Climate Data Sets Showing Global Temperature Increase since 1850 (MLOST is the Merged Land-Ocean Surface Temperature Analysis produced by the National Climatic Center of the National Oceanic and Atmospheric Administration; HadCRUT4 is produced by the Hadley Centre of the UK Met Office and the Climatic Research Unit of the University of East Anglia; and GISS is produced by the Goddard Institute of Space Studies at the National Aeronautics and Space Administration).
This measurable outcome is grounded in considerable research and has enabled a high level of scientific agreement.5 This research began with information from ice cores, tree rings, and weather data that have been collected since the 1600s. The International Meteorological Organization, founded in 1873, developed protocols and standards for collecting weather data which made possible longitudinal analysis. Approximately 50 years later, scientists such as G. S. Callendar began to collect time series data on temperature. In addition, “The high-accuracy measurements of atmospheric CO2 concentration, initiated by Charles David Keeling in 1958, constitute the master time series documenting the changing composition of the atmosphere.”6 These changes are depicted in Figure 4.2.
Graph Showing the Relationship between CO2 Levels and Global Temperature over the Past 400,000 Years (EPICA is the European Partnership for Ice Coring in Antarctica; Dome C is the site of the Concordia Research Station, which is jointly run by France and Italy. Vostok data are collected by Russia at its Vostok Station in Antarctica).6
The universal narrative that has emerged today from this research is familiar to everyone worldwide. Contemporary global warming is being driven by human behavior. No matter what our response, this process will continue for decades and perhaps centuries because changes in the composition of the atmosphere and land cover have triggered transformative processes that have not yet played themselves out and established new equilibria. However, action today could have an important mitigating effect. The best models suggest that the distinguishing impact of climate change is an accentuation of familiar phenomena such as drought, flooding and extreme weather. Arid areas will tend to receive less precipitation, whereas coastal areas and flood plains will tend to receive more, and storms will tend to worsen. How intense and how frequent these amplifications are may depend on how much more greenhouse gas we continue to add to the atmosphere.
Social and ecological systems are currently being affected in multiple ways, and this impact will continue into the future. However, these patterns will not be uniform across the planet and will display considerable variability by region. Some changes will not be foreseen at all. This is partly because climate change is affected by phenomena that have proven impossible to model, at least so far. Examples include changes in cloud cover and unpredictable feedback responses from both natural and human systems. This unpredictability is in part because complex adaptive systems, such as forests, display non-linear behavior and generate new properties. In short, while much is known about anthropogenic climate change, and broad patterns of future climate change are being predicted, there remain important areas of uncertainty.
Based on these current research findings, it is widely assumed that disasters will increase in the decades ahead. IPCC concludes that climate change “leads to changes in the frequency, intensity, spatial extent, duration, and timing of extreme weather and climate events, and can result in unprecedented extreme weather and climate events.”7 In addition, a 2012 report by the Joint United Nations Environment Programme/Office for the Coordination of Humanitarian Affairs (UNEP/OCHA) Environment Unit states that
The lack of precise data about future emissions levels and climate change impacts translates into a growing degree of uncertainty concerning the frequency and intensity of extreme weather events, as historical trends and risks no longer apply. As such, communities living in areas exposed to storm surges, flooding, and landslides face greater exposure to climate risks, even while it is unclear just how much greater those risks will be.8
In short, disasters are expected to increase dramatically but what, where, and when are uncertain.
The broad contours of future disasters related to climate change can be summarized in terms of:
an expected increase in the frequency and intensity of extreme events such as fires, cyclones and floods; and
an expected increase in the intensity and duration of longer term events such as heat waves and droughts.
These will be experienced by human populations that, in many cases, are likely to be more vulnerable to such future weather events than they have been in the past. This vulnerability results from the likelihood of:
demographic changes including an increase in the number of elderly and in the number of urban dwellers;
the displacement of large numbers of people into high risk areas such as flood plains due mainly to poverty;
public health setbacks in many regions due to water scarcity, food scarcity, and the spread of pathogens, which are themselves challenges intensified by climate change;
the degradation of infrastructure, such as waste management and drainage systems, in many regions of the world;
the erosion of ecosystems such as forests that provide a natural buffer against many forms of natural disaster;
difficult local conditions under which aid is delivered, especially when the provision of emergency assistance occurs in places where access, sanitation, mobility, and resource allocation are problematic; and
heightened competition for scarce emergency assistance resources.
Patterns of vulnerability are expected to reflect demographic and socioeconomic indicators, with risk closely associated to age, gender, and income. But the actual rate and scale of disasters related to climate change also will likely be affected by:
whether climate change leads to unforeseen feedbacks and new equilibria that change its current trajectory; and
whether human ingenuity leads to better levels and forms of communication, preparedness, and resilience.
In other words, the evidence in support of global climate change is compelling and the processes through which this is occurring are well-understood. From a contemporary data-based perspective, it is reasonable to predict an increase in weather-related disasters such as floods, storms, tornados, droughts, fires, and heat waves. This increase will tend to amplify familiar conditions – that is, areas prone to floods, droughts, or heat waves are likely to experience more of the same. Much analysis suggests that the vulnerability of people throughout the world is increasing because of demographic changes, public health setbacks, and the erosion of infrastructure and natural ecosystems that have the capacity to buffer against disaster. At the same time, climate is a complex system that can transform and stabilize in unexpected ways, and humans are a resourceful species that can adapt to new environments. Hence, the passage of time could find the world’s population better or worse off than current global climate models predict.
The IPCC argues that
Projected changes in climate extremes under different emissions scenarios generally do not strongly diverge in the coming two to three decades, but these signals are relatively small compared to natural climate variability over this time frame. Even the sign of projected changes in some climate extremes over this time frame is uncertain. For projected changes by the end of the 21st century, either model uncertainty or uncertainties associated with emissions scenarios used becomes dominant, depending on the extreme. Low-probability, high-impact changes associated with the crossing of poorly understood climate thresholds cannot be excluded, given the transient and complex nature of the climate system. Assigning “low confidence” for projections of a specific extreme neither implies nor excludes the possibility of changes in this extreme. The following assessments of the likelihood and/or confidence of projections are generally for the end of the 21st century and relative to the climate at the end of the 20th century.9
The final conclusion is that the more extreme weather expected over the next three decades will still likely fall within the stable natural variability parameters of the past several millennia. After that, the parameters themselves could change but there is less confidence in predicting this.
Given the previous information, it is easy to understand why efforts to link climate change and disaster tend to aggregate into one of two quite different scenarios. The first scenario has received most of the attention in scientific communities, political arenas, and popular media, Here, the negative impacts of climate change increase steeply throughout the next several decades, damaging natural and social systems and displacing, killing, and injuring hundreds of millions and possibly billions of people. Severe weather events like Hurricanes Katrina and Sandy ravage coastal communities around the world. Heat waves devastate cities like London, Los Angeles, and Shanghai – perhaps as often as thirty or forty times a year. Stagnant air traps ozone and particulates in urban space and respiratory ailments like asthma increase sharply. The warming of the planet allows tropical insects to migrate into upper and lower latitudes, leading to malaria and other epidemics in places where people have no experience with them. Droughts transform much of sub-Saharan Africa and large areas of the United States and China into dust bowls. Much of the world faces chronic food and water insecurity. Wildfires burn out of control around the world and some places experience a new disaster – the fire tornado. Meanwhile, the melting of the Greenland ice sheet and the sudden release of vast quantities of methane gas trapped in permafrost lead to a reversal of the ocean conveyer. This results in the loss of ocean flow that today warms much of the United Kingdom and Europe and disruption of the monsoon upon which the livelihoods of billions of people in Asia depend. Much of humankind must confront a struggle to survive against a turbulent, erratic, and inhospitable climate. In fact, by as soon as 2025 a state shift could occur – a situation in which the global climate experiences a sudden and dramatic shift to a new regime, and extremely inhospitable weather (the extremes of the past millennia) becomes the new global norm. Efforts to survive often become violent, and as a result, disasters and wars tend to occur together.10–19
Given the areas of uncertainty noted previously, however, a second scenario has also been developed in which the social effects of climate change are imagined to be rather small. Milder impacts would result because phenomena arise that have not been captured in global climate models. Increases in cloud cover could blunt global warming and establish new equilibria that maintain a fairly stable and congenial global climate regime. Moreover, climate change could prove to have benefits for large parts of the world such as longer growing seasons and easy access to natural resources previously hidden by ice. Humans would play a major role in this scenario, because wherever climate change effects create significant damage, human ingenuity might discover effective coping and adaptation responses.20
While these two scenarios both have thoughtful and well-informed advocates, the first is clearly dominant.21 Ironically, this has not translated into the aggressive mitigation and adaptation responses that such a scenario would seem to authorize. As such, the world has gravitated toward accepting the worst-case scenario in words but not in actions.22 Hence, a future of unprecedented disasters affecting much of the world’s population is fully plausible.
Current State of the Art
While many studies exist on the real and potential social impacts of climate change, the issue that receives the greatest attention from the disaster perspective is hydrological intensification, and especially flooding. This is because flooding causes approximately 50% of all of the damage from natural disasters. Floods have directly affected almost half of the world’s population in the past four decades, and there is a clear trend toward more flooding. A considerable amount of infrastructure is situated in flood plains, and major reinsurance companies like Swiss Re and Munich Re have suggested that much of this will soon be uninsurable by the private sector.
A recent overview of flood activity from 1980 to 2009 reports that an average of 131 floods occur each year. Eighty-one percent of all floods identified in the study occurred in the last two-thirds of the survey time period. During this period, flooding caused about 540,000 deaths and affected over 2.8 billion people. No other natural disaster comes close to this level of devastation on an annual basis.23
However, trends in the broader set of disasters that could be associated with climate change are also alarming. According to a 2012 UNEP/OCHA report that examines the interaction between climate change and urbanization, “The period between 2002 and 2011 included over 4000 disasters linked to natural hazards, resulting in over one million deaths and greater than $1 billion in losses.”24 In 2010, the International Federation of the Red Cross and Red Crescent (IFRC) reported that 7,184 disasters took place in the first decade of the new millennium causing 1,105,352 deaths, affecting over 2.5 billion people, and costing some $986,691,000,000 USD. A total of 4,014 of these were natural disasters, and in turn 91% of these were climate-related disasters.25 This larger set of climate-related disasters includes:
cyclones
drought
flooding
heat waves
hurricanes
pandemic disease outbreaks
tornado fires
tornados
wildfires
From the perspective of IPCC, UNEP, OCHA, and many other organizations, humankind is likely to experience more devastating disasters in the next few decades than it has in the past several millennia. This is due to two interrelated phenomenon: climate change is pushing weather toward and even beyond historical extremes and, at the same time, human exposure and vulnerability are increasing due to multiple factors, including climate change itself.
The widespread perception that the world’s inhabitants are becoming more vulnerable is based partly on the increasing occurrence rates for many forms of natural disasters as well as on the net impact assessments of several global trends. In particular, world population is growing at the rate of about 90 million people per year. Even though fertility rates in the vast majority of countries are at or below replacement levels, this growth is not expected to reach a plateau until at least mid-century due to the large proportion of women who are fertile.
This growth is largely taking place in the urban areas of the developing world. These urban areas are often situated along coastlines and in flood plains, and typically do not have infrastructure, such as drainage systems, that is likely to be effective under most climate change scenarios. In other words, large numbers of people are living in areas vulnerable to natural hazards. In addition, both the number of people and the number of hazards are increasing even as the infrastructure is aging and often of low quality. Developed countries generally are not experiencing population growth, but their citizens are undergoing an unprecedented aging. Soon, these nations will have substantial populations at heightened risk for extreme weather events such as heat waves. It is an alarming prospect that more people in developing countries, and more elderly people in developed countries, are all living in brittle cities that are potentially exposed to the most severe weather events in human history.
Other global trends may add layers of complication to this situation. For example, recent analyses of Gravity Recovery and Climate Experiment (GRACE) satellite data, which record fluctuations in gravitational force on the surface of the earth, show that large groundwater systems worldwide are shrinking. This is mainly due to unsustainable pumping for irrigation. Of particular concern is the groundwater depletion being experienced by both the Indian subcontinent and the Tibetan Plateau, home to some 2 billion people. Climate change could accelerate the decline of some ground water reserves through contamination from saltwater intrusion due to sea level rise and reduction of replenishing surface waters. However, the major threat is that certain forms of hydrological intensification induced by climate change, such as extreme drought, will be an even greater burden in areas where the alternate source of water is diminishing. In the case of Asia, such changes are taking place in the region that already is the most vulnerable to natural disasters on the planet. Maplecroft’s Natural Disaster Risk Ranking, for example, identifies South Asia as the highest risk region of the world, including Bangladesh (ranked 1), Pakistan (ranked 4), and India (ranked 11).
The expansion of the built environment could add another source of stress to this volatile situation. For example, many of Asia’s major rivers such as the Brahmaputra, Ganges, Indus, Irrawaddy, Mekong, Salween, Yangzi, and Yellow Rivers originate in Tibet. They have enormous hydroelectric power potential, and there are plans in China and India to build hundreds of new dams to harness this power and to store water for emergencies. However, little is known about the resilience of contemporary dam designs under conditions of extreme weather. They might fail. In addition, serious concerns exist that such plans will also weaken the resilience of downstream countries by amplifying water insecurity. The dams will also reduce the flow of silt, which aggregates into barriers that provide natural protection against flooding in countries such as Bangladesh.
The list of global trends that could increase vulnerability to the impact of climate change could be expanded for pages. For example, the 2007 recession underscored the potential magnitude of any economic crisis today. Such events are an almost inevitable outcome of a globalized economy in which there are powerful incentives to diffuse and shift risk. Economic crisis reduces the surge capacity of a country, curtails investment into resilience, and makes emergency response more difficult. Similarly, medical researchers are concerned that the misuse of large quantities of powerful drugs has created conditions amenable to a growing array of multiple drug resistant (MDR) and extremely drug resistant (XDR) pathogens that could seriously weaken public health around the world. The main point is that there are many reasons for concern that vulnerability to climate-related disasters is growing, and will continue to grow for decades.
The combination of more extreme weather events, a growing population of people vulnerable to these events, fragile infrastructure, weak governments, public health setbacks, and economic crises aligns nicely with the scenario described previously that focuses on the likelihood of escalating catastrophe. What, then, can disaster response mean in a world in which the lives, livelihoods, and property of tens and perhaps hundreds of millions of people are put at considerable and escalating risk each year? The answer to this question depends on three types of social investment.
The first area of investment involves mitigation and associated technologies, institutions, and practices. In the disaster literature, mitigation refers to “the effort to reduce loss of life and property by lessening the impact of disasters. Mitigation is taking action now – before the next disaster – to reduce human and financial consequences later (analyzing risk, reducing risk, insuring against risk).”26 In the realm of climate change, mitigation
refers to efforts to reduce or prevent emission of greenhouse gases. Mitigation can mean using new technologies and renewable energies, making older equipment more energy efficient, or changing management practices or consumer behavior. It can be as complex as a plan for a new city, or as a simple as improvements to a cook stove design. Efforts underway around the world range from high-tech subway systems to bicycling paths and walkways. Protecting natural carbon sinks like forests and oceans, or creating new sinks through silviculture (forest management) or green agriculture are also elements of mitigation.27
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