Environmental degradation is both a driver and consequence of disasters, reducing the capacity of the environment to meet social and ecological needs.
Over consumption of natural resources results in environmental degradation, reducing the effectiveness of essential ecosystem services, such as the mitigation of floods and landslides. This leads to increased risk from disasters, and in turn, natural hazards can further degrade the environment.
The reduction of the capacity of the environment to meet social and ecological objectives and needs is described as environmental degradation (UNISDR, 2009a). This degradation and the associated decline of ecosystems and their invaluable services (the benefits we obtain) are driving disaster risk. Changes to the environment can influence the frequency and intensity of hazards, as well as our exposure and vulnerability to these hazards. For instance, deforestation of slopes often leads to an increase in landslide hazard and removal of mangroves can increase the damage caused by storm surges (UNISDR, 2009b).
52% of land in Africa is considered degraded (UNISDR, 2015a).
Land degradation is both a cause and effect of rural poverty and vulnerability. Poor rural households in developing countries suffer disproportionately from land degradation, the direct effects of which include losses in soil organic content, nutrients and water storage and regulation, which in turn lead to a loss of productive capacity and wildlife habitat. In the low input-low output agricultural systems common to poor rural areas, such as sub-Saharan Africa, nutrient inputs to the soil are almost always less than the outputs (UNISDR, 2009b). Land degradation, therefore, particularly drives drought risk (UNISDR, 2013a; Erian et al., 2012 in UNISDR, 2015a), but can also drive climate change, leading to increases in average (mean) temperatures and decreases in mean precipitation at the local level (UNISDR, 2011).
Most ecosystems have been intentionally or unintentionally modified to increase the supply of certain services. However, an increase in the supply of services can frequently lead to declines in other services, because ecosystems produce many services simultaneously. For example, increased food production changes the absorption capacity of the land and can lead to reduced flood protection (UNISDR, 2009b).
Rates of overconsumption now exceeds the biocapacity of the planet by 50% (UNISDR, 2015a).
Population growth and economic development area seen as ubiquitous drivers of environmental change through energy, transport, urbanisation, and globalisation (UNEP, 2012). Economic growth is often associated with ecosystem destruction and degradation, for example with the conversion of mangrove forests into shrimp farms, primary forests into plantations to produce palm oil or soya, or wetlands and floodplains into urban developments, or with the processes of land degradation and aquifer exhaustion associated with intensive agriculture (UNISDR, 2015a). The pursuit of unlimited economic growth has led to an increasing and unsustainable overconsumption of energy, fresh water, forests and marine habitats, clean air and rich soil at the global scale.
As with other risk drivers, consumption is characterized by social and geographical inequality. Many of the disaster risks associated with the overconsumption of energy and natural capital are not borne by those who benefit from the consumption and wealth generated, but is instead transferred to others who rarely see the benefits of consumption (UNISDR, 2015a). This situation can lead to the redistribution of disaster risks and the associated losses and impacts - thus driving risk inequality (UNISDR, 2015a).
Concentrating on the deeper, underlying causes of environmental degradation will allow the goals and targets set out in international, regional and national agreements to be met in a more effective way (UNEP, 2012).
At the local level, reducing environmental degradation and ecosystem decline requires acknowledgement of the links between unsustainable development and poverty. Communities are often driven to degrade their natural environment as short-term coping mechanism for dealing with immediate problems; for instance, surviving a failed harvest by selling wood. Strategies for reducing poverty by investing in environment-sensitive development should therefore support efforts to reduce disaster risk and enhance resilience.
Coastal ecosystems, including coral reefs, sea grasses, mangroves and other beach vegetation, play a key role in mitigating impacts of storm surges and coastal flooding (UNISDR, 2011).
A number of approaches and tools in environmental management, including environmental impact assessments, now take explicit account of disaster risk, while increasing investments are now being made in ecosystem approaches to disaster risk management at all levels (UNISDR, 2015b).
However, there are still only few examples of integrated community-level approaches that have been scaled up with success. One exception is the grassroots approach to water management at the border between Guatemala and Mexico, where local initiative has turned into national strategy (IUCN, 2012 in (UNISDR, 2015a).
At the policy level, there are common elements in successful policies across the regions, which extend to managing climate change. Tools such as integrated water resources and coastal zone management; the removal of environmentally harmful subsidies, especially on fossil fuels and/or carbon taxes; renewable energy, marine protected areas, and cross-boundary biodiversity conservation, are all examples of policies used in more than one region, but customized to each context. Formal, robust, and well-established governance mechanisms and structures at all governance levels are a necessary foundation for successful implementation of environmental policies (UNEP, 2012).
Innovative schemes including ‘green infrastructure’ projects that maximise ecosystem services, including the reduction of flood risks, have been implemented (UNISDR, 2015a). For example, in Napa Valley, California, green infrastructure in the form of wetlands creation and protection as well as floodplain restoration is combined with a set of grey infrastructure investments such as conventional rock and concrete flood protection (UNISDR, 2015a). Mangrove conservation and restoration is another area where considerable efforts have been invested, though the results are still mixed (UNISDR, 2015a).
Transboundary cooperation, including knowledge sharing, is important when natural areas are shared. Improved environmental governance is needed if environmental degradation and the unsustainable use of natural resources are to be reversed (UNEP, 2012).
The tropical forest alliance, for instance, is a global public private partnership that aims to help business remove deforestation from their entire supply chain whilst at the same time promoting the economic and social development of the communities concerned. Governance of land and forest must, therefore be participatory, transparent and accountable and, thus, needs to engage local and indigenous people in decision-making (UNEP, 2014).