Natural Disasters and Extreme Events in Agriculture

Natural disasters play a major role in agricultural development and the economic cost associated with all natural disasters has increased 14 fold since the 1950s. Natural disasters are classified into hydro-meteorological and geophysical disasters. Definitions of various types of hydrometeorological disasters such as floods, droughts, cyclones, forest fires, heatwaves were presented. Evidence available from different parts of the world showed that there is a rising trend in the occurrence of natural disasters from 1993 to 2002. Impacts of droughts, cyclones, floods, forest and bush fires on agriculture, rangeland and forestry were described with suitable examples. While the predominant impacts from these disasters are negative, there are some positive impacts as well. Environmental degradation is one of the major factors contributing to the vulnerability of agriculture, forestry and rangelands to natural disasters because it directly magnifies the risk of natural disasters. Some methodological issues concerning the characterization of the impacts of natural disasters in agriculture, rangeland and forestry were described. There is an urgent need to mitigate the effects hydro-meteorological disasters through improved use of climate and weather information and forecasts, early warning systems, and appropriate methods of management of land and natural resources.

Drought is a slow-onset, insidious natural hazard. Vulnerability to drought is increasing in all drought-prone nations and the traditional crisis management approach to address the impacts of these events has proven to be ineffective, untimely, and poorly coordinated. Amore risk-based management approach has been gaining acceptance worldwide because it addresses the underlying cause of impacts — vulnerability. This approach includes development of national policies and mitigation plans directed at identifying the causes of drought impacts and improved early warning systems that provide information to decision makers in a timely manner. This paper discusses the conceptual framework for improved drought preparedness planning with an emphasis on reducing societal vulnerability to future episodes of drought.

Extreme events in the Southwest Pacific (SWP) are widespread and largely centre on tropical cyclones, droughts and floods. These events are directly influenced by the state of the El Niño Southern Oscillation (ENSO). The impacts of climate extremes are dramatic, particularly on Small Island Developing States (SIDS) of the SWP region. They cause destruction and widespread damage to human, socio, economic and development well being of local communities, examples being tropical cyclones Ofa, Val and more recently Heta, Olaf and Percy that devastated Samoa, Niue, Tonga and the Cook Islands and the severe impacts of the 1997–1998 El Niño event on Papua New Guinea and Fiji. Although warming in the SWP region is decreasing, extremes of low temperature, the trend of more El Niño episodes in the 20th century, based on observations, has increased both dry periods and extreme rainfalls in significant parts of the region, especially near the Date Line. The phase of ENSO also significantly affects temperature and rainfall anomalies and extreme across the region, with sharp gradients between contrasting areas of above and below average departures. ENSO also changes tropical cyclone track, density and occurrence, with El Niño events increasing the frequency and displacing tropical cyclones more towards the central South Pacific, and La Niña episodes decreasing the frequency and confining tracks to the west of the Date Line.

Seasonal to Inter-annual (SI) prediction has become a major research area and application tool that offers much promise for early warning and disaster preparedness to extreme events. In the SIDS of the SWP region, the Island Climate Update (ICU), a multinational virtual type regional climate prediction tool, with success hit rates (percentage of prediction being correct after comparing it with what actually happened) greater than 70 percent being achieved in some parts of the region since it was launched in September 1999, provides an extremely useful regional mechanism for preparing and predicting seasonal rainfall departures and other extreme events associated with ENSO for SIDS. The ICU could be used as a model in other regions.

Extreme events can cause severe damage in several sectors such as agriculture, forests and fisheries. In order to facilitate early detection of these harmful episodes, adequate climate and agrometeorological databases must be ensured. Some observational data and products necessary for early detection are presented in this paper. It briefly reviews the main features of proper databases that provide quality controlled data and products, useful to the end-users, easily accessible and in a timely manner. The data can be accessed through the standardization of database management and electronic accessibility. The main features and importance of data collection, automatic weather stations (AWS), database management and relational database management systems (RDBMS) are described. Examples of agrometeorological databases, database management systems and their applications and accessibility are given. Remote sensing (geostationary satellites, NOAA-Advanced Very High Resolution Radiometer (AVHRR), radar and lighting detectors) offers a valuable source of spatial information and can be complementary or even alternative to ground-based observations. Due to the processing of data from various sources in agrometeorology, and the need to display them in maps, geographical information systems (GIS) are in wider use today. GIS can help to identify the risk, extent and severity of many extreme events. Some examples of applications of remote sensing and GIS are presented. Finally, training, interdisciplinary collaboration and communication between users and developers of products are referred as essential means to achieve these goals.

Disasters induced by natural disasters carry significant consequences for agriculture, forestry and fishery sectors. In this paper, an attempt was made to give a brief account of tools available for forecasting or warning of natural disasters including floods, droughts, tropical cyclones, forest fires, and volcanoes. Use of such tools is important to decrease the impact on natural disasters on agriculture and forestry. Amongst the most well known predictions schemes is the El Niõ — Southern Oscillation (ENSO). This and other prediction tools have been discussed with suitable examples.

Agricultural production is highly dependent on weather, climate and water availability and is adversely affected by the weather and climate related disasters. Impacts of extreme events on the agricultural sector can be positive or negative. While it is easier to contemplate negative impacts of extreme events such as droughts, tropical cyclones and floods, there are several positive impacts or benefits of extreme events. In order to assess the impact of weather disaster on agriculture, one must link two fundamental aspects, first, the disaster proper i.e. the destructive power of the event and secondly, the characteristics of the agricultural system which has been hit. Agricultural planning and practices need to be worked out with consideration to the overall water requirements within an individual agroclimatic zone. Sustainable strategies must be developed to alleviate the impact of natural disasters on crop productivity. All such strategies are location, time, crop, crop stage and socio-economic condition specific. Remote sensing satellite information helps minimise damages e.g. the death of cattle, humans etc. and the damage of agricultural production in time of natural calamities by early warning system.

Damage from catastrophic events is both social and economic. Perhaps one of the most challenging aspects of modern life is our increasing ability to communicate, especially in the developed countries. This communication has brought an increased sense of connectedness but also made people more aware of the occurrence and consequences of natural disasters. In this paper we explore the potential for changes in frequency and magnitude of weather-related natural disasters and some of their connections to climate change and variability. Although changes in climate may have great consequence, increasing climate variability may become the most immediate challenge for world society. Both observations and simulation models show that as the potential for climate variability increases, natural disasters have become more frequent and of deeper economic impact. In areas of the world where these devastating events appear to occur and then quickly reoccur in a different guise, the sharing of information and resources becomes a pivotal issue for collective security. New technologies can help us understand these events and prepare for them. New social institutions may also be needed to cope with these issues on a global scale.

Tropical cyclones are perhaps the most devastating of all natural disasters and the vulnerability to tropical cyclones is becoming more pronounced because of high population growth rates in the tropical and subtropical coastal regions. Tropical cyclones cause a range of destruction in the coastal areas. Various features of tropical cyclones affecting China and their impacts on lowland agriculture and coastal fisheries were described.

Frost and high temperature injury are two important agrometeorological disasters in China. In this paper, the concept of frost and its differences from other low temperature injuries are presented. Recent studies on injury mechanism of frost are introduced. Frost-prone areas, crops harmed, and statistical characteristics in China are analyzed and summarized. Frost preventive and preparedness measures in China are discussed. The detrimental impacts of high temperature injury on crops, vegetables, fruit trees, milk yield, livestock, and fish in China are also briefly reviewed.

The drylands of the world are affected by moderate to severe land degradation from wind erosion and there is evidence that the frequency of sand storms/dust storms in increasing. Human induced change is by far the most significant factor in the alarming increase of sand storms in some regions. The definition of sand storms and dust storms were presented and the classifications currently in use were discussed. The occurrence of wind erosion at any place is a function of weather events interacting with soil and land management through its effects on soil structure, tilth and vegetation cover. The mechanics of sand and dust storms and their spatial and temporal distribution was described. The impacts of sand and dust storms were described in terms of crop damage, soil productivity losses, economic losses, mass migration, health impacts, and impacts on climate. Not all the impacts are negative and the positive impacts of sand and dust storms were described. Measures to combat sand and dust storms include reduction of the impact of wind speed through the use of live wind breaks or shelterbelts; protection of the loose soil particles through the use of crop residues or plastic sheets or chemical adhesives; and increasing the cohesion of soil particles by mechanical tillage operations or soil mulching. Future strategies for reducing the impacts of sand storms and dust storms must be based on community-based approaches that integrate effective crop and land management strategies as well as policy interventions to promote more effective soil conservation measures at the national and regional scales.

Severe droughts have occurred frequently in various parts of the United States throughout the 20th Century. These natural disasters caused severe hardship not only on the agriculture sector of society, but also on the entire socio-economic infrastructure. Until recently, governments and relief agencies responded to a drought disaster from a crisis perspective in a purely reactive approach. However, a comprehensive disaster management approach has emerged over the past decade, shifting from reactive relief to proactive risk management. Risk management is based on preparedness and mitigation measures. Interagency collaboration led to the development of a coordinated national drought policy.

This Chapter describes recent events in the development and application of a national drought policy in Australia. Prior to the 1990s, Government assistance to drought-affected farmers and pastoralists was based on the assumption that drought was an unpredictable natural disaster. A paradigm shift towards the present policy of “self reliance” occurred in the early 1990s. Under this policy, farmers were expected to be able to manage through most droughts, with Government assistance only available in the event of droughts of unusual length or severity — so-called “exceptional circumstances.” Details of the policy, and its application in, and following, drought situations, are briefly outlined.

Illustrated by the experience of 2002–03, one of Australia’s worst-ever droughts, we show that the development of drought policy in Australia is an ongoing process, in which attempts to apply aspects of the policy in practice generally reveal deficiencies, leading to subsequent modification of the policy. Areview of National Drought Policy conducted by the Australian Government after the 2002–03 drought generated a number of recommendations. Among these were: the nearly universal endorsement by stakeholders that proactive drought preparedness measures should be encouraged by Governments; and that improvements were needed to the reliability of seasonal predictions, with calls for better-coordinated research into climate variability, and better presentation of prediction information.

The Chapter also describes changes in water management policy in Australia, which also underwent a fundamental change during the early 1990s. Case studies are provided of certain aspects of the policy, including the application of water entitlements in rural areas, and water restrictions in urban areas.

The Chapter discusses some likely future developments, including discussion of the possible implications for drought policy posed by future climate change.

This Chapter describes the role of public education and training in mitigating the effects of natural disaster in Australia. Emphasis is on weather- and climate-related disasters, which have historically caused heavy economic losses, and sometimes significant loss of life. Three main themes are identified: (a) the continued development of a community-oriented approach to hazard minimisation, in which communities are encouraged and trained to take measures to protect themselves and their property when adverse weather or climate situations threaten; (b) issues involved in educating potential beneficiaries in the effective use of climate information to minimise impacts from climate extremes; (c) underpinning both the foregoing to some extent, the importance of developing a sound communication strategy between authorities responsible for disaster management, the people likely to be affected, and the media.

In describing the community involvement programs (Sect. 13.3), attention is focussed on responses to the threat posed by bushfires in southern Australia, and tropical cyclones in northern Australia. Public education campaigns, designed to minimise adverse effects of severe storms, skin damage due to solar radiation, and heatwaves are also described (the latter two elements are not high profile hazards, but have been responsible for many deaths in Australia). Sect. 13.4 briefly describes capacity-building activities designed to enable the effective use of seasonal climate predictions, a valuable tool in mitigating the effects of drought, both within Australia and over the South Pacific. It is shown that, while extensive educational and awareness campaigns over the past decade have led to increased use of seasonal climate predictions in decision-making by the agricultural sector, a number of barriers remain to more widespread acceptance of this tool. Section 13.5 highlights the importance of good two-way communication between service providers and end users to ensure information is relevant, adequately understood, and effectively applied. The role of the media in communicating information during times of major climate events, such as drought, is also discussed. We conclude with a summary of some promising avenues for improving the effectiveness of managing natural disaster through educational and training activities, along with some thoughts on the implications of future climate change.

Efficient management of risks due to meteorological disasters is very important in China because of their increasing occurrence and limited capability for prevention and preparedness in China. Losses due to meteorological and related disasters account for more than 70% of the natural disaster losses in China. Early warning and prediction of agrometeorological disasters includes improvements in statistical prediction models, predictions based on climate prediction and agrometeorological models, and early warning for agrometeorological disasters using GIS. Risk assessments of agrometeorological disasters are based on identification of risk and use of models to characterize disaster intensity, disaster loss and the capability to combat disasters. Several ways of popularizing the preventive measures of agrometeorological disasters were described with suitable examples.

Natural disasters are known to cause severe economic losses and in many developing countries in the form of decline in agricultural production, destruction of food reserves, damage to water supplies, etc. This report focuses on land use strategies to mitigate natural disasters including tropical storms, floods, droughts, dust storms and sand storms, frosts, volcanoes, landslides, bush, and forest fires. It is important that disaster preparedness and prevention projects are built into a wider development strategy. Mitigation efforts need an integrated and concerted action by all the agencies concerned. Long term disaster reduction efforts should aim at promoting appropriate land-use in the disaster-prone areas, by harmonizing land suitability with agricultural development strategies.

Drought is a many faceted natural disaster that leads to serious socioeconomic impacts particularly affecting agricultural production and water supplies. There are two distinct phases in which the application of the knowledge of weather and climate can reduce the impact of drought on the communities. The first is the long term planning in which strategies can be devised, and precautions taken to reduce impact. The second phase is the action taken during the onset of the event to reduce adverse effect. Efforts were made to stabilize dryland agriculture by evolving contingent crop production strategies in rainfed areas of India. Drought management policies included agricultural planning and practices with consideration of overall water requirement within the individual agroclimatic zones.

The ill effects of drought, to a considerable extent, can be alleviated by adopting proper crop management strategies. These strategies may vary from moisture conservation to manipulation of plant population, and even mid-season corrections. Rainfall also can be harvested in either farm ponds or in village tanks and can be recycled. In case of drought mitigation, it was recommended that economies diversify to include agro-industry or various tertiary products, which could create new forms of income. The focus in mitigation should be on measures like improvement in agriculture, management of rangeland, development of water resource and animal husbandry. There is an urgent need to develop appropriate policies and strengthen institutional mechanisms for drought preparedness and mitigation accompanied by concrete programs.

Drought and flood are the most frequent and severe natural disaster. With the development of remote sensing and GIS technology, early detection and monitoring of drought and flood using remote sensing and GIS has become a reality in China. The paper summaries the status of the field including the methods and data used. It especially presents the methods and products for early detection and monitoring of drought and flood developed by National Satellite Meteorological Center (NSMC), and gives an example of Flood monitoring.

Using the Doppler radar radial velocity data simulated by Rankine combined vortex and observed by a Doppler radar and typhoon yearbooks, the applied study about the objective positioning methods of a typhoon was made. Two methods had been established. A series of simulated and actual tests were made for the two methods. The results show that the errors of the two methods in simulated tests are below 0.5 ∼ 1 km and those of radial maximum wind are below 0.12 km. Compared to the best operational track data, the errors of the two algorithms in actual tests are below 3 ∼ 13 km, sometimes those are below 3 km. So it is feasible to decide the center of a tropical cyclone with the data of a single Doppler radar radial velocity in operational tropical cyclone positioning. The positioning results of the two methods are of important reference and guidance in operational tropical cyclone forecasting and warning.

Forest, shrub-steppe, and grassland fires have come under the inclusive terminology of wildland fire. In the past decade, fire occurrence and area of surface burned has increased dramatically. This increase in wildland fire frequency and intensity has been driven by climate variability and in some countries, worsened by fuel management policies. Many areas that have been burned are in remote areas of the world where collection of information on fires is either difficult or impossible on the ground. Satellite remote sensing has been applied to this problem with some remarkable successes in locating large fires, mapping the areas burned, and tracking smoke plumes. For smaller fires, pixel size limitations have led to use of aircraft based sensor development. To understand fire ecological consequences, parameters such as fire intensity, fuel consumed, and heat release rate to atmosphere must be understood. In parts of the Southwest Pacific Region, the potential for fire occurrence is exacerbated by lack of infrastructure common to more developed areas. The use of remote sensing, geographic information systems, and computer models will allow fires to manage to lower risks.