Cuba Country Case Study:
Impacts and Responses to the 1997-98 El Niño Event
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Executive Summary
Setting
The Republic of Cuba is an independent state located in the Caribbean Basin. It encompasses an archipelago of 110,860 square kilometers and is administratively divided in 14 provinces, and these are further subdivided into 168 municipalities. The political and administrative capital of Cuba is Havana (with more than 2 million inhabitants) which, in turn, constitutes the smallest province in terms of area in the country. In 1998, the Cuban population was estimated at 11,139,900 inhabitants, which translates into a population density of about 100 inhabitants per square kilometer.
The agricultural area in Cuba is over 6,000,000 hectares (ha), of which more than 2,000,000 ha are devoted to the permanent cultivation of sugar cane. Almost 3,000,000 ha of the Cuban territory are covered by forest. The State owns 53.7% of the arable land, while the rest (46.3%) belongs to the private sector.
The gross domestic product (GDP) of Cuba underwent important variations in the last several years. At the beginning of the 1990s, the Cuban economy, which had been linked closely to the economies of the Socialist countries of Eastern Europe, suffered a severe impact caused by the disintegration of the Soviet Union (its main commercial partner) and the collapse of the Communist governments in Eastern Europe. This fact, along with the existence and permanence of an economic blockade imposed by the government of the United States since 1960, caused an important contraction in growth rates, which have remained under 0.5% for the GDP during these years. Since 1995, important transformations began to take place, including a wider opening to foreign investment and an accelerated development of tourism and related activities. In 1997, increments above 2% per year were registered, maintaining a growing trend until the present.
The climate of Cuba can be considered tropical or tropical oceanic, characterized by a well-defined rainy season (occasionally referred to as the "wet season" with warm temperatures, and a "dry season" when the precipitation is sparse and the temperature cooler.
The rainy season extends from May through October and accounts for nearly 70% of the annual total rainfall. The dry season runs across the remainder of the year (November through April), when Cuba is affected by weather events in the higher latitudes. These events are mainly responsible for the few rainy episodes in this season.
Climate-Related and Other Natural Hazards
Among the severe weather events that affect Cuba, tropical cyclones (TCs) are considered the most important. The number of tropical hurricanes that affect Cuba annually is quite variable, with totals that run from zero to 5. The western region of Cuba is the most affected during the hurricane season, with an average of one hurricane every 1.9 years.
Another important natural hazard in Cuba is drought. The frequency of this climate anomaly in Cuba has increased in the last few decades, bringing very harmful consequences for agricultural production and for soil conservation. Cuban soils are experiencing important symptoms of salinity and desertification in coastal and semi-arid areas. The frequency of years with moderate and severe droughts has doubled in the last 30 years.
Droughts are usually combined with high evaporation rates, which result in reduced soil moisture and a drop in the groundwater level. Occasionally, when droughts are interrupted by episodes of torrential rains, the interaction between rainfall intensity and soil loss causes intense erosion processes in soils with poor vegetative cover and a high surface drainage capacity.
Heavy precipitation (HP) is also a concern. HP episodes are those that accumulate 100 mm or more of rain in a single location during 24 hours or less. During the 1965-90 period, the occurrence of HP was about 85 days per year, on average, in the country. In El Niño years, there is a notable increase in the number of days with HP – an annual average of 100 days.
In Cuba, a thunderstorm is classified as a severe local storm (SLS) when it is associated with tornadoes, destructive wind gusts of more than 90 km/h, hail, and/or waterspouts. Based on a study of 25 El Niño years, only 4 had no major SLS events. In particular, the number of devastating tornadoes increases during El Niño years. Therefore, in El Niño years the presence of SLS episodes of extreme force should be expected.
Level of Scientific Research Relating to El Niño and Other Climate-Related Hazards
Since 1991, Cuba has maintained an intense research effort on El Niño, attempting to establish impacts and to use El Niño as a climate forecasting tool. In 1995, a five-year project with the study of ENSO as its central objective – its predictability of impacts on the climate of Cuba – was built into the National Scientific Program, "Global Changes and the Evolution of the Cuban Environment." Among other goals, the program aims to develop a deeper knowledge of ENSO's impacts on the climate of Cuba, demonstrating that other climate forcing factors are able to mitigate the impacts of ENSO's extremes.
Starting in 1997, research related to El Niño and Cuba became more focused on its socio-economic impacts. In 1999, a new national five-year project was developed, supported by funds from the National Environment Agency. This project focused on ENSO warning systems and the prediction of ENSO's extremes and their impacts on the nation's climate and society.
For these reasons, it can be affirmed that at the time of the onset of the 1997-98 El Niño event, the level of scientific development reached by Cuba in studies related to these extreme events was high, allowing for efficient monitoring and prediction activities.
With regard to other climate-related hazards, a wide spectrum of studies has been developed in the last twenty years, focused mainly on hurricanes and drought episodes. There have been many studies regarding the climatology, forecasting, and impacts of hurricanes in Cuba. In the last five years, a strong concern has developed related to the role of tropical cyclones in interannual variability of climate and of seasonal forecasts. In fact, Cuba is considered one of the countries in the Americas with the highest scientific development in the study of these dangerous systems.
Meteorological conditions in Cuba that generate serious droughts have been deeply analyzed and, recently, Cuba's Climate Center was able to develop a national system of drought monitoring for the country.
The 1997-98 Event
Cuban interest in El Niño underwent a sharp step-like change in the 1990s, passing from having been a mysterious and virtually unknown climate-related process to policy makers and the public, to becoming one of the main factors to be considered when speaking about Cuba's climate. In March 1997, information coming from the US National Centers for Environmental Prediction (NCEP) indicated the possibility that an El Niño event was in progress. In April, the prediction method of an ENSO Index developed in Cuba indicated an increase of this index suggesting warm El Niño conditions until August. Consequently, in May 1997, the Cuban Climate Center released an alert on the possible development of an El Niño event for the current year.
In June 1997, it became evident that the evolution of this event pointed toward the development of a strong mature El Niño. Consequently, this was noted in a Special Warning Number 2, released at the beginning of July.
All the information flowed toward three levels. The first level, composed of the Ministry of Science, Technology and Environment, the Advisers Team of the Ministers' Council of Cuba and Civil Defense, possesses the highest level of responsibility for the development of disaster preparedness strategies in the country. In turn, it constitutes the source of information from which other government agencies base their preparation policies. The second level is made up of the media, and a third level includes the different agencies of international assistance.
Much of the international information on the evolution of the event was obtained by means of the Internet. Another key element in monitoring activities was information from the global telecommunication systems. At the national level, the main source of information (predictions and evaluations) was the Institute of Meteorology.
The first reference in the media to El Niño and its effect in Cuba appeared on 21 February 1987, when the newspaper Granma published an article entitled, "Does El Niño Return?" In the 1990s, due to the progress in scientific research in this field in addition to the creation of the first system of climatic monitoring in Cuba, interest in El Niño increased. Funds granted to research projects on El Niño increased in addition to a more active dissemination of El Niño information to the public by way of the official media. After the 1994-95 event, news coverage significantly intensified. The mention immediately prior to El Niño's 1997-98 onset was in January 1997.
The first reports about the 1997-98 El Niño in the media appeared by the middle of 1997 in Cuban radio and TV news programs. In the press, news about El Niño's development appeared in September 1997. Between September 1997 and August 1998, 11 articles on El Niño were published in the press. The bulk of the reports relating to the 1997-98 El Niño was published in 1998. There was a general tendency in the Cuban press to increase reporting about El Niño in the winter. Traditionally, in Cuba this is the time in which El Niño's biggest impacts should be expected.
The Cuban media were not prolific in comparisons of the 1997-98 event with previous events. In several journalistic articles and other reports, some references to the 1982-83 El Niño appeared, but in almost all cases, it had been done with the objective of illustrating potential impacts and not by way of a comparison of these events.
Teleconnections
Studies agree on ENSO's influence on winter circulation in the Caribbean. This is similar to what takes place in the United States and is mainly due to frequent intrusions during winter of the extratropical westerlies from the North American continent. In Cuba, the influence of El Niño becomes more significant in the second half of winter. The biggest natural disasters in this season are associated with extratropical cyclone systems that form under El Niño conditions.
In summer, the interrelationship between circulation over the Cuban region and El Niño becomes less evident. In general, no significant relationships have been found in surface circulation. However, changes in upper-air circulation patterns should bring an increase of the vertical wind shear during El Niño years, establishing a connection between ENSO warm events and an observed diminishing of the activity of tropical hurricanes in the Atlantic. This constitutes an important positive impact for the region.
The existence of significant relationships between the anomalies of sea surface temperatures in the tropical Pacific Ocean and tropical cyclone activity in the Atlantic, with a tendency toward a reduction of this activity during El Niño years, was established in 1964. There is also a significant relationship between El Niño years and the duration of the cyclone (hurricane) season.
Climate-Related Anomalies and Impacts in the 1982-83 Event
In terms of disasters, the impact of the 1982-83 event was the most severe ever experienced in Cuba. In the winter of 1982-83, a record 26 extratropical cyclones developed in the Gulf of Mexico. Anomalies of unusual intensity and frequency affected Cuban territory. The most well-known event associated with the 1982-83 El Niño was the intense coastal flooding that plagued Havana, a level of flooding not witnessed since the Great Hurricane of 1926. It occurred on March 17 and flooded extensive urban areas of the city of Havana, producing severe damages to its infrastructure.
Damages throughout the country related to this event were considerable. More than 40,000 acres of tobacco were completely destroyed, 65% of tomato production was severely damaged, strong winds demolished more than a million and a half of banana trees with an estimated production capacity of 50,000 metric tons. Damages to potatoes were estimated at more than 120,000 metric tons lost, representing one-fourth of the entire crop for that year. Sugar cane was also heavily damaged with a considerable reduction in yield.
The impacts in other societal sectors were also considerable. Although major disease outbreaks did not occur, due to the intense efforts of the Cuban health system, increases were detected in the incidence of non-transferable illnesses such as bronchial asthma associated with the stress caused by severe weather conditions.
Climate-Related Physical and Social Impacts of the 1997-98 El Niño
In the 1997 rainy season, there were high maximum temperatures, especially in September when new records were reached. Rainfall distribution was very irregular. At the beginning of October, most of the country showed monthly accumulations below 50% of the historical average. Irregularities in rainfall distribution were linked to a very reduced level of cyclone activity.
In the dry season, anomalies of daily mean and minimum temperatures exhibited a shift toward higher values. Rain in the November-March period in Cuba was very much above average. As a consequence of an increase in the number of extratropical lows, nationwide occurrences of strong winds, intense rains, thunderstorms, and other dangerous meteorological processes were recorded. In addition, starting in April 1998, an intense drought lasted during April, May, and June, causing the most significant rainfall deficit recorded since 1941 for the April-June period. Drought conditions were very severe in almost all parts of Cuba but were most unfavorable in the eastern region. The percentage of the historical rainfall average at the end of June 1998 was only 56% for Cuba. This caused serious impacts, disrupting water supplies for human consumption in some major cities. The province of Guantánamo was the most affected. In addition to the precipitation anomalies, temperatures also reflected significant positive anomalies.
In winter, soil moisture was not favorable for the sucrose accumulation in sugar cane plants and, consequently, an important drop in industrial yields was reported. In addition, the 1998 drought produced the total loss of 8,000 ha of "spring cane" (cane which is sown from May to July) in the eastern regions. The loss in sugar cane production was more than 700,000 metric tons.
The anomalous rains in the dry season adversely affected the potato crop. Losses were estimated at more than 18,077 metric tons. High humidity, heavy winds, and hailstorms that were reported in some locations reduced the expected lifetime of plantations. In some areas, there were disease outbreaks that generated additional losses, mainly in Havana Province.
Fields of banana plants were severely affected by strong winds that demolished or damaged over 6,710 ha in the western provinces. Until January 31, 1998, tobacco farmers had reported the loss of 3,350 ha because of wind. In addition, the temperature regime was unfavorable because anomalies higher than 1.5 degrees C negatively impacted the tobacco leaves. Also, weather conditions were favorable for the propagation of pests and plant diseases (in particular the Blue Mold).
The summer drought adversely affected milk production. In the eastern provinces alone, losses surpassed 20 million liters during the summer of 1997. Nearly 13,000 animals died from malnutrition in the state sector, and it was necessary to evacuate more than 25,000 cattle to safer places. Feed had to be provided to another 225,000 by different methods.
In lobster fishing, a decreasing population in fishing areas was noted which, together with the days when fishing activities were disrupted by bad weather, caused losses on the order of US$9 million. In other marine fisheries such as shrimp and different varieties of fishes, the main losses resulted from many days without capture because of an increase in bad-weather events during the winter.
Regarding human health, cases of bronchial asthma and acute diarrheic illness declined during the 1997-98 event. In the case of bronchial asthma, this can be explained by the presence of a warmer (with reduced inter-seasonal contrast) winter. The decrease in acute diarrheic illness was due to more a humid winter and the delay in the onset of the rainy season (caused by the onset of the summer drought). The most significant anomalies in acute respiratory illnesses took place in June 1998, coincidentally with the existence of markedly warmer and drier conditions than expected. The increase caused by these anomalies in the city of Havana brought losses of nearly US$6 million, and 23,242 cases more than expected.
The direct impacts of the 1997-98 El Niño on population and housing occurred for the most part during the dry season or winter (November 1997-April 1998). They were associated with the occurrence of severe meteorological events that caused considerable damages and economic losses. These events, although they did not exhibit extreme characteristics like those observed during the 1982-83 winter, they caused comparable losses. Nearly 20,000 people suffered some kind of property damage, and more than 12,000 were evacuated.
Reliability of Attributions
The current level of research on the ENSO cycle and its impacts in Cuba allows us to believe in many of these attributions with an acceptable margin of confidence. It seems clear that the increase in precipitation in the winter season is a usual characteristic in years under El Niño conditions. However, in the case of the intense summer drought in 1998, considerations about a reliable attribution are more complex.
In an analysis of the last 24 years of attributions, a direct association of drought with El Niño was not found. However, the remarkable and uncommon characteristics of the 1997-98 El Niño leave a wide margin for speculation. It seems reasonable to think that, if the onset of this event began earlier than many other events (including the 1982-83 event) and reached its mature stage in a different period, its effect on the regional and global circulation took place with a different climatic background. Consequently, its impacts on regional climate would have to be different.
The temperature anomalies that occurred, as much in the winter as in the summer, could be considered as a logical result of the deviations observed in the precipitation and in the weather. However, it is important to emphasize that temperature in Cuba has shown an important warming trend during the last few decades. In the last 50 years, monthly mean minimum temperatures in Cuba have risen around 1.7 degrees C, a considerable warming rate.
Responses
At the end of the 1997 summer, the National Headquarters of the Civil Defense sent to groups in the Central Administration of the State warnings about a developing El Niño, indicating preventive measures to be adopted in order to reduce the expected impacts in each sphere of responsibility. In addition, exceptional measures were taken to keep active the prevention system created during the 1997 hurricane season, for possible future disasters.
From April 1997, the Meteorological Service began to keep farmers and other agricultural entities systematically informed about expected weather and climate anomalies. For its part, the Ministry of Agriculture formulated a set of indicators and measures for all companies and agricultural entities in the country. Because seasonal predictions anticipated an increase in rains during the dry season, the Sugar Ministry anticipated the timing of the sugar harvest for 1997-98. In addition, based on forecasts and on the onset of drought, the Sugar Ministry made the decision to postpone a massive seeding of sugar cane, which had been programmed for the spring season in those regions where the prediction of water reserves indicated the possibility of unfavorable conditions.
Due to the onset of the agriculture drought in the summer, and the prediction of its possible intensification, the Ministry of Agriculture decided to protect cattle and main crops and to avoid forest fires. However, such measures were not applied with effectiveness. In a general sense, Cuban agriculture does not yet have an appropriate "culture" about El Niño, nor does it have a good understanding of how to use climatic predictions more efficiently.
Cuba has developed a national plan for the handling of a wide range of possible disasters. It constitutes a plan for emergencies that allows the authorities in each region to execute, in an organized way, measures to protect the population and economic resources before the occurrence of any disasters.
El Niño events are not explicitly considered in Cuba's national disaster plans as a disaster. The fundamental cause of this is the nature of the Cuban system of civil defense, which is essentially built for facing emergencies caused by specific meteorological events, such as intense rains, droughts, coastal floods, strong winds, etc., regardless of their origin or the atmospheric systems with which they are associated. Perhaps the only exceptions to this rule are tropical cyclones, historically considered Cuba's most dangerous natural hazard and the only meteorological system explicitly considered to be a disaster in Cuba's disaster preparedness plans.
It seems clear that in El Niño years, a higher number of severe meteorological events becomes more probable and some increase in frequency occurs. For these reasons and the experience of the 1997-98 event suggest that, regardless of the levels of current scientific uncertainties, clear distinctions could be identified between El Niño and non-El Niño years. These distinctions should not be ignored in our national plans against disasters.
It is a real possibility that as the knowledge about El Niño and its impacts in Cuba continues to improve, and as the national monitoring service establishes more reliable climatic forecasts, the associated severe events will reach an important place in disaster prevention plans, similar, perhaps, to what currently happens with the impacts related to tropical cyclones.
The main factor behind of the Cuban response to the impacts of climatic anomalies is the existence of a centralized structure with wide participation at all levels of society. The fact that the National System of Civil Defense is attached to the general plans for the military defense of the country assures that there will be a high level of response and availability of resources. If a single aspect has to be noted to best describe the main virtue of the Cuban disaster response system, it would be the fact that its main priority is preserving human life, even at the cost of major resources.
Another outstanding positive aspect is the close connection between decision makers and the centers in charge of the country's monitoring services. This is executed through a flow of information that guarantees exchanges among the different decision levels. That the state assigned to a unique institute the task of "climate monitoring" is also one of the strengths of the Cuban system. This guarantees equity of approaches and a concentration of scientific effort toward the main concerns. The role that the media played in developing a clearer popular perception about El Niño also constitutes a positive aspect to be highlighted.
However, the system also exhibited some weaknesses. The popular and institutional perception of what El Niño is remains incomplete and occasionally erroneous. In spite of efforts carried out by the Cuban government, an education system structured to teach the public about the phenomenon and its impacts does not yet exist. In general, most professional education courses do not include subjects related to the climate system. This means that future decision makers in different economic sectors will not possess a solid understanding on climate-society issues in the scientific field. Although major research has been developed about ENSO's impacts on the climate of Cuba, this knowledge still has a wide margin of uncertainty. Each El Niño (and La Niña) event is different from one to another, which makes it difficult to improve the efficiency of the prevention system, which is run according to previously established guidelines. In addition, it negatively influences the state of preparation of society, affecting the credibility in predictions and the level of general knowledge. Because of this, some socio-economic sectors occasionally show some resistance to taking measures in response to an El Niño forecast. Consequently, this diminishes the general effectiveness of society's responses.
Another point to be considered is about the capacity of certain levels of the society and the economy to show better responses when forecasts have varying lead times or responses. Although strategic measures can in theory be taken many months in advance, it is not realistic to think that smaller communities subjected to the daily tensions of an economy of subsistence would be able to deal with preventive measures even a few weeks in advance with a high level of effectiveness.
Users still do not use climate forecasts effectively. The language of an early warning forecast about El Niño does not always cover the expectations or needs of decision makers who are more interested in obtaining information about the cost of the possible impacts on specific socio-economic activities than in knowing more detail about climatic variables.
Finally, it should be emphasized that the 1997-98 El Niño influenced, in an important way, Cuban society's preparedness for and responses to the 1998-2000 La Niña. Both events existed very close together in time, causing the long-lasting 1997-98 drought to spread into the 1998-99 winter. This brought severe consequences to the already stressed Cuban economy. Nevertheless, this coincidence (a decaying El Niño and an emerging La Niña) contributed considerably to a more effective response to La Niña's impacts; Cuban experience with El Niño had made possible better preparedness.
Lessons Learned
- The existence of a very strong signal of El Niño's impacts in Cuba was certainly demonstrated in the case of the 1997-98 event. Although this El Niño had unique features, which differed from other strong events, many of the expected influences over Cuba's climate did take place. However, unexpected effects, such as an intense summer drought, severely stressed the Cuban economy.
- One difference with other underdeveloped countries is that Cuba has a high level of scientific research on the ENSO cycle and with other climate-related hazards research. It also has a well-defined structure for monitoring weather and climate. These factors were crucial in successfully dealing with the impacts of the 1997-98 El Niño.
- The 1997-98 event proved that the response mechanisms of the Cuban government were capable of coping effectively with the major impacts of El Niño, including the government's request for international assistance. In fact, many of the expected negative impacts were avoided because of timely measures taken in many economic and social sectors.
- Many scientific uncertainties still remain, however, regarding the impacts of El Niño (and La Niña) in various parts of Cuba. The level of knowledge of the general public and of policy makers about the ENSO cycle is incomplete and sometimes erroneous. A comprehensive education program targeting all levels of society would change this.
- The Cuban society tends to respond to early warnings of ENSO's extremes by applying predetermined behavioral responses based on individual experience or on some "average" condition. As yet, current predictions are unable to establish how far from average the intensity of the predicted event will be or what the real impacts might be. Consequently, earlier warning about the onset of ENSO's extremes would be more useful only if it gives more answers to users than do the current forecast methods and content.
