As discussed in the previous sections, the re- gional temperature, precipitation and cloud- cover environmental responses to BC and O3 concentrations layered over large-scale changes in the global climate system, will have many implications for the human condition and may increase risks in regions where populations have particularly low resilience in the face of change. This section focuses on two regions of the world, South Asia and the Arctic, which
have been identified as being particularly sus- ceptible to environmental change resulting from BC and O3 and whose communities’ are particularly vulnerable to such change.
South Asia
One region of the world where the links be- tween BC and O3, regional climate, and hy- drologic change are particularly acute is South Asia. In this region, high levels of BC and O3 are likely to change regional weather patterns (see Section 4.2.2) affecting the availability and distribution of reliable water supplies. The link between regional climate and hydrol- ogy is further complicated in South Asia by the important role that snow and glacier ice
play in the Himalayan Range, defining the
regional hydrology and the links between BC, albedo and energy balances. At some level, changes in the regional hydrology would have implications for the management of installed
Figure 4.12. Simulated change (colour scale, g C/m2/yr) in diffuse fraction contribution to land carbon
139 hydraulic infrastructure that is operated to
meet multiple objectives, including the gener- ation of hydropower and the provision of wa- ter to urban, industrial, and agricultural users. South Asia is a region which is industrializing rapidly, yet still a large number of people live in poverty, and are vulnerable to changes in climate and water supply. While this is true for the large number of rural poor reliant on ag- riculture, these people also lack infrastructure and resources to withstand natural disasters. People living in Himalayan valleys below rap- idly developing glacial lakes (Box 4.6) are vul-
nerable to flooding of large areas that would
result from these lakes bursting.
Whilst there is no evidence to link the recent
floods in Pakistan to climate change, their
impact illustrates the vulnerability of large
numbers of people. The floods that hit Paki- stan during the summer of 2010 came about through an unprecedented meteorological event caused by unusual holding patterns in the jet stream that coincided with the summer monsoon rains. The result was a series of sus- tained, extremely heavy precipitation events, the worst seen in the country for the past 80
years, leading to floods of unprecedented
ferocity and duration that overwhelmed the infrastructure and management systems of the country. What the situation in Pakistan does indicate is how vulnerable countries can be to known hydrologic variability. Large in- vestments in physical infrastructure, including large dams, are needed, e.g. Pakistan can store
only 30 days of the average flow of the Indus.
This challenge is made more serious by un- certainties about climate change and its effect on rainfall and snowmelt in the Himalayas.
Forty-fiveper cent of the normal flow of
the Indus comes from glacial and snowmelt and, as has been shown in previous sections, BC and O3 are potentially very important in determining the state of these Himalayan glaciers. While the Ganges basin is less de- pendent on glacier meltwater as a source of
river flow, water users on the Gangetic Plain still benefit from mountain snow and ice, par- ticularly in dry seasons, and are involved in livelihood activities that leave them vulnerable to change. The geo-political situation between nations in the Himalayas adds yet another level of complexity to this vulnerable system.
Figure 4.13. A framework to understand vulnerability and how it is affected by multiple factors (from Turner
140
The Arctic
The Arctic, which has experienced tempera- ture rises twice that of the global mean over recent decades, is a region in which changes are already resulting in increased impacts in vulnerable ecosystems and human popula- tions. In particular, the traditional economic and cultural activities of Arctic indigenous communities have already suffered.
Many indigenous communities rely on fishing,
hunting, herding and linked activities. Already under cultural stress for several centuries, en-
vironmental changes in Arctic flora and fauna
have placed these traditional activities at even greater risk. Recession of sea-ice around Green- land has, for example, made travel and hunting by dogsled or snowmobile dangerous or impossi- ble during increasingly long periods of the year.
Patterns in fish populations have also changed,
threatening Arctic livelihoods. New research, conducted under the auspices of the Inter- national Polar Year (2007-09), suggests that
already-declining Arctic fish and sea mammal
populations are at extreme near-term risk from the recession of sea-ice because of the depen- dence and specialization of the Arctic food chain on ice cover. Total collapse may occur within the space of two to three years after the disappearance of summer sea-ice, projected to occur around 2030 if current rates are not somehow slowed (Søreide et al., 2010).
The combination of permafrost melt and sea- level rise has proven too much for many Arctic
communities, with flooding, collapse of roads
and buildings causing several communities to abandon traditional sites and move inland. Such damage is anticipated to accelerate and move further south should present rates of warming not be slowed. Norway and Sweden are among the nations that have already com-
mitted significant resources to managing these
changes, including plans for wholesale move- ment of populations in anticipation of dam- age from permafrost melt and more frequent and severe weather events (O’Brien et al., 2006; SOU, 2007).
Large industry has also experienced the im- pact of these changes. Reports from Russia,
Canada and the USA indicate that repairs to oil and gas pipelines cannot keep pace with collapse from permafrost melt, leading to ex- tensive leakage of CH4 which will exacerbate global warming in addition to presenting in- creased risk from oil spills and explosions (Ac- climatise, 2009; USGCRP, 2009; Lesikhina et al., 2007, Williams and Wallis, 2009). 4.7.2 Increased vulnerability from black carbon and ozone affects on human health
Human health can be directly affected by regional climate change. Impacts can occur through a number of different means which include changes in temperature leading to increased occurrences of heat-stress – though these may, to some extent, be off-set by milder winters leading to reduced cold-stress. Changes in hydrology, mediated by precipi- tation and glacial melt, leading to riverine
flooding. In the worst case this can lead to death but also to other flood-related health
problems including both mental and physical effects through water-borne diseases. These diseases may be caused by increases in water temperature and increases in wash-off reduc- ing water quality leading to poor sanitation; by increases in vector-borne diseases such as malaria and tick fever and by increases in incidences of food poisoning as a result of food contamination. Physical effects can also be caused by increased frequencies of storms and high winds, leading to an increase in in-
juries from flying debris.
Human health impacts, including mortal- ity and morbidity, directly arising from BC (considered here as PM2.5) and O3 can mani- fest themselves as differential responses at an individual level resulting from exacerba- tions of the effect of exposure by underlying disease status, by psychosocial factors such as stress, or by socio-material factors includ- ing poverty. Examples include: people with diabetes have twice the risk of cardiovascular mortality following exposure to PM air pol- lution (Bateson and Schwartz, 2004), race and educational level strongly modify the mortality risk on very hot days (O'Neill et al., 2003), and genes related to oxidative
141 stress defenses modify the risk of air pollu-
tion (Madrigano et al., 2009; Curjuric et al., 2009; Chahine et al., 2007). Overall, there is some evidence of gender differences in the health effects of air pollutants, and clear
evidence of susceptibility being modified
by obesity and diabetes, the prevalence of which is rapidly increasing in the developing world especially in China and India.
Of particular importance, the health effects of O3 have been shown to be higher when temperature is higher, suggesting the pat- tern of increased temperature and O3 will be particularly toxic, especially in populations unable to afford or use air conditioning. The health effects of BC on birth weight were found to be worse in people with a poor standard of living (Zeka et al., 2008). These issues can be addressed through attempts
to define sub-populations with two or three
times the risk, providing evidence that expo- sure contributes to health disparities as well as ill health. This can then be coupled with differential exposure, where the wealthier people have cleaner cooking fuels, live in less polluted areas, etc, which also contribute to health disparities. For example, exposure to BC is highest in less developed countries that depend on biomass fuels but within these countries, this is more prevalent amongst poorest people. Using such covariation of exposures with susceptibility factors, a recent risk assessment showed a considerable dispar- ity in the impact of air pollution on mortality in Mexico (Stevens et al., 2008), and, relevant to cumulative risk assessment, showed the same disparity gradient for poor water quality and cooking fuel use.
These countries, and many of their inhabit- ants, often lack the resilience to deal suc- cessfully with challenges. Most studies of air pollution and mortality have reported CRF slopes that increase with age. The age pyra- mid is changing in the developing world and an increased age of the population, as well as increased prevalence of diabetes is ex- pected by 2030. This will exacerbate the ef- fects of pollution. Finally, these differential impacts, both within and between countries, generally result in a greater additional bur-
den to the people who have the worst health
in the first place.
4.7.3 Increased vulnerability of