EDUARDO CESARChange in the climate may make the forests may way to the CerradoEDUARDO CESAR
There is a liaison to expand the knowledge about the effects of climate changes on Brazil. A group of researchers from various disciplines is preparing a book, which should be launched before the end of the year with the support of the Ministry of Science and Technology (MCT), the objective of which is to estimate consequences of global warming for Brazil and to propose alternatives for facing up to them. “The idea is to create a discussion forum as if it were a sort of Brazilian IPCC”, says Marcos Buckeridge, a researcher from the Botany Department of the Biosciences Institute of the University of São Paulo (USP), who conceived the initiative and is coordinating it.
Brazilians’ health should suffer blows on several flanks, observes Paulo Saldiva, a professor from USP’s School of Medicine and the author of a chapter of the book on the issue. The extremes of temperature, with epidemics breaking out and the droughts and the floods, are foreseeable phenomena, but they have an effect that is limited in time. Saldiva reveals himself to be particularly concerned with the long-term effects of exposure to the atmospheric pollutants – there is no evidence in Brazil that the pollution caused by cars in the big cities is going to diminish. “The consequences to health of the climate changes are going to manifest themselves more in terms in an increase either in the number or in the severity of already-known problems, such as cardiac ailments, asthma, cancer and respiratory infections”, he wrote. “Few will die of hyperthermia or hypothermia during the extreme events of the climate, but thousands will die of heart attacks and respiratory diseases”, he explains. It is estimated that each year pollution will be responsible for the deaths of 3,500 inhabitants of the city of São Paulo.
The effect of the increase of the temperatures on biodiversity will be unequal. Mammals, which are capable of regulating their body temperature, will suffer less with the hotter environment. But the climate changes may bring about alterations in the scenery with sufficient vigor to define the fate of several species. Mario de Vivo, a researcher from USP’s Zoology Museum, observes that a probable scenario is the advance of the Cerrado into the transition zone with the Amazon Forest. “If the climate becomes drier, that may trigger off the extinction of species from the forest and benefit animals that are typical of the Cerrado, like the maned wolf, the giant anteater and the giant armadillo”, says the researcher, the author of the chapter of the book on mammals. The situation of the amphibians is more complex. Toads, frogs, caecilians and salamanders usually rest during the day, avoiding the sun and the high temperatures and coming into activity after dusk. A significant part of their respiration is done through the skin, which always needs to be humid. “Amphibians have high sensitivity to environmental alterations”, says biologist Célio Haddad, from the Herpetology Laboratory of the São Paulo State University (Unesp) of Rio Claro, who wrote the chapter on amphibians. Another disadvantage is that amphibians tend to be endemic. Many species are circumscribed to given regions, which makes them more vulnerable to processes of extinction. Haddad says, however, that other species may come out winning. “Biodiversity is going to be impoverished, but species with greater capacity for adaptation will have the chance to grow in the terrain left by others”, he explains.
Drowned mangrove swamps
The rise in the sea level forecasts fearful scenarios for coastal species: it is expected that the deltas of the big rivers will retreat, pushed by the water from the sea. “The predominant ecosystem on Marajó Island, in the estuary of the Amazon, may be transplanted to the interior. And the mangrove swamps may simply be drowned, putting in risk the whole chain of species that depend on them”, says Mario de Vivo. It is evaluated that the advance of the waters will be slow, allowing the species to have time to look for a higher place to live in. “But in some stretches of the coast with lower declivity the advance may be sudden. For the amphibians, it may be a big problem, because they do not tolerate the salinity of the seawater”, says Célio Haddad, who foresees scenarios of ecological imbalance, with harmful effects for man as well. “In the absence of the amphibians, insects like skeeters and the dengue mosquito that serve as their food can proliferate more quickly”, the researcher says. In a river like the Amazon, which has a slight declivity and runs slowly towards the sea, the invasion of the marine currents in the depths of the watercourses may pollute aquifers. “Perhaps there isn’t a great problem of supply in the Amazon, because the area isn’t densely populated, but, in other countries, this phenomenon may lead to the lack of drinking water for a part of the population”, says Carlos Nobre, a researcher from the National Institute for Space Research (INPE).
Coffee plantations
The increase in the temperature should have implications for the geography of Brazilians agricultural crops. Coffee, rice, beans, corn and soybeans may have their areas reduced to half, if the temperature of the Earth rises 5.8°C in relation to the current average. Based on current climate models, researches from Unicamp’s Center of Meteorological and Climatic Researches Applied to Agriculture (Cepagri) and The Brazilian Agricultural Research Corporation (Embrapa) Information Technology suggest that Brazil may lose of its area with potential for coffee plantations in Goiás, Minas Gerais and São Paulo, with losses of up to US$ 500 million a year, should the temperature go up 1°C. With another three degrees, the area for planting coffee would fall to one third of the current area. With another six degrees, the coffee plantations would be extinct on São Paulo’s land. The tendency would be their transfer to the South. And the wheat and sunflower plantations in the South could become unviable.
There is a consensus that reducing the effects and adapting to them will depend on an aggregate of measures. “Each country will have to discuss options in keeping with the impact and the regional economic and social consequences. That has to involve the scientific community and the authorities and inspire policies of State”, says Paulo Artaxo, a researcher from the Physics Institute at USP and the coordinator of the Millennium Institute of the Large Scale Biosphere – Atmosphere Experiment in Amazonia (LBA). Brazil, says Artaxo, has a big role to perform in the global combat against the effects of warming. “We may become an energy power in a few decades. We will be big producers of renewable fuels, like alcohol. That is a tangible prospect”, he says. “If the country does not neglect the Amazon, it will have a lot of clout in the international negotiations on the climate.”
Debts
The book published by Marcos Buckeridge on the consequences of warming in Brazil intends to hazard solutions. A natural way is to take more and more advantage of the opportunities created by the so-called Clean Development Mechanism (CDM), an artifice created by the Kyoto Protocol that authorized the developed countries to offset their environmental debts by investing in clean technology projects, implanted by developing countries. Brazil loses only to India in the ranking of the ranking of the beneficiaries of this market, which should have a turnover of over US$ 40 billion by 2010. For researcher Carlos Clemente Cerri, from USP’s Agriculture Nuclear Energy Center, the potential for implanting reforestation projects under the auspices of the CDM is enormous. “One viable alternative would be the development of more incentive programs for the recovery of degraded areas in riverine woodlands, promoting a change in the use of the land in extensive areas and generating the so-called carbon credits”, wrote Cerri, who also advocates other initiatives to reduce the carbon emissions resulting from agriculture, such as the use of direct planting techniques and the mechanization of the sugarcane harvest, which is increasingly replacing the burning of the sugarcane fields.
On another front, Buckeridge suggests that the reforestation techniques should cover the planting of different kinds of species: trees with more rapid growth, classified as pioneer and initial secondary species, are important for setting off the recovery process of the degraded areas, but bets have also to be laid on other species, such as the late secondary, more resistant to shade, which seem to accumulate more CO2 in the course of their lives. This succession is the one observed in nature: first, the trees of rapid growth and a shorter life cycle. When they die, their place is taken by trees with a longer life cycle, like perobas and jequitibás. One of his group who is studying for a doctorate and is a student of the Biodiversity and Environment Program of the Botany Institute, João Godoy, has just defended his thesis, demonstrating by means of experiments in the laboratory that carbon sequestration is greater with an ecological succession system, when compared with the isolated planting of species of native trees.
Another important fact obtained by Buckeridge’s group concerns the response of sugarcane to the excess of carbon in the atmosphere. Amanda Pereira de Souza, a student at Unicamp’s Cell Biology Department, accompanied the development of sugarcane seedlings that grew in an environment with an excess of carbon (720 parts per million, about twice the current average, which amounts to 384). It was found that the production of biomass increased 60%, with an equivalent rise in the productivity of alcohol and an even greater production of sucrose. Such a performance is not repeated with other crops, like soybeans, which disperses part of the energy that it accumulates on the processes of flowering and producing seeds. The discoveries suggest that global warming may produce benefic effects in the sugarcane crop, which is now a great vocation of Brazilian agribusiness. Buckeridge thinks it possible to link the two finds and proposes a strategy: carry on with the planting of sugarcane, but also use part of the areas occupied today with plantations to regenerate forest corridors. “We would gain on various fronts: we would continue producing alcohol as the main source of renewable energy, we would help to regenerate biodiversity, by forming the corridors for the plants, animals and microorganism to be able to circulate amongst the remaining and, we hope, growing forest fragments”, he explains. “Furthermore, as several countries are probably going to develop different kinds of technology for producing clean energy, the Brazilian alcohol produced in this way would have an environmental preservation seal of great value for trading in the future” (see Pesquisa FAPESP, No. 82).
The Brazilian scientific community, as we see, is fostering a joint effort to assist in the question of the global changes. “Due to the level of unprecedented complexity, the problem of the global climate changes can only be attacked in an effective way by a set of brains working in a network in various places in the world”, Buckeridge says. “It won’t be a task for just one scientist.”
The next reports
The somber prospects for climate changes heralded about last month by the IPCC (Intergovernmental Panel on Climate Change) will gain more defined contours in April and May. This body, which is a forum of scientists linked to the United Nations, is preparing the launch of two new chapters of its report, in which it is going to investigate the practical consequences of warming and the proposals for how to face up to it. One of the documents will be disclosed in Brussels on April 6 and will deal with the impacts of the climate changes and the possible ways for adaptation. The other should be disclosed in Bangkok on May 4 and will address the options and courses for combating warming. After foreseeing an average increase in temperature of between 1.8 and 4°C and a rise of from 18 to 59 centimeters in the level of the sea by the end of the century, the IPCC will now say how this will affect people and countries’ economies – and will suggest strategies for adapting to the changes, or, when possible, for alleviating them.
Both the documents should republish the shocking debate about the irreversibility of some effects of the warming. The final version of the summaries of the reports has not yet been defined. As the participants of the IPCC are going to base themselves on the strength of the scientific literature published in the last few years, new forthright statements are expected, with the gradual transformation of the map of agriculture on the planet: certain crops may be swept from their current latitudes, with an impact on the world’s food supply. The impact of the rise in the level of the sea should forecast equally uncomfortable scenarios. In the best of the hypotheses, 1% of the population of the planet will suffer some effect with the shrinkage of the coastal strips. In the worst, 2% of the world population will have to look for another place to live, which may make the figure of climate refugees tangible. It is quite probable that the report will affirm that the planet’s biodiversity has already begun to be depleted by virtue of the climate changes. According to an article published last year in the Nature magazine, two thirds of the species of Atelopus toads, found in Central America, have become extinct in recent years, suggesting that a kind of fungus that is spreading, favored by high temperatures, could be the cause of the disappearance. The attack, the researchers say, is a result of the increase in the temperature, which left the toads more susceptible to the microbe. The documents from Brussels and Bangkok may also make headway in suggesting strategies capable, for example, of changing the profile of the production and the consumption of energy in the next few decades, making the planet less dependent on oil.
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