5. Climate Change and Biodiversity

The Intergovernmental Panel on Climate Change (IPCC) released its 4th Assessment Report in 2007, strengthening earlier findings that recent greenhouse gas (GHG) emissions have far exceeded pre-industrial values but adding that emissions had climbed even faster in the decade from 1995 to 2005 than ever before (IPCC, 2007a). Isotherms (lines connecting places with the same temperature) are shifting at a rate of 40km per decade in the northern hemisphere and at these rates, along with compounding factors such as habitat loss and pollution, some species will find it difficult to adapt (Hansen et al., 2006).

Box 5.1 What's changing in climate change?

Key findings from the report from the biodiversity perspective include:

More recent evidence presented by IPCC scientists (March 2009) reported that even the dire evidence presented in the 4th Assessment Report was too optimistic. Warming between 2000 and 2007 was unprecedented, mainly due to rapid economic growth in China and India powered largely by coal.

Solomon et al. (2009) reported that the severity of the impacts resulting from climate change was related not only to the magnitude of the change but also to the potential for irreversibility. They concluded that the carbon dioxide emissioninduced climate change will be largely irreversible for as many as 1,000 years after emissions stop because of the length of time required for temperatures to decrease in response to decreased emissions.

As delegates met in April 2009 in Bonn, Germany, for a preparatory meeting for the United Nations Framework Convention on Climate Change (UNFCCC) COP 15 in Copenhagen in December 2009, the news of the collapse of the Wilkins Ice Shelf, an Antarctic ice plate the size of Manhattan, was on everyone's mind as a dramatic indicator of accelerating climate change and gave even greater urgency to the negotiations taking place.

The projected impacts of increasing temperatures are presented graphically in Figure 5.1.

Figure 5.1 Impacts of increased temperatures (IPCC, 2007a)

The impacts of climate change alone are causing significant changes to our environment. However, climate change is also a threat multiplier and a threat accelerator – amplifying the impacts of other biodiversity threats already stressing nature, including habitat degradation, pollution, invasive species, emerging infectious diseases and overexploitation. Ultimately, delivery of virtually all ecosystem services will be affected, some more than others. The human response to these changes will be a major preoccupation in the coming decades.

With the sense of urgency generated through media and scientific reports, climate is now widely recognized as everyone's issue – businesses, conservationists, local communities, municipal governments, private land owners, protected area managers and many others. Partnerships among these diverse sectors of society, generated by climate action, could also benefit biodiversity. Action is needed now, both to manage the avoidable impacts through mitigation and, increasingly, to cope with the unavoidable impacts through adaptation.


For biodiversity, the impact of climate change is already evident. A review of 1,700 species showed that nature was following climate trends, with range shifts averaging 6.1km per decade towards the poles, and spring events advancing by 2.3 days per decade. This provides strong evidence that climate is already changing the natural world (Parmesan et al., 2003).

The recently-released Climatic Atlas of European Breeding Birds reports that the potential breeding distribution of most of Europe's breeding birds will shift several hundred kilometres north (Huntley et al., 2007). Many cold-blooded species such as reptiles are projected to fare poorly in a warming world (Kearney et al., 2009). In addition, amphibian species extirpations and extinctions have been linked with climate change (Ron et al., 2003; Burrowes et al. 2004; Pounds et al., 2006). Marine fishes are predicted to be affected by rising water temperatures which will change oxygen levels in the world's oceans (Poertner and Knust, 2007), and increasing carbon dioxide is increasing the acidity of the oceans, with severe impacts on some marine communities (such as coral reefs). Climate change will affect species distribution, demography and life histories, with consequences for human livelihoods including changing patterns of human disease distribution (Box 5.2).

Box 5.2 Some examples of climate change impacts on species

Changes in species distribution

Changes in population demography

Changes in species behaviour

Climate change impacts on species are not distributed equally across the spectrum of life either taxonomically or geographically. Groups of species that are more vulnerable include those that are already rare or threatened; migratory species; species with restricted ranges (narrow endemics); polar communities; peripheral populations; genetically impoverished species; and specialized species including alpine and island species. Those with the highest specializations in terms of lifestyle or location are typically most at risk. Using such characteristics, the Species Survival Commission (SSC) has completed an assessment of species vulnerable to climate change and therefore potentially at an increased risk of extinction (Vié et al., 2009). They reported that:

While climate change is having a negative impact on some species, it is creating more favourable conditions for others. The traits of species that make them invasive – ability to survive in adverse conditions, rapid growth rates, and wide dispersal – will often help them succeed under climate change. Acting together, climate change and invasive species can put many native species in situations beyond their ability to adapt. For example, Mytilus galloprovincialis, an invasive blue mussel species, has a higher tolerance for warm water temperatures and increased salinity levels than the native blue mussel, Mytilus trossulus, in California. Thus, M. galloprovincialis has replaced the native mussel along much of the southern and central California coastline (Braby and Somero, 2006).

Climate change is also having impacts at ecosystem levels and it is expected that polar ecosystems and the Mediterranean-type ecosystems of the Mediterranean basin, California, Chile, South Africa and Western Australia will be particularly strongly affected by climate change (Lavorel, 1998; Sala et al., 2000). The 2008 update of the Status of Coral Reefs of the World included both good and bad news. Western Pacific and Indian Ocean reefs, which had earlier suffered severe bleaching as a result of increased ocean temperatures, were reported to be recovering but the overall impacts of climate change and of human activity remained significant threats to long-term survival of the world's reefs (Wilkinson, 2008). High altitude ecosystems and cloud forests are also at risk. Replacement of tropical forest by savannah is expected in eastern Amazonia along with vegetation changes in north-east Brazil as a result of synergistic effects of land use and climate change (Magrin et al., 2007).

Climate change will certainly alter the way biodiversity is managed and conserved. Burns et al. (2003) reviewed the impact of climate change on mammalian diversity in US National Parks and reported that because of species losses of up to 20% and rapid influxes of new species, protected areas may not be able to fulfil their original mandates in terms of conservation. Management agencies will need to determine how protected areas can best be designed and managed today to enable them to adapt to possible future climate changes, and help mitigate the causes of climate change (for example, by storing carbon in vegetation, soils, and waters). UNESCO's World Heritage Committee has recognized that climate change is already affecting the world's protected areas and is likely to affect many more in the years to come. In response, they have adopted a strategy to assist countries as they address this threat (UNESCO, 2006).

With measurable impacts already evident at both species and ecosystem levels, the delivery of ecosystem services inevitably will be affected. For example, scientists are projecting changes in rainfall for southern Africa as a result of changes in temperature in the Indian Ocean, with resulting decreases in agricultural output and increases in food insecurity in the region (Funk et al., 2008). Conversely, ecosystems can play a role in mitigating those impacts. Sheil and Murdiyarso (2009) report on the potential role that forests play in hydrological cycles and maintaining rainfall. These and similar findings provide strong arguments in support of landscape approaches to climate change adaptation and mitigation.


Small island states are especially vulnerable to most of the impacts of climate change. Their land area decreases as sea level rises, their protecting reefs diminish as oceans acidify, and their vegetation cover has difficulty adapting to new climates because of their low levels of diversity. Many islands already suffer environmental degradation as a result of pollution, habitat destruction, invasive alien species, and overexploitation. With the addition of climate change impacts, only the most hardy of species can be expected to survive (often invasive species).

A landscape-scale approach is needed to help islands in their efforts to adapt to climate change impacts. Where inland forests and wetlands are linked to coastal ecosystems, they should be managed as an integrated entity. Different categories of protected areas can serve as an important part of the landscape mosaic that can help ecosystems adapt to the impacts of climate change.

Islands also provide excellent laboratories in which to study both impacts of climate change and responses to mitigation and adaptation action. IUCN, through the Mangroves for the Future Initiative, is working with other organizations to manage coastal ecosystems sustainably so as to enhance their adaptive capacity and enhance resilience of the communities that depend of them.


Climate change mitigation seeks to avoid the unmanageable; climate change adaptation seeks to manage the unavoidable. Responses, in terms of both mitigation and adaptation, must be developed on the basis of improved understanding of the dynamic context and cascade of impacts across all threats and the potential impacts across stakeholders. In late 2006, the UK Government issued a detailed report on the economics of climate change (Box 5.3) which concluded that action to stop climate change makes good economic sense. The report specifically highlighted forest conservation as a highly cost-effective way to slow climate change thereby making the case for avoiding deforestation for both climate and conservation reasons (Stern, 2006).

Box 5.3 Key messages of the Stern Report on Climate Change

Letting climate change proceed under a “business-as-usual” scenario would impose costs of between 5% and 20% of world GDP, whereas shifting to a low-carbon economy that stabilizes the climate would cost about 1% of world GDP. In short, the report finds that the benefits of stabilizing the climate far outweigh the costs.

Climate change impacts will vary widely among nations and, as in previous analyses, developing countries appear likely to be worst affected.

Source: Stern, 2006

IUCN's Members, through Resolution WCC 4.075 and others, have affirmed the strong links between conservation, biodiversity and climate action. That action recognizes the role of ecosystems including forests, peatlands, grasslands, watersheds and coastal ecosystems in supporting climate change mitigation and adaptation. In particular, in terms of international climate change policy under the UNFCCC, IUCN has focused on two key opportunities for biodiversity – Reducing Emissions from Deforestation and forest Degradation in developing countries (REDD) and Ecosystem-based Adaptation (EbA).


In terms of mitigation, REDD provides real opportunities to both mitigate climate impacts while also conserving global forest resources and the associated ecosystem services and dependent livelihoods. Deforestation and forest ecosystem degradation are significant causes of the global warming recorded in the past century, accounting for 17% of global GHG emissions, more than the entire transport sector. The UK Government's Eliasch Review (2008) contends that “without tackling forest loss, it is highly unlikely that we could achieve stabilization of greenhouse gas concentrations in the atmosphere at a level that avoids the worst effects of climate change”.

Another resource that the world can look to is the standing carbon stocks (forests) in the world's protected areas – calculated at 312 Gt of carbon or about 15% of the global total of sequestered carbon (CBD, 2008).

But a REDD mechanism under the UNFCCC that does not incorporate the considerations of those people most directly affected will inevitably fail. A successful REDD mechanism requires attention to governance issues if it is not to alienate or disenfranchise local forest-dependent communities, exacerbating conflict and thus undermining the prospect of securing permanent and additional reductions in emissions. Countries can draw on a substantial body of international agreements and best practice guidance to provide the necessary underpinning for national level REDD mechanisms. These include the United Nations Non-legally Binding Instrument on all types of forests; the Expanded Programme of Work on Forest Biodiversity of the Convention on Biological Diversity; and the United Nations Declaration on the Rights of Indigenous Peoples, among others.


Ecosystem services (Chapter 4) underpin human well-being and some of them are critical for regulating our climate and managing the impacts of climate change. On the other hand, the changes to climate patterns that are inevitable will undermine some of the services that ecosystems provide, thereby threatening human livelihoods. The increases in sea level, violent storms, melting glaciers, and droughts and floods influenced by global warming will result in millions of people losing their homes and livelihoods, and sometimes even their lives.

Evidence suggests that a diverse system will be more resilient when faced with environmental change and thus show greater ecosystem adaptability. In essence, a greater diversity of species and populations performing similar functions within an ecosystem is likely to result in a greater probability of ecosystem processes being maintained in the face of environmental change (McCann, 2000). EbA identifies and implements a range of strategies for the management, conservation and restoration of ecosystems to ensure that they continue to provide the services that enable people to adapt to the impacts of climate change2. EbA is a cost-effective, immediate and accessible adaptation solution. Examples of EbA include the management of coastal ecosystems to reduce flooding during storm surges. Mangroves, salt marshes and other coastal vegetation types provide natural infrastructure which reduces the inland impacts of wave energy, acts as a barrier to debris, and reduces coastal erosion. Another example includes maintaining and enhancing the resilience of ecosystems at the landscape-scale, through systems of effectively managed protected areas and improvements in the management of surrounding lands and seas.

Climate change impacts on people will be differently distributed among different regions, generations, age classes, income groups, occupations, and gender. Rural communities, which are often most directly dependent on local natural resources, will be most affected, especially those in the most vulnerable ecosystems. The poor, primarily but by no means exclusively in developing countries, will be disproportionately affected due to their limited capacity to adapt to change and dependence on resources such as water and food that will be affected by climate change (IPCC, 2007b). Conversely, these groups can also be powerful agents of change by playing a key role in disaster reduction, deforestation and energy uses. Further, EbA is a means of adaptation that is often more accessible to the rural poor than technology or infrastructure solutions. EbA can be a means for supporting indigenous peoples by harnessing traditional knowledge in order to adapt to changing climatic conditions that also incorporates gender-specific needs in relation to natural resources.

The impacts of climate change could put poverty reduction strategies at risk and undermine efforts made to achieve the full range of Millennium Development Goals (MDGs). Therefore, poverty reduction strategies and development planning should incorporate EbA as an integral element of overall programmes to address both poverty reduction and climate change adaptation. Many tools are available to assist local communities in identifying their vulnerability to climate change impacts and also their options in adapting for the future. Among these, CRiSTAL (www.cristaltool.org), a climate risk screening tool developed by the International Institute for Sustainable Development (IISD), IUCN, Intercooperation and the Stockholm Environment Institute (SEI), helps development and conservation planners work with local communities to integrate climate change adaptation needs into their projects.


In managing the impacts of climate change, we cannot ignore the impact of energy choices, both on mitigation and adaption planning and implementation. This will be discussed in more detail in Chapter 7. In addition, climate change issues should include aspects of rights-based approaches, synergies across international instruments considering climate change, and inclusion of disaster risk reduction as a complementary approach (Chapter 10).

The Stockholm Declaration (1972) stated that people have “the fundamental right to freedom, equality and adequate conditions of life, in an environment of a quality that permits a life of dignity and well-being”. The impacts of climate change will put at risk many of the basic elements that support those “adequate conditions of life” and therefore can be considered to affect human rights. Therefore, any actions taken in terms of adaptation should include consideration of human rights as an essential element. In April 2009, the Office of the United Nations High Commissioner for Human Rights, by request of the United Nations Human Rights Council, released a report on the relationship between climate change and human rights (UN, 2009).

Governance of issues relating to climate change is not simply the purview of the UNFCCC and government Parties. The linkages between climate change and biodiversity require action in many other relevant international agreements (McNeely, 2008). The Convention on Biological Diversity, for example, discusses the role of biodiversity for both sequestering carbon and adapting to climate change, while the conventions on wetlands (Ramsar) and desertification (UNCCD) deal with habitats whose effective management will contribute towards adapting to climate change in the coming decades. The United Nations Convention on the Law of the Sea (UNCLOS) deals specifically with marine ecosystems, and recent research is indicating how important marine environments are in addressing issues involving climate change. The Convention on Migratory Species (CMS) deals with wide-ranging species that are likely to be influenced by climate change and therefore could support the adaptation process. Given limited resources and time, a critical issue will be to focus on more effective coordination of action across these instruments as well as providing strong enforcement and implementation measures.

Climate change adaptation and disaster risk reduction are complementary approaches. Through the Hyogo Framework for Action 2005–2015, countries have committed to integrate climate change adaptation and disaster risk reduction through the identification of climate-related disaster risks, the design of specific risk reduction measures, and the improved and routine use of climate risk information by planners, engineers and other decision makers.

Climate change is the preeminent driver of change in today's world and an increasing threat to biodiversity and the ecosystem services it provides. As the world gathers in Copenhagen to discuss and agree on a post-2012 climate change framework, it is vital that States negotiating at the UNFCCC should:

But the job does not belong to governments alone. In the wake of the financial crisis, initiatives to renew the global economy should also take advantage of the opportunity to de-carbonize that economy including development of innovative incentives, such as carbon markets, that will provide models for broader payments for ecosystem services. Prices paid for goods and services must include the “social cost of carbon” to reflect the impacts on climate change of the entire process of raw material supply, production, distribution and consumption. This needs to apply to all countries including for exported products. Some have suggested that countries should levy a “carbon tariff” on imports, to reflect any GHG emissions associated with their production. Carbon taxes on imports may be unpalatable to some, but it can be argued with equal conviction that they are essential to the survival of the planet.

Protected areas have already demonstrated their value for conserving biodiversity that otherwise might well be lost. When properly designed and managed, protected areas can also provide the capacity to mitigate and adapt to climate change. Conserving forest cover within protected areas could be a useful contribution towards REDD, provided the challenge of proving “additionality” can be overcome, while landscape-scale management of ecosystems that include protected areas will be an important aspect of climate adaptation planning.

Last, but certainly not least, efforts to mitigate climate change must ensure that alternative energy strategies, including the use of biofuels as an energy option, fully account for and guard against any associated negative impacts on climate, biodiversity and livelihoods.

2 This definition draws from and is fully consistent with the draft report of the Convention on Biological Diversity's Ad-Hoc Technical Expert Group (AHTEG) on climate change and biodiversity.

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