of the century ranged from 1.8–4.0°C depending on the scenario, with likely ranges running from 1.1–2.9°C to 2.4–6.4°C. (These ranges exemplify the uncertainties in climate projection.) Even with concentrations held constant, the world faces a rise of 0.6°C (0.3–0.9°C) over this period. To put these figures in context, the globe warmed by 0.74°C (0.56–0.92°C) between 1906 and 2005, mostly during the last 50 years. Further increases of 1–2°C above 1990–2000 levels would have a net negative effect on most people.²¹ Climate change will not be uniform, but will vary from region to region.²²

The terms ‘global warming’ and ‘climate change’ are often used interchangeably. The choice of one term over the other can be politically motivated, although advocates on opposite sides of a policy issue will often use the same vocabulary for opposite reasons. But in fact the terms do allow some important distinctions. ‘Global warming’ is simple shorthand for the observed increase in the average annual temperature of the planet over the last two centuries or so, and its projection into the future. This increase has been around 0.76°C (0.57–0.95°C) since 1850–1899 – the earliest period for which direct measurements are available. This may seem ludicrously small compared to the differences in temperature we experience every day, between day and night, across seasons or between different regions even within a single country. This is because average values obscure more complex and subtle changes in precisely such measures. ‘Climate change’ covers these aspects, as well as those not related to temperature, such as precipitation, climate stability and frequency of extreme events.

The use of the term ‘global warming’, moreover, obscures one of the most important features of climate change. Climate change has been and will continue to be far from uniform around the world: it shows great variation from region to region. The anticipated climate change in any particular part of the globe is driven not just by average warming but by changes in global ocean and atmospheric circulation patterns that directly impact climate by, for example, strengthening or weakening monsoons. Cyclical patterns like ENSO can also be strengthened or weakened, and more persistent geographic shifts in climate zones can occur, as they have in the past. The most basic difference is between land and water: continents will warm more than seas, and continental interiors will warm more than areas close to the ocean. The amount of warming, too, tends to vary by latitude, with higher latitudes projected to warm more, and according to factors such as the presence of large mountain ranges, which also affect precipitation.²³

Precipitation patterns in particular will vary significantly, in terms of both total amount and the chronological distribution and intensity of precipitation events. Although, overall, precipitation is expected to increase with global warming, within this global average some regions could see declines. For example, for projections to the end of the century under one scenario, the best estimate for global temperature increase is 2.8°C.²⁴ However, the median annual temperature increase ranges from 1.8–4.9°C depending on region. The projected increase is 2.5°C or less for Southeast Asia, southern South America, and the small island states of the Caribbean, tropical nort...

Table of contents

• Contents
• ACKNOLEDGEMENTS
• INTRODUCTION
• CHAPTER ONE Global Warming and Climate Change
• CHAPTER TWO Climate and History
• CHAPTER THREE Darfur: The First Modern Climate-Change Conflict
• CHAPTER FOUR Conflict, Instability and State Failure: The Climate Factor
• CHAPTER FIVE Climate Change and Security
• CHAPTER SIX Conclusion
• GLOSSARY
• NOTES