Climate Change

By John Murphy
Last updated 24 Aug 2010

There is a well known adage, whose source is commonly attributed to Humphrey Bogart, that things are never so bad they can’t be made worse. A read through the morning’s papers this year would seem to confirm this seemingly undeniable truth for those with a concern for the environment. The Mexican gulf oil spill has horrified the United States public as they have been able to watch BP’s online live stream of crude pouring from the sea floor, Muscovites have choked on dense smog caused by wild fires, while in Pakistan and China devastating floods have taken the lives of thousands and destroyed the livelihoods of countless more souls.

All these catastrophes fit into the narrative currently driving environmental debates that we are facing an era of sustained increases in natural disasters and ecological change that will fundamentally challenge the way we live our lives while pushing vulnerable wildlife populations and their habitats to the very edge of existence. By far and away the dominant issue driving this disaster narrative is that of climate change and its impact across the globe. For example the WWF proclaim 

We face a high risk of severe and irreversible environmental change unless the release of greenhouse gases starts to decline within the next 10 years. If we fail to act, the consequences for people and nature could be devastating. (1)

However, while there has been widespread coverage in the media telling us of the pending doom of polar bears and the peril we are placed in by the melting Greenland ice sheet, there has been somewhat of a scarcity of detailed information accessible to the general reader informing us exactly what the the “severe and irreversible environmental change”  actually entails for Africa, especially in relation to conservation efforts. Questions abound such as how reliable are these predictions of climate change? And what strategies should conservationists and their supporters be adopting in order to mitigate and adapt conservation efforts to climate change (3,4)?

Not surprisingly, if you can actually manage to access reliable, objective information on climate change in Africa and its implications for conservation, what becomes apparent quite soon is that we are not faced with a simplistic, across the board case of uniformed rising temperatures and complete environmental disaster. In reality the more likely outcome of ongoing climate change will be a complex process of environmental change that will require sophisticated responses by conservationists to not only mitigate and adapt against the ill-effects of climate change but also take advantage of the windows of opportunity that may arise. 

A fully comprehensive investigation of the possible effects of climate change and its implications for conservation is well beyond the remit of this short article. For that readers should start by visiting the website of the Intergovernmental Panel on Climate Change (5) (IPCC), but what we can do is give some indication of the kind of scenarios that conservationists are expected to face in the not too distant future. Furthermore, in the hope of creating a concise image of this challenging future we will focus on the possible implications for efforts to conserve one of the world’s most iconic species, the African Lion. 

Climate Change and Africa 

Regrettably the debate concerning climate change has been somewhat over shadowed by accusations that the scientific data upon which climatologists predictions are based is somehow inherently flawed. Some sceptics have gone so far as to suggest that anthropogenic climate change is in fact a charade dreamt up by environmentalists. Needless to say that is not the perspective put forward in this article. Although we do not have the space available here to explore the evidence in detail there is now a comprehensive body of evidence, gathered from multiple, independently verified sources, supporting the argument that the Earth is undergoing environmental change caused by greenhouse gas emissions originating from human activities (6,7). 

However, what is evident from research, and is often misconstrued by sceptics, is that there are uncertainties as to what sort of future environment will result from climate change. This is especially so for the developing world. But this is not evidence of conspiracy but rather a result of the fact that the available sources of information and resources to collate and analyse data is not uniformly distributed across the world. As with most aspects of life there is a disproportional bias towards the industrialised countries of the northern hemisphere in terms of available data and the financial and physical resources to study it. As such, this means that when compared to the likely impact of climate change on the natural resources of Europe and the United States there is much less information and research on the southern hemisphere, especially sub-Saharan Africa. For conservationists here this means they have less reliable guides as to future climate regimes. This then inevitably impacts on the choices conservationists can make in terms of mitigation and adaptations in conservation planning (8,9). 

Nevertheless, the mechanisms and models used to predict future climate scenarios, not just for Africa but the world as a whole, have improved over the course of the last decade helping increase the levels of confidence in how accurately we can predict the effects of climate change. Some uncertainty still persists, as the physical forces that influence and determine the climate over vast land masses such as the African continent are complex and varied. For example, although our knowledge has improved since the first publication of serious studies of African climate change there is still work to do in improving our knowledge of important influencing factors such as the El Nino Southern Oscillation (ENSO) which plays an important role in Africa’s inter-annual rainfall variability (10). We are also improving our understanding of the influence of variables such as vegetation cover and land use that contribute, as well as change in response, to climate change thus further adding to environmental variation across the continent (11). 

Furthermore, the use of complex mathematical climate models based upon established physical laws including the conservation of mass, energy, and momentum, and the testing of these models veracity on currently experienced climatic conditions over multiple observations means that we can increasingly predict future climate scenarios with greater confidence. This is particularly so with regards to our future predictions for changes in temperature (12). 

So, bearing these qualifications in mind, what exactly do we know about the implications of African climate change on the continents great diversity of wildlife? Well, the best place to start is by taking a look over what climatic changes have been recorded during the last few decades. 

The Changing Climate of Africa

Temperature levels across the African continent have been rising over the last century, particularly so since the 1960s. This rise in temperature is not uniformly distributed but rather varied across regions with a higher mean temperature rise in southern Africa compared to tropical regions; 0.3°C compared to 0.1°C. There is also local variation in climate, for example, South Africa and Ethiopia have witnessed a faster increase in minimum temperatures over maximum or mean temperatures while southern and western Africa overall have seen an increase in the number of warm days with fewer cold spells. However, illustrative of the complicated nature of climate change is the evidence recorded from coastal areas of east Africa that shows these areas have actually experienced a decrease in temperatures (13).

The situation regarding precipitation levels is no less complicated; indeed most studies thus far reflect a more nuanced situation than that experienced with temperature records. For instance there is a wide variation in precipitation over both space and time.  Inter-annual as well as multi-decadal rainfall records show significant variation across the continent with western Africa experiencing a decrease of up to 40 per cent between the 1960s and 1990s (14) . However, within this geographic area there has been localised variation with a 10 per cent increase in rainfall along the Guinean coast over the last three decades (15). In contrast, no long term trend has been identified across southern Africa but there have been occurrences of more severe dry spells and droughts with some large variances in rainfall from year to year since the 1970s with countries across the region from Angola to Mozambique experiencing heavy rainfalls with changes in seasonal precipitation (16,17). East Africa meanwhile has been experiencing two increasingly distinct weather patterns between northern and southern areas with increasing rainfall in the north and reduced rainfall in the south .

Thus it is evident from even a casual review of African climate that a complex situation with many varying environmental conditions is being experienced across the continent. But what can we predict about future climate change on the continent?

Africa’s Future Climate 

Predicting future climate change in Africa, as mentioned earlier, is significantly hampered by a lack of resources, nevertheless, the IPCC has been able to compile and collate data to establish a basis for forecasting future trends (19). 

Drawn from this data conservative estimates suggest that annual mean surface temperatures in Africa may rise by 4°C compared to the 1990s with some regional variations. What sort of variation? Well, increased vegetation density in the tropics spurred on by higher levels of carbon dioxide in the atmosphere could result in an actual reduction in temperatures. Southern African temperatures, meanwhile, could experience temperature rises of up to 7°C. However, these future scenarios may well be influenced, and in the case of the tropics reversed, by any land use conversions that take place in the coming decades (20). 

If that sounds complicated, well, ascertaining future precipitation patterns for Africa is arguably an even more convoluted affair. Thus, unfortunately, we must have less confidence in our ability to produce reliable data compared to temperature forecasts. This is as a result of such issues as the multifarious factors that influence rainfall across the continent including the sophistication and sensitivity of the hydrological cycle; dust aerosol concentrations and sea surface temperature anomalies, as well as ongoing deforestation across the tropics (21). 

While acknowledging these shortcomings in climate data, there is a growing body of studies that allow us to make some tentative predictions . Once again there are expected to be considerable variations across the continent with very significant reductions in precipitation across the north Mediterranean coast, as much as 20 per cent, while at the same time tropical and eastern Africa may witness an increase in rainfall by as much as 7 per cent. Southern Africa, most alarmingly, is forecast to experience a reduction in precipitation by as much as 40 per cent in western areas. Once again within this broader geographical zone we can expect sub-regional variation. For example, some studies have suggested there will be a reduction in early summer precipitation with an increase in late summer rainfall over eastern areas of southern Africa (23). 

On top of this broader change in the climate of Africa scientists also suggest that we shall witness more frequent extreme weather events during the next century with severe droughts being accompanied by exceptional rainfall events (24). 

Despite the shortcomings of some of our data sets it must surely be apparent to all but the most ardent sceptic that climatic change in Africa will drive environmental transformation that will profoundly affect all aspects of life. From access to water for both humans and wildlife, through to agriculture, commerce and our relationship with the natural world the coming century will present us with a challenging environment as a result of anthropogenic climate change.

In the following paragraphs we shall examine how some of these predicted climate changes may impact on efforts to prevent the extinction of arguably Africa’s most iconic species, the Lion. 

Climate Change and the Consequences for Lion Conservation

The decline in the distribution of the African Lion (Panthera leo) across the continent in the last century is shocking with some experts estimating that the wild lion population for the entire continent may be as low as 23 000 often existing in fragmented populations (25). In some countries such as South Africa the lion can now only be found within the confines of fenced reserves and national parks with the health and long term viability of these populations dependent on the management of their habitat by humans (26). Increasing human encroachment into lion habitat is thought to have played a major role in this decline from mid-20th century population estimates of more than 200,000 (27). Now, the prospect of environmental transformation as a result of climate change adds further complexity to efforts to conserve remaining lion populations, as over the course of the coming decades we are likely to witness significant alterations to habitat as well as other important factors such as disease prevalence. 

To investigate these challenges we shall discuss what are thought to be the most likely key issues resulting from environmental change for conservation programmes. In particular we focus on issues such as the prospect of physical habitat change and the implications of land transformation; complications arising from the influence of climate change on infectious disease; and the broader impact of climate change on a key sustainable development strategy, tourism. In discussing these topics we shall hope to give at least some indication of the complexity of the challenges faced in the coming years. 

Climate and Land Transformation

One of the most significant influences on wildlife will be how climate change impacts on human land use as agriculture changes with the prevalent environmental conditions. For instance, by 2100 parts of the Sahara will be most vulnerable to agricultural losses as production may be reduced by 7 per cent. Western and central Africa could experience losses of between 2 and 4 per cent with southern Africa losing between 0.4 and 1.3 per cent (28).

By the 2080s there may well be a significant loss of rain fed land suitable for cereal production as arid or semi arid land increases by 5 to 8 per cent, approximately 60 to 90 million hectares, with crop production such as maize in southern Africa susceptible to increased ENSO volatility. Once again there will be localised variations with some dryland areas expected to be able to increase agricultural production due to increased rainfall (29).

Such change in agricultural production is of considerable importance when placed within the context of the all too often competing interests of farmers and conservationists. For example, one implication of agricultural change that could create problems for conservation efforts is the potential for climate change to lead to an increase of livestock production within the small scale livestock sector. Again the issue is not straight forward, as an increase of 2.5°C to 5°C would be expected to lead to a reduction in large scale cattle farming, but small scale farmers’ livestock tends to consist of more heat tolerant animals such as goats. However, further complicating the issue is the effect of higher precipitation which would be detrimental to both small and large scale producers due to land conversion from grassland to forest coupled with increased exposure to disease vectors which are anticipated to thrive in an altered climate (30).

Needless to say changes in agricultural practice will have very important implications for lion conservation. Today, one of the main threats to lions is conflict with humans. For example, the recent droughts experienced in Kenya have coincided with reports of Maasai pastoralists killing lions who they regard as threatening their livestock (31).

Even land that has been designated for protection from human encroachment within national parks and reserves will experience change in coming decades providing challenges to lion survival with African mammals becoming increasingly susceptible to extinction from habitat loss. A recent study by Wilfred Thuiller and colleagues at South Africa’s Global Change Research Group concluded that mammals will become highly vulnerable to extinction as they are exposed to habitat change without being able to migrate to more suitable areas either outside, or in neighbouring, protected areas. Indeed, assuming that species are not able to migrate to more suitable habitat, which will become available as a result of the same climate change that detrimentally impacts on current species range, the study estimated that up to 40 per cent of African mammals will fall into the IUCNs critically endangered category. An example of this is likely to be experienced in South Africa’s Kruger National Park where Nyala (Tragelaphus angasii) and Zebra (Equus quagga) numbers could possibly drop by up to 66 per cent (32,33)  .

However, crucially the same study concluded that conservationists could mitigate against the scale of species loss if conditions were created allowing for migration of animals to new habitat. For instance, if movement was possible to land no longer suitable for agriculture but favourable to wild animals the percentage of species falling into the critically endangered category could be reduced to between 10 and 20 per cent. But it must be acknowledged that this migration is a lot easier to conceptualise than actualise in today’s Africa where protected areas are increasingly fragmented and divided by human settlement (34).

Granted, there have been efforts to promote transfrontier conservation areas with the political and physical boundaries removed from contiguous protected areas but there still remain significant hurdles to be crossed for these initiatives to achieve widespread sustained success. For example, to unite non-contiguous conservation areas there will be a need to establish wildlife corridors to enable migration. This is not a straight forward process as transfrontier conservation areas have drawn strong criticisms especially from human rights groups. These groups claim that transfrontier areas represent a modern day equivalent of land grabbing by environmentalists focused on animal welfare, as well as safari tour operators and politicians seeking to benefit from tourism revenues, with little concern for the impact of the expansion of protected areas on poor rural communities. If this is the case then a very considerable struggle may lie ahead in getting communities to accept wildlife corridors and the costs involved through increased contact with wildlife. This problem is particularly relevant to lion conservation as villagers may fear not just livestock loss but also the dangers posed to their own personal safety (35,36) .

Thus, if large predators such as lions are to find their way to new suitable habitat it may very well be the case that increased direct human intervention is required through relocation or reintroduction programmes (37).

Overall the changing nature of Africa’s landscape will have an important impact on the long term chances of lion survival as climate change influences the availability and location of vegetation vital for the maintenance of key prey species. But while a changing landscape can be a fairly obvious factor in determining the range of species climate change will also affect the ongoing presence of wildlife in more subtle but no less important ways. For instance, a recently published study investigating the relationship between landscape and lion populations noted how “climatic parameters explained 62 per cent of overall variance in demographic parameters (38)” for lions including an influence on pride structure, as this was shown to correlate to precipitation levels particularly in the driest months.

A further less apparent issue concerning the impact of climate change on lions will be how a changing environment not only alters the life cycle of prey species but also the micro organisms that actually prey on lions themselves.

Climate Change and Disease

Although Africa is a beautiful continent to behold with its splendid and varied natural wonders there lies within this natural beauty a dark side of nature in terms of disease causing microbes that reside within the wilderness of both savannah and forest as well as throughout the continents many sprawling urban centres.

AIDS, malaria, and tuberculosis are some of the well known diseases that cause misery and suffering for sub-Saharan Africa’s human population but the wildlife of Africa are also constantly exposed to diseases that play a role in shaping the continents ecosystems.

Illustrative of this situation is the lion’s relationship with a number of pathogens including feline immunodeficiency virus (FIV), a feline virus similar to HIV in humans; canine distemper virus (CDV); bovine tuberculosis; and other infectious diseases such as babesiosis.

Indeed, a growing concern for conservationists is how these diseases, which under normal circumstances may not overtly effect lion populations, may react to changing environmental conditions.

This is because scientists have noted in recent years how warming temperatures can promote the development of pathogens increasing the likelihood of diseases becoming more prevalent. An example of how this could occur is through a rising of minimum temperatures during winter months resulting in disease vectors not being killed off during cold spells (39) .

Warming temperatures may also increase the possibility that pathogens will spread beyond their current range exposing species to pathogens to which they may have little or no natural resistance. In fact, it is already thought this is occurring, as changes in ENSO seem to correlate with the spread of a host of pathogens including coral diseases, oyster pathogens, crop pathogens, Rift Valley fever and cholera (40).

Climate influenced Disease in Lions 

A specific example of how variation in climate can affect disease trends in lions can be drawn from research in Tanzania’s Serengeti National Park. Here researchers noted how a dramatic change in climate regimes could possibly explain a drastic increase in the virulence of diseases which resulted in the lions of the Serengeti dying in unusually high numbers (41). 

The research focused on the alarming number of lion deaths in the Serengeti during the mid-1990s and early 2000s. During the years 1994 and 2001 the Serengeti lions were devastated by outbreaks of canine distemper virus (CDV) with almost 40 per cent of the lions dying during the 2001 outbreak. What was very surprising about this level of mortality was that previous outbreaks of CDV had not produced such terrible illness amongst the Serengeti lions. 

In order to try and solve the mystery of why lions were apparently succumbing to illnesses which previously had not had a substantial impact on their health researchers undertook extensive surveys of surviving lions as well as performing autopsies on the remains of dead lions (42). 

The results of these investigations were startling. It transpired that the lions were not only infected by the distemper virus but were also heavily infected with blood parasites causing babesiosis, a malaria like infection spread by ticks. Interestingly this infection would not normally be associated with mortality in lions. However, the lions were also found to be in a state of general poor health exhibiting signs of severe anaemia, clinical dehydration and being covered in skin ulcers resulting from infestations of Stomoxys flies (43).

It seems the Serengeti lions had been exposed to an unusually large amount of multiple, simultaneous infections which simply overwhelmed their immune systems (see note below). But what was the cause of this sudden outbreak of disease?

Well, it seems that prior to the outbreak of CDV the Serengeti had experienced severe episodes of drought resulting in very high die offs of cape buffalo (Syncerus caffer). The droughts were then followed by heavy rains which allowed for a surge in tick numbers amongst the remaining debilitated buffalo. As these highly stressed buffalo continued to die lions feeding on their carcasses, it is thought, were exposed to unusually high amounts of disease carrying ticks. Hence when distemper broke out the lions were already suffering from an exceptionally high number of blood borne parasites as well as the stress of the recently experienced severe weather conditions. This then is why the lions were so vulnerable to disease and died in strikingly high numbers (44). 

The implications of the 1994 and 2001 disease outbreaks do not bode well for lions. These disease outbreaks may be an alarming indicator of epidemics to come as future climate scenarios predict a significantly higher number of droughts followed by exceptional rains (45). Under these volatile weather conditions pathogens previously thought to be inconsequential may come to play an increasingly important role in the considerations of conservationists striving to protect dwindling lion numbers. 

Furthermore, emerging disease outbreaks may not only impact directly on lion populations but also on one of the most commonly proposed tools for conserving the species, tourism. This is because, like lions, humans may also be more susceptible to increasingly widespread pathogens and thus less willing to travel to areas on safari where they may be exposed to nasty bugs such as malaria or Rift Valley fever. In the final section of this article we shall consider the implications of climate change on tourism and what this could entail for conservation efforts. 

(note - It should also be noted that nearly all lions found in the Serengeti are thought to be infected with FIVple, the lion version of the feline immunodeficiency virus. At the time of the study it was thought that FIVple did not contribute to morbidity (illness) in lions, however, scientists, including those involved in the Serengeti study, are now revising this assumption.

The Significance of Threats to Tourism 

In the era of sustainable development initiatives tourism lies at the very heart of many conservation strategies especially in rural areas where conservationists are struggling to convince communities to accept the presence of predators such as lions. In areas of high conflict between lions and humans such as experienced in parts of Kenya, conservationists are keen to promote the revenue generating potential of big cats, with a male lion in Amboseli National Reserve, for instance, estimated to be capable of attracting up to US$ 128 000 a year in tourist revenues (46). 

The continuing popularity of the “gap year” or career break tourism sector has also opened up new funding streams for conservation. Tourists of an environmentally conscious disposition can now participate as volunteers on conservation projects across the world contributing to the preservation of a wide range of species from sea turtles (Pongo pygmaeus) (47). In 2007 tourists travelling as conservation volunteers from the United Kingdom alone spent nearly GB£ 12 million visiting conservation projects often providing the main source of revenue for the host project (48). 

The volunteer tourist sector is of particular significance for lion conservation as most travellers wish to participate on projects that will provide the opportunity to get a “hands on” experience with charismatic species such as the lion. This aspect of volunteer tourism allows conservationists to not only fund research but also channel revenue towards communities that must tolerate the presence of predators if these species are to survive. By providing an economic incentive for tolerating predators it is hoped that communities will not only desist from killing wildlife but will actually come to view them as an important source of economic benefit. This “win-win” scenario for both conservation and development has been the holy grail of conservationists since the advent of the concept of sustainable development in the late 20th century (49). 

However, as we discussed above, climate change may lead to an increase in the amount and severity of pathogens across the African continent with diseases such as malaria and Rift Valley fever encroaching into new areas . The fear is this increased risk of illness will deter tourists from travelling to rural areas where their spending can make the most significant impact. Some of the more recent studies seeking to predict tourist trends in a world increasingly affected by climate change suggest that tourists will in future avoid travelling to low lying or tropical areas and instead either stay at home or visit areas at higher altitudes (51). 

Furthermore, environmentalists themselves may inadvertently be harming tourisms potential to act as a source of sustainable development by discouraging people to travel on long haul flights because of fears that international travel contributes to carbon emissions (52). 

However, while acknowledging that tourism may be negatively affected by climate change it is also possible that in regions where agriculture becomes less economically viable wildlife tourism may be able to fill the income gap providing an alternative source of revenue for communities encouraging them to promote the conservation of wildlife. 

Climate Change and Conservation: A Complex Multifaceted Affair 

Even from this brief overview of the challenges produced by climate change in Africa we can see how we are faced with a complex, nuanced future. Climate changes environmental impact will affect widespread and varied habitats in many different ways, possibly altering the African landscape dramatically. While numerous species, including lions, will be pushed to the edge of existence in many of the areas they currently inhabit, it is possible that with carefully enacted conservation plans we may be able to mitigate and adapt to this future environment including possibly establishing new, viable wildlife populations in newly emerging habitats. 

Ultimately we are faced with a future of great uncertainty and only time will tell how successful our efforts will be in protecting the wildlife of Africa from humanities ongoing pollution of this very special and unique world. 


References

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