Rainwater Tanks a Weapon Against Drought
By Mario Osava
The construction of a million rainwater collection tanks in the Brazilian Northeast is underway. The region is considered one of the most vulnerable to the effects of global warming.
RIO DE JANEIRO, Dec 11 (Tierramérica).- The impoverished population of the Brazilian Northeast, one of regions most vulnerable to the effects of climate change, is preparing for long-term coexistence with drought, through various projects such as the construction of one million tanks to collect rainwater.
The large region could see a 4.5-degree Celsius rise in average temperatures by the end of the century, under the worst-case scenario, according to CPTEC, a weather and climate research center.
Scientists warn that global warming will accelerate desertification in the area, increasing poverty and fuelling emigration. Figures from the Brazilian Institute of Geography and Statistics state that 48.4 percent of the population in the Northeast is poor, nearly triple the rate of the Southeast (17 percent, on average) and of the South (18.3 percent).
The semiarid region of the northeastern interior "is the most vulnerable to climate change, with a portion of it tending to become fully arid," said José Antonio Marengo, CPTEC researcher.
The "Semi-Árido" covers nearly 1.1 million square kilometers of the Northeast, and the northern part of the southeastern state of Minas Gerais. This is 13 percent of the national territory, and is home to 29 million people.
Also known as the "polygon of droughts", it has the attention of the National Program for Combating Desertification and Mitigating the effects of Drought (PAN), which was recently put into effect, in compliance with the 1996 United Nations convention on desertification.
The program will be "a tool for preventing catastrophe," says its coordinator at the Ministry of Environment, José Roberto de Lima.
It marks a change in the traditional approach in the Semi-Árido, by integrating efforts of various government agencies, with the active participation of society an "generating synergies" amongst efforts by the ministries of environment, integration and agriculture, but also by non-governmental organizations, said Lima.
One tactic that has seen success in recent years was to seek ways to live with the droughts, instead of investing in big projects like dams to create reservoirs, which proved to be inefficient for distributing water to the population.
Manufacturing a million rainwater collection tanks is one of the projects under way, promoted by the Articulação no Semi-Árido (ASA), a network of 750 NGOs, labor unions and community and religious institutions.
"We're approaching 200,000 tanks produced with the help of the people," said Paulo Pedro de Carvalho, agronomist and program coordinator for the non-governmental Caatinga Center, in the northeastern state of Pernambuco. Caatinga is the name of the local vegetation: sinuous bushes that are resistant to drought.
With this project, intended to ensure the rural population has water for drinking and cooking, Carvalho hopes that they reach the goal of one million tanks in the next five years.
Furthermore, ASA is trying to disseminate, with participatory and educational methods, other technologies to boost small farm production, such as small underground reservoirs and other forms of storing water that prevent evaporation.
"Evaporation is a big factor in the water shortages of the area. The big reservoirs lose a large portion of their water," said Carvalho.
Decades ago, successive plans for development, agriculture, industry, social programs, forestry and waterworks were implemented in attempts to reduce poverty in the northeastern Semiarid. The new focus, of learning to coexist with the climate and preserve the ecosystem, now has to respond also to the urgency imposed by the threat of global warming.
But meteorological forecasting presents a high degree of uncertainty.
Some experts, like Mario de Miranda Leitao, meteorologist and researcher into the effects of climate on agriculture, point to "beneficial" aspects of warmer average temperatures, given that heat could increase evaporation from the oceans, feeding clouds and possibly reversing desertification.
"The increase in evaporation would accentuate the formation of clouds and subsequent rainfall in many parts of the world, among them the Brazilian Semiarid near the Atlantic Ocean," Miranda offered as a hypothesis, though he did not rule out "grave consequences" of the greenhouse effect around the world.
But for Marengo of the CPTEC, if that phenomenon were to come about, "it would be intense and but passing rains, insufficient for filling reservoirs, an would quickly evaporate with the intense heat and drier air."
The scientific debate continues, but for now there is consensus about the urgent need to "create a structure for living with drought."
"What is especially needed is to store water in an appropriate way in the semiarid climate, including to avoid social problems that affect the entire country, given that migration from the Semiarid is filling up the large Brazilian cities, aggravating inequalities and conflicts," said Miranda.
* This story is part of a series of features on sustainable development by IPS (Inter Press Service) and IFEJ (International Federation of Environmental Journalists).