eduardo cesarA dry tributary of the Sao Francisco river: interior of the Northeast could become even driereduardo cesar
Cities that disappear under the sea and the Amazon transformed into desert is in store for us in the immediate future. But yes, there is the risk of the annual average temperature rising over the next few decades throughout South America. Areas almost like deserts could spring up in the interior of the Northeast, according to the scenarios about the future climate using, for the first time, regional climate models, developed at the National Institute for Space Research (INPE). The results suggest a Brazil that will be less humid and tropical and warmer and drier.
These transformations could affect the production of electric energy, due to the water in the rivers and reservoirs evaporating quicker, and human health: illnesses such as malaria and dengue fever could propagate more intensely under a climate that would be warmer and more humid; however, in a warmer and drier climate, respiratory illnesses are the ones that could become more common. The Brazilian economy, especially agriculture, could take on another profile. Previous estimates, carried out based upon global models, had already pointed to progressive reductions in basic agricultural crops such as wheat, corn and coffee, whose planted areas would tend to displace themselves to the south of the country as the warmth would increase.
At the same time a research line is gaining force that alerts to the need for preventative actions and for the urgency of seeds adapted to a warmer climate as a manner of avoiding the lack of food supply to the population. “The future climate scenarios must be looked upon as the raw material for more in-depth studies about the impacts of climate change on the biodiversity, health, agriculture and the economy”, says José Antonio Marengo Orsini, a meteorologist from INPE’s Weather Forecast and Climate Studies Center (CPTEC) and the coordinator of this work. “We could also build foundations for public policies that would aim to reduce the damages associated with climate change, by way of the reduction of deforestation and the emission of greenhouse effect gases.”
Up until now it was only possible to imagine the impacts of climate changes in Brazil by way of the projections of global models. Made by the United States or European institutions, they provided a large scale panoramic vision, with average continental temperatures, not very useful for the evaluation of regional climatic impacts. As they deal with a much smaller scale, the regional models indicate, for example, if there could be a variation in the volume of water in the river basins and thus forecast problems in the supply of cities or for navigation. “It’s as if we can now look at Brazil using a magnifying glass”, suggests Marengo. In the opinion of Pedro Leite da Silva Dias, a professor at the University of São Paulo (USP), regional models such as that of the INPE could be highly useful in order to understand specific climate processes and to attempt to discover if the sea wind will continue to reach the city of São Paulo or if it is going to change the frequency of storms in Paraguay to the south of Brazil.
Vulnerability
The graphs and the maps with the projections of climate change, which came out of the CPTEC super computers indicate an elevation of 2 to 3 Celsius degrees in the annual average temperature of almost all of the coastal belt and a good part of the interior of Brazil, whilst in an area to the north of the Amazon equivalent to the size of the state of São Paulo the warming could reach 6°C. These projections refer to the optimistic scenario, which presupposes the integral resolution of the goals for pollution reduction as laid out in the Kyoto Protocol. In this case, everything would be done to avoid the damages caused by global warming.
In the other extreme, the pessimistic scenario presupposes that nothing will be done or nothing will function to deter global warming, and the emissions of carbon dioxide gas, one of the main agents of global warming, will remain high. Under this darker prospect, in accordance with the INPE projections, a large stretch that covers the main Brazilian state capital cities will be subject to average annual temperatures of up to 4°C higher. The major part of the country will be subject to an annual average temperature rise of up to 6°C and a small section of land to the north of the Amazon could go beyond this and represent an elevation of up to 8°C in relation to the period 1961 until 1990, adopted throughout the world as the starting point for climate models.
The quantity and distribution of rainfall must also be modified, in accordance with the CPTEC/INPE projections. The two extreme scenarios, of low and high emission of carbon dioxide gas, suggest that it could rain less both in the Amazon and the Central-West, jeopardizing the survival of the Amazon Rainforest and the Pantanal (swampland), which depend on humidity, and in the Northeast Region. In the South and Southeast of Brazil and in at least half of Argentina the average rainfall will tend to increase, although with a smaller contribution of humidity coming from the Amazon.
The first projections of the future climate in Brazil using regional climate models suggest the possibility of more frequent extreme climatic events, already suggested by the global models, although not with so much detail. In practice: strong and short duration rains that result in more intense storms than those of today or, contrary, more prolonged droughts, which could transform the semi-arid region of the interior of the Northeast into an almost arid region. An average of 16 global models coming from the Intergovernmental Panel on Climate Change (IPCC), by the way, had already indicated a reduction of 40% in the rainfall of the Northeast Region of Brazil.
Late rains
According to this new study, rains could become rarer especially during winter, when the Amazon would be subject to average temperatures 4°C higher and the Southeast from 2° to 3°C, in the optimistic scenario. “This verification is worrying”, says Marengo, “because spring is the start of the rainy season throughout Brazil”. If in fact it were to rain less in spring, the summer rains, which begin at the end of October in the Southeast and in December in the North, could be late two or three months and damage the supply of food, since it is exactly the first rains at the end of the year that mark the time to plant rice, beans, corn, soy and wheat. The drought that left boats high and dry in the middle of dry river beds and isolated almost 300,000 people in the states of Amazonas and Pará last year, was caused exactly by a two month lateness in the arrival of the rains.
“The Amazon drought of 2005 represents a type of extreme climatic episode, which could become more frequent in the second half of the 21st century”, says Marengo. A recent study, of which he is one of the authors, showed that the most serious drought in the Amazon during the last century must not have been caused by global warming or by deforestation, as at the beginning had been alleged, but probably resulted from the overlap of warmer sea water and winds in the northern Atlantic ocean and to the south of the equator, a rare climatic phenomenon that helps to also explain hurricane Katrina in the south of the United States. “The scenarios of regional models that we can make up could be on the right track, because they indicate the possibility of the occurrence of other phenomena similar to drought, which have already occurred”, says the INPE researcher, who worked in the teams headed by Tércio Ambrizzi, from USP, and Eneas Salati, from the Brazilian Foundation for Sustainable Development (FBDS), in collaboration with researchers from the Hadley Centre, in the UK. “We have to prepare ourselves for these extreme situations.”
But nothing should change from day to night. According to the preliminary calculations from the INPE team, the average temperature should alter in a very slow and gradual manner until 2030, accompanying a smooth curve, more precisely, the start of a parabola, which represents the accumulation of carbon dioxide gas in the atmosphere and should also reflect the rhythm of global warming. Only then should the more accentuated changes begin to take place, which should end up in this more severe picture, of more intense droughts in the North and Northeast and heavier rains in the Southeast and South at around 2070 to 2100.
Until then, there can only be a notion of the impacts of climate changes, based on the projections made by way of global climate models, which offer a less detailed vision than the regional coverage, both Argentina and Peru have already made their own models, presented at a conference that took place during 2005 in São Paulo, even though they applied to areas smaller than that of Brazil. The melting of the Andean glaciers should accelerate and reduce the quantity of water in the homes of the capital populations and in towns at altitude in both Peru and Chile. One of the models from the IPCC suggests that the Amazon Rainforest could have a lower and less dense vegetation, a savanna, at around 2040. A half meter elevation in the sea level would be enough to cause stronger tidewaters and worsen coastal erosion. “The Dutch are already reinforcing their dykes”, says Dias.
Of course: it is impossible to predict with exactitude the behavior of temperature, of atmospheric pressure, of humidity, of solar radiation and of ground and high altitude winds by way of the mathematical equations that make up the climate models. Even the calculations about the variation of global temperature go through adjustments. The third report from the IPCC, put together starting from images with a graphic resolution of 400 km2, forecast in 2001 that the average temperature in Brazil would rise by 1.6°C in the optimistic scenario and by up to 5.8°C in the pessimistic one. The next report, to be published in 2007, indicates that the warming could go from 2°C until 4.5°C, respectively, within the scenarios of low or of high pollution.
Soya, jungle and winds
“We can’t say if the precipitation in the Amazon region will go down by 50% or 80%, but for sure it will be lower’, he says. The only thing is that even subtle changes could be fatal. Two studies published this year, one in the Proceedings of the National Academy of Sciences (PNAS) and the other in Earth Interactions, have shown that the mechanized plantations of soya, which have transformed the forest into immense open areas, have contributed to leaving the climate of the region warmer by amplifying the quantity of solar radiation absorbed by the ground and reducing the circulation of water through the soil and atmosphere. Monitored by way of satellite images, these deforested areas present a temperature 3°C higher than the forests close by. “As well as the climate becoming warmer”, says Alexandre Oliveira, a biologist from USP, “the water cycle can change, making the environment drier and diminishing the circulation of atmospheric humidity”. In this case, the Amazon winds that arrive in the South and South east will arrive with less humidity, worsening the effects of drought upon agricultural lands and the cities.
eduardo cesarRisk in the field: coffee production could fall even with subtle temperature elevationseduardo cesar
“Now we need to apply the results”, says Marengo, who is able to count upon financing from the Conservation and Sustainable Usage of the Brazilian Biodiversity Project (Probio) of the Ministry of the Environment (MMA), from the Ministry of Science and Technology (MCT) and from the Global Opportunity Fund (GOF) of the British government.
Researcher Marco Aurélio Machado, from INPE, has begun to apply this regional model to forecast the impact of climate changes upon Brazilian agriculture. The conclusions to which he is arriving only detail out those obtained by way of planetary climate models. “Loses are inevitable”, concludes Hilton Silveira Pinto, the associate director of the Meteorology Research and Applied Climate to Agriculture Center (Cepagri) of the State University of Campinas (Unicamp).
Research from the Cepagri and Embrapa Information, based on the projections of global climate models suggest that Brazil could lose around 25% of the area with coffee planting potential in the states of Goias, Minas Gerais and São Paulo, with losses estimated at US$ 500 million per year, if the temperature were to rise 1°C. Three degrees or more and the area for planting would fall to a third of what it is today. Six degrees more in the average temperature, in accordance with the worst projections both for the global models and now for the regional models, would practically imply the extinction of the São Paulo coffee plantations and of the current producing states.
The coffee would then gain the today cooler lands of the states of Paraná, Santa Catarina and Rio Grande do Sul, even arriving in Argentina. For their part, the planting of wheat and the sunflower of the South would tend to become unviable due to the rise in temperature. Over the last two years wheat production has fallen by 50%, in consequence the price of flour should increase by 25% in 2007.
Eggs without shells
“Over the next fifteen years there will be reasonable alterations in the country’s agricultural scenario”, says Hilton Pinto, whose team also made up simulations for other agricultural crops: rice plantations will suffer loses of 30% in São Paulo and Bahia, beans could fall by 21% in Sao Paulo and by 41% in the Northeast, and corn by 16% in Sao Paulo and by 71% in the Northeast with only a 1°C annual average temperature rise.
Animals are also a concern, because equally they allow themselves to become depressed when the weather warms: chickens lay eggs without shells or die, pigs abort and younger suckling pigs die and cows produce less milk. In a sample of what is intended to avoid, during a heat wave in September 2004 the temperature was 4°C above the normal average for some days and caused damage estimated at US$ 50 million only in the State of São Paulo.
The prospect of us drinking coffee from Argentina may well only be a desire of vengeance of the Argentinean after having lost to the Brazilian team at football. “Definitively”, advised researcher Hilton Pinto, “an increase in temperature is already happening”. According to him, since 1890 until today, the minimum temperatures have risen by 2.7°C and the maximums by 1.3°C in São Paulo, the state that generates 35% of the national agricultural income.
Another indication that the weather might be willing to wait: for four years in a row, from 2001 until 2004, coffee production in the south of the State of Minas Gerais suffered a calamity because the maximum temperature went beyond 34°C. The most intense heat arrived in October and killed a good part of the young and fragile floral offshoots that give origin to the fruit. “It’s highly unlikely that climate events such as this are due only to natural climate variability”, commented researcher Dias, from USP. “We could already have a faint signal of global warming in Brazil and of the impacts that it can cause.”
The Projects
1. Description of current climate and the definition of climate changes for Brazilian territories during the 21st century; Coordinator
José Antonio Marengo Orsini – CPTEC/Inpe; Investment R$ 260,000.00 (Ministry of the Environment -Probio)
2. Using regional climate change scenarios for studies on vulnerability and adaptation in Brazil and South America; Coordinator José Antonio Marengo Orsini – CPTEC/Inpe; Investment R$ 520,000.00 (Global Opportunity Fund)
